diff --git "a/Codename+One/developer-guide.pdf.txt" "b/Codename+One/developer-guide.pdf.txt"
new file mode 100644--- /dev/null
+++ "b/Codename+One/developer-guide.pdf.txt"
@@ -0,0 +1,38566 @@
+Codename One Developer Guide
+
+Contents
+
+Preface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  1
+
+1. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  5
+
+1.1. Build Cloud . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  5
+
+1.1.1. Why Build Servers? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  6
+
+1.1.2. How does Codename One Work? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  6
+
+Lightweight Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  7
+
+Why ParparVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  8
+
+Windows Phone/UWP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  8
+
+JavaScript Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  9
+
+Desktop and Android . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  9
+
+1.1.3. Versions In Codename One. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  9
+
+1.2. History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  9
+
+1.3. Core Concepts of Mobile Programming. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  10
+
+1.3.1. Density. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  10
+
+1.3.2. Touch Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  12
+
+1.3.3. Device Fragmentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  13
+
+1.3.4. Performance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  13
+
+App Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  13
+
+Power Drain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  13
+
+1.3.5. Sandbox and Permissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  14
+
+1.4. Installing Codename One . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  14
+
+1.5. IntelliJ/IDEA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  14
+
+1.6. NetBeans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  15
+
+1.7. Eclipse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  16
+
+1.8. Hello World Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  17
+
+1.8.1. Running . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  19
+
+1.8.2. The Source Code Of The Hello World App . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  20
+
+1.8.3. Building and Deploying On Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  24
+
+Signing/Certificates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  25
+
+Build and Install . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  30
+
+1.9. Kotlin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  32
+
+1.9.1. Hello Kotlin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  32
+
+2. Basics: Themes, Styles, Components and Layouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  37
+
+2.1. Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  37
+
+2.1.1. Layout Managers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  38
+
+Terse Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  43
+
+Flow Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  43
+
+Box Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  45
+
+Border Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  47
+
+Grid Layout. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  49
+
+2.1.2. Table Layout. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  50
+
+The Full Potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  52
+
+TextMode Layout. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  54
+
+2.1.3. Layered Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  55
+
+Insets and Reference Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  56
+
+auto Insets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  57
+
+% Insets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  58
+
+Insets, Margin, and Padding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  58
+
+Component References: Linking Components together . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  59
+
+2.1.4. GridBag Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  62
+
+2.1.5. Group Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  64
+
+2.1.6. Mig Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  66
+
+2.2. Themes and Styles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  66
+
+2.2.1. Theme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  68
+
+Native Theme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  72
+
+2.3. GUI Builder. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  76
+
+2.3.1. Hello World . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  78
+
+NetBeans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  78
+
+IntelliJ/IDEA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  79
+
+Eclipse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  80
+
+Basic Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  81
+
+Events. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  84
+
+Underlying XML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  85
+
+2.3.2. Auto-Layout Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  87
+
+The Inset Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  87
+
+Auto Snap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  88
+
+Smart Insets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  88
+
+The Widget Control Pad. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  88
+
+Keyboard Short-Cuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  89
+
+Sub-Containers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  89
+
+The Canvas Resize Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  90
+
+3. Theme Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  91
+
+3.1. Understanding Codename One Themes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  91
+
+3.2. Customizing Your Theme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  92
+
+3.3. Customizing The Title . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  95
+
+3.3.1. Background Priorities and Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  95
+
+3.3.2. The Background Behavior and Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  96
+
+3.3.3. The Color Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  105
+
+3.3.4. Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  106
+
+3.3.5. Padding and Margin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  106
+
+3.3.6. Borders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  107
+
+3.3.7. 9-Piece Image Border . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  108
+
+Customizing The 9-Piece Border . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  111
+
+3.3.8. Horizontal/Vertical Image Border. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  113
+
+3.3.9. Empty Border. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  114
+
+3.3.10. Round Border . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  114
+
+3.3.11. Rounded Rectangle Border. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  115
+
+3.3.12. Bevel/Etched Borders. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  115
+
+3.3.13. Derive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  116
+
+3.3.14. Fonts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  117
+
+Font Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  121
+
+4. Advanced Theming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  123
+
+4.1. Working With UIID’s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  123
+
+4.2. Theme Layering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  123
+
+4.3. Override Resources In Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  124
+
+4.4. Theme Constants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  125
+
+4.5. Native Theming. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  136
+
+4.6. Under the Hood of the Theme Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  136
+
+4.7. Understanding Images and Multi-Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  138
+
+4.8. Use Millimeters for Padding/Margin and Font Sizes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  140
+
+4.8.1. Fractions of Millimeters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  140
+
+4.9. Creating a Great Looking Side Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  141
+
+4.10. Converting a PSD To A Theme. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  145
+
+4.10.1. Breaking Down the PSD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  147
+
+Removing the Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  149
+
+The Camera Button. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  150
+
+4.10.2. The Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  153
+
+4.10.3. Styling The UI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  156
+
+Not Quite There Yet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  158
+
+5. CSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  159
+
+5.1. Activating CSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  159
+
+5.2. Supported CSS Selectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  160
+
+5.2.1. Inheriting properties using cn1-derive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  161
+
+5.3. Special Selectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  161
+
+5.3.1. #Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  161
+
+5.3.2. #Constants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  161
+
+5.3.3. Default . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  163
+
+5.4. Standard CSS Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  163
+
+5.5. Custom Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  164
+
+5.6. CSS Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  164
+
+5.7. CSS Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  165
+
+5.7.1. text-decoration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  165
+
+5.7.2. border . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  166
+
+Round Borders. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  166
+
+5.7.3. background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  168
+
+Background Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  168
+
+Gradients. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  168
+
+5.7.4. cn1-background-type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  174
+
+5.8. Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  175
+
+5.8.1. Image DPI and Device Densities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  175
+
+5.8.2. Multi-Images vs Regular Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  176
+
+5.8.3. Multi-Images as Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  176
+
+5.8.4. Image Constants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  177
+
+5.9. Image Recipes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  178
+
+5.9.1. Import Multiple Images In Single Selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  178
+
+5.9.2. Loading Images from URLs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  179
+
+5.9.3. Generating 9-Piece Image Borders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  179
+
+5.9.4. Image Backgrounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  180
+
+Example Setting Background Image to Scale Fill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  181
+
+5.10. Image Compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  181
+
+5.11. Fonts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  181
+
+5.11.1. font-family . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  182
+
+Using TTF Fonts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  182
+
+5.11.2. font-size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  183
+
+5.11.3. text-decoration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  183
+
+5.11.4. Some Sample CSS Directives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  184
+
+5.12. Media Queries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  188
+
+5.12.1. Compound Media Queries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  189
+
+5.12.2. Order or Precedence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  190
+
+5.12.3. Font Scaling Constants. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  190
+
+6. The Components of Codename One. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  193
+
+6.1. Container . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  193
+
+6.1.1. Composite Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  193
+
+6.2. Form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  194
+
+6.3. Dialog. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  196
+
+6.3.1. Styling Dialogs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  197
+
+6.3.2. Tint and Blurring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  198
+
+6.3.3. Popup Dialog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  200
+
+Styling The Arrow Of The Popup Dialog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  200
+
+6.4. InteractionDialog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  201
+
+6.5. Label . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  202
+
+6.5.1. Label Gap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  203
+
+6.5.2. Autosizing Labels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  203
+
+6.6. TextField and TextArea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  204
+
+6.6.1. Masking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  207
+
+6.6.2. The Virtual Keyboard. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  207
+
+Action Button Client Property . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  208
+
+Next and Done on iOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  208
+
+6.6.3. Clearable Text Field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  209
+
+6.7. TextComponent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  209
+
+6.7.1. Error Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  210
+
+6.7.2. InputComponent and PickerComponent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  211
+
+6.7.3. Underlying Theme Constants and UIID’s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  212
+
+6.8. Button . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  213
+
+6.8.1. Uppercase Buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  214
+
+6.8.2. Raised Button. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  214
+
+6.8.3. Ripple Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  215
+
+6.9. CheckBox/RadioButton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  216
+
+6.9.1. Toggle Button . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  217
+
+6.10. ComponentGroup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  218
+
+6.11. MultiButton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  219
+
+6.11.1. Styling The MultiButton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  221
+
+6.12. SpanButton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  221
+
+6.13. SpanLabel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  221
+
+6.14. OnOffSwitch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  222
+
+6.14.1. Validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  223
+
+6.15. InfiniteProgress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  224
+
+6.16. InfiniteScrollAdapter and InfiniteContainer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  225
+
+6.16.1. The InfiniteContainer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  227
+
+6.17. List, MultiList, Renderers & Models. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  228
+
+6.17.1. InfiniteContainer/InfiniteScrollAdapter vs. List/ContainerList. . . . . . . . . . . . . . . . . . . . . .  228
+
+6.17.2. Why Isn’t List Deprecated?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  229
+
+6.17.3. MVC In Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  229
+
+6.17.4. Understanding MVC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  229
+
+Why is this useful? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  230
+
+6.17.5. Important - Lists & Layout Managers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  231
+
+6.17.6. MultiList & DefaultListModel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  231
+
+Going Further With the ListModel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  233
+
+6.17.7. List Cell Renderer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  235
+
+6.17.8. Generic List Cell Renderer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  237
+
+Custom UIID Of Entry in GenenricListCellRenderer/MultiList . . . . . . . . . . . . . . . . . . . . . . . . . .  240
+
+Rendering Prototype . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  240
+
+6.17.9. ComboBox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  241
+
+6.18. Slider . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  242
+
+6.19. Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  243
+
+6.19.1. Sorting Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  249
+
+6.20. Tree . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  249
+
+6.21. ShareButton. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  252
+
+6.22. Tabs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  254
+
+6.23. MediaManager & MediaPlayer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  256
+
+6.24. ImageViewer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  258
+
+6.25. ScaleImageLabel & ScaleImageButton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  261
+
+6.26. Toolbar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  262
+
+6.26.1. Search Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  265
+
+6.26.2. South Component . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  267
+
+6.26.3. Title Animations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  267
+
+6.27. BrowserComponent & WebBrowser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  269
+
+6.27.1. BrowserComponent Hierarchy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  271
+
+6.27.2. NavigationCallback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  271
+
+6.27.3. JavaScript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  272
+
+So what was wrong with the old API? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  273
+
+The New API. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  273
+
+Synchronous Wrappers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  274
+
+Multi-use Callbacks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  275
+
+Passing Parameters to Javascript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  275
+
+Proxy Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  276
+
+Legacy JSObject Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  277
+
+The JavaScript Bridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  278
+
+6.27.4. Cordova/PhoneGap Integration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  280
+
+6.28. AutoCompleteTextField . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  281
+
+6.28.1. Using Images In AutoCompleteTextField . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  283
+
+6.29. Picker. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  285
+
+6.30. SwipeableContainer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  289
+
+6.31. EmbeddedContainer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  290
+
+6.32. MapComponent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  290
+
+6.33. Chart Component . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  293
+
+6.33.1. Device Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  293
+
+6.33.2. Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  294
+
+6.33.3. Chart Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  294
+
+6.33.4. How to Create A Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  296
+
+6.34. Calendar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  297
+
+6.35. ToastBar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  298
+
+6.35.1. Actions In ToastBar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  300
+
+6.36. SignatureComponent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  301
+
+6.37. Accordion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  301
+
+6.38. Floating Hint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  302
+
+6.39. Floating Button . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  303
+
+6.39.1. Using Floating Button as a Badge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  304
+
+6.40. SplitPane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  304
+
+7. Animations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  307
+
+7.1. Layout Reflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  307
+
+7.2. Layout Animations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  307
+
+7.2.1. Unlayout Animations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  311
+
+7.2.2. Hiding & Visibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  312
+
+7.2.3. Synchronicity In Animations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  312
+
+Animation Fade and Hierarchy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  313
+
+7.2.4. Sequencing Animations Via AnimationManager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  314
+
+Animation Manager to the Rescue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  315
+
+7.3. Low Level Animations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  315
+
+7.3.1. Why Not Just Write Code In Paint?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  316
+
+7.4. Transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  316
+
+7.4.1. Replace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  317
+
+7.4.2. Slide Transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  318
+
+7.4.3. Fade and Flip Transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  320
+
+7.4.4. Bubble Transition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  321
+
+7.4.5. Morph Transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  323
+
+7.4.6. SwipeBackSupport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  323
+
+8. The EDT - Event Dispatch Thread. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  325
+
+8.1. What Is The EDT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  325
+
+8.2. Call Serially (And Wait) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  326
+
+8.2.1. callSerially On The EDT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  327
+
+8.3. Debugging EDT Violations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  327
+
+8.4. Invoke And Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  328
+
+9. Monetization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  333
+
+9.1. Google Play Ads. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  333
+
+9.2. In App Purchase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  333
+
+9.2.1. The SKU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  333
+
+9.2.2. Types of Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  334
+
+9.2.3. The "Hello World" of In-App Purchase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  334
+
+9.2.4. Making it Consumable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  338
+
+9.2.5. Non-Renewable Subscriptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  339
+
+9.2.6. The Server-Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  340
+
+The Receipts API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  340
+
+9.2.7. The "Hello World" of Non-Renewable Subscriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  340
+
+Implementing the Receipt Store . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  341
+
+Synchronizing Receipts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  345
+
+Expiry Dates and Subscription Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  346
+
+Allowing the User to Purchase the Subscription . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  347
+
+9.2.8. subscribe() vs purchase() . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  349
+
+Handling Purchase Callbacks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  349
+
+9.2.9. Screenshots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  349
+
+9.2.10. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  351
+
+9.2.11. Auto-Renewable Subscriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  351
+
+9.2.12. Auto-Renewable vs Non-Renewable.  Best Choice? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  352
+
+9.2.13. Learning By Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  352
+
+9.2.14. Building the IAP Demo Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  352
+
+Setting up the Client Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  352
+
+Setting up the Server Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  353
+
+Setting up the Database. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  353
+
+Testing the Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  354
+
+9.2.15. Looking at the Source of the App . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  357
+
+Client Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  357
+
+Server-Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  359
+
+9.2.16. The CN1-IAP-Validator Library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  361
+
+9.2.17. The validateAndSaveReceipt() Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  362
+
+9.2.18. Google Play Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  365
+
+Creating the App in Google Play . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  365
+
+Testing The App. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  367
+
+Creating Google Play Receipt Validation Credentials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  367
+
+9.2.19. iTunes Connect Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  371
+
+Setting up In-App Products. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  371
+
+Creating Test Accounts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  371
+
+Setting up Receipt Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  372
+
+10. Graphics, Drawing, Images & Fonts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  373
+
+10.1. Basics - Where & How Do I Draw Manually?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  373
+
+10.2. Glass Pane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  375
+
+10.3. Shapes & Transforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  376
+
+10.4. Device Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  376
+
+10.5. A 2D Drawing App . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  376
+
+10.5.1. Implementing addPoint() . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  378
+
+10.5.2. Using Bezier Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  378
+
+10.5.3. Detecting Platform Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  380
+
+10.6. Transforms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  380
+
+10.6.1. Device Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  381
+
+10.7. Example: Drawing an Analog Clock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  381
+
+10.7.1. The AnalogClock Component. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  382
+
+10.7.2. Setting up the Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  382
+
+10.7.3. Drawing the Tick Marks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  383
+
+10.7.4. Drawing the Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  385
+
+10.7.5. Drawing the Hands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  387
+
+10.7.6. The Final Result . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  390
+
+10.7.7. Animating the Clock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  390
+
+10.8. Starting and Stopping the Animation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  391
+
+10.9. Shape Clipping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  391
+
+10.10. The Coordinate System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  393
+
+10.10.1. Relative Coordinates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  394
+
+10.10.2. Transforms and Rotations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  395
+
+10.10.3. Event Coordinates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  398
+
+10.11. Images. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  398
+
+10.11.1. Loaded Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  398
+
+10.11.2. The RGB Image’s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  399
+
+Internal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  399
+
+RGBImage class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  399
+
+10.11.3. EncodedImage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  400
+
+10.11.4. MultiImage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  401
+
+10.11.5. FontImage & Material Design Icons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  401
+
+Material Design Icons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  402
+
+10.11.6. Timeline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  403
+
+10.11.7. Image Masking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  403
+
+10.11.8. URLImage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  404
+
+Mask Adapter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  406
+
+URLImage In Lists. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  406
+
+11. Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  409
+
+11.1. High Level Events. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  409
+
+11.1.1. Chain Of Events. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  409
+
+11.1.2. Action Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  409
+
+Types Of Action Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  410
+
+Source Of Event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  410
+
+Event Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  410
+
+NetworkEvent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  411
+
+11.1.3. DataChangeListener. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  412
+
+11.1.4. FocusListener. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  412
+
+11.1.5. ScrollListener. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  413
+
+11.1.6. SelectionListener . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  413
+
+11.1.7. StyleListener . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  414
+
+11.1.8. Event Dispatcher. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  414
+
+11.2. Low Level Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  414
+
+11.2.1. Low Level Event Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  415
+
+11.2.2. Drag Event Sanitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  416
+
+11.3. BrowserNavigationCallback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  416
+
+12. File System, Storage, Network & Parsing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  419
+
+12.1. Jar Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  419
+
+12.2. Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  419
+
+12.2.1. The Preferences API. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  422
+
+12.3. File System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  423
+
+12.3.1. File Paths & App Home . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  423
+
+12.3.2. Storage vs. File System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  425
+
+12.4. SQL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  426
+
+12.5. Network Manager & Connection Request . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  428
+
+12.5.1. Threading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  430
+
+12.5.2. Arguments, Headers & Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  430
+
+Arguments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  430
+
+Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  431
+
+Headers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  431
+
+Server Headers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  432
+
+Error Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  432
+
+Error Stream . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  433
+
+12.5.3. GZIP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  434
+
+12.5.4. File Upload . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  434
+
+12.5.5. Parsing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  435
+
+Parsing CSV. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  435
+
+JSON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  436
+
+XML Parsing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  439
+
+XPath Processing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  440
+
+Properties Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  446
+
+12.6. Debugging Network Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  447
+
+12.6.1. Simpler Downloads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  447
+
+Downloading Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  447
+
+12.7. Rest API. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  449
+
+12.7.1. Rest in Practice - Twilio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  449
+
+12.8. Webservice Wizard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  451
+
+12.9. Connection Request Caching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  455
+
+12.9.1. getCachedData() . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  456
+
+12.9.2. cacheUnmodified() . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  456
+
+12.9.3. purgeCache & purgeCacheDirectory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  457
+
+12.10. Cached Data Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  457
+
+12.11. Externalizable Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  457
+
+12.12. UI Bindings & Utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  462
+
+12.13. Logging & Crash Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  463
+
+12.14. Sockets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  463
+
+12.15. Properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  465
+
+12.15.1. Properties in Java . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  467
+
+Encapsulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  467
+
+Introspection & Observability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  468
+
+12.15.2. The Cool Stuff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  468
+
+Constructors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  469
+
+Seamless Serialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  470
+
+Seamless SQL Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  471
+
+Preferences Binding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  473
+
+UI Binding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  474
+
+UI Generation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  476
+
+13. Push Notifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  479
+
+13.1. Understanding Push Notifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  479
+
+13.2. Implementing Push Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  479
+
+13.3. The Push Lifecycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  480
+
+13.3.1. Registration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  480
+
+13.3.2. Sending a Push Notification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  481
+
+13.3.3. Receiving a Push Notification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  481
+
+13.4. Testing Push Support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  481
+
+13.5. Push Types and Message Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  484
+
+13.5.1. Example Push Type 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  485
+
+13.5.2. Example Push Type 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  485
+
+13.5.3. Example Push Type 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  486
+
+13.5.4. Example Push Type 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  486
+
+13.5.5. Example Push Type 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  487
+
+13.5.6. Example Push Type 100 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  487
+
+13.5.7. Example Push Type 101 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  487
+
+13.6. Rich Push Notifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  488
+
+13.6.1. Image Attachment Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  488
+
+13.6.2. Notification Actions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  490
+
+13.7. Deploying Push-Enabled Apps to Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  493
+
+13.7.1. The Push Bureaucracy - Android . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  493
+
+13.7.2. The Push Bureaucracy - iOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  496
+
+13.7.3. The Push Bureaucracy - UWP (Windows 10) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  498
+
+13.7.4. The Push Bureaucracy - Javascript. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  499
+
+13.8. Sending Push Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  500
+
+13.8.1. Sending a Push Message From Codename One. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  501
+
+13.8.2. Sending Push Message From A Java or Generic Server . . . . . . . . . . . . . . . . . . . . . . . . . . . .  502
+
+Server JSON Responses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  503
+
+14. Miscellaneous Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  505
+
+14.1. Phone Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  505
+
+14.1.1. SMS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  505
+
+14.1.2. Dialing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  506
+
+14.1.3. E-Mail. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  506
+
+14.2. Contacts API. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  507
+
+14.3. Localization & Internationalization (L10N & I18N) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  510
+
+14.3.1. Localization Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  511
+
+14.3.2. RTL/Bidi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  512
+
+14.4. Location - GPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  513
+
+14.4.1. Location In The Background - Geofencing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  514
+
+14.5. Background Music Playback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  516
+
+14.6. Capture - Photos, Video, Audio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  516
+
+14.6.1. Capture Asynchronous API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  523
+
+14.7. Gallery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  523
+
+14.8. Analytics Integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  524
+
+14.8.1. Application Level Analytics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  525
+
+14.8.2. Overriding The Analytics Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  525
+
+14.9. Native Facebook Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  525
+
+14.9.1. Getting Started - Web Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  525
+
+14.9.2. IDE Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  528
+
+14.9.3. The Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  528
+
+14.9.4. Facebook Publish Permissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  529
+
+14.10. Google Sign-In . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  530
+
+14.10.1. iOS Setup Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  530
+
+14.10.2. Android Setup Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  533
+
+14.10.3. OAuth Setup (Simulator and REST API Access) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  536
+
+Client ID, Client Secret and Redirect URL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  536
+
+14.10.4. Javascript Setup Instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  537
+
+14.10.5. The Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  537
+
+14.11. Lead Component . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  538
+
+14.11.1. Blocking Lead Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  539
+
+14.12. Pull To Refresh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  541
+
+14.13. Running 3rd Party Apps Using Display’s execute. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  541
+
+14.14. Automatic Build Hint Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  542
+
+14.15. Easy Thread . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  543
+
+14.16. Mouse Cursor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  544
+
+14.17. Working With GIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  544
+
+14.17.1. cn1lib’s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  544
+
+14.17.2. Resource Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  545
+
+14.17.3. Eclipse Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  545
+
+14.17.4. IntelliJ/IDEA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  546
+
+15. Performance, Size & Debugging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  549
+
+15.1. Reducing Resource File Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  549
+
+15.2. Improving Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  550
+
+15.3. Performance Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  551
+
+15.4. Network Speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  552
+
+15.5. Debugging Codename One Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  553
+
+15.6. Device Testing Framework/Unit Testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  553
+
+15.7. EDT Error Handler and sendLog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  554
+
+15.8. Kitchen Sink Case Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  555
+
+15.8.1. Scroll Performance - Threads aren’t magic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  556
+
+16. Advanced Topics/Under the Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  559
+
+16.1. Sending Arguments To The Build Server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  559
+
+16.2. Offline Build . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  574
+
+16.2.1. Prerequisites for iOS Builds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  574
+
+16.2.2. Prerequisites for Android Builds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  575
+
+16.2.3. Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  575
+
+16.2.4. Building. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  576
+
+16.2.5. FAQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  577
+
+Should I use the Offline Builder? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  577
+
+Can I Move/Backup my Builders? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  577
+
+Can I install the builders for all our developers? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  577
+
+What Happens if I Cancel? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  578
+
+When are Versions Released? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  578
+
+Are Version Numbers Sequential? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  578
+
+Why is this Feature Limited to Enterprise Subscribers? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  578
+
+How Different is the Code From Cloud Builds? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  578
+
+16.3. Android Permissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  578
+
+16.3.1. Permissions Under Marshmallow (Android 6+) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  579
+
+Enabling Permissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  580
+
+Permission Prompts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  580
+
+Code Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  582
+
+Simulating Prompts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  583
+
+AndroidNativeUtil’s checkForPermission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  583
+
+16.4. On Device Debugging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  583
+
+16.4.1. Android Studio Debugging (Easy Way) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  584
+
+16.4.2. Android Studio Debugging the Hard Way . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  584
+
+16.5. Native Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  585
+
+16.5.1. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  585
+
+Use the Android Main Thread (Native EDT). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  588
+
+Gradle Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  589
+
+16.5.2. Objective-C (iOS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  590
+
+Using the iOS Main Thread (Native EDT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  591
+
+Use Cocoapods For Dependencies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  592
+
+16.5.3. Javascript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  592
+
+JavaScript Examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  594
+
+16.5.4. Native GUI Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  595
+
+16.5.5. Type Mapping & Rules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  596
+
+16.5.6. Android Native Permissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  598
+
+16.5.7. Native AndroidNativeUtil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  599
+
+16.5.8. Broadcast Receiver. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  599
+
+Listening & Permissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  602
+
+16.5.9. Native Code Callbacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  603
+
+Accessing Callbacks from Objective-C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  604
+
+Accessing Callbacks from Javascript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  605
+
+Callbacks of the SMS Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  606
+
+Asynchronous Callbacks & Threading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  607
+
+16.6. Libraries - cn1lib . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  608
+
+16.6.1. Why Not Use JAR?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  609
+
+16.6.2. How To Use cn1libs? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  609
+
+16.6.3. Creating a Simple cn1lib . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  610
+
+16.6.4. Build Hints in cn1libs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  610
+
+16.7. Integrating Android 3rd Party Libraries & JNI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  614
+
+16.8. Drag & Drop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  615
+
+16.9. Continuous Integration & Release Engineering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  617
+
+16.10. Android Lollipop ActionBar Customization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  617
+
+16.11. Intercepting URL’s On iOS & Android . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  618
+
+16.11.1. Passing Launch Arguments To The App . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  618
+
+16.12. Native Peer Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  619
+
+16.12.1. Why does Codename One Need Native Widgets at all? . . . . . . . . . . . . . . . . . . . . . . . . . . .  619
+
+16.12.2. So what’s the problems with native widgets? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  620
+
+16.12.3. So how do we show dialogs on top of Peer Components? . . . . . . . . . . . . . . . . . . . . . . . . .  620
+
+16.12.4. Why can’t we combine peer component scrolling and Codename One scrolling? . . .  620
+
+16.12.5. Native Components In The First Form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  620
+
+16.13. Integrating 3rd Party Native SDKs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  620
+
+16.13.1. Step 1 : Review the FreshDesk SDKs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  621
+
+16.13.2. Step 2: Designing the Codename One Public API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  621
+
+16.13.3. Step 3: The Architecture and Internal APIs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  621
+
+Things to Notice. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  623
+
+16.13.4. Step 4: Implement the Public API and Native Interface . . . . . . . . . . . . . . . . . . . . . . . . . . .  623
+
+Adapting Method Signatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  623
+
+Callbacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  624
+
+Initialization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  626
+
+The Resulting Public API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  627
+
+The Native Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  629
+
+Connecting the Public API to the Native Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  631
+
+Implementing the Glue Between Public API and Native Interface. . . . . . . . . . . . . . . . . . . . . . .  632
+
+16.13.5. Step 5: Implementing the Native Interface in Android . . . . . . . . . . . . . . . . . . . . . . . . . . . .  633
+
+16.13.6. Step 6: Bundling the Native SDKs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  635
+
+The FreshDesk SDK. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  635
+
+Dependencies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  635
+
+16.13.7. Step 7 : Injecting Android Manifest and Proguard Config . . . . . . . . . . . . . . . . . . . . . . . . .  637
+
+Proguard Config . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  639
+
+Troubleshooting Android Stuff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  640
+
+16.14. Part 2: Implementing the iOS Native Code. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  640
+
+16.14.1. Using the MobihelpNativeCallback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  641
+
+16.14.2. Bundling Native iOS SDK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  641
+
+16.14.3. Troubleshooting iOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  642
+
+16.14.4. Adding Required Core Libraries and Frameworks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  642
+
+16.15. Part 3 : Packaging as a cn1lib . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  643
+
+16.16. Building Your Own Layout Manager. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  643
+
+16.16.1. Porting a Swing/AWT Layout Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  645
+
+16.17. Port a Language to Codename One . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  645
+
+16.17.1. What is a JVM Language? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  645
+
+16.17.2. How Hard is it to Port a JVM Language to Codename One?. . . . . . . . . . . . . . . . . . . . . . . .  646
+
+Step 1: Assess the Language . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  646
+
+Step 2: Convert the Runtime Library into a CN1Lib . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  651
+
+Step 3: Hello World . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  652
+
+Step 4: A More Complex Hello World. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  653
+
+Step 5: Automation and Integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  653
+
+16.18. Update Framework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  655
+
+16.18.1. How does it Work? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  655
+
+16.18.2. What isn’t Covered. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  656
+
+17. Signing, Certificates & Provisioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  657
+
+17.1. Common Terms In Signing & Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  657
+
+17.1.1. What Is A Certificate? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  657
+
+17.1.2. What Is Provisioning? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  657
+
+17.1.3. What’s a Signing Authority? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  657
+
+17.1.4. What is UDID? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  657
+
+17.1.5. Should I Reuse the Same Certificate for All Apps? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  658
+
+17.2. iOS Signing Wizard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  658
+
+17.2.1. Logging into the Wizard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  658
+
+17.2.2. Selecting Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  659
+
+17.2.3. Decisions & Edge Cases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  660
+
+17.2.4. App IDs and Provisioning Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  661
+
+17.2.5. Installing Files Locally. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  662
+
+17.2.6. Building Your App . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  663
+
+17.3. Advanced iOS Signing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  663
+
+17.4. Provisioning Profile & Certificates Visual Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  664
+
+17.4.1. iOS Code Signing Failure Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  667
+
+17.5. Android. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  669
+
+17.5.1. Generating an Android Certificate Manually . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  669
+
+17.6. RIM/BlackBerry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  670
+
+17.7. J2ME. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  670
+
+18. Working with iOS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  671
+
+18.1. Troubleshooting iOS Debug Build installs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  671
+
+18.2. The iOS Screenshot/Splash Screen Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  672
+
+18.2.1. Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  673
+
+18.2.2. Mutable first screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  673
+
+18.2.3. Unsupported component . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  674
+
+18.3. Launch Screen Storyboards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  674
+
+18.3.1. Launch Storyboard vs Launch Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  674
+
+18.4. Local Notifications on iOS and Android . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  674
+
+18.4.1. Sending Notifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  675
+
+Example Sending Notification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  675
+
+18.4.2. Receiving Notifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  675
+
+Example Receiving Notification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  676
+
+18.4.3. Canceling Notifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  676
+
+18.5. iOS Beta Testing (Testflight) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  677
+
+18.6. Accessing Insecure URL’s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  677
+
+18.7. Using Cocoapods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  677
+
+18.7.1. Including Multiple Pods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  678
+
+18.7.2. Other Pod Related Build Hints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  678
+
+18.7.3. Converting PodFile To Build Hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  678
+
+18.8. Including Dynamic Frameworks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  679
+
+19. Working with JavaScript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  681
+
+19.1. Limitations of the Javascript Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  681
+
+19.1.1. No Multithreaded Code inside Static Initializers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  681
+
+19.2. Troubleshooting Build Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  682
+
+19.3. ZIP, WAR, or Preview.  What’s the difference? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  683
+
+19.4. Setting up a Proxy for Network Requests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  685
+
+19.4.1. Step 1: Setting up a Proxy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  685
+
+19.4.2. Step 2: Configuring your Application to use the Proxy . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  685
+
+19.5. Using the CORS Proxy for Same Origin Requests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  686
+
+Using Apache as a Proxy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  687
+
+19.6. Customizing the Splash Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  687
+
+19.7. Debugging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  687
+
+19.8. Including Third-Party Javascript Libraries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  688
+
+19.8.1. Libraries vs Resources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  688
+
+19.8.2. The Javascript Manifest File. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  689
+
+How to NOT generate the <script> tag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  690
+
+Library Directories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  690
+
+Including Remote Libraries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  691
+
+Including CSS Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  692
+
+Embedding Variables in URLs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  693
+
+19.9. Browser Environment Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  693
+
+19.10. Changing the Native Theme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  694
+
+19.10.1. Example:  Using Android Theme on Android . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  695
+
+19.11. Disabling the 'OnBeforeUnload' Handler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  695
+
+19.11.1. Example: Toggling the BeforeUnload Prompt On/Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  695
+
+19.12. Deploying as a Progressive Web App . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  696
+
+19.12.1. Customizing the App Manifest File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  697
+
+19.12.2. Related Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  697
+
+19.12.3. Device/Browser Support for PWAs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  698
+
+19.13. Playing Media and Opening Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  699
+
+20. Working with UWP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  701
+
+20.1. Deploying Outside of the Windows App Store (Sideloading). . . . . . . . . . . . . . . . . . . . . . . . . . . .  701
+
+20.1.1. Side-loading to Windows 10 Mobile Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  701
+
+Enabling Developer Mode on Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  701
+
+Building App for UWP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  703
+
+Installing App On Device. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  703
+
+20.1.2. Side-loading to Windows 10 Desktop Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  704
+
+Enabling Developer Mode on PC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  704
+
+Building the App . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  705
+
+Installing the App . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  706
+
+20.1.3. Building for the Windows Store . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  707
+
+20.2. Debugging UWP Apps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  710
+
+20.2.1. No Line Numbers in Stack Traces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  710
+
+20.3. Customizing the Status Bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  712
+
+20.4. Associating App with File Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  712
+
+21. Working with Mac OS X . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  715
+
+21.1. Mac OS Desktop Build Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  715
+
+21.1.1. Bundle Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  715
+
+21.1.2. Understanding Mac Certificates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  715
+
+21.1.3. Obtaining Certificates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  716
+
+21.1.4. Exporting Certificates as P12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  717
+
+21.1.5. Entitlements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  718
+
+22. Security. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  719
+
+22.1. Constant Obfuscation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  719
+
+22.2. Storage Encryption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  721
+
+22.3. Disabling Screenshots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  722
+
+22.4. Blocking Copy & Paste . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  722
+
+22.5. Blocking Jailbreak . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  722
+
+22.6. Strong Android Certificates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  723
+
+22.6.1. The Bad News . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  723
+
+22.6.2. The Good. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  724
+
+22.7. Certificate Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  724
+
+22.7.1. Certificate Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  724
+
+23. Travis CI Integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  727
+
+23.1. Quick Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  727
+
+23.1.1. Enabling Travis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  727
+
+Activating/Deactivating Jobs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  729
+
+23.1.2. Pushing to GitHub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  730
+
+23.1.3. Activate Repository On Travis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  731
+
+23.1.4. Setting Environment Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  731
+
+23.1.5. Testing Travis Script . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  732
+
+23.1.6. Writing Unit Tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  733
+
+Disabling Travis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  733
+
+24. Working with Codename One Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  735
+
+24.1. Checking out the Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  735
+
+24.2. Building Sources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  735
+
+24.3. Running Unit Tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  735
+
+24.4. Running iOS Unit Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  735
+
+24.4.1. Installing npm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  736
+
+24.4.2. Installing and Running Appium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  736
+
+24.4.3. Running the Unit tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  736
+
+24.4.4. Overriding the Codename One Build Server Target . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  736
+
+Preface
+
+This 
+
+developer 
+
+guide 
+
+is 
+
+automatically 
+
+generated 
+
+from 
+
+the  wiki 
+
+pages 
+
+at
+
+https://github.com/codenameone/CodenameOne/wiki 
+
+[https://github.com/codenameone/CodenameOne/
+
+wiki].
+
+You  can  edit  any  page  within  the  wiki  pages  using  AsciiDoc.  Your  changes  might  make  it  (after
+
+review) into the official documentation available on the web here: https://www.codenameone.com/
+
+manual/ and available as a PDF file here: https://www.codenameone.com/files/developer-guide.pdf
+
+[https://www.codenameone.com/files/developer-guide.pdf].
+
+Occasionally this book is updated to the print edition available here: https://www.amazon.com/dp/
+
+1549910035
+
+We  also  recommend  that  you  check  out  the  full  JavaDoc  [https://www.codenameone.com/javadoc/]
+
+reference for Codename One which is very complete.
+
+You  can  download  the  full  Codename  One  source  code  from  the  Codename  One  git  repository
+
+[https://github.com/codenameone/CodenameOne/]  where  you  can  also  edit  the  JavaDocs  and  submit  pull
+
+requests to include new features into Codename One [https://www.codenameone.com/blog/how-to-use-the-
+
+codename-one-sources.html].
+
+1
+
+Authors
+
+This document includes content from multiple authors and community wiki edits. If you edit pages
+
+within the guide feel free to add your name here alphabetized by surname:
+
+• Shai Almog [https://github.com/codenameone/]
+
+• Ismael Baum [https://github.com/Isborg]
+
+• Eric Coolman [https://twitter.com/ericcoolmandev]
+
+• Chen Fishbein [http://github.com/chen-fishbein/]
+
+• Steve Hannah [http://github.com/shannah/]
+
+• Matt [https://github.com/kheops37]
+
+2
+
+Rights & Licensing
+
+You  may  copy/redistribute/print  this  document  without  prior  permission  from  Codename  One.
+
+However, you may not charge for the document itself although charging for costs such as printing
+
+is permitted.
+
+Notice that while you can print and reproduce sections arbitrarily such changes must explicitly and
+
+clearly 
+
+state 
+
+that 
+
+this 
+
+is  a  modified  copy  and 
+
+link 
+
+to 
+
+the  original 
+
+source  at
+
+https://www.codenameone.com/manual/ in a clear way!
+
+3
+
+Conventions
+
+This guide uses some notations to provide tips and further guidance.
+
+In case of further information that breaks from the current tutorial flow we use a sidebar as such:
+
+Sidebar
+
+Dig  deeper  into  some  details  that  don’t  quite  fit  into  the  current  flow.  We  use  sidebars  for
+
+things that are an important detour, you can skip them while reading but you might want to
+
+come back and read them later.
+
+Here are common conventions for highlighting notes:
+
+ This is an important note
+
+
+
+This is a helpful tip
+
+ This is a general informational note, something interesting but not crucial
+
+ This is a warning something we should pay attention to
+
+This  convention  is  used  when  we  refer  to  a  button  or  a  widget  to  press  in  the  UI.  E.g.  press  the
+
+button labeled Press Here.
+
+Quotes are presented as:
+
+This is a quote
+
+— By Author
+
+Bold is used for light emphasis on a specific word or two within a sentence.
+
+4
+
+1. Introduction
+
+Codename  One  is  a  Write  Once  Run  Anywhere  mobile  development  platform  for  Java/Kotlin
+
+developers. It integrates with IntelliJ/IDEA, Eclipse or NetBeans to provide seamless native mobile
+
+development.
+
+Codename One’s mission statement is:
+
+Unify the complex and fragmented task of mobile device programming into
+
+a single set of tools, APIs and services. As a result create a more manageable
+
+approach  to  mobile  application  development  without  sacrificing  the
+
+power/control given to developers.
+
+This  effectively  means  bringing  that  old  "Write  Once  Run  Anywhere"  (WORA)  Java  mantra  to
+
+mobile devices without "dumbing it down" to the lowest common denominator.
+
+The things that make Codename One stand out from other tools in this field are:
+
+• Write  Once  Run  Anywhere  support  with  no  special  hardware  requirements  and  100%  code
+
+reuse
+
+• Compiles Java/Kotlin into native code for iOS, UWP (Universal Windows Platform), Android and
+
+even JavaScript/PWA
+
+• Open Source and Free with commercial backing/support
+
+• Easy to use with 100% portable Drag and Drop GUI builder
+
+• Full access to underlying native OS capabilities using the native OS programming language (e.g.
+
+Objective-C) without compromising portability
+
+• Provides full control over every pixel on the screen
+
+• Lets you use native widgets (views) and mix them with Codename One components within the
+
+same hierarchy (heavyweight/lightweight mixing)
+
+• Supports seamless Continuous Integration out of the box
+
+Codename One can trace its roots to the open source LWUIT project started at Sun Microsystem in
+
+2007 by Chen Fishbein (co-founder of Codename One). It’s a huge project that’s been under constant
+
+development for over a decade!
+
+1.1. Build Cloud
+
+One  of  the  things  that  make  Codename  One  stand  out  is  the  build  cloud  approach  to  mobile
+
+development.  iOS  native  development  requires  a  Mac  with  xcode.  Windows  native  development
+
+requires a Windows machine. To make matters worse, Apple, Google and Microsoft make changes
+
+to their tools on a regular basis…
+
+This makes it hard to keep up.
+
+When  we  develop  an  app  in  Codename  One  we  use  the  builtin  simulator  when  running  and
+
+5
+
+debugging. When we want to build a native app we can use the build cloud where Macs create the
+
+native  iOS  apps  and  Windows  machines  create  the  native  Windows  apps.  This  works  seamlessly
+
+and makes Codename One apps native as they are literally compiled by the native platform. E.g. for
+
+iOS builds the build cloud uses Macs running xcode (the native Apple tool) to build the app.
+
+ Codename  One  doesn’t  send  source  code  to  the  build  cloud,  only  compiled
+
+bytecode!
+
+Notice that Codename One also provides an option to build offline which means corporations that
+
+have policies forbidding such cloud architectures can still use Codename One with some additional
+
+overhead/complexity of setting up the native build tools. Since Codename One is open source some
+
+developers  use  the  source  code  to  compile  applications  offline  but  that’s  outside  the  scope  of  this
+
+book.
+
+1.1.1. Why Build Servers?
+
+The build servers allow building native iOS Apps without a Mac and native Windows apps without
+
+a Windows machine. They remove the need to install/update complex toolchains and simplify the
+
+process of building a native app to a right click.
+
+E.g.: Since building native iOS applications requires a Mac OS X machine with a recent version of
+
+xcode  Codename  One  maintains  such  machines  in  the  cloud.  When  developers  send  an  iOS  build
+
+such  a  Mac  will  be  used  to  generate  C  source  code  using  ParparVM  [https://github.com/codenameone/
+
+CodenameOne/tree/master/vm]  and  it  will  then  compile  the  C  source  code  using  xcode  &  sign  the
+
+resulting binary using xcode. You can install the binary to your device or build a distribution binary
+
+for the appstore. Since C code is generated it also means that your app will be "future proof" in a
+
+case of changes from Apple. You can also inject Objective-C native code into the app while keeping
+
+it 100% portable thanks to the "native interfaces" capability of Codename One.
+
+Subscribers can receive the C source code back using the include sources feature of Codename One
+
+and use those sources for benchmarking, debugging on devices etc.
+
+The same is true for most other platforms. For the Android, J2ME & Blackberry the standard Java
+
+code is executed as is.
+
+Java  8  syntax  is  supported  thru  retrolambda  [https://github.com/orfjackal/retrolambda]  installed  on  the
+
+Codename  One  servers.  This  is  used  to  convert  bytecode  seamlessly  down  to  Java  5  syntax  levels.
+
+Java 5 syntax is translated to the JDK 1.3 cldc subset on J2ME/Blackberry to provide those language
+
+capabilities and API’s across all devices. This is done using a server based bytecode processor based
+
+on  retroweaver  and  a  great  deal  of  custom  code.  Notice  that  this  architecture  is  transparent  to
+
+developers as the build servers abstract most of the painful differences between devices.
+
+1.1.2. How does Codename One Work?
+
+Codename  One  uses  a  SaaS  based  approach  so  the  information  in  this  appendix  might  (and
+
+probably  will)  change  in  the  future  to  accommodate  improved  architectures.  I  included  this
+
+information for reference only, you don’t need to understand this in order to follow the content of
+
+the book…
+
+6
+
+Since  Android  is  already  based  on  Java,  Codename  One  is  already  native  to  Android  and  “just
+
+works” with the Android VM (ART/Dalvik).
+
+On  iOS,  Codename  One  built  and  open  sourced  ParparVM,  which  is  a  very  conservative  VM.
+
+ParparVM  features  a  concurrent  (non-blocking)  GC  and  it’s  written  entirely  in  Java/C.  ParparVM
+
+generates  C  source  code  matching  the  given  Java  bytecode.  This  effectively  means  that  an  xcode
+
+project is generated and compiled on the build servers. It’s as if you handcoded a native app and is
+
+thus “future proof” for changes that Apple might introduce. E.g. Apple migrated to 64bit and later
+
+introduced  bitcode  support  to  iOS.  ParparVM  needed  no  modifications  to  comply  with  those
+
+changes.
+
+ Codename One translates the bytecode to C which is faster than Swift/Objective-C.
+
+The port code that invokes iOS API’s is hand coded in Objective-C
+
+For Windows 10 desktop and Mobile support, Codename One uses iKVM to target UWP (Universal
+
+Windows Platform) and has open sourced the changes to the original iKVM code.
+
+JavaScript  build  targets  use  TeaVM  to  do  the  translation  statically.  TeaVM  provides  support  for
+
+threading  using  JavaScript  by  breaking  the  app  down  in  a  rather  elaborate  way.  To  support  the
+
+complex  UI  Codename  One  uses  the  HTML5  Canvas  API  which  allows  absolute  flexibility  for
+
+building applications.
+
+For desktop builds Codename One uses javapackager, since both Macs and Windows machines are
+
+available in the cloud the platform specific nature of javapackager is not a problem.
+
+Lightweight Architecture
+
+What makes Codename One stand out is the approach it takes to UI: “lightweight architecture”.
+
+Lightweight architecture is the “not so secrete sauce” to Codename One’s portability. Essentially it
+
+means  all  the  components/widgets  in  Codename  One  are  written  in  Java.  Thus  their  behavior  is
+
+consistent  across  all  platforms  and  they  are  fully  customizable  from  the  developer  code  as  they
+
+don’t rely on OS internal semantics. This allows developers to preview the application accurately in
+
+the simulators and GUI builders.
+
+One  of  the  big  accomplishments  in  Codename  One  is  its  unique  ability  to  embed  “heavyweight”
+
+widgets  into  place  among  the  “lightweights”.  This  is  crucial  for  apps  such  as  Uber  where  the  cars
+
+and  widgets  on  top  are  implemented  as  Codename  One  components  yet  below  them  we  have  the
+
+native map component.
+
+Codename  One  achieves  fast  performance  by  drawing  using  the  native  gaming  API’s  of  most
+
+platforms e.g. OpenGL ES on iOS. The core technologies behind Codename One are all open source
+
+including  most  of  the  stuff  developed  by  Codename  One  itself,  e.g.  ParparVM  but  also  the  full
+
+library, platform ports, designer tool, device skins etc.
+
+7
+
+Lightweight Architecture Origin
+
+Lightweight components date back to Smalltalk frameworks, this notion was popularized in
+
+the  Java  world  by  Swing.  Swing  was  the  main  source  of  inspiration  to  Codename  One’s
+
+predecessor  LWUIT.  Many  frameworks  took  this  approach  over  the  years  including  JavaFX
+
+and most recently Ionic in the JavaScript world.
+
+Why ParparVM
+
+On  iOS,  Codename  One  uses  ParparVM  [https://github.com/codenameone/CodenameOne/tree/master/vm]
+
+which  translates  Java  bytecode  to  C  code  and  boasts  a  non-blocking  GC  as  well  as  64  bit/bitcode
+
+support.  This  VM  is  fully  open  source  in  the  Codename  One  git  repository  [https://github.com/
+
+codenameone/CodenameOne/].  In  the  past  Codename  One  used  XMLVM  [http://www.xmlvm.org/]  to
+
+generate native code in a very similar way but the XMLVM solution was too generic for the needs of
+
+Codename One. ParparVM [https://github.com/codenameone/CodenameOne/tree/master/vm] boasts a unique
+
+architecture  of  translating  code  to  C  (similarly  to  XMLVM),  because  of  that  Codename  One  is  the
+
+only solution of its kind that can guarantee future iOS compatibility since the officially supported
+
+iOS toolchain is always used instead of undocumented behaviors.
+
+ XMLVM could guarantee that in theory but it is no longer maintained
+
+The key advantages of ParparVM over other approaches are:
+
+• Truly Native — since code is translated to C rather than directly to ARM or LLVM code the app
+
+is "more native". It uses the official tools and approaches from Apple and can benefit from their
+
+advancements e.g. latest bitcode changes or profiling capabilities.
+
+• Smaller  Class  Library — ParparVM  includes  a  very  small  segment  of  the  full  JavaAPI’s
+
+resulting  in  final  binaries  that  are  smaller  than  the  alternatives  by  orders  of  magnitude.  This
+
+maps directly to performance and memory overhead.
+
+• Simple and Extensible — to work with ParparVM you need a basic understanding of C. This is
+
+crucial for the fast moving world of mobile development, as Apple changes things left and right
+
+we need a more agile VM.
+
+Windows Phone/UWP
+
+In the past Codename One had 2 major Windows VM port rewrites and 3 or 4 rendering pipelines
+
+within those ports (depends on how you would define a "rewrite").
+
+ The old Windows Phone port was deprecated and is no longer supported, the UWP
+
+port is the only supported Windows mobile target
+
+Codename  One  now  targets  UWP  by  leveraging  a  modified  version  of  iKVM  [https://github.com/
+
+shannah/cn1-ikvm-uwp] to build native Windows Universal Applications.
+
+iKVM uses a bytecode to CLR translation process that effectively converts Java bytecode directly to
+
+the .net equivalent. This is paired with a port of the Codename One API’s that was built for the UWP
+
+environment.  The  UWP  port  generates  native  Windows  10  applications  that  can  support  ARM
+
+8
+
+Windows  devices  natively  as  well  as  desktops  etc.  These  binaries  can  be  uploaded  directly  to
+
+Microsofts online store without special processing.
+
+JavaScript Port
+
+The  JavaScript  port  of  Codename  One  is  based  on  the  amazing  work  of  the  TeaVM  project
+
+[http://teavm.org:]. The team behind TeaVM effectively built a JVM that translates Java bytecode into
+
+JavaScript source code while maintaining threading semantics using a very imaginative approach.
+
+The  JavaScript  port  allows  unmodified  Codename  One  applications  to  run  within  a  desktop  or
+
+mobile  browser.  The  port  itself  is  based  on  the  HTML5  Canvas  API,  this  provides  a  pixel  perfect
+
+implementation of the Codename One API.
+
+ The JavaScript port is only available for Enterprise grade subscribers of Codename
+
+One
+
+Desktop and Android
+
+The  other  ports  of  Codename  One  use  the  VM’s  available  on  the  host  machines/environments  to
+
+execute  the  runtime.  Retrolambda  [https://github.com/orfjackal/retrolambda]  is  used  to  provide  Java  8
+
+language features in a portable way.
+
+The Android port uses the native Android tools including the gradle build environment in the latest
+
+versions.
+
+The  desktop  port  creates  a  standard  JavaSE  application  which  is  packaged  with  the  JRE  and  an
+
+installer.
+
+ The Desktop port is only available to pro grade subscribers of Codename One
+
+1.1.3. Versions In Codename One
+
+One  of  the  confusing  things  about  Codename  One  is  the  versions.  Since  Codename  One  is  a  SaaS
+
+product versioning isn’t as simple as a 2.x or 3.x moniker. However, to conform to this convention
+
+Codename One does make versioned releases which contribute to the general confusion.
+
+When a version of Codename One is released the version number refers to the libraries at the time
+
+of  the  release.  These  libraries  are  then  frozen  and  are  made  available  to  developers  who  use  the
+
+Versioned  Builds 
+
+[https://www.codenameone.com/how-do-i---get-repeatable-builds-build-against-a-consistent-
+
+version-of-codename-one-use-the-versioning-feature.html] feature. The plugin, which includes the designer
+
+as well as all development that is unrelated to versioned builds continues with its regular updates
+
+immediately  after  release.  The  same  is  true  for  the  build  servers  that  move  directly  to  their
+
+standard update cycle.
+
+1.2. History
+
+9
+
+Figure 1. LWUIT App Screenshot circa 2007
+
+Codename  One  was  started  by  Chen  Fishbein  and  Shai  Almog  who  authored  the  Open  Source
+
+LWUIT  project  at  Sun  Microsystems  (circa  2007).  The  LWUIT  project  aimed  to  solve  the
+
+fragmentation within J2ME/Blackberry devices by creating a higher standard of user interface than
+
+the  common  baseline  at  the  time.  LWUIT  received  critical  acclaim  and  traction  within  multiple
+
+industries  but  was  limited  by  the  declining  feature  phone  market.  It  was  forked  by  several
+
+companies  including  Nokia.  It  was  used  as  the  base  standard  for  DTV  in  Brazil.  Another  fork  has
+
+brought  a  LWUIT  into  high  end  cars  from  Toyota  and  other  companies.  This  fork  later  adapted
+
+Codename One as well.
+
+In 2012 Shai and Chen formed Codename One as they left Oracle. The project has taken many of the
+
+basic  concepts  developed  within  the  LWUIT  project  and  adapted  them  to  the  smartphone  world
+
+which is still experiencing similar issues to the device fragmentation of the old J2ME phones.
+
+1.3. Core Concepts of Mobile Programming
+
+Before  we  proceed  I’d  like  to  explain  some  universal  core  concepts  of  mobile  programming  that
+
+might not be intuitive. These are universal concepts that apply to mobile programming regardless
+
+of the tools you are using.
+
+You  can  skip  this  section  if  you  feel  you  are  familiar  enough  with  the  core  problems/issues  in
+
+mobile app development.
+
+1.3.1. Density
+
+Density is also known as DPI (Dots Per Inch) or PPI (pixels or points per inch). Density is confusing,
+
+unintuitive  and  might  collide  with  common  sense.  E.g.  an  iPhone  7  plus  has  a  resolution  of
+1080x1920  pixels  and  a  PPI  of  401  for  a  5  inch  screen.  On  the  other  hand  an  iPad  4  has  1536x2048
+pixels with a PPI of 264 on a 9.7 inch screen… Smaller devices can have higher resolutions!
+
+As the following figure shows, if a Pixel 2 XL had pixels the size of an iPad it would have been twice
+
+the size of that iPad. While in reality it’s nearly half the height of the iPad!
+
+10
+
+Figure 2. Device Density vs. Resolution
+
+Differences  in  density  can  be  extreme.  A  second  generation  iPad  has  132  PPI,  where  modern
+
+phones  have  PPI  that  crosses  the  600  mark.  Low  resolution  images  on  high  PPI  devices  will  look
+
+either  small  or  pixelated.  High  resolution  images  on  low  PPI  devices  will  look  huge,  overscaled
+
+(artifacts) and will consume too much memory.
+
+11
+
+Figure 3. How the Same Image Looks in Different Devices
+
+The exact same image will look different on each device, sometimes to a comical effect. One of the
+
+solutions for this problem is multi-images. All OS’s support the ability to define different images for
+
+various densities. I will discuss multi-images later in Chapter 2.
+
+This  also  highlights  the  need  for  working  with  measurements  other  than  pixels.  Codename  One
+
+supports millimeters (or dips) as a unit of measurement. This is highly convenient and is a better
+
+representation of size when dealing with mobile devices.
+
+But  there  is  a  bigger  conceptual  issue  involved.  We  need  to  build  a  UI  that  adapts  to  the  wide
+
+differences in form factors. We might have fewer pixels on an iPad but because of its physical size
+
+we  would  expect  the  app  to  cram  more  information  into  that  space  so  the  app  won’t  feel  like  a
+
+blown up phone application. There are multiple strategies to address that but one of the first steps
+
+is in the layout managers.
+
+I’ll discuss the layout managers in depth in Chapter 2 but the core concept is that they decide where
+
+a UI element is placed based on generic logic. That way the user interface can adapt automatically
+
+to the huge variance in display size and density.
+
+1.3.2. Touch Interface
+
+The  fact  that  mobile  devices  use  a  touch  interface  today  isn’t  news…  But  the  implications  of  that
+
+aren’t immediately obvious to some developers.
+
+UI  elements  need  to  be  finger  sized  and  heavily  spaced.  Otherwise  we  risk  the  “fat  finger”  effect.
+
+12
+
+That means spacing should be in millimeters and not in pixels due to device density.
+
+Scrolling  poses  another  challenge  in  touch  based  interfaces.  In  desktop  applications  it’s  very
+
+common  to  nest  scrollable  items.  However,  in  touch  interfaces  the  scrolling  gesture  doesn’t  allow
+
+such nuance. Furthermore, scrolling on both the horizontal and vertical axis (side scrolling) can be
+
+very inconvenient in touch based interfaces.
+
+1.3.3. Device Fragmentation
+
+Some developers single out this wide range of resolutions and densities as “device fragmentation”.
+
+While it does contribute to development complexity for the most part it isn’t a difficult problem to
+
+overcome.
+
+Densities aren’t the cause of device fragmentation. Device fragmentation is caused by multiple OS
+
+versions with different behaviors. This is very obvious on Android and for the most part relates to
+
+the  slow  rollout  of  Android  vendor  versions  compared  to  Googles  rollout.  E.g.  7  months  after  the
+
+Android 8 (Oreo) release in 2018 it was still available on 1.1% of the devices. The damning statistic
+
+is that 12% of the devices in mid 2018 run Android 4.4 Kitkat released in 2013!
+
+This makes QA difficult as the disparity between these versions is pretty big. These numbers will be
+
+out  of  date  by  the  time  you  read  this  but  the  core  problem  remains.  It’s  hard  to  get  all  device
+
+manufacturers  on  the  same  page  so  this  problem  will  probably  remain  in  the  foreseeable  future
+
+despite everything.
+
+1.3.4. Performance
+
+Besides the obvious need for performance and smooth animation within a mobile app there are a
+
+couple of performance related issues that might not be intuitive to new developers: size and power.
+
+App Size
+
+Apps are installed and managed via stores. This poses some restrictions about what an app can do.
+
+But  it  also  creates  a  huge  opportunity.  Stores  manage  automatic  update  and  to  some  degree  the
+
+marketing/monetization of the app.
+
+A  good  mobile  app  is  updated  once  a  month  and  sometimes  even  once  a  week.  Since  the  app
+
+downloads automatically from the store this can be a huge benefit:
+
+• Existing users are reminded of the app and get new features instantly
+
+• New users notice the app featured on a “what’s new” list
+
+If  an  app  is  big  it  might  not  update  over  a  cellular  network  connection.  Google  and  Apple  have
+
+restrictions on automatic updates over cellular networks to preserve battery life and data plans. A
+
+large  app  might  negatively  impact  users  perception  of  the  app  and  trigger  uninstalls  e.g.  when  a
+
+phone is low on available space.
+
+Power Drain
+
+Desktop developers rarely think about power usage within their apps. In mobile development this
+
+is a crucial concept. Modern device OS’s have tools that highlight misbehaving applications and this
+
+13
+
+can lead to bad reviews.
+
+Code that loops forever while waiting for input will block the CPU from sleeping and slowly drain
+
+the battery.
+
+Worse. Mobile OS’s kill applications that drain the battery. If the app is draining the battery and is
+
+minimized (e.g. during an incoming call) the app could be killed. This will impact app performance
+
+and usability.
+
+1.3.5. Sandbox and Permissions
+
+Apps installed on the device are “sandboxed” to a specific area so they won’t harm the device or its
+
+functionality. The filesystem of mobile applications is restricted so one application can’t access the
+
+files of another application. Things that most developers take for granted on the desktop such as a
+
+“file picker” or accessing the image folder don’t work on devices!
+
+This means that when your application works on a file it belongs only to your application. In order
+
+to share the file with a different application you need to ask the operating system to do that for you.
+
+Furthermore, some features require a “permission” prompt and in some cases require special flags
+
+in system files. Apps need to request permission to use sensitive capabilities e.g. Camera, Contacts
+
+etc. 
+
+Historically  Android  developers  just  declared  required  permissions  for  an  app  and  the  user  was
+
+prompted  with  permissions  during  install.  Android  6  adopted  the  approach  used  by  iOS  of
+
+prompting the user for permission when accessing a feature.
+
+This  means  that  in  runtime  a  user  might  revoke  a  permission.  A  good  example  in  the  case  of  an
+
+Uber  app  is  the  location  permission.  If  a  user  revokes  that  permission  the  app  might  lose  its
+
+location.
+
+1.4. Installing Codename One
+
+ The minimum JDK for Codename One is JDK 8
+
+ The  following  screenshots  are  from  Mac  OS  but  the  process  should  work  exactly
+
+the same on Windows and Linux
+
+1.5. IntelliJ/IDEA
+
+Codename One recommends IntelliJ/IDEA 2016 or newer.
+
+ Codename  One  doesn’t  support  Android  Studio!  You  can  use  IntelliJ/IDEA
+
+community edition instead
+
+14
+
+Figure 4. IntelliJ Installation Instructions
+
+1.6. NetBeans
+
+NetBeans  install  is  pretty  simple  although  the  default  “plugin  center”  for  NetBeans  is  notoriously
+
+unreliable.  That’s  why  we 
+
+recommend  using 
+
+the  Codename  One  plugin 
+
+center:
+
+https://www.codenameone.com/files/netbeans/updates.xml
+
+15
+
+Figure 5. NetBeans Installation Instructions
+
+
+
+Make  sure  you  are  using  a  NetBeans  version  that  includes  Java  support,  don’t
+
+download a version for Ruby/PHP or J2ME and make sure the IDE runs on top of
+
+JDK 8
+
+1.7. Eclipse
+
+Codename One supports Eclipse Neon 2 or newer. There are a few pitfalls that can happen with an
+
+Eclipse install specifically when other JVM versions are installed on your machine.
+
+ If you are new to Java, Eclipse might be intimidating. It’s a very powerful IDE but
+
+its configuration is rough
+
+Make sure your JAVA_HOME environment variable points at JDK 8 and that the path to the JDK 8 bin
+directory  is  first  in  the  PATH  statement.  If  all  else  fails  edit  the  eclipse.ini  file  to  force  Eclipse  to
+use your JDK 8 install. See this site for help with editing the eclipse.ini file: https://wiki.eclipse.org/
+Eclipse.ini
+
+16
+
+Figure 6. Eclipse Installation Instructions
+
+ In order to run the app in Eclipse make sure to select the .launch file in Eclipse
+
+1.8. Hello World Application
+
+Before we get to the code there are few important things we need to go over with the new project
+
+wizard.
+
+We  need  to  create  a  new  project.  We  need  to  pick  a  project  name  and  I’ll  leave  that  up  to  you
+although it’s hard to go wrong with HelloWorld. The following four values are important:
+
+• App Name - This is the name of the app and the main class, it’s important to get this right as it’s
+
+hard to change this value later
+
+• Package Name - It’s crucial you get this value right. Besides the difficulty of changing this after
+
+the fact, once an app is submitted to iTunes/Google Play with a specific package name this can’t
+
+be changed! See the sidebar "Picking a Package Name".
+
+• Theme - There are various types of builtin themes in Codename One, for simplicity I pick Native
+
+as it’s a clean slate starting point
+
+• Template  -  There  are  several  builtin  app  templates  that  demonstrate  various  features,  for
+
+simplicity I always pick Bare Bones which includes the bare minimum
+
+17
+
+Figure 7. The New App Wizard
+
+18
+
+Picking a Package Name
+
+Apple, Google and Microsoft identify applications based on their package names. If you use a
+
+domain  that  you  don’t  own  it’s  possible  that  someone  else  will  use  that  domain  and  collide
+with you. In fact some developers left the default com.mycompany domain in place all the way
+into production in some cases.
+
+This can cause difficulties when submitting to Apple, Google or Microsoft. Submitting to one
+
+of them is no guarantee of success when submitting to another.
+
+To come up with the right package name use a reverse domain notation. So if my website is
+goodstuff.co.uk my package name should start with uk.co.goodstuff. I highly recommend the
+following guidelines for package names:
+
+• Lower Case - some OS’s are case sensitive and handling a mistake in case is painful. The
+
+Java convention is lower case and I would recommend sticking to that although it isn’t a
+
+requirement
+
+• Avoid Dash and Underscore - You can’t use a dash character (-) for a package name in
+Java.  Underscore  (_)  doesn’t  work  for  iOS.  If  you  want  more  than  one  word  just  use  a
+deeper package e.g.: com.mydomain.deeper.meaningful.name
+
+• Obey  Java  Rules  -  A  package  name  can’t  start  with  a  number  so  you  can’t  use
+
+com.mydomain.1sler. You should avoid using Java keywords like this, if etc.
+
+• Avoid Top Level - instead of using uk.co.goodstuff use uk.co.goodstuff.myapp. That would
+
+allow you to have more than one app on a domain
+
+1.8.1. Running
+
+We can run the HelloWorld application by pressing the Play or Run button in the IDE for NetBeans or
+IntelliJ. In Eclipse we first need to select the simulator .launch file and then press run. When we do
+that the Codename One simulator launches. You can use the menu of the simulator to control and
+
+inspect details related to the device. You can rotate it, determine it’s location in the world, monitor
+
+networking calls etc.
+
+With  the  Skins  menu  you  can  download  device  skins  to  see  how  your  app  will  look  on  different
+devices.
+
+
+
+Some  skins  are  bigger  than  the  screen  size,  uncheck  the  Scrollable  flag  in  the
+Simulator menu to handle them more effectively
+
+Debug works just like Run by pressing the IDE’s debug button. It allows us to launch the simulator in
+debug mode where we can set breakpoints, inspect variables etc.
+
+19
+
+Figure 8. HelloWorld Running on the Simulator with an iPhone X Skin
+
+Simulator vs. Emulator
+
+Codename  One  ships  with  a  simulator  similarly  to  the  iOS  toolchain  which  also  has  a
+
+simulator. Android ships with an emulator. Emulators go the extra mile. They create a virtual
+
+machine that’s compatible with the device CPU and then boot the full mobile OS within that
+
+environment. This provides an accurate runtime environment but is painfully slow.
+
+Simulators  rely  on  the  fact  that  OS’s  are  similar  and  so  they  leave  the  low  level  details  in
+
+place  and  just  map  the  API  behavior.  Since  Codename  One  relies  on  Java  it  can  start
+
+simulating  on  top  of  the  virtual  machine  on  the  desktop.  That  provides  several  advantages
+
+including  fast  development  cycles  and  full  support  for  all  the  development  tools/debuggers
+
+you can use on the desktop.
+
+Emulators make sense for developers who want to build OS level services e.g. screensavers or
+
+low level services. Standard applications are better served by simulators.
+
+1.8.2. The Source Code Of The Hello World App
+
+After  clicking  finish  in  the  new  project  wizard  we  have  a  HelloWorld  project  with  a  few  default
+settings. I’ll break the class down to small pieces and explain each piece starting with the enclosing
+
+class:
+
+Listing 1. HelloWorld Class
+
+public class HelloWorld { ①
+    private Form current; ②
+    private Resources theme; ③
+
+    // ... class methods ...
+}
+
+① This  is  the  main  class,  it’s  the  entry  point  to  the  app,  notice  it  doesn’t  have  a  main  method  but
+
+rather callback which we will discuss soon
+
+② Forms  are  the  “top  level”  UI  element  in  Codename  One.  Only  one  Form  is  shown  at  a  time  and
+
+everything you see on the screen is a child of that Form
+
+③ Every  app  has  a  theme,  it  determines  how  everything  within  the  application  looks  e.g.  colors,
+
+fonts etc.
+
+20
+
+Next  let’s  discuss  the  first  lifecycle  method  init(Object).  I  discuss  the  lifecycle  in  depth  in  the
+Application Lifecycle Sidebar.
+
+Listing 2. HelloWorld init(Object)
+
+public void init(Object context) { ①
+    updateNetworkThreadCount(2); ②
+    theme = UIManager.initFirstTheme("/theme"); ③
+    Toolbar.setGlobalToolbar(true); ④
+    Log.bindCrashProtection(true); ⑤
+    addNetworkErrorListener(err -> { ⑥
+        err.consume(); ⑦
+        if(err.getError() != null) { ⑧
+            Log.e(err.getError());
+        }
+        Log.sendLogAsync(); ⑨
+        Dialog.show("Connection Error", ⑩
+            "There was a networking error in the connection to " +
+            err.getConnectionRequest().getUrl(), "OK", null);
+    });
+}
+
+① init is the first of the four lifecycle methods. It’s responsible for initialization of variables and
+
+values
+
+② By default Codename One has one thread that performs all the networking, we set the default to
+
+two which gives better performance
+
+③ The theme determines the appearance of the application. We’ll discuss this in the next chapter
+
+④ This enables the Toolbar API by default, it allows finer control over the title bar area
+
+⑤ Crash protection automatically sends device crash logs through the cloud
+
+⑥ In  case  of  a  network  error  the  code  in  this  block  would  run,  you  can  customize  it  to  handle
+
+networking errors effectively
+
+⑦ consume() swallows the event so it doesn’t trigger other alerts, it generally means “we got this”
+
+⑧ Not all errors include an exception, if we have an exception we can log it with this code
+
+⑨ This will email the log from the device to you if you have a pro subscription
+
+⑩ This shows an error dialog to the user, in production you might want to remove that code
+
+init(Object)  works  as  a  constructor  to  some  degree. We  recommend  avoiding  the  constructor  for
+the main class and placing logic in the init method instead. This isn’t crucial but we recommend it
+
+since the constructor might happen too early in the application lifecycle.
+
+In  a  cold  start  init(Object)  is  invoked  followed  by  the  start()  method.  However,  start()  can  be
+invoked more than once if an app is minimized and restored, see the sidebar Application Lifecycle:
+
+21
+
+Listing 3. HelloWorld start()
+
+public void start() {
+    if(current != null){ ①
+        current.show(); ②
+        return;
+    }
+    Form hi = new Form("Hi World", BoxLayout.y()); ③
+    hi.add(new Label("Hi World")); ④
+    hi.show(); ⑤
+}
+
+① If  the  app  was  minimized  we  usually  don’t  want  to  do  much,  just  show  the  last  Form  of  the
+
+application
+
+② current is a Form which is the top most visual element. We can only have one Form showing and
+
+we enforce that by using the show() method
+
+③ We  create  a  new  simple  Form  instance.  It  has  the  title  “Hello  World”  and  arranges  elements
+
+vertically (on the Y axis)
+
+④ We  add  another  Label  below  the  title,  see  figure  [TitleAndLabelImage].  We  will  discuss
+
+component hierarchy later
+
+⑤ The show() method places the Form on the screen. Only one Form can be shown at a time
+
+Figure 9. Title and Label in the UI
+
+There  are  some  complex  ideas  within  this  short  snippet  which  I’ll  address  later  in  this  chapter
+when talking about layout. The gist of it is that we create and show a Form. Form is the top level UI
+element, it takes over the whole screen. We can add UI elements to that Form object, in this case the
+Label.  We  use  the  BoxLayout  to  arrange  the  elements  within  the  Form  from  top  to  the  bottom
+vertically.
+
+22
+
+Application Lifecycle
+
+A few years ago Romain Guy (a senior Google Android engineer) was on stage at the Google
+IO conference. He asked for a show of hands of people who understand the Activity lifecycle
+(Activity  is  similar  to  a  Codename  One  main  class).  He  then  proceeded  to  jokingly  call  the
+audience members who lifted their hands “liars” claiming that after all his years in Google he
+
+still doesn’t understand it…
+
+Lifecycle  seems  simple  on  the  surface  but  hides  a  lot  of  nuance.  Android’s  lifecycle  is
+
+ridiculously  complex.  Codename  One  tries  to  simplify  this  and  also  make  it  portable.
+
+Sometimes complexity leaks out and the nuances can be difficult to deal with.
+
+Simply explained an application has three states:
+
+• Foreground  -  it’s  running  and  in  the  foreground  which  means  the  user  can  physically
+
+interact with the app
+
+• Suspended  -  the  app  isn’t  in  the  foreground,  it’s  either  paused  or  has  a  background
+
+process running
+
+• Not Running - the app was never launched, was killed or crashed
+
+The lifecycle is the process of transitioning between these 3 states and the callbacks invoked
+
+when such a transition occurs. The first time we launch the app we start from a “Cold Start”
+
+(Not  Running  State)  but  on  subsequent  launches  the  app  is  usually  started  from  the  "Warm
+
+Start" (Suspended State).
+
+Figure 10. Codename One Application Lifecycle
+
+Codename One has four standard callback methods in the lifecycle API:
+
+• init(Object) - is invoked when the app is first launched from a Not Running state.
+
+23
+
+• start() - is invoked for two separate cases. After start() is finished the app transitions to
+
+the Foreground state.
+
+◦ Following init(Object) in case of a cold start. Cold start refers to starting the app from
+
+a Not Running state.
+
+◦ When the app is restored from Suspended state. In this case init(Object) isn’t invoked
+
+• stop()  -  is  invoked  when  the  app  is  minimized  e.g.  when  switching  to  a  different  app.
+
+After stop() is finished the app transitions to the Suspended state.
+
+• destroy() - is invoked when the app is destroyed e.g. killed by a user in the task manager.
+After destroy() is finished the app is no longer running hence it’s in the Not Running state.
+
+ destroy() is optional there is no guarantee that it will be invoked. It should
+
+be used only as a last resort
+
+Now that we have a general sense of the lifecycle lets look at the last two lifecycle methods:
+
+Listing 4. HelloWorld stop() and destroy()
+
+public void stop() { ①
+    current = getCurrentForm(); ②
+    if(current instanceof Dialog) { ③
+        ((Dialog)current).dispose();
+        current = getCurrentForm();
+    }
+}
+
+public void destroy() { ④
+}
+
+① stop() is invoked when the app is minimized or a different app is opened
+
+② As the app is stopped we save the current Form so we can restore it back in start() if the app is
+
+restored
+
+③ Dialog  is  a  bit  of  a  special  case  restoring  a  Dialog  might  block  the  proper  flow  of  application
+
+execution so we dispose them and then get the parent Form
+
+④ destroy()  is  a  very  special  case.  Under  normal  circumstances  you  shouldn’t  write  code  in
+
+destroy(). stop() should work for most cases
+
+That’s it. Hopefully you have a general sense of the code. It’s time to run on the device.
+
+1.8.3. Building and Deploying On Devices
+
+24
+
+Figure 11. Codename One Settings
+
+You  can  use  the  project  settings  to  configure  almost  anything.  Specifically,  the  application  title,
+
+application version, application icon etc. are all found in the right click menu of your IDE.
+
+Just right click your Codename One project icon in any IDE, select Codename One → Codename One
+
+Settings.
+
+There  are  many  options  within  this  UI  that  control  almost  every  aspect  of  the  application  from
+
+signing to basic settings.
+
+Signing/Certificates
+
+All of the modern mobile platforms require signed applications but they all take radically different
+
+approaches when implementing it.
+
+Signing is a process that marks your final application for the device with a special value. This value
+
+(signature) is a value that only you can generate based on the content of the application and your
+
+certificate.  Effectively  it  guarantees  the  app  came  from  you.  This  blocks  a  3rd  party  from  signing
+
+their apps and posing as you to the appstore or to the user. It’s a crucial security layer.
+
+A  certificate  is  the  tool  we  use  for  signing.  Think  of  it  as  a  mathematical  rubber  stamp  that
+
+generates a different value each time. Unlike a rubber stamp a signature can’t be forged!
+
+Signing on Android
+
+ Backup your Android certificate and save its password!
+
+If you lose your Android certificate you will not be able to update your app
+
+Android  uses  a  self  signed  certificate  approach.  You  can  just  generate  a  certificate  by  describing
+
+who you are and picking a password!
+
+Anyone can do that. However, once a certificate is published it can’t be replaced…
+
+If this wasn’t the case someone else could potentially push an “upgrade” to your app. Once an app is
+
+submitted with a certificate to Google Play this app can’t be updated with any other certificate.
+
+With that in mind generating an Android certificate is trivial.
+
+ The following chart illustrates a process that’s identical on all IDE’s
+
+25
+
+Figure 12. Process of Certificate Generation for Android
+
+
+
+Your certificate will generate into the file Keychain.ks in your home directory
+
+Make  sure  to  back  that  up  and  the  password  as  losing  these  can  have  dire
+
+consequences
+
+Should I Use a Different Certificate for Each App?
+
+In  theory  yes.  In  practice  it’s  a  pain…  Keeping  multiple  certificates  and  managing  them  is  a
+
+pain so we often just use one.
+
+The  drawback  of  this  approach  occurs  when  you  are  building  an  app  for  someone  else  or
+
+want to sell the app. Giving away your certificate is akin to giving away your house keys. So it
+
+makes sense to have separate certificates for each app.
+
+Signing and Provisioning iOS
+
+Code signing for iOS relies on Apple as the certificate authority. This is something that doesn’t exist
+
+on  Android.  iOS  also  requires  provisioning  as  part  of  the  certificate  process  and  completely
+
+separates the process for development/release.
+
+But first let’s start with the good news:
+
+• Losing  an  iOS  certificate  is  no  big  deal  -  in  fact  we  revoke  them  often  with  no  impact  on
+
+shipping apps
+
+26
+
+• Codename One has a wizard that hides most of the pain related to iOS signing
+
+In iOS Apple issues the certificates for your applications. That way the certificate is trusted by Apple
+
+and is assigned to your Apple iOS developer account. There is one important caveat: You need an
+
+iOS Developer Account and Apple charges a 99USD Annual fee for that.
+
+
+
+The 99USD price and requirement have been around since the introduction of the
+
+iOS  developer  program  for  roughly  10  years  at  the  time  of  this  writing.  It  might
+
+change at some point though
+
+Apple  also  requires  a  “provisioning  profile”  which  is  a  special  file  bound  to  your  certificate  and
+
+app. This file describes some details about the app to the iOS installation process. One of the details
+
+it includes during development is the list of permitted devices.
+
+Figure 13. The Four Files Required for iOS Signing and Provisioning
+
+We need 4 files for signing. Two certificates and two provisioning profiles:
+
+27
+
+1. Production — The production certificate/provisioning pair is used for builds that are uploaded
+
+to iTunes
+
+2. Development — The  development  certificate/provisioning 
+
+is  used 
+
+to 
+
+install  on  your
+
+development devices
+
+The certificate wizard automatically creates these 4 files and configures them for you.
+
+Figure 14. Using the iOS Certificate Wizard Steps 1 and 2
+
+Figure 15. Using the iOS Certificate Wizard Steps 3 and 4
+
+28
+
+Figure 16. Using the iOS Certificate Wizard Steps 5 and 6
+
+
+
+If you have more than one project you should use the same iOS P12 certificate files
+
+in  all  the  projects  and  just  regenerate  the  provisioning.  In  this  situation  the
+
+certificate wizard asks you if you want to revoke the existing certificate which you
+
+shouldn’t revoke in such a case. You can update the provisioning profile in Apple’s
+
+iOS developer website.
+
+One important aspect of provisioning on iOS is the device list in the provisioning step. Apple only
+
+allows  you  to  install  the  app  on  100  devices  during  development.  This  blocks  developers  from
+
+skipping  the  appstore  altogether.  It’s  important  you  list  the  correct  UDID  for  the  device  in  the  list
+
+otherwise install will fail.
+
+ There  are  several  apps  and  tools  that  offer  the  UDID  of  the  device,  they  aren’t
+
+necessarily reliable and might give a fake number!
+
+29
+
+Figure 17. Get the UDID of a Device
+
+
+
+You can right click the UDID and select copy to copy it
+
+The simplest and most reliable process for getting a UDID is via iTunes. I’ve used other approaches
+
+in the past that worked but this approach is guaranteed.
+
+
+
+Ad  hoc  provisioning  allows  1000  beta  testers  for  your  application  but  it’s  a  more
+
+complex process that we won’t discuss here although it’s supported by Codename
+
+One
+
+Build and Install
+
+Before  we  continue  with  the  build  we  should  sign  up  at  https://www.codenameone.com/build-
+
+server.html  where  you  can  soon  follow  the  progress  of  your  builds.  You  need  a  Codename  One
+
+account in order to build for the device.
+
+Now  that  we  have  certificates  the  process  of  device  builds  is  literally  a  right  click  away  for  both
+
+OS’s. We can right click the project and select Codename One  → Send iOS Debug Build  or Codename
+
+One → Send Android Build.
+
+30
+
+Figure 18. Right click menu options for sending device builds
+
+ The first time you send a build you will be prompted for the email and password
+
+you provided when signing up for Codename One
+
+Once you send a build you should see the results in the build server page:
+
+Figure 19. Build Results
+
+
+
+On  iOS  make  sure  you  use  Safari  when  installing,  as  3rd  party  browsers  might
+
+have issues
+
+Once you go through those steps you should have the HelloWorld app running on your device. This
+
+process is non-trivial when starting so if you run into difficulties don’t despair and seek help at the
+
+discussion 
+
+forum 
+
+(https://www.codenameone.com/discussion-forum.html)  or  stack  overflow
+
+(https://stackoverflow/tags/codenameone/).  Once  you  go  through  signing  and  installation,  it
+
+becomes easier.
+
+
+
+You  can  also  install  the  application  either  by  emailing  the  install  link  to  your
+
+account (using the e-mail Link button)
+
+You can also download the binaries in order to upload them to the appstores.
+
+31
+
+1.9. Kotlin
+
+Codename One started before Kotlin became public. Kotlin has since shown itself as an interesting
+
+option  for  developers  especially  within  the  Android  community. With  that  in  mind  we  decided  to
+
+integrate support for Kotlin into Codename One.
+
+To use Kotlin with Codename One you will need the following:
+
+• You need to use IntelliJ/IDEA - Currently only the IDEA version of the Codename One plugin has
+
+Kotlin support
+
+• You  need  to  install  the  Kotlin  support  libraries  from  the  extension  manager  tool  in  Codename
+
+One Preferences
+
+• Don’t  use  the  project  conversion  tools  or  accept  the  warning  that  the  project  isn’t  a  Kotlin
+
+project. We do our own build process
+
+• Warnings  and  errors  aren’t  listed  correctly  and  a  build  that  claimed  to  have  2  errors  actually
+
+passed…
+
+• This will increase your jar size by roughly 730kb which might make it harder for free tier users
+
+You  can  install  the  Kotlin  libraries  which  are  required  for  compilation  by  using  the  extension
+
+manager.
+
+In the right click menu select Codename One → Codename One Preferences.
+
+Select  Extensions  type  in  kotlin  and  install.  Then  right  click  the  project  select  Codename One  →
+Refresh Libs.
+
+1.9.1. Hello Kotlin
+
+Due  to  the  way  Kotlin  works  you  can  just  create  a  regular  Java  project  and  convert  sources  to
+
+Kotlin. You can mix Java and Kotlin code without a problem and Codename One would "just work".
+
+The hello world Java source file looks like this (removed some comments and whitespace):
+
+32
+
+public class MyApplication {
+    private Form current;
+    private Resources theme;
+
+    public void init(Object context) {
+        theme = UIManager.initFirstTheme("/theme");
+        Toolbar.setGlobalToolbar(true);
+        Log.bindCrashProtection(true);
+    }
+
+    public void start() {
+        if(current != null){
+            current.show();
+            return;
+        }
+        Form hi = new Form("Hi World", BoxLayout.y());
+        hi.add(new Label("Hi World"));
+        hi.show();
+    }
+
+    public void stop() {
+        current = getCurrentForm();
+        if(current instanceof Dialog) {
+            ((Dialog)current).dispose();
+            current = getCurrentForm();
+        }
+    }
+
+    public void destroy() {
+    }
+}
+
+When  you  select  that  file  and  select  the  menu  option  Code  →  Convert Java file to Kotlin File  you
+
+should get this:
+
+33
+
+class MyApplication {
+    private var current: Form? = null
+    private var theme: Resources? = null
+
+    fun init(context: Any) {
+        theme = UIManager.initFirstTheme("/theme")
+        Toolbar.setGlobalToolbar(true)
+        Log.bindCrashProtection(true)
+    }
+
+    fun start() {
+        if (current != null) {
+            current!!.show()
+            return
+        }
+        val hi = Form("Hi World", BoxLayout.y())
+        hi.add(Label("Hi World"))
+        hi.show()
+    }
+
+    fun stop() {
+        current = getCurrentForm()
+        if (current is Dialog) {
+            (current as Dialog).dispose()
+            current = getCurrentForm()
+        }
+    }
+
+    fun destroy() {
+    }
+}
+
+That’s pretty familiar. The problem is that there are two bugs in the automatic conversion… That is
+
+the code for Kotlin behaves differently from standard Java.
+
+The  first  problem  is  that  Kotlin  classes  are  final  unless  declared  otherwise  so  we  need  to  add  the
+
+open keyword before the class declaration as such:
+
+open class MyApplication
+
+This is essential as the build server will fail with weird errors related to instanceof.
+
+ This only applies to the main class of the project, other classes in Codename One
+
+can remain final
+
+The second problem is that arguments are non-null by default. The init method might have a null
+argument. So this fails with an exception. The solution is to add a question mark to the end of the
+call: fun init(context: Any?).
+
+34
+
+So the full working sample is:
+
+open class MyApplication {
+    private var current: Form? = null
+    private var theme: Resources? = null
+    fun init(context: Any?) {
+        theme = UIManager.initFirstTheme("/theme")
+        Toolbar.setGlobalToolbar(true)
+        Log.bindCrashProtection(true)
+    }
+
+    fun start() {
+        if (current != null) {
+            current!!.show()
+            return
+        }
+        val hi = Form("Hi World", BoxLayout.y())
+        hi.add(Label("Hi World"))
+        hi.show()
+    }
+
+    fun stop() {
+        current = getCurrentForm()
+        if (current is Dialog) {
+            (current as Dialog).dispose()
+            current = getCurrentForm()
+        }
+    }
+
+    fun destroy() {
+    }
+}
+
+Once  all  of  that  is  in  place  Kotlin  should  just  work.  This  should  be  possible  for  additional  JVM
+
+languages in the future.
+
+35
+
+36
+
+2. Basics: Themes, Styles, Components and
+Layouts
+
+Let’s  start  with  a  brief  overview  of  the  ideas  within  Codename  One.  We’ll  dig  deeper  into  these
+
+ideas as we move forward.
+
+2.1. Components
+
+Every  button,  label  or  element  you  see  on  the  screen  in  a  Codename  One  application  is  a
+
+Component  [https://www.codenameone.com/javadoc/com/codename1/ui/Component.html].  This  is  a  highly
+
+simplified version of this class hierarchy:
+
+Figure 20. The Core Component Class Hierarchy
+
+The  Form  [https://www.codenameone.com/javadoc/com/codename1/ui/Form.html]  is  a  special  case  Component.
+It’s the root component that you can show to the user. Container is a Component type that can hold
+other components within it. This lets us create elaborate hierarchies by nesting Container instances.
+
+Figure 21. Component UML
+
+37
+
+A Codename One application is effectively a series of forms, only one Form can be shown at a time.
+The Form includes everything we see on the screen. Under the hood the Form is comprised of a few
+separate pieces:
+
+Figure 22. Structure of a Form
+
+• Content Pane - this is literally the body of the Form. When we add a Component into the Form it goes
+
+into the content pane. Notice that Content Pane is scrollable by default on the Y axis!
+
+• Title Area - we can’t add directly into this area. The title area is managed by the Toolbar class.
+Toolbar is a special component that resides in the top portion of the form and abstracts the title
+design. The title area is broken down into two parts:
+
+◦ Title of the Form and its commands (the buttons on the right/left of the title)
+
+◦ Status Bar - on iOS the area on the top includes a special space so the notch, battery, clock
+
+etc. can fit. Without this the battery indicator/clock or notch would be on top of the title
+
+Now  that  we  understand  this  let’s  look  at  the  new  project  we  created  and  open  the  Java  file
+TodoApp.java. In it we should see the lines that setup the UI in the start() method:
+
+2.1.1. Layout Managers
+
+A  layout  manager  is  an  algorithm  that  decides  the  size  and  location  of  the  components  within  a
+Container. Every Container has a layout manager associated with it. The default layout manager is
+FlowLayout.
+
+To understand layouts we need to understand a basic concept about Component. Each component has
+a  “preferred  size”.  This  is  the  size  in  which  a  component  “wants”  to  appear.  E.g.  for  a  Label  the
+preferred size will be the exact size that fits the label text, icon and padding of the component.
+
+38
+
+Understanding Preferred Size
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/Component.html]  class
+The  Component 
+contains many useful methods. One of the most important ones is calcPreferredSize() which
+is invoked to recalculate the size a component “wants” when something changes
+
+
+
+By  default  Codename  One  invokes  the  getPreferredSize()  method  and  not
+calcPreferredSize() directly.
+getPreferredSize() invokes calcPreferredSize() and caches the value
+
+The preferred size is decided by the component based on internal constraints such as the font
+
+size, border sizes, padding etc.
+
+When a layout manager positions and sizes the component, it MIGHT take the preferred size
+
+into account. Notice that it MIGHT ignore it entirely!
+
+E.g.  FlowLayout 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/layouts/FlowLayout.html]
+
+always 
+
+gives 
+
+components 
+
+their 
+
+exact 
+
+preferred 
+
+size, 
+
+yet 
+
+BorderLayout
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/layouts/BorderLayout.html] resizes the center
+
+component by default (and the other components are resized on one of their axis).
+
+You can define a group of components to have the same preferred width or height by using
+the setSameWidth and setSameHeight methods e.g.:
+
+Listing 5. setSameWidth/Height
+
+Component.setSameWidth(cmp1, cmp2, cmp3, cmp4);
+Component.setSameHeight(cmp5, cmp6, cmp7);
+
+Codename One has a setPreferredSize method that allows developers to explicitly request the
+size  of  the  component.  However,  this  caused  quite  a  lot  of  problems.  E.g.  the  preferred  size
+
+should change with device orientation or similar operations. The API also triggered frequent
+
+inadvertent  hardcoding  of  UI  values  such  as  forcing  pixel  sizes  for  components.  As  a  result
+
+the method was deprecated.
+
+We recommend developers use setSameWidth, setSameHeight when sizing alignment is needed.
+setHidden  when  hiding 
+last  resort  we  recommend  overriding
+calcPreferredSize.
+
+is  needed.  As  a 
+
+A  layout  manager  places  a  component  based  on  its  own  logic  and  the  preferred  size  (sometimes
+referred  to  as  “natural  size”).  A  FlowLayout  will  just  traverse  the  components  based  on  the  order
+they were added and size/place them one after the other. When it reaches the end of the row it will
+
+go to the new row.
+
+39
+
+Use FlowLayout Only for Simple Things
+
+
+
+FlowLayout is great for simple things but has issues when components change their
+sizes dynamically (like a text field). In those cases it can make bad decisions about
+
+line breaks and take up too much space
+
+Figure 23. Layout Manager Primer Part I
+
+Figure 24. Layout Manager Primer Part II
+
+Scrolling  doesn’t  work  well  for  all  types  of  layouts  as  the  positioning  algorithm  within  the  layout
+might  break.  Scrolling  on  the  Y  axis  works  great  for  BoxLayout  Y  which  is  why  I  picked  it  for  the
+TodoForm:
+
+Table 1. Scrolling in Layout Managers
+
+Layout
+
+Flow Layout
+
+Border Layout
+
+Box Layout Y
+
+Box Layout X
+
+Grid Layout
+
+LayeredLayout
+
+40
+
+Scrollable
+
+Possible on Y axis only
+
+Scrolling is blocked
+
+Scrollable only on the Y axis
+
+Scrollable only on the X axis
+
+Scrollable
+
+Not scrollable (usually)
+
+Nesting Scrollable Containers
+
+Only  one  element  can  be  scrollable  within  the  hierarchy,  otherwise  if  you  drag  your  finger
+over the Form Codename One won’t know which element you are trying to scroll. By default
+form’s  content  pane  is  scrollable  on  the  Y  axis  unless  you  explicitly  disable  it  (setting  the
+layout to BorderLayout implicitly disables scrolling).
+
+It’s important to notice that it’s OK to have non-scrollable layouts, e.g. BorderLayout, as items
+within  a  scrollable  container  type.  E.g.  in  the  TodoApp  we  added  TodoItem  which  uses
+BorderLayout into a scrollable BoxLayout Form.
+
+Layouts can be divided into two distinct groups:
+
+• Constraint  Based  -  BorderLayout  (and  a  few  others  such  as  GridBagLayout,  MigLayout  and
+
+TableLayout)
+
+• Regular - All of the other layout managers
+
+When we add a Component to a Container with a regular layout we do so with a simple add method:
+
+Listing 6. Adding to a Regular Container
+
+Container cnt = new Container(BoxLayout.y());
+cnt.add(new Label("Just Added"));
+
+This works great for regular layouts but might not for constraint based layouts. A constraint based
+layout accepts another argument. E.g. BorderLayout needs a location for the Component:
+
+Listing 7. Adding to a Regular Container
+
+cnt.add(NORTH, new Label("Just Added"));
+
+This  line  assumes  you  have  an  import  static  com.codename1.ui.CN.*;  in  the  top  of  the  file.  In
+BorderLayout (which is a constraint based layout) placing an item in the NORTH places it in the top of
+the Container.
+
+
+
+The CN class is a class that contains multiple static helper methods and functions.
+It’s specifically designed for static import in this way to help keep our code terse
+
+41
+
+Static Global Context
+
+The  CN  class  is  a  thin  wrapper  around  features  in  Display,  NetworkManager,  Storage,
+FileSystemStorage etc. It also adds common methods and constants from several other classes
+so Codename One code feels more terse e.g. we can do:
+
+import static com.codename1.ui.CN.*;
+
+
+
+That’s  optional,  if  you  don’t  like  static  imports  you  can  just  write  CN.  for
+every element
+
+From that point on you can write code that looks like this:
+
+callSerially(() -> runThisOnTheEDT());
+
+Instead of:
+
+Display.getInstance().callSerially(() -> runThisOnTheEDT());
+
+The same applies for most network manager calls e.g.:
+
+addToQueue(myConnectionRequest);
+
+Instead of:
+
+NetworkManager.getInstance().addToQueue(myConnectionRequest);
+
+Some  things  were  changed  so  we  won’t  have  too  many  conflicts  e.g.  Log.p  or  Log.e  would
+have been problematic so we now have:
+
+log("my log message");
+log(myException);
+
+Instead  of  Display.getInstance().getCurrent()  we  now  have  getCurrentForm()  since
+getCurrent()  is  too  generic.  For  most  methods  you  should  just  be  able  to  remove  the
+NetworkManager or Display access and it should "just work".
+
+The motivation for this is three fold:
+
+• Terse code
+
+• Small performance gain
+
+42
+
+• Cleaner API without some of the baggage in Display or NetworkManager
+
+Some of our samples in this guide might rely on that static import being in place. This helps
+
+us keep the code terse and readable in the code listings.
+
+Terse Syntax
+
+Almost every layout allows us to add a component using several variants of the add method:
+
+Listing 8. Versions of add
+
+Container cnt = new Container(BoxLayout.y());
+cnt.add(new Label("Just Added")); ①
+cnt.addAll(new Label("Adding Multiple"), ②
+    new Label("Second One"));
+
+cnt.add(new Label("Chaining")). ③
+    add(new Label("Value"));
+
+① Regular add
+
+② addAll accepts several components and adds them in a batch
+
+③ add returns the parent Container instance so we can chain calls like that
+
+In the race to make code “tighter” we can make this even shorter. Almost all layout managers have
+
+their own custom terse syntax style e.g.:
+
+Listing 9. Terse Syntax
+
+Container boxY = BoxLayout.encloseY(cmp1, cmp2); ①
+Container boxX = BoxLayout.encloseX(cmp3, cmp4);
+Container flowCenter = FlowLayout. ②
+    encloseCenter(cmp5, cmp6);
+
+① Most layouts have a version of enclose to encapsulate components within
+
+② FlowLayout has variants that support aligning the components on various axis
+
+To  sum  this  up,  we  can  use  layout  managers  and  nesting  to  create  elaborate  UI’s  that  implicitly
+
+adapt to different screen sizes and device orientation.
+
+Flow Layout
+
+43
+
+Figure 25. Flow Layout
+
+Flow 
+
+layout 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/layouts/FlowLayout.html] 
+
+lets 
+
+the
+
+components “flow” horizontally and break a line when reaching the edge of the container. It’s the
+
+default layout manager for containers. Because it’s so flexible it’s also problematic as it can result in
+
+incorrect  preferred  size  values  for  the  parent  Container  [https://www.codenameone.com/javadoc/com/
+
+codename1/ui/Container.html].  This  can  create  a  reflow  issue,  as  a  result  we  recommend  using  flow
+
+layout only for trivial cases. Avoid it for things such as text input etc. As the size of the text input
+
+can vary in runtime.
+
+Form hi = new Form("Flow Layout", new FlowLayout());
+hi.add(new Label("First")).
+    add(new Label("Second")).
+    add(new Label("Third")).
+    add(new Label("Fourth")).
+    add(new Label("Fifth"));
+hi.show();
+
+Flow layout also supports terse syntax shorthand such as:
+
+Container flowLayout = FlowLayout.encloseIn(
+        new Label("First"),
+        new Label("Second"),
+        new Label("Third"),
+        new Label("Fourth"),
+        new Label("Fifth")));
+
+Flow  layout  can  be  aligned  to  the  left  (the  default),  to  the  center,  or  to  the  right.  It  can  also  be
+
+vertically aligned to the top (the default), middle (center), or bottom.
+
+44
+
+Figure 26. Flow layout aligned to the center
+
+Figure 27. Flow layout aligned to the right
+
+Figure 28. Flow layout aligned to the center horizontally & the middle vertically
+
+Components within the flow layout get their natural preferred size by default and are not stretched
+
+in any axis.
+
+
+
+Box Layout
+
+The  natural  sizing  behavior  is  often  used  to  prevent  other  layout  managers  from
+
+stretching  components.  E.g.  if  we  have  a  border  layout  element  in  the  south  and
+
+we  want  it  to  keep  its  natural  size  instead  of  adding  the  element  to  the  south
+parent.add(BorderLayout.SOUTH,
+
+directly 
+FlowLayout.encloseCenter(dontGrowThisComponent)).
+
+using 
+
+wrap 
+
+can 
+
+we 
+
+it 
+
+BoxLayout 
+places
+elements in a row (X_AXIS) or column (Y_AXIS) according to box orientation. Box is a very simple and
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/layouts/BoxLayout.html] 
+
+45
+
+predictable layout that serves as the "workhorse" of component lists in Codename One.
+
+You can create a box layout Y using something like this:
+
+Form hi = new Form("Box Y Layout", new BoxLayout(BoxLayout.Y_AXIS));
+hi.add(new Label("First")).
+    add(new Label("Second")).
+    add(new Label("Third")).
+    add(new Label("Fourth")).
+    add(new Label("Fifth"));
+
+Which results in this
+
+Figure 29. BoxLayout Y
+
+Box layout also supports a shorter terse notation which we use here to demonstrate the X axis box.
+
+Container box = BoxLayout.encloseX(new Label("First"),
+        new Label("Second"),
+        new Label("Third"),
+        new Label("Fourth"),
+        new Label("Fifth")));
+
+Figure 30. BoxLayout X
+
+The  box  layout  keeps  the  preferred  size  of  its  destination  orientation  and  scales  elements  on  the
+other axis. Specifically X_AXIS will keep the preferred width of the component while growing all the
+components  vertically  to  match  in  size.  Its  Y_AXIS  counterpart  keeps  the  preferred  height  while
+
+46
+
+growing the components horizontally.
+
+This behavior is very useful since it allows elements to align as they would all have the same size.
+
+In  some  cases  the  growing  behavior  in  the  X  axis  is  undesired,  for  these  cases  we  can  use  the
+X_AXIS_NO_GROW variant.
+
+Figure 31. BoxLayout X_AXIS_NO_GROW
+
+FlowLayout vs. BoxLayout.X_AXIS
+
+
+
+When  applicable  we  recommend  BoxLayout  over  FlowLayout  as  it  acts  more
+consistently  in  all  situations.  Another  advantage  of  BoxLayout  is  the  fact  that  it
+grows and thus aligns nicely
+
+Border Layout
+
+Figure 32. Border Layout
+
+Border  layout  [https://www.codenameone.com/javadoc/com/codename1/ui/layouts/BorderLayout.html]  is  quite
+unique. BorderLayout is a constraint-based layout that can place up to five components in one of the
+five positions: NORTH, SOUTH, EAST, WEST or CENTER.
+
+Form hi = new Form("Border Layout", new BorderLayout());
+hi.add(BorderLayout.CENTER, new Label("Center")).
+    add(BorderLayout.SOUTH, new Label("South")).
+    add(BorderLayout.NORTH, new Label("North")).
+    add(BorderLayout.EAST, new Label("East")).
+    add(BorderLayout.WEST, new Label("West"));
+hi.show();
+
+
+
+The Constraints are Included in the CN class
+
+You can use the static import of the CN class and then the syntax can be add(SOUTH,
+new Label("South"))
+
+47
+
+The  layout  always  stretches  the  NORTH/SOUTH  components  on  the  X-axis  to  completely  fill  the
+container and the EAST/WEST components on the Y-axis. The center component is stretched to fill the
+remaining area by default. However, the setCenterBehavior allows us to manipulate the behavior of
+the center component so it is placed in the center without stretching.
+
+E.g.:
+
+Form hi = new Form("Border Layout", new BorderLayout());
+((BorderLayout)hi.getLayout()).setCenterBehavior(BorderLayout.CENTER_BEHAVIOR_CENTER);
+hi.add(BorderLayout.CENTER, new Label("Center")).
+    add(BorderLayout.SOUTH, new Label("South")).
+    add(BorderLayout.NORTH, new Label("North")).
+    add(BorderLayout.EAST, new Label("East")).
+    add(BorderLayout.WEST, new Label("West"));
+hi.show();
+
+Results in:
+
+Figure 33. Border Layout with CENTER_BEHAVIOR_CENTER
+
+
+
+Scrolling is Disabled in Border Layout
+
+Because of its scaling behavior scrolling a border layout makes no sense. Container
+implicitly blocks scrolling on a border layout, but it can scroll its parents/children
+
+In the case of RTL the EAST and WEST values are implicitly reversed as shown in this image:
+
+Figure 34. Border Layout in RTL mode
+
+RTL and Bidi
+
+RTL  (Right  To  Left)  or  Bidi  (bi-directional)  are  common  terms  used  for  languages  such  as
+
+Hebrew, Arabic etc. These languages are written from the right to left direction hence all the
+
+UI needs to be “reversed”. Bidi denotes the fact that while the language is written from right
+
+to left, the numbers are still written in the other direction hence two directions…
+
+48
+
+Preferred Size Still Matters
+
+
+
+The preferred size of the center component doesn’t matter in border layout but the
+preferred size of the sides is. E.g. If you place an very large component in the SOUTH
+it will take up the entire screen and won’t leave room for anything
+
+Grid Layout
+
+GridLayout 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/layouts/GridLayout.html]  accepts  a
+
+predefined  grid  (rows/columns)  and  grants  all  components  within  it  equal  size  based  on  the
+
+dimensions of the largest components.
+
+
+
+The  main  use  case  for  this  layout  is  a  grid  of  icons  e.g.  like  one  would  see  in  the
+
+iPhone home screen
+
+If  the  number  of  rows  *  columns  is  smaller  than  the  number  of  components  added  a  new  row  is
+implicitly added to the grid. However, if the number of components is smaller than available cells
+
+(won’t fill the last row) blank spaces will be left in place.
+
+In this example we can see that a 2x2 grid is used to add 5 elements, this results in an additional
+
+row that’s implicitly added turning the grid to a 3x2 grid implicitly and leaving one blank cell.
+
+Form hi = new Form("Grid Layout 2x2", new GridLayout(2, 2));
+hi.add(new Label("First")).
+    add(new Label("Second")).
+    add(new Label("Third")).
+    add(new Label("Fourth")).
+    add(new Label("Fifth"));
+
+Figure 35. Grid Layout 2x2
+
+When we use a 2x4 size ratio we would see elements getting cropped as we do here. The grid layout
+
+uses the grid size first and doesn’t pay too much attention to the preferred size of the components it
+
+holds.
+
+49
+
+Figure 36. Grid Layout 2x4
+
+Grid  also  has  an  autoFit  attribute  that  can  be  used  to  automatically  calculate  the  column  count
+
+based on available space and preferred width. This is really useful for working with UI’s where the
+
+device orientation might change.
+
+There is also a terse syntax for working with a grid that has two versions, one that uses the "auto
+
+fit"  option  and  another  that  accepts  the  number  of  columns.  Here’s  a  sample  of  the  terse  syntax
+
+coupled with auto fit followed by screenshots of the same code in two orientations:
+
+GridLayout.encloseIn(new Label("First"),
+    new Label("Second"),
+    new Label("Third"),
+    new Label("Fourth"),
+    new Label("Fifth")));
+
+Figure 37. Grid Layout autofit portrait
+
+Figure 38. Grid Layout autofit landscape
+
+2.1.2. Table Layout
+
+The  TableLayout  [https://www.codenameone.com/javadoc/com/codename1/ui/table/TableLayout.html]  is  a  very
+
+elaborate  constraint  based  layout  manager  that  can  arrange  elements  in  rows/columns  while
+
+50
+
+defining constraints to control complex behavior such as spanning, alignment/weight etc.
+
+Note the Different Package for TableLayout
+
+
+
+The  TableLayout  is  in  the  com.codename1.ui.table  package  and  not  in  the  layouts
+package.
+This  is  due  to  the  fact  that  TableLayout  was  originally  designed  for  the  Table
+[https://www.codenameone.com/javadoc/com/codename1/ui/table/Table.html] class.
+
+Despite being constraint based the TableLayout isn’t strict about constraints and will implicitly add a
+constraint  when  one  is  missing.  This  is  unlike  the  BorderLayout  which  will  throw  an  exception  in
+this case.
+
+ Unlike GridLayout TableLayout won’t implicitly add a row if the row/column count
+
+is incorrect
+
+Form hi = new Form("Table Layout 2x2", new TableLayout(2, 2));
+hi.add(new Label("First")).
+    add(new Label("Second")).
+    add(new Label("Third")).
+    add(new Label("Fourth")).
+    add(new Label("Fifth"));
+hi.show();
+
+Figure 39. 2x2 TableLayout with 5 elements, notice that the last element is missing
+
+TableLayout  supports  the  ability  to  grow  the  last  column  which  can  be  enabled  using  the
+setGrowHorizontally  method.  You  can  also  use  a  shortened  terse  syntax  to  construct  a  TableLayout
+however since the TableLayout is a constraint based layout you won’t be able to utilize its full power
+with this syntax.
+
+The default usage of the encloseIn method below uses the setGrowHorizontally flag.
+
+Container tl = TableLayout.encloseIn(2, new Label("First"),
+                new Label("Second"),
+                new Label("Third"),
+                new Label("Fourth"),
+                new Label("Fifth")));
+
+51
+
+Figure 40. TableLayout.encloseIn() with default behavior of growing the last column
+
+The Full Potential
+
+TableLayout is a beast, to truly appreciate it we need to use the constraint syntax which allows us to
+span, align and set width/height for the rows and columns.
+
+TableLayout  works  with  a  Constraint  [https://www.codenameone.com/javadoc/com/codename1/ui/table/
+TableLayout.Constraint.html]  instance  that  can  communicate  our  intentions  into  the  layout  manager.
+
+Such constraints can include more than one attribute e.g. span and height.
+
+ TableLayout constraints can’t be reused for more than one component
+
+The constraint class supports the following attributes
+
+Table 2. Constraint Properties
+
+column
+
+row
+
+width
+
+height
+
+spanHorizontal
+
+spanVertical
+
+horizontalAlign
+
+verticalAlign
+
+The column for the table cell. This defaults to -1
+
+which will just place the component in the next
+
+available cell
+
+Similar to column, defaults to -1 as well
+
+The column width in percentages, -1 will use the
+
+preferred size. -2 for width will take up the rest
+
+of the available space
+
+Similar to width but doesn’t support the -2 value
+
+The cells that should be occupied horizontally
+
+defaults to 1 and can’t exceed the column count -
+
+current offset.
+
+Similar to spanHorizontal with the same
+
+limitations
+
+The horizontal alignment of the content within
+
+the cell, defaults to the special case -1 value to
+take up all the cell space can be either -1,
+Component.LEFT, Component.RIGHT or
+Component.CENTER
+
+Similar to horizontalAlign can be one of -1,
+Component.TOP, Component.BOTTOM or
+Component.CENTER
+
+
+
+You only need to set width/height to one cell in a column/row
+
+The table layout constraint sample tries to demonstrate some of the unique things you can do with
+
+52
+
+constraints.
+
+TableLayout tl = new TableLayout(2, 3); ①
+Form hi = new Form("Table Layout Cons", tl);
+hi.setScrollable(false); ②
+hi.add(tl.createConstraint(). ③
+            widthPercentage(20),
+                new Label("AAA")).
+
+        add(tl.createConstraint(). ④
+            horizontalSpan(2).
+            heightPercentage(80).
+            verticalAlign(Component.CENTER).
+            horizontalAlign(Component.CENTER),
+                new Label("Span H")).
+
+        add(new Label("BBB")).
+
+        add(tl.createConstraint().
+            widthPercentage(60).
+            heightPercentage(20),
+                new Label("CCC")).
+
+        add(tl.createConstraint().
+            widthPercentage(20),
+                new Label("DDD"));
+
+① We need the TableLayout instance to create constraints. A constraint must be created for every
+
+component and must be used with the same layout as the parent container
+
+② To  get  the  look  in  the  screenshot  we  need  to  turn  scrolling  off  so  the  height  constraint  doesn’t
+take up available height. Otherwise it will miscalculate available height due to scrolling. You can
+scroll a TableLayout but sizing will be different
+
+③ We create the constraint and instantly apply width to it. This is a shorthand syntax for the code
+
+block below
+
+④ We can chain constraint creation using a call like this so multiple constraints apply to a single
+cell. Notice that we don’t span and set width on the same axis (horizontal span + width), doing
+
+something like that would create confusing behavior
+
+Here is the full code mentioned in item 3:
+
+TableLayout.Constraint cn = tl.createConstraint();
+cn.setWidthPercentage(20);
+hi.add(cn, new Label("AAA")).
+
+53
+
+Figure 41. TableLayout constraints can be used to create very elaborate UI’s
+
+TextMode Layout
+
+TextModeLayout  is  a  unique  layout  manager.  It  acts  like  TableLayout  on  Android  and  like
+BoxLayout.Y_AXIS in other platforms. Internally it delegates to one of these two layout managers so
+in a sense it doesn’t have as much functionality of its own.
+
+E.g. this is a sample usage of TextModeLayout:
+
+TextModeLayout tl = new TextModeLayout(3, 2);
+Form f = new Form("Pixel Perfect", tl);
+TextComponent title = new TextComponent().label("Title");
+TextComponent price = new TextComponent().label("Price");
+TextComponent location = new TextComponent().label("Location");
+TextComponent description = new TextComponent().label("Description").multiline(true);
+
+f.add(tl.createConstraint().horizontalSpan(2), title);
+f.add(tl.createConstraint().widthPercentage(30), price);
+f.add(tl.createConstraint().widthPercentage(70), location);
+f.add(tl.createConstraint().horizontalSpan(2), description);
+f.setEditOnShow(title.getField());
+f.show();
+
+Figure 42. TextModeLayout on iOS
+
+Figure 43. TextModeLayout on Android with the same code
+
+As you can see from the code and samples above there is a lot going on under the hood. On Android
+we want a layout that’s similar to TableLayout so we can “pack” the entries. On iOS we want a box
+
+54
+
+layout Y type of layout but we also want the labels/text to align properly…
+
+The  TextModeLayout  isn’t  really  a  layout  as  much  as  it  is  a  delegate.  When  running  in  the  Android
+mode  (which  we  refer  to  as  the  “on  top”  mode)  the  layout  is  almost  an  exact  synonym  of
+TableLayout and in fact delegates to an underlying TableLayout. In fact there is a public final table
+instance within the layout that you can refer to directly…
+
+There is one small difference between the TextModeLayout and the underlying TableLayout and that’s
+our choice to default to align entries to TOP with this mode.
+
+
+
+Aligning  to  TOP  is  important  for  error  handling  for  TextComponent  in  Android
+otherwise the entries “jump”
+
+When  working  in  the  non-android  environment  we  use  a  BoxLayout  on  the  Y  axis  as  the  delegate.
+There’s one thing we do here that’s different from a default box layout: grouping. Grouping allows
+the labels to align by setting them to the same width, internally it invokes Component.setSameWidth().
+Since  text  components  hide  the  labels  there  is  a  special  group  method  there  that  can  be  used.
+However, this is implicit with the TextModeLayout which is pretty cool.
+
+TextModeLayout  was  created  specifically  for  the  TextComponent  and  InputComponent  so  check  out  the
+section about them in the components chapter.
+
+2.1.3. Layered Layout
+
+When  used  without  constraints, 
+
+the  LayeredLayout  [https://www.codenameone.com/javadoc/com/
+
+codename1/ui/layouts/LayeredLayout.html]  places  the  components  in  order  one  on  top  of  the  other  and
+
+sizes them all to the size of the largest component. This is useful when trying to create an overlay
+
+on top of an existing component. E.g. an “x” button to allow removing the component.
+
+Figure 44. The X on this button was placed there using the layered layout code below
+
+The  code  to  generate  this  UI  is  slightly  complex  and  contains  very  few  relevant  pieces.  The  only
+
+truly relevant piece is this block:
+
+hi.add(LayeredLayout.encloseIn(settingsLabel,
+        FlowLayout.encloseRight(close)));
+
+We are doing three distinct things here:
+
+55
+
+1. We are adding a layered layout to the form
+
+2. We  are  creating  a  layered  layout  and  placing  two  components  within.  This  would  be  the
+
+equivalent of just creating a LayeredLayout Container and invoking add twice
+
+3. We use FlowLayout to position the X close button in the right position
+
+
+
+When  used  without  constraints,  the  layered  layout  sizes  all  components  to  the
+
+exact  same  size  one  on  top  of  the  other.  It  usually  requires  that  we  use  another
+
+container within; in order to position the components correctly
+
+This is the full source of the example for completeness:
+
+Form hi = new Form("Layered Layout");
+int w = Math.min(Display.getInstance().getDisplayWidth(), Display.getInstance().getDisplayHeight());
+Button settingsLabel = new Button("");
+Style settingsStyle = settingsLabel.getAllStyles();
+settingsStyle.setFgColor(0xff);
+settingsStyle.setBorder(null);
+settingsStyle.setBgColor(0xff00);
+settingsStyle.setBgTransparency(255);
+settingsStyle.setFont(settingsLabel.getUnselectedStyle().getFont().derive(w / 3, Font.STYLE_PLAIN));
+FontImage.setMaterialIcon(settingsLabel, FontImage.MATERIAL_SETTINGS);
+Button close = new Button("");
+close.setUIID("Container");
+close.getAllStyles().setFgColor(0xff0000);
+FontImage.setMaterialIcon(close, FontImage.MATERIAL_CLOSE);
+hi.add(LayeredLayout.encloseIn(settingsLabel,
+        FlowLayout.encloseRight(close)));
+
+Forms  have  a  built  in  layered  layout  that  you  can  access  via  getLayeredPane(),  this  allows  you  to
+overlay elements on top of the content pane.
+
+The 
+
+layered  pane 
+
+is  used 
+
+internally  by 
+
+components 
+
+such  as 
+
+InteractionDialog
+
+[https://www.codenameone.com/javadoc/com/codename1/components/InteractionDialog.html], 
+
+AutoComplete
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/AutoCompleteTextField.html] etc.
+
+
+
+Codename One also includes a GlassPane that resides on top of the layered pane.
+
+Its  useful  if  you  just  want  to  "draw"  on  top  of  elements  but  is  harder  to  use  than
+
+layered pane
+
+Insets and Reference Components
+
+As of Codename One 3.7, LayeredLayout [https://www.codenameone.com/javadoc/com/codename1/ui/layouts/
+
+LayeredLayout.html] 
+
+supports 
+
+insets 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/layouts/
+
+LayeredLayout.LayeredLayoutConstraint.Inset.html] for its children. This effectively allows you to position
+
+child  components  precisely  where  you  want  them,  relative  to  their  container  or  siblings.  This
+
+functionality forms the under-pinnings of the GUI Builder’s Auto-Layout mode.
+
+As an example, suppose you wanted to position a button in the lower right corner of its container.
+
+This  can  be  achieved  with  LayeredLayout  [https://www.codenameone.com/javadoc/com/codename1/ui/
+
+56
+
+layouts/LayeredLayout.html] as follows:
+
+Container cnt = new Container(new LayeredLayout());
+Button btn = new Button("Submit");
+LayeredLayout ll = (LayeredLayout)cnt.getLayout();
+cnt.add(btn);
+ll.setInsets(btn, "auto 0 0 auto");
+
+The result is:
+
+The only thing new here is this line:
+
+ll.setInsets(btn, "auto 0 0 auto");
+
+This is called after btn has already been added to the container. It says that we want its insets to be
+"auto" on the top and left, and 0 on the right and bottom. This insets string follows the CSS notation
+of  top  right  bottom  left  (i.e.  start  on  top  and  go  clockwise),  and  the  values  of  each  inset  may  be
+provided in pixels (px), millimetres (mm), percent (%), or the special "auto" value. Like CSS, you can
+
+also specify the insets using a 1, 2, or 3 values. E.g.
+
+1. "1mm" - Sets 1mm insets on all sides.
+
+2. "1mm 2mm" - Sets 1mm insets on top and bottom; 2mm on left and right.
+
+3. "1mm 10% 2mm" - Sets 1mm on top, 10% on left and right, and 2mm on bottom.
+
+4. "1mm 2mm 1px 50%" - Sets 1mm on top, 2mm on right, 1px on bottom, and 50% on left.
+
+auto Insets
+
+The  special  "auto"  inset  indicates  that  it  is  a  flexible  inset.  If  all  insets  are  set  to  "auto",  then  the
+
+component will be centered both horizontally and vertically inside its "bounding box".
+
+
+
+The  "inset  bounding  box"  is  the  containing  box  from  which  a  component’s  insets
+
+are  measured.  If  the  component’s  insets  are  not  linked  to  any  other  components,
+
+then  its  inset  bounding  box  will  be  the  inner  bounds  (i.e.  taking  padding  into
+
+account) of the component’s parent container.
+
+If one inset is fixed (i.e. defined in px, mm, or %), and the opposite inset is "auto", then the "auto"
+
+57
+
+inset  will  simply  allow  the  component  to  be  its  preferred  size.  So  if  you  want  to  position  a
+
+component to be centered vertically, and 5mm from the left edge, you could do:
+
+ll.setInsets(btn, "auto auto auto 5mm");
+
+Resulting in:
+
+Figure 45. Button vertically centered 5mm from left edge
+
+Move it to the right edge with:
+
+ll.setInsets(btn, "auto 5mm auto auto");
+
+% Insets
+
+Percent (%) insets are calculated with respect to the inset bounding box. A 50% inset is measured as
+
+50% of the length of the bounding box on the inset’s axis. E.g. A 50% inset on top would be 50% of
+
+the  height  of  the  inset  bounding  box.  A  50%  inset  on  the  right  would  be  50%  of  the  width  of  the
+
+inset bounding box.
+
+Insets, Margin, and Padding
+
+A  component’s  position  in  a  layered  layout  is  determined  as  follows:  (Assume  that  cmp  is  the
+component that we are positioning, and cnt is the container (In pseudo-code):
+
+x = cnt.paddingLeft + cmp.calculatedInsetLeft + cmp.marginLeft
+y = cnt.paddingTop + cmp.calculatedInsetTop + cmp.marginTop
+w = cnt.width - cnt.verticalScroll.width - cnt.paddingRight - cmp.calculatedInsetRight - cmp.marginRight - x
+h = cnt.height - cnt.horizontalScroll.height - cnt.paddingBottom - cmp.calculatedInsetBottom - cmp.marginBottom - y
+
+
+
+The  calculatedInsetXXX  values  here  will  be  the  same  as  the  corresponding
+provided inset if the inset has no reference component. If it does have a reference
+
+component, then the calculated inset will depend on the position of the reference
+
+component.
+
+If no inset is specified, then it is assumed to be 0. This ensures compatibility with designs that were
+
+created before layered layout supported insets.
+
+58
+
+Component References: Linking Components together
+
+If  all  you  need  to  do  is  position  a  component  relative  to  its  parent  container’s  bounds,  then  mere
+
+insets provide you with sufficient vocabulary to achieve this. But most UIs are more complex than
+
+this and require another concept: reference components. In many cases you will want to position a
+
+component relative to another child of the same container. This is also supported.
+
+For example, suppose I want to place a text field in the center of the form (both horizontally and
+
+vertically),  and  have  a  button  placed  beside  it  to  the  right.  Positioning  the  text  field  is  trivial
+(setInset(textField,  "auto")),  but  there  is  no  inset  that  we  can  provide  that  would  position  the
+button  to  the  right  of  the  text  field.  To  accomplish  our  goal,  we  need  to  set  the  text  field  as  a
+
+reference component of the button’s left inset - so that the button’s left inset is "linked" to the text
+
+field. Here is the syntax:
+
+Container cnt = new Container(new LayeredLayout());
+LayeredLayout ll = (LayeredLayout)cnt.getLayout();
+Button btn = new Button("Submit");
+TextField tf = new TextField();
+cnt.add(tf).add(btn);
+ll.setInsets(tf, "auto")
+  .setInsets(btn, "auto auto auto 0")
+  .setReferenceComponentLeft(btn, tf, 1f);
+
+This would result in:
+
+Figure 46. Button’s left inset linked to text field
+
+The two active lines here are the last two:
+
+  .setInsets(btn, "auto auto auto 0") ①
+  .setReferenceComponentLeft(btn, tf, 1f); ②
+
+① Sets the left inset on btn to 0.
+
+② Links btn’s left inset to `tf so that it is measured from the text field. The third parameter (
+1.0) is the reference position. This will generally either be 0 (meaning the reference point is the
+left edge of the text field), or 1 (meaning the reference point is the right edge of the text field). In
+
+59
+
+this case we set a reference position of 1.0 because we want the button to be aligned to the text
+field’s right edge.
+
+The  reference  position  is  defined  as  the  distance,  expressed  as  a  fraction  of  the
+
+reference  component’s  length  on  the  inset’s  axis,  between  the  reference
+
+component’s leading (outer) edge and the point from which the inset is measured.
+
+
+
+A reference position of 0 means that the inset is measured from the leading edge of
+
+the reference component. A value of 1.0 means that the inset is measured from the
+
+trailing  edge  of  the  reference  component.  A  value  of  0.5  means  that  the  inset  is
+
+measured  from  the  center  of  the  reference  component.  Etc…  Any  floating  point
+
+value can be used. The designer currently only makes use of 0 and 1.
+
+The definition above may make reference components and reference position seem more complex
+
+than it is. Some examples:
+
+1. For a top inset:
+
+a. referencePosition  ==  0  ⇒  the  inset  is  measured  from  the  top  edge  of  the  reference
+
+component.
+
+b. referencePosition  ==  1  ⇒  the  inset  is  measured  from  the  bottom  edge  of  the  reference
+
+component.
+
+2. For a bottom inset:
+
+a. referencePosition  ==  0  ⇒  the  inset  is  measured  from  the  bottom  edge  of  the  reference
+
+component.
+
+b. referencePosition  ==  1  ⇒  the  inset  is  measured  from  the  top  edge  of  the  reference
+
+component.
+
+3. For a left inset:
+
+a. referencePosition  ==  0  ⇒  the  inset  is  measured  from  the  left  edge  of  the  reference
+
+component.
+
+b. referencePosition  ==  1  ⇒  the  inset  is  measured  from  the  right  edge  of  the  reference
+
+component.
+
+4. For a right inset:
+
+a. referencePosition  ==  0  ⇒  the  inset  is  measured  from  the  right  edge  of  the  reference
+
+component.
+
+b. referencePosition  ==  1  ⇒  the  inset  is  measured  from  the  left  edge  of  the  reference
+
+component.
+
+60
+
+Layers In Codename One
+
+Codename  One  allows  placing  components  one  on  top  of  the  other  and  we  commonly  use
+layered layout to do that. The form class has a builtin Container that resides in a layer on top
+of the content pane of the form.
+
+When  you  add  an  element  to  a  form  it  implicitly  goes  into  the  content  pane.  However,  you
+can use getLayeredPane() and add any Component there. Such a Component will appear above the
+content pane. Notice that this layer resides below the title area (on the Y axis) and won’t draw
+
+on top of that.
+
+When  Codename  One  introduced  the  layered  pane  it  was  instantly  useful.  However,  its
+
+popularity caused conflicts. Two separate pieces of code using the layered pane could easily
+collide with one another. Codename One solved it with getLayeredPane(Class c, boolean top).
+This  method  allocates  a  layer  for  a  specific  class  within  the  layered  pane.  This  way  if  two
+different  classes  use  this  method  instead  of  the  getLayeredPane()  method  they  won’t  collide.
+Each  will  get  its  own  container  in  a  layered  layout  within  the  layered  pane  seamlessly.  The
+top flag indicates whether we want the layer to be the top most or bottom most layer within
+the  layered  pane  (assuming  it  wasn’t  created  already).  This  allows  you  to  place  a  layer  that
+
+can appear above or below the already installed layers.
+
+We only make use of the layered pane in this book but there are two additional layers on top
+
+of it. The form layered pane is identical to the layered pane but spans the entire height of the
+Form (including the title area). As a result the form layered pane is slower as it needs to handle
+some special cases to support this functionality.
+
+The glass pane is the top most layer, unlike the layered pane it’s purely a graphical layer. You
+can only draw on the glass pane with a Painter instance and a Graphics object. You can’t add
+components into that layer.
+
+Figure 47. The Layered Pane
+
+61
+
+2.1.4. GridBag Layout
+
+GridBagLayout 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/layouts/GridBagLayout.html]  was
+
+introduced  to  simplify  the  process  of  porting  existing  Swing/AWT  code  with  a  more  familiar  API.
+
+The  API  for  this  layout  is  problematic  as  it  was  designed  for  AWT/Swing  where  styles  were
+
+unavailable. As a result it has its own insets API instead of using elements such as padding/margin.
+
+Our  recommendation  is  to  use  Table  which  is  just  as  powerful  but  has  better  Codename  One
+
+integration.
+
+To  demonstrate  GridBagLayout  we  ported  the  sample  from  the  Java  tutorial  [http://docs.oracle.com/
+javase/tutorial/uiswing/layout/gridbag.html] to Codename One.
+
+62
+
+Button button;
+hi.setLayout(new GridBagLayout());
+GridBagConstraints c = new GridBagConstraints();
+//natural height, maximum width
+c.fill = GridBagConstraints.HORIZONTAL;
+button = new Button("Button 1");
+c.weightx = 0.5;
+c.fill = GridBagConstraints.HORIZONTAL;
+c.gridx = 0;
+c.gridy = 0;
+hi.addComponent(c, button);
+
+button = new Button("Button 2");
+c.fill = GridBagConstraints.HORIZONTAL;
+c.weightx = 0.5;
+c.gridx = 1;
+c.gridy = 0;
+hi.addComponent(c, button);
+
+button = new Button("Button 3");
+c.fill = GridBagConstraints.HORIZONTAL;
+c.weightx = 0.5;
+c.gridx = 2;
+c.gridy = 0;
+hi.addComponent(c, button);
+
+button = new Button("Long-Named Button 4");
+c.fill = GridBagConstraints.HORIZONTAL;
+c.ipady = 40;      //make this component tall
+c.weightx = 0.0;
+c.gridwidth = 3;
+c.gridx = 0;
+c.gridy = 1;
+hi.addComponent(c, button);
+
+button = new Button("5");
+c.fill = GridBagConstraints.HORIZONTAL;
+c.ipady = 0;       //reset to default
+c.weighty = 1.0;   //request any extra vertical space
+c.anchor = GridBagConstraints.PAGE_END; //bottom of space
+c.insets = new Insets(10,0,0,0);  //top padding
+c.gridx = 1;       //aligned with button 2
+c.gridwidth = 2;   //2 columns wide
+c.gridy = 2;       //third row
+hi.addComponent(c, button);
+
+Notice that because of the way gridbag works we didn’t provide any terse syntax API for it although
+
+it should be possible.
+
+63
+
+Figure 48. GridbagLayout sample from the Java tutorial running on Codename One
+
+2.1.5. Group Layout
+
+GroupLayout [https://www.codenameone.com/javadoc/com/codename1/ui/layouts/GroupLayout.html] is a layout
+
+that would be familiar to the users of the NetBeans GUI builder (Matisse) [https://netbeans.org/features/
+
+java/swing.html]. Its a layout manager that’s really hard to use for manual coding but is powerful for
+some elaborate use cases. Although MiGLayout and LayeredLayout might be superior options.
+
+It  was  originally  added  during  the  LWUIT  days  as  part  of  an  internal  attempt  to  port  Matisse  to
+
+LWUIT.  It’s  still  useful  to  this  day  as  developers  copy  and  paste  Matisse  code  into  Codename  One
+
+and produce very elaborate layouts with drag and drop.
+
+Since the layout is based on an older version of GroupLayout some things need to be adapted in the
+code or you should use the special "compatibility" library for Matisse to get better interaction. We
+
+also recommend tweaking Matisse to use import statements instead of full package names, that way
+if you use Label just changing the awt import to a Codename One import will make it use work for
+Codenmae One’s Label.
+
+Unlike any other layout manager GroupLayout adds the components into the container instead of the
+standard API. This works nicely for GUI builder code but as you can see from this sample it doesn’t
+
+make the code very readable:
+
+Form hi = new Form("GroupLayout");
+
+Label label1 = new Label();
+Label label2 = new Label();
+Label label3 = new Label();
+Label label4 = new Label();
+Label label5 = new Label();
+Label label6 = new Label();
+Label label7 = new Label();
+
+label1.setText("label1");
+
+label2.setText("label2");
+
+label3.setText("label3");
+
+label4.setText("label4");
+
+label5.setText("label5");
+
+label6.setText("label6");
+
+label7.setText("label7");
+
+GroupLayout layout = new GroupLayout(hi.getContentPane());
+hi.setLayout(layout);
+layout.setHorizontalGroup(
+    layout.createParallelGroup(GroupLayout.LEADING)
+
+64
+
+    .add(layout.createSequentialGroup()
+        .addContainerGap()
+        .add(layout.createParallelGroup(GroupLayout.LEADING)
+            .add(layout.createSequentialGroup()
+                .add(label1, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
+                .addPreferredGap(LayoutStyle.RELATED)
+                .add(layout.createParallelGroup(GroupLayout.LEADING)
+                    .add(label4, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
+                    .add(label3, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
+                    .add(label2, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)))
+            .add(label5, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
+            .add(layout.createSequentialGroup()
+                .add(label6, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
+                .addPreferredGap(LayoutStyle.RELATED)
+                .add(label7, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)))
+        .addContainerGap(296, Short.MAX_VALUE))
+);
+layout.setVerticalGroup(
+    layout.createParallelGroup(GroupLayout.LEADING)
+    .add(layout.createSequentialGroup()
+        .addContainerGap()
+        .add(layout.createParallelGroup(GroupLayout.TRAILING)
+            .add(label2, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
+            .add(label1, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE))
+        .addPreferredGap(LayoutStyle.RELATED)
+        .add(label3, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
+        .addPreferredGap(LayoutStyle.RELATED)
+        .add(label4, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
+        .addPreferredGap(LayoutStyle.RELATED)
+        .add(label5, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
+        .addPreferredGap(LayoutStyle.RELATED)
+        .add(layout.createParallelGroup(GroupLayout.LEADING)
+            .add(label6, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
+            .add(label7, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE))
+        .addContainerGap(150, Short.MAX_VALUE))
+);
+
+Figure 49. GroupLayout Matisse generated UI running in Codename One
+
+If you are porting newer Matisse code there are simple changes you can do:
+
+• Change addComponent to add
+
+• Change addGroup to add
+
+• Remove references to ComponentPlacement and reference LayoutStyle directly
+
+65
+
+2.1.6. Mig Layout
+
+MigLayout 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/layouts/mig/MigLayout.html] 
+
+is 
+
+a
+
+popular cross platform layout manager that was ported to Codename One from Swing.
+
+ MiG is still considered experimental so proceed with caution!
+
+The API was deprecated to serve as a warning of its experimental status.
+
+The  best  reference 
+
+for  MiG  would  probably  be 
+
+its  quick  start  guide 
+
+(PDF 
+
+link)
+
+[http://www.miglayout.com/QuickStart.pdf]. As a reference we ported one of the samples from that PDF to
+
+Codename One:
+
+Form hi = new Form("MigLayout", new MigLayout("fillx,insets 0"));
+
+hi.add(new Label("First")).
+    add("span 2 2", new Label("Second")).  // The component will span 2x2 cells.
+    add("wrap", new Label("Third")).      // Wrap to next row
+    add(new Label("Forth")).
+    add("wrap", new Label("Fifth")).    // Note that it "jumps over" the occupied cells.
+    add(new Label("Sixth")).
+    add(new Label("Seventh"));
+hi.show();
+
+Figure 50. MiG layout sample ported to Codename One
+
+It should be reasonably easy to port MiG code but you should notice the following:
+
+• MiG  handles  a  lot  of  the  spacing/padding/margin  issues  that  are  missing  in  Swing/AWT.  With
+
+Codename One styles we have the padding and margin which are probably a better way to do a
+
+lot of the things that MiG does
+
+• The add method in Codename One can be changed as shown in the sample above.
+
+• The constraint argument for Coedname One add calls appears before the Component instance.
+
+2.2. Themes and Styles
+
+Next we need to introduce you to 3 important terms in Codename One: Theme, Style and UIID.
+
+Themes  are  very  similar  conceptually  to  CSS,  in  fact  they  can  be  created  with  CSS  syntax  as  we’ll
+
+66
+
+discuss  soon.  The  various  Codename  One  ports  ship  with  a  native  theme  representing  the
+
+appearance of the native OS UI elements. Every Codename One application has its own theme that
+
+derives the native theme and overrides behavior within it.
+
+If the native theme has a button defined, we can override properties of that button in our theme.
+
+This  allows  us  to  customize  the  look  while  retaining  some  native  appearances.  This  works  by
+
+merging the themes to one big theme where our application theme overrides the definitions of the
+
+native theme. This is pretty similar to the cascading aspect of CSS if you are familiar with that.
+
+Themes  consist  of  a  set  of  UIID  definitions.  Every  component  in  Codename  One  has  a  UIID
+
+associated  with  it.  UIID  stands  for  User  Interface  Identifier.  This  UIID  connects  the  theme  to  a
+
+specific  component.  A  UIID  maps  to  CSS  classes  if  you  are  familiar  with  that  concept.  However,
+
+Codename  One  doesn’t  support  the  complex  CSS  selector  syntax  options  as  those  can  impact
+
+runtime performance.
+
+E.g. see this code where:
+
+Listing 10. setUIID on TextField
+
+nameText.setUIID("Label");
+
+This is a text field component (user input field) but it will look like a Label.
+
+Effectively we told the text field that it should use the UIID of Label when it’s drawing itself. It’s very
+common to do tricks like that in Codename One. E.g. button.setUIID("Label") would make a button
+appear like a label and allow us to track clicks on a “Label”.
+
+The  UIID’s  translate  the  theme  elements  into  a  set  of  Style  objects.  These  Style  objects  get  their
+initial values from the theme but can be further manipulated after the fact. So if I want to make the
+
+text field’s foreground color red I could use this code:
+
+Listing 11. setUIID on TextField
+
+nameText.getAllStyles().setFgColor(0xff0000);
+
+The color is in hexadecimal RRGGBB format so 0xff00 would be green and 0xff0000 would be red.
+
+getAllStyles() returns a Style object but why do we need “all” styles?
+
+Each component can have one of 4 states and each state has a Style object. This means we can have
+4 style objects per Component:
+
+• Unselected — used  when  a  component  isn’t  touched  and  doesn’t  have  focus.  You  can  get  that
+
+object with getUnselectedStyle().
+
+• Selected — used when a component is touched or if focus is drawn for non-touch devices. You
+
+can get that object with getSelectedStyle().
+
+• Pressed — used when a component is pressed. Notice it’s only applicable to buttons and button
+
+subclasses usually. You can get that object with getPressedStyle().
+
+67
+
+• Disabled — used  when  a  component 
+
+is  disabled.  You  can  get 
+
+that  object  with
+
+getDisabledStyle().
+
+The  getAllStyles()  method  returns  a  special  case  Style  object  that  lets  you  set  the  values  of  all  4
+styles from one class so the code before would be equivalent to invoking all 4 setFgColor methods.
+However, getAllStyles() only works for setting properties not for getting them!
+
+Don’t use getStyle() for manipulation
+
+
+
+getStyle()  returns  the  current  Style  object  which  means  it  will  behave
+inconsistently.  The  paint  method  uses  getStyle()  as  it  draws  the  current  state  of
+the  Component  but  other  code  should  avoid  that  method.  Use  the  specific  methods
+getPressedStyle(),
+instead: 
+getDisabledStyle() and getAllStyles()
+
+getUnselectedStyle(), 
+
+getSelectedStyle(), 
+
+As  you  can  see,  it’s  a  bit  of  a  hassle  to  change  styles  from  code  which  is  why  the  theme  is  so
+
+appealing.
+
+2.2.1. Theme
+
+A theme allows the designer to define the styles externally via a set of UIID’s (User Interface ID’s),
+
+the themes are created via the Codename One Designer tool and allow developers to separate the
+
+look of the component from the application logic.
+
+
+
+You can customize the theme using CSS which we’ll discuss a bit later
+
+The theme is stored in the theme.res file in the src root of the project. We load the theme file using
+this line of code in the init(Object) method in the main class of the application:
+
+Listing 12. Theme Loading Code
+
+theme = UIManager.initFirstTheme("/theme");
+
+This  code  is  shorthand  for  resource  file  loading  and  for  the  installation  of  theme.  You  could
+
+technically  have  more  than  one  theme  in  a  resource  file  at  which  point  you  could  use
+initNamedTheme()  instead.  The  resource  file  is  a  special  file  format  that  includes  inside  it  several
+features:
+
+• Themes
+
+• Images
+
+• Localization Bundles
+
+• Data files
+
+It also includes some legacy features such as the old GUI builder.
+
+ We’re mentioning the legacy GUI builder for reference only we won’t discuss the
+
+old GUI builders in this guide
+
+68
+
+We can open the designer tool by double clicking the res file. The UI can be a bit overwhelming at
+
+first so I’ll try to walk slowly through the steps.
+
+Figure 51. Codename One Designer Feature Map
+
+
+
+If you end up using CSS this section isn’t crucial but it’s worth browsing through as
+
+using the designer tool helps in tracking CSS issues
+
+There are two crucial features in this tool: theming and images.
+
+Figure 52. Add a New Image
+
+You will notice there is more than one type of image. We’ll discuss multi-images later.
+
+69
+
+Now  we  can  go  back  to  the  theme  view  in  the  designer  tool  and  press  the  Add  button  in  the
+Unselected  tab.  Notice  we  have  tabs  for  every  state  of  Style  as  well  as  a  special  tabl  for  theme
+constants that we will discuss later.
+
+Figure 53. The Add Button
+
+After pressing that button we should see something that looks like this:
+
+Figure 54. Add the Theme Entry for the Toolbar
+
+
+
+Don’t forget to press the save button in the designer after making changes
+
+There are several other options in the add theme entry dialog. Lets go over them and review what
+
+we should do for each tab in this UI:
+
+70
+
+Figure 55. The Rest of the Add Theme Entry Dialog - Part I
+
+71
+
+Figure 56. The Rest of the Add Theme Entry Dialog - Part II
+
+We’ll cover these options in-depth in the theming chapters.
+
+Native Theme
+
+By  default  Codename  One  applications  are  created  with  a  theme  that  derives  from  the  builtin  OS
+
+native  theme.  You  can  add  additional  themes  into  the  resource  file  by  pressing  the  Add A New
+
+Theme button. You can also create multiple themes and ship them with your app or download them
+
+dynamically.
+
+You can create a theme from scratch or customize one of the Codename one themes to any look you
+
+desire.
+
+
+
+To preview the look of your theme in the various platforms use the  Native Theme
+
+menu option in the designer
+
+Figure 57. The native theme menu option
+
+72
+
+You can easily create deep customizations that span across all themes by adding a UIID or changing
+
+an  existing  UIID.  E.g.  looking  at  the  getting  started  application  that  ships  with  the  plugin  you  will
+
+notice a green button. This button is defined using the "GetStarted" UIID which is defined within the
+
+designer as:
+
+• A green background
+
+• White foreground
+
+• A thin medium sized font
+
+• Center aligned text
+
+• A small amount of spacing between the text and the edges
+
+To achieve the colors we define them in the color tab.
+
+
+
+We  define  the  transparency  to  255  which  means  the  background  will  be  a  solid
+
+green  color.  This  is  important  since  the  native  OS’s  might  vary  with  the  default
+
+value for background transparency so this should be defined explicitly
+
+Figure 58. The Color tab for the get started button theme settings
+
+The  alignment  of  the  text  is  pretty  simple,  notice  that  the  alignment  style  attribute  applies  to  text
+
+and doesn’t apply to other elements. To align other elements we use layout manager logic.
+
+73
+
+Figure 59. The alignment tab for the get started button theme settings
+
+Padding can be expressed in pixels, millimeters (approximate) or percentages of the screen size.
+
+
+
+We recommend using millimeters for all measurements to keep the code portable
+
+for various device DPI’s.
+
+74
+
+Figure 60. The padding tab for the get started button theme settings
+
+The font uses native OS light font but has a fallback for older OS’s that don’t support truetype fonts.
+
+The  "True  Type"  font  will  be  applicable  for  most  modern  OS’s.  In  the  case  of  the  "native:"  fonts
+
+Android devices will use  Roboto whereas iOS devices will use  Helvetica Neue. You can supply your
+
+own TTF and work with that.
+
+ Since  Codename  One  cannot  legally  ship  Helvetica Neue  fonts  the  simulator  will
+
+fallback to Roboto on PC’s.
+
+
+
+At the time of this writing the desktop/simulator version of the Roboto font doesn’t
+
+support  many  common  character  sets  (languages).  This  will  have  no  effect  on  an
+
+Android device where thenative font works properly.
+
+75
+
+Figure 61. The font tab for the get started button theme settings
+
+2.3. GUI Builder
+
+The  GUI  builder  allows  us  to  arrange  components  visually  within  a  UI  using  drag  and  drop,
+
+property  sheets  etc.  With  the  GUI  builder  we  can  create  elaborate,  rich  UI’s  without  writing  the
+
+layout code.
+
+76
+
+Why two GUI Builders?
+
+The original old GUI builder has its roots in our work at Sun Microsystems, it was developed
+
+directly into the designer tool and stores it’s data as part of the resource file. When creating
+
+an application for the old GUI builder you must define it as a "visual application" which will
+
+make it use the old GUI builder.
+
+The roots of this GUI builder are pretty old. When we initially built it we still had to support
+
+feature phones with 2mb of RAM and the iPad wasn’t announced yet. Due to that we picked
+
+an  architecture  that  made  sense  for  those  phones  with  a  greater  focus  on  navigation  and
+
+resource  usage.  Newer  mobile  applications  are  rivaling  desktop  applications  in  complexity
+
+and in those situations the old GUI builder doesn’t make as much sense
+
+The  old  GUI  builder  is  in  the  designer  tool,  it’s  a  Swing  application  that  includes  the  theme
+
+design etc.
+It generates a Statemachine class that contains all the main user GUI interaction code.
+
+The new GUI builder is a standalone application that you launch from the right click menu by
+
+selecting a form as explained below. Here are screenshots of both to help you differentiate:
+
+Figure 62. The old GUI builder
+
+Figure 63. The same UI in the new GUI builder
+
+As of version 3.7, the new GUI Builder also supports an auto layout mode which allows you to
+
+freely position and resize components on a canvas. This mode is now the default for new GUI
+
+forms, and it always uses LayeredLayout as the root layout manager.
+
+77
+
+Figure 64. The new GUI builder in auto-layout mode
+
+2.3.1. Hello World
+
+Creating a hello world app in the new GUI builder is actually pretty trivial, you need to start with a
+
+regular handcoded application. Not a GUI builder application as it refers to the old GUI builder!
+
+This is the exact same hello world application we created before…
+
+Following  are  the  instructions  for  creating  a  form  and  launching  the  GUI  builder.  While  they  are
+
+similar there are minor IDE differences. Usage of the GUI builder is identical in all IDE’s as the GUI
+
+builder is a separate application.
+
+NetBeans
+
+In NetBeans you need to follow these 4 steps:
+
+Figure 65. Right click the package select  New  →  Other
+
+78
+
+Figure 66. In the Codename One section select the GUI builder form
+
+Figure 67. Type in the name of the form and click finish, you can change the type to be a Container or Dialog
+
+Figure 68. Launch the GUI builder thru the right click menu on the newly created file
+
+IntelliJ/IDEA
+
+In IntelliJ you need to follow these 3 steps:
+
+Figure 69. Right click the package select  New  → Codename One AutoLayout Form (or Dialog/Container)
+
+79
+
+Figure 70. Type in a name for the new form
+
+Figure 71. Launch the GUI builder thru the right click menu on the newly created file
+
+Eclipse
+
+In Eclipse you need to follow these 4 steps:
+
+Figure 72. Right click the package select  New  →  Other
+
+Figure 73. In the Codename One section select the GUI builder option
+
+80
+
+Figure 74. Type in the name of the form and click finish, you can change the type to be a Container or Dialog
+
+Figure 75. Launch the GUI builder thru the right click menu on the newly created file
+
+Basic Usage
+
+Notice  that  the  UI  of  the  new  GUIBuilder  might  change  in  various  ways  but  the  basic  concepts
+
+should remain the same.
+
+The  GUI  builder  is  controlled  via  it’s  main  toolbar,  notice  that  your  changes  will  only  be  applied
+
+when you click the Save button on the right:
+
+Figure 76. The features of the left toolbar
+
+81
+
+Figure 77. The features of the right toolbar
+
+The main UI includes four important parts:
+
+• Main Form — This is where we place the components of the UI we are building
+
+• Component Tree — This is a logical representation of the component hierarchy within the  Main
+
+Form. It’s often easier to pick a component from the tree rather than the form itself
+
+• Property Inspector — When we select an element in the tree or form we can see its details here.
+
+We can then edit the various details of the component in this area
+
+• Palette — Components can be dragged from the palette to the Main Form and placed in the UI
+
+Figure 78. The four parts of the GUI builder
+
+We’ll start by selecting the Component Palette and dragging a button into the UI:
+
+82
+
+Figure 79. You can drag any component you want from the palette to the main UI
+
+By  default  the  auto-layout  mode  of  the  GUI  builder  uses  layered  layout  to  position  components.
+Sides  can  be  bound  to  a  component  or  to  the  Form.  We  then  use  distance  units  to  determine  the
+binding  behavior.  The  GUI  builder  tries  to  be  "smart"  and  guesses  your  intention  as  you  drag  the
+
+components along.
+
+When you select the component you placed you can edit the properties of that component:
+
+Figure 80. Properties allow you to customize everything about a component
+
+There are five property sheets per component:
+
+• Basic Settings — These include the basic configuration for a component e.g. name, icon, text etc.
+
+• Advanced Settings — These include features that aren’t as common such as icon gap, mask etc.
+
+• Events — By  clicking  a  button  in  this  tab  a  method  will  be  added  to  the  source  file  with  a
+
+callback matching your component name. This will let you bind an event to a button, text field
+
+etc.
+
+• Layout — You can determine the layout of the parent Container here. For auto-layout this should
+
+stay as layered layout, however you can nest other layout types in here
+
+• Style Customization — This  isn’t  a  theme,  if  you  want  to  customize  the  style  of  a  specific
+
+component you can do that through this UI. The theme works on a more global/reusable level
+
+and this is designed for a specific component only
+
+For  things  like  setting  the  text  on  the  component  we  can  use  a  convenient  "long  click"  on  the
+
+83
+
+component to edit the text in place as such:
+
+Figure 81. Use the long click to edit the text "in place"
+
+Events
+
+When  a  component  supports  broadcasting  events  you  can  bind  such  events  by  selecting  it,  then
+
+selecting the events tab and clicking the button matching the event type
+
+Figure 82. The events tab is listed below supported event types can be bound above
+
+Once an event is bound the IDE will open to the event code e.g.:
+
+public void onButton_1ActionEvent(com.codename1.ui.events.ActionEvent ev) {
+}
+
+
+
+Some  IDE’s  only  generate  the  project  source  code  after  you  explicitly  build  the
+
+project so if your code needs to access variables etc. try building first
+
+Within  the  code  you  can  access  all  the  GUI  components  you  defined  with  the  gui_  prefix  e.g.
+Button_1 from the UI is represented as:
+
+84
+
+private com.codename1.ui.Button gui_Button_1 = new com.codename1.ui.Button();
+
+Underlying XML
+
+Saving  the  project  generates  an  XML  file  representing  the  UI  into  the  res  directory  in  the  project,
+the GUI file is created in a matching hierarchy in the project under the res/guibuilder directory:
+
+Figure 83. The java and GUI files in the hierarchy
+
+ If you refactor (rename or move) the java file it’s connection with the GUI file will
+
+break. You need to move/rename both
+
+You can edit the GUI file directly but changes won’t map into the GUI builder unless you reopen it.
+
+These files should be under version control as they are the main files that change. The GUI builder
+
+file for the button and label code looks like this:
+
+<?xml version="1.0" encoding="UTF-8"?>
+
+<component type="Form" layout="FlowLayout" flowLayoutFillRows="false" flowLayoutAlign="1"
+flowLayoutValign="0"  title="My new title" name="MyForm">
+  <component type="Button" text="Button" name="Button_1" actionEvent="true">
+  </component>
+  <component type="Label" text="Hi World" name="Label_1">
+  </component>
+</component>
+
+This format is relatively simple and is roughly the same format used by the old GUI builder which
+
+makes  the  migration  to  the  new  GUI  builder  possible.  This  file  triggers  the  following  Java  source
+
+file:
+
+package com.mycompany.myapp;
+
+/**
+ * GUI builder created Form
+
+85
+
+ *
+ * @author shai
+ */
+public class MyForm extends com.codename1.ui.Form {
+
+    public MyForm() {
+        this(com.codename1.ui.util.Resources.getGlobalResources());
+    }
+
+    public MyForm(com.codename1.ui.util.Resources resourceObjectInstance) {
+        initGuiBuilderComponents(resourceObjectInstance);
+    }
+
+//-- DON'T EDIT BELOW THIS LINE!!!
+    private com.codename1.ui.Label gui_Label_1 = new com.codename1.ui.Label();
+    private com.codename1.ui.Button gui_Button_1 = new com.codename1.ui.Button();
+
+// <editor-fold defaultstate="collapsed" desc="Generated Code">
+    private void guiBuilderBindComponentListeners() {
+        EventCallbackClass callback = new EventCallbackClass();
+        gui_Button_1.addActionListener(callback);
+    }
+
+    class EventCallbackClass implements com.codename1.ui.events.ActionListener,
+com.codename1.ui.events.DataChangedListener {
+        private com.codename1.ui.Component cmp;
+        public EventCallbackClass(com.codename1.ui.Component cmp) {
+            this.cmp = cmp;
+        }
+
+        public EventCallbackClass() {
+        }
+
+        public void actionPerformed(com.codename1.ui.events.ActionEvent ev) {
+            com.codename1.ui.Component sourceComponent = ev.getComponent();
+            if(sourceComponent.getParent().getLeadParent() != null) {
+                sourceComponent = sourceComponent.getParent().getLeadParent();
+            }
+
+            if(sourceComponent == gui_Button_1) {
+                onButton_1ActionEvent(ev);
+            }
+        }
+
+        public void dataChanged(int type, int index) {
+        }
+    }
+    private void initGuiBuilderComponents(com.codename1.ui.util.Resources resourceObjectInstance) {
+        guiBuilderBindComponentListeners();
+        setLayout(new com.codename1.ui.layouts.FlowLayout());
+        setTitle("My new title");
+        setName("MyForm");
+        addComponent(gui_Label_1);
+        addComponent(gui_Button_1);
+        gui_Label_1.setText("Hi World");
+        gui_Label_1.setName("Label_1");
+        gui_Button_1.setText("Click Me");
+        gui_Button_1.setName("Button_1");
+    }// </editor-fold>
+
+//-- DON'T EDIT ABOVE THIS LINE!!!
+    public void onButton_1ActionEvent(com.codename1.ui.events.ActionEvent ev) {
+    }
+
+}
+
+86
+
+ Don’t touch the code within the DON’T EDIT comments…
+
+The GUI builder uses the "magic comments" approach where code is generated into those areas to
+
+match the XML defined in the GUI builder. Various IDE’s generate that code at different times. Some
+
+will  generate  it  when  you  run  the  app  while  others  will  generate  it  as  you  save  the  GUI  in  the
+
+builder.
+
+You can write code freely within the class both by using the event mechanism, by writing code in
+
+the constructors or thru overriding functionality in the base class.
+
+2.3.2. Auto-Layout Mode
+
+As of version 3.7, new forms created with the GUI Builder will use auto-layout mode. In this mode
+
+you  can  move  and  resize  your  components  exactly  as  you  see  fit.  You  aren’t  constrained  to  the
+
+positions dictated by the form’s layout manager.
+
+
+
+All forms designed in auto-layout mode use LayeredLayout
+
+Auto-Layout  Mode  is  built  upon  the  inset  support  in  LayeredLayout.  Component
+
+positioning uses insets and reference components, not absolute positioning
+
+As  an  example,  let’s  drag  a  button  onto  a  blank  form  and  see  what  happens.  The  button  will  be
+
+"selected" initially after adding, it so you’ll see its outline, and resize handles for adjusting its size
+
+and position. You’ll also see four floating labels (above, below, to the left, and to the right) that show
+
+the corresponding side’s inset values and allow you to adjust them.
+
+Figure 84. A button selected on the canvas in auto-layout mode.  You can drag it to reposition it, or resize it
+
+using the resize handles.
+
+Press the mouse inside the bounds of the button and drag it around to reposition it. You will notice
+
+that the inset labels change to reflect the new inset values. If you drag the button close to the edge
+
+of  the  form,  the  corresponding  inset  value  will  change  to  millimetres.  If  you  move  farther  away
+
+from the edge, it will change to percentage values.
+
+The Inset Control
+
+Let’s take a closer look at the inset control (the inset controls are the black buttons that appear to
+
+the top, bottom, left, and right of the selected component).
+
+Figure 85. The inset control allows you to change the inset size and units, toggle it between fixed and
+
+flexible, and link it to another component.
+
+Each control has three sections:
+
+1. The  inset  value  drop-down  menu.  This  shows  the  current  value  of  the  inset  (e.g.  0mm,  25%,
+
+87
+
+auto, etc…). If you click on this, it will open a menu that will allow you to change the units. If the
+
+inset  is  currently  in  millimetres,  it  will  have  options  for  pixels,  and  percent.  If  the  inset  is  in
+
+percent, it will have options for pixels and millimetres. Etc.. It also includes a text field to enter
+
+a an inset value explicitly.
+
+2.
+
+3.
+
+The "Link" Button 
+
+ - If the inset is linked to a reference component, then this button will
+
+be highlighted "blue", and hovering over it will highlight the reference component in the UI so
+
+that  you  can  clearly  see  which  component  it  is  linked  to.  Clicking  on  this  button  will  open  a
+
+dialog that will allow you to "break" this link. You can drag this button over any component in
+
+the form to "link".
+
+The  "Lock"  Button" 
+
+  -  This  button  allows  you  to  toggle  the  inset  between  "flexible"  (i.e.
+
+auto) and "fixed" (i.e. millimetres or percent).
+
+Auto Snap
+
+Notice the "auto-snap" checkbox that appears in the top-right corner of the designer.
+
+Figure 86. Auto-snap checkbox
+
+Auto-snap does exactly what it sounds like: It automatically snaps two components together when
+
+you  drag  them  near  each  other.  This  is  handy  for  linking  components  together  without  having  to
+
+explicitly  link  them  (using  the  "link"  button).  This  feature  is  turned  on  by  default.  If  auto-snap  is
+
+turned  off,  you  can  still  initiate  a  "snap"  by  holding  down  the  ALT/Option  key  on  your  keyboard
+
+during the drag.
+
+Smart Insets
+
+Beside the "auto-snap" checkbox is another checkbox named "Smart Insets".
+
+Figure 87. Smart insets checkbox
+
+Smart Inset uses some heuristics during a drag to try to determine how the insets should be linked.
+
+Currently the heuristics are quite basic (it tries to link to the nearest neighbor component in most
+
+cases), but we will be working on improving this for future releases. This feature is turned off by
+
+default while it is still being refined. The goal is to improve this to the point where it always makes
+
+the  correct  link  choices  -  at  which  time  you  will  be  able  to  use  the  designer  without  having  any
+
+knowledge of insets or reference components.
+
+The Widget Control Pad
+
+88
+
+Figure 88. Widget control pad
+
+When a component is selected, you should see a black floating panel appear in the lower right of
+
+the screen.
+
+This is the widget control pad, and it provides an alternative view of the component’s links. It also
+
+provides  a  useful  list  of  incoming  links  (i.e.  components  that  "depend  on"  this  component’s
+
+positioning).  In  some  cases,  you  may  want  to  disconnect  incoming  links  so  that  you  can  drag  the
+
+component without affecting the position of dependent components.
+
+This control pad also includes game-pad-like controls (up, down, left, right), that allow you to "tab"
+
+the  component  to  the  next  guide  in  that  direction.  Tab  positions  exist  at  component  edges  in  the
+
+form. This is useful for aligning components with each other.
+
+Keyboard Short-Cuts
+
+1. Arrow Keys - Use the up/down/left/right arrow keys to nudge the currently selected component
+
+a little bit at a time. This is a convenient way to move the component to a position that is more
+
+precise than can easily be achieved with a mouse drag.
+
+2. Arrow Keys + SHIFT - Hold down the SHIFT key while pressing an arrow key and it will "tab"
+
+the  component  to  the  next  tab  marker.  The  form  has  implicit  tab  markers  at  the  edge  of  each
+
+component on the form.
+
+3. ALT/Option Key + Click or Drag - Holding down the option/alt key while clicking or dragging a
+
+component will resulting in "snapping" behaviour even if auto-snap is turned off.
+
+Sub-Containers
+
+In  some  cases,  you  may  need  to  add  sub-containers  to  your  form  to  aid  in  grouping  your
+
+components together. You can drag a container onto your form using the "Container" palette item
+
+(under "Core Components"). The default layout the subcontainer will be LayeredLayout so that you
+
+are  able  to  position  components  within  the  sub-container  with  precision,  just  like  on  the  root
+
+container.
+
+You  can  also  change  the  layout  of  subcontainers  to  another  classical  layout  manager  (e.g.  grid
+
+layout, box layout, etc..) and drag components directly into it just as you did with the old designer.
+
+This is very useful if parts of your form lend themselves. As an example, let’s drag a container onto
+
+the  canvas  that  uses  BoxLayout  Y.  (You  can  find  this  under  the  "Containers"  section  of  the
+
+component palette).
+
+Drag the button (that was previously on the form) over that container, and you should see a drop-
+
+zone become highlighted.
+
+89
+
+Figure 89. Dropping container on child container with box layout y
+
+You  can  drop  the  button  directly  there.  You  can  As  you  drag  more  components  into  the  sub-
+
+container, you’ll see them automatically laid out vertically.
+
+Figure 90. Box Layout Y dropping 2nd child
+
+The Canvas Resize Tool
+
+When  designing  a  UI  with  the  new  designer  it  is  very  important  that  you  periodically  test  the
+
+form’s "resizing" behavior so that you know how it will behave on different devices. Components
+
+may appear to be positioned correctly when the canvas is one size, but become out of whack when
+
+the  container  is  resized.  After  nearly  every  manipulation  you  perform,  it  is  good  practice  to  drag
+
+the canvas resize tool (the button in the lower right corner of the designer) smaller and bigger so
+
+you can see how the positions are changed. If things grow out of whack, you may need to toggle an
+
+inset  between  fixed  and  auto,  or  add  a  link  between  some  of  the  components  so  that  the  resizing
+
+behavior matches your expectations.
+
+90
+
+3. Theme Basics
+
+This chapter covers the creation of a simple hello world style theme and its visual customization. It
+
+uses the Codename One Designer tool to demonstrate basic concepts in theme creation such as 9-
+
+piece  borders,  selectors  and  style  types. We  would  recommend  reviewing  this  even  if  you  end  up
+
+using CSS.
+
+3.1. Understanding Codename One Themes
+
+Codename One themes are pluggable CSS like elements that allow developers to determine/switch
+
+the  look  of  the  application  in  runtime.  A  theme  can  be  installed  via  the  UIManager  class
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/plaf/UIManager.html]  and  themes  can  be  layered
+
+one on top of the other (like CSS). A theme can be generated from CSS as well, we’ll cover this (and
+
+the supported CSS syntax) soon.
+
+By  default,  Codename  One  themes  derive  the  native  operating  system  themes,  although  this
+
+behavior is entirely optional.
+
+A  theme 
+
+initializes  the  Style  [https://www.codenameone.com/javadoc/com/codename1/ui/plaf/Style.html]
+
+objects,  which  are  then  used  by  the  components  to  render  themselves  or  by  the  LookAndFeel
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/plaf/LookAndFeel.html]  and  DefaultLookAndFeel
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/plaf/DefaultLookAndFeel.html]  classes  to  create  the
+
+appearance of the application.
+
+Codename  One 
+
+themes  have  some  built-in  defaults.  E.g.  borders 
+
+for  buttons  and
+
+padding/margin/opacity  for  various  components.  These  are  a  set  of  “common  sense”  defaults  that
+
+can be overridden within the theme.
+
+Codename One themes are effectively a set of UIID’s mapped to a Style [https://www.codenameone.com/
+
+javadoc/com/codename1/ui/plaf/Style.html] object. Codename One applications always have a theme, you
+
+can modify it to suit your needs and you can add multiple themes within the main resource file.
+
+You  can  also  add  multiple  resource  files  to  a  project  and  work  with  them.  In  code  a  theme  is
+
+initialized using this code in your main class:
+
+private Resources theme;
+
+public void init(Object context) {
+    theme = UIManager.initFirstTheme("/theme");
+}
+
+The  initFirstTheme  method  is  a  helper  method  that  hides  some  try/catch  logic  as  well  as  some
+verbosity. This could be expressed as:
+
+91
+
+try {
+    theme = Resources.openLayered("/theme");
+    UIManager.getInstance().setThemeProps(theme.getTheme(theme.getThemeResourceNames()[0]));
+} catch(IOException e){
+    e.printStackTrace();
+}
+
+3.2. Customizing Your Theme
+
+We can launch the designer tool by double clicking on the theme.res file found in typical Codename
+One applications. In the left side you can see the section picker and within it the Theme section.
+
+Figure 91. The theme area in the designer
+
+When you select the theme you will see the theme default view.
+
+92
+
+Figure 92. Theme default view
+
+There are several interesting things to notice here the preview section allows us to instantly see the
+
+changes we make to the theme data.
+
+Figure 93. Theme preview section
+
+The theme state tabs and constant tabs allow us to pass between the various editing modes for the
+
+theme and also add theme constants.
+
+We discussed styles before, you can pick the right style mode through the tabs.
+
+93
+
+Figure 94. You can use these tabs to add the various types of styles and theme constants
+
+The most important section is the style section. It allows us to add/edit/remove style UIID’s.
+
+Notice the  Default Style section, it allows us to customize global defaults for the styles. Use it with
+
+caution as changes here can have wide implications.
+
+Figure 95. The theme selection area allows us to add, edit and delete entries. Notice the default style entry
+
+which is a unique special case
+
+When we add an entry to the style we can just type the desired UIID into the box at the top of the
+
+dialog. We can also pick a UIID from the combo box but that might not include all potential options.
+
+
+
+You can use the Component Inspector tool in the simulator to locate a component
+
+and its UIID in a specific Form [https://www.codenameone.com/javadoc/com/codename1/ui/
+
+Form.html]
+
+Figure 96. When pressing the Add/Edit entry we can edit a specific style entry UIID
+
+When we add/edit an entry an important piece of the puzzle is the  Derive check box that appears
+
+next  to  all  of  the  UIID  entries.  All  styles  derive  from  the  base  style  and  usually  from  the  native
+
+94
+
+theme defaults, so when this flag is checked the defaults will be used.
+
+When  you  uncheck  that  checkbox  the  fields  below  it  become  editable  and  you  can  override  the
+
+default behavior. To restore the default just recheck that flag.
+
+
+
+A common oddity for developers is that when they press  Add and don’t derive any
+
+entry nothing is actually added. The entries in the theme are essentially key/value
+
+pairs so when you don’t add anything there are no keys so the entry doesn’t show
+
+up
+
+3.3. Customizing The Title
+
+The title is a great target for customization since it includes a few interesting "complexities".
+
+The Title is surrounded by a TitleArea container that encloses it, above the title you will also see
+the StatusBar UIID that prevents the status details from drawing on top of the title text.
+
+Figure 97. Title Area UIID’s
+
+
+
+The StatusBar UIID is a special case that is only there on iOS. In iOS the application
+needs  to  render  the  section  under  the  status  bar  (which  isn’t  the  case  for  other
+OS’s) and the StatusBar UIID was added so developers can ignore that behavior.
+
+3.3.1. Background Priorities and Types
+
+A slightly confusing aspects of styles in Codename One is the priorities of backgrounds. When you
+
+define  a  specific  type  of  background  it  will  override  prior  definitions,  this  even  applies  to
+
+inheritance.
+
+E.g. if the theme defined a border for the Button UIID (a very common case) if you will try to define
+the background image or the background color of Button those will be ignored!
+
+
+
+The solution is to derive the border and select the Empty border type
+
+The order for UIID settings for background is as follows:
+
+1. Border  -  if  the  component  has  a  border  it  can  override  everything.  Image  borders  always
+
+override all background settings you might have.
+
+2. Image or gradient - an image or gradient background overrides background color/transparency
+
+settings.
+
+3. Background Color/Transparency - If transparency is larger than 0 then this takes effect.
+
+95
+
+3.3.2. The Background Behavior and Image
+
+Lets start in the first page of the style entry, we’ll customize the background behavior for the Title
+UIID and demonstrate/explain some of the behaviors.
+
+The pictures below demonstrate the different types of background image behaviors.
+
+Figure 98. IMAGE_SCALED scales the image without preserving aspect ratio to fit the exact size of the
+
+component
+
+Figure 99. IMAGE_SCALED_FILL scales the image while preserving aspect ratio so it fills the entire space of
+
+the component
+
+96
+
+
+
+Aspect ratio is the ratio between the width and the height of the image. E.g. if the
+image  is  100x50  pixels  and  we  want  the  width  to  be  200  pixels  preserving  the
+aspect ratio will require the height to also double to 200x100.
+We highly recommend preserving the aspect ratio to keep images more "natural".
+
+Figure 100. IMAGE_SCALED_FIT scales the image while preserving aspect ratio so it fits within the
+
+component
+
+Figure 101. IMAGE_TILE_BOTH tiles the image on both axis of the component
+
+97
+
+Figure 102. IMAGE_TILE_VERTICAL_ALIGN_LEFT tiles the image on the left side of the component
+
+Figure 103. IMAGE_TILE_VERTICAL_ALIGN_CENTER tiles the image in the middle of the component
+
+98
+
+Figure 104. IMAGE_TILE_VERTICAL_ALIGN_RIGHT tiles the image on the right side of the component
+
+Figure 105. IMAGE_TILE_HORIZONTAL_ALIGN_TOP tiles the image on the top of the component
+
+99
+
+Figure 106. IMAGE_TILE_HORIZONTAL_ALIGN_CENTER tiles the image in the middle of the component
+
+Figure 107. IMAGE_TILE_HORIZONTAL_ALIGN_BOTTOM tiles the image to the bottom of the component
+
+100
+
+Figure 108. IMAGE_ALIGNED_TOP places the image centered at the top part of the component
+
+Figure 109. IMAGE_ALIGNED_BOTTOM places the image centered at the bottom part of the component
+
+101
+
+Figure 110. IMAGE_ALIGNED_LEFT places the image centered at the left part of the component
+
+Figure 111. IMAGE_ALIGNED_RIGHT places the image centered at the right part of the component
+
+102
+
+Figure 112. IMAGE_ALIGNED_TOP_LEFT places the image at the top left corner
+
+Figure 113. IMAGE_ALIGNED_TOP_RIGHT places the image at the top right corner
+
+103
+
+Figure 114. IMAGE_ALIGNED_BOTTOM_LEFT places the image at the bottom left corner
+
+Figure 115. IMAGE_ALIGNED_BOTTOM_RIGHT places the image at the bottom right corner
+
+104
+
+Figure 116. IMAGE_ALIGNED_CENTER places the image in the middle of the component
+
+3.3.3. The Color Settings
+
+The color settings are much simpler than the background behavior. As explained above the priority
+
+for color is at the bottom so if you have a border, image or gradient defined the background color
+
+settings will be ignored.
+
+Figure 117. Add theme entry color settings
+
+There are three color settings:
+
+• Foreground  color  is  the  RRGGBB  color  that  sets  the  style  foreground  color  normally  used  to
+
+draw the text of the component. You can use the color picker button on the side to pick a color
+
+• Background same as foreground only determines the background color of the component
+
+• Transparency  represents  the  opacity  of  the  component  background  as  a  value  between  0
+
+(transparent) and 255 (opaque)
+
+105
+
+
+
+Setting the background will have no effect unless transparency is higher than 0. If
+
+you don’t explicitly define this it might have a different value based on the native
+
+theme
+
+3.3.4. Alignment
+
+Not  all  component  types  support  alignment  and  even  when  they  do  they  don’t  support  it  for  all
+
+elements.  E.g.  a  Label  [https://www.codenameone.com/javadoc/com/codename1/ui/Label.html]  and 
+
+its
+
+subclasses support alignment but will only apply it to the text and not the icon.
+
+Notice  that  Container  [https://www.codenameone.com/javadoc/com/codename1/ui/Container.html]  doesn’t
+
+support alignment. You should use the layout manager to tune component positioning.
+
+Figure 118. Alignment of the text within some component types
+
+
+
+Aligning text components to anything other than the default alignment might be a
+
+problem if they are editable. The native editing capabilities might collide with the
+
+alignment behavior.
+
+ Bidi/RtL layout reverses the alignment value so left becomes right and visa versa
+
+3.3.5. Padding and Margin
+
+Padding  and  margin  are  concepts  derived  from  the  CSS  box  model.  They  are  slightly  different  in
+
+Codename One, where the border spacing is part of the padding, but other than that they are pretty
+
+similar:
+
+106
+
+Figure 119. Padding and Margin/Box Model
+
+In the diagram, we can see the component represented in yellow occupying its preferred size. The
+
+padding portion in gray effectively increases the components size. The margin is the space between
+
+components, it allows us to keep whitespace between multiple components. Margin is represented
+
+in red in the diagram.
+
+The  theme  allows  us  to  customize  the  padding/margin,  and  specify  them  for  all  4  sides  of  a
+
+component. They can be specified in pixels, millimeters/dips, or screen percentage:
+
+Figure 120. Padding tab
+
+
+
+We recommend using millimeters for all spacing to make it look good for all device
+
+densities. Percentages make sense only in very extreme cases
+
+3.3.6. Borders
+
+Borders are a big subject in their own right, the UI for their creation is also a bit confusing:
+
+107
+
+Figure 121. Border entry in the theme
+
+3.3.7. 9-Piece Image Border
+
+A common border type is the 9-piece image border, to facilitate that border type we have a special
+
+Image Border Wizard.
+
+A 9 piece image border is a common convention in UI theming that divides a border into 9 pieces 4
+
+representing corners, 4 representing the sides and one representing the middle.
+
+
+
+Android  uses  a  common  variation  on  the  9-piece  border:  9-patch.  The  main
+
+difference between the 9-piece border and 9-patch is that 9-piece borders tile the
+
+sides/center whereas 9-patch scales them
+
+9-piece  image  borders  work  better  than  background  images  for  many  use  cases  where  the
+
+background needs to "grow/shrink" extensively and might need to change aspect ratio.
+
+They  don’t  work  well  in  cases  where  the  image  is  asymmetric  on  both  axis.  E.g.  a  radial  gradient
+
+image. 9-piece images in general don’t work very well with complex gradients.
+
+The image border wizard simplifies the process of generating a 9-piece image border using a 3 stage
+
+process.
+
+108
+
+Figure 122. Stage 1: create or pick an image from an existing PNG file that we will convert to a 9-piece
+
+image
+
+
+
+Use an image that’s designed for a high DPI device
+
+For  your  convenience  you  can  create  a  rudimentary  image  with  the  create  image  stage  but  for  a
+
+professional looking application you would usually want to use a design by a professional designer.
+
+109
+
+Figure 123. Stage 2: Cutting the image and adapting it to the DPI’s
+
+The second stage is probably the hardest and most important one in this wizard!
+
+You  can  change  the  values  of  the  top/bottom/left/right  spinners  to  move  the  position  of  the  guide
+
+lines  that  indicate  the  various  9  pieces.  The  image  shows  the  correct  cut  for  this  image  type  with
+
+special attention to the following:
+
+• The left/right position is high enough to fit in the rounded corners in their entirety. Notice that
+
+we didn’t just leave 1 pixel as that performs badly, we want to leave as much space as possible!
+
+• The  top  and  bottom  lines  have  exactly  one  pixel  between  them.  This  is  to  avoid  breaking  the
+
+gradient. E.g. if we set the lines further apart we will end up with this:
+
+Figure 124. This is why it’s important to keep the lines close when a gradient is involved, notice the tiling
+
+effect…
+
+Figure 125. When the lines are close together the gradient effect grows more effectively
+
+• The  elements  on  the  right  hand  side  include  the  Generate Multi Image  options.  Here  you  can
+
+indicate the density of the source image you are using (e.g. if its for iPhone 5 class device pick
+
+Very High). You can then select in the checkboxes below the densities that should be generated
+
+automatically  for  you.  This  allows  fine  detail  on  the  border  to  be  maintained  in  the  various
+
+high/low resolution devices.
+
+We go into a lot of details about multi images in the advanced theming section.
+
+
+
+110
+
+Figure 126. Stage 3: Styles to which the border is applied
+
+The  last  page  indicates  the  styles  to  which  the  wizard  will  apply  the  border.  Under  normal  usage
+
+you don’t really need to touch this as its properly filled out.
+
+You can define the same border for multiple UIIDs from here though.
+
+Border Minimum Size
+
+A  common  oddity  when  using  the  image  borders  is  the  fact  that  even  when  padding  is
+
+removed the component might take a larger size than the height of the text within it.
+
+The reason for that is the border. Because of the way borders are implemented they can’t be
+
+drawn  to  be  smaller  than  the  sum  of  their  corners.  E.g.  the  minimum  height  of  a  border
+
+would be the height of the bottom corner + the height of the top corner. The minimum width
+
+would be the width of the left + right corners.
+
+This  is  coded  into  the  common  preferred  size  methods  in  Codename  One  and  components
+
+generally don’t shrink below the size of the image border even if padding is 0.
+
+Customizing The 9-Piece Border
+
+Normally  we  can  just  use  the  9-piece  border  wizard  but  we  can  also  customize  the  border  by
+
+pressing the "…" button on the border section in the theme.
+
+111
+
+Figure 127. Press this to customize borders
+
+The UI for the 9-piece border we created above looks like this.
+
+Figure 128. 9-piece border in edit mode
+
+You can pick the image represented by every section in the border from the combo boxes. They are
+
+organized in the same way the border is with the 9-pieces placed in the same position they would
+
+occupy when the border is rendered.
+
+112
+
+ Notice that the other elements in the UI are disabled when the image border type
+
+is selected.
+
+3 Image Mode
+
+The 9-piece border has a (rarely used) special case: 3 image mode. In this mode a developer
+
+can  specify  the  top  left  corner,  the  top  image  and  the  center  image  to  produce  a  9  piece
+
+border. The corner and top piece are then rotated dynamically to produce a standard 9-piece
+
+border on the device.
+
+This  is  useful  for  reducing  application  code  size  but  isn’t  used  often  as  it  requires  a  more
+
+symetric UI.
+
+ Don’t  confuse  the  3-image  mode  for  the  9-piece  border  with  the
+
+horizontal/vertical image border below
+
+3.3.8. Horizontal/Vertical Image Border
+
+The  9-piece  border  is  the  workhorse  of  borders  in  Codename  One,  however  there  are  some  edge
+
+cases of UI elements that should grow on one axis and not on another. A perfect example of this is
+
+the  iOS  6  style  back  button.  If  we  tried  to  cut  it  into  a  9-piece  border  the  arrow  effect  would  be
+
+broken.
+
+Figure 129. Horizontal image border is commonly used for UI’s that can’t grow vertically e.g. the iOS 6 style
+
+back button
+
+113
+
+The  horizontal  and  vertical  image  borders  accept  3  images  of  their  respective  AXIS  and  build  the
+
+border  by  placing  one  image  on  each  side  and  tiling  the  center  image  between  them.  E.g.  A
+
+horizontal border will never grow vertically.
+
+
+
+In RTL/Bidi  [1] modes the borders flip automatically to show the reverse direction.
+An iOS style back button will point to the right in such languages.
+
+3.3.9. Empty Border
+
+Empty borders enforce the removal of a border. This is important if you would like to block a base
+
+style from having a border.
+
+E.g.  Buttons  have  borders  by  default. 
+
+If  you  would 
+
+like 
+
+to 
+
+create  a  Button
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/Button.html]  that  is  strictly  of  solid  color  you
+
+could just define the border to be empty and then use the solid color as you see fit.
+
+ There is a null border which is often confused with an empty border. You should
+
+use empty border and not null border
+
+3.3.10. Round Border
+
+Circles and completely round border sides are problematic for multi-resolutions. You need to draw
+
+them dynamically and can’t use image borders which can’t be tiled/cut to fit round designs (due to
+
+physical constraints of the round shape).
+
+We designed the RoundBorder to enable two distinct types of borders:
+
+• Circular borders - e.g. Android floating action
+
+• Rectangles with round (not rounded) sides
+
+Round  Border  is  a  bit  confusing  since  we  already  support  a  rounded  border  type.  The  rounded
+
+border type is a rectangle with rounded corners whereas the round border has completely round
+
+sides or appears as a circle.
+
+To make matters worse the round border has a ridiculous number of features/configurations that
+
+would  have  made  the  already  cluttered  UI  darn  near  impossible  to  navigate.  To  simplify  this  we
+
+split the UI into 3 tabs for standard borders, image borders and round border.
+
+114
+
+Figure 130. Round Border
+
+3.3.11. Rounded Rectangle Border
+
+The RoundRectBorder was developed based on the RoundBorder and has similar features. It produces a
+rounded rectangle UI.
+
+
+
+Don’t confuse the Rounded Rectangle border with the deprecated Rounded border…
+
+It’s a pretty simple border type akin to the RoundBorder.
+
+Figure 131. Rounded Rectangle Border
+
+3.3.12. Bevel/Etched Borders
+
+We generally recommend avoiding bevel/etched border types as they aren’t as efficient and look a
+
+bit dated in todays applications. We cover them here mostly for completeness.
+
+115
+
+Figure 132. Bevel border
+
+Figure 133. Etched border
+
+3.3.13. Derive
+
+Derive allows us to inherit the behavior of a UIID and extend it with some customization.
+
+E.g. Lets say we created a component that’s supposed to look like a title, we could do something like:
+
+cmp.setUIID("Title");
+
+But  title  might  sometimes  be  aligned  to  the  left  (based  on  theme)  and  we  always  want  our
+
+component to be center aligned. However, we don’t want that to affect the actual titles in the app…
+
+To solve this we can define a MyTitle UIID and derive the Title UIID. Then just customize that one
+attribute.
+
+Figure 134. Derive title
+
+116
+
+Issues With Derive
+
+Style inheritance is a problematic topic in every tool that supports such behavior. Codename
+
+One styles start from a global default then have a system default applied and on top of that
+
+have the native OS default applied to them.
+
+At  that  point  a  developer  can  define  the  style  after  all  of  the  user  settings  are  in  place.
+
+Normally this works reasonably well, but there are some edge cases where inheriting a style
+
+can fail.
+
+When  you  override  an  existing  style  such  as  Button  and  choose  to  derive  from  Button  in  a
+different  selection  mode  or  even  a  different  component  altogether  such  as  Label  you  might
+trigger a recursion effect where a theme setting in the base theme depends on something in a
+
+base triggering an infinite loop.
+
+To avoid this always inherit only from UIID’s you defined e.g. MyButton.
+
+3.3.14. Fonts
+
+Codename One currently supports 3 font types:
+
+• System fonts — these are very simplistic builtin fonts. They work on all platforms and come in
+
+one of 3 sizes. However, they are ubiquitous and work in every platform in all languages.
+
+• TTF files — you can just place a TTF file in the src directory of the project and it will appear in
+
+the True Type combo box.
+
+• Native fonts — these aren’t supported on all platforms but generally they allow you to use a set
+
+of platform native good looking fonts. E.g. on Android the devices Roboto font will be used and
+
+on iOS San Francisco or Helvetica Neue will be used. This is the recommended font type we
+
+suggest for most use cases!
+
+ If  you  use  a  TTF  file  MAKE  SURE  not  to  delete  the  file  when  there  MIGHT  be  a
+
+reference to it. This can cause hard to track down issues!
+
+
+
+Notice  that  a  TTF  file  must  have  the  ".ttf"  extension,  otherwise  the  build  server
+
+won’t be able to recognize the file as a font and set it up accordingly (devices need
+
+fonts to be defined in very specific ways). Once you do that, you can use the font
+
+from code or from the theme
+
+117
+
+Figure 135. Font Theme Entry
+
+ System fonts are always defined even if you use a TTF or native font. If the native
+
+font/TTF is unavailable in a specific platform the system font will be used instead.
+
+You  can  size  native/TTF  fonts  either  via  pixels,  millimeters  or  based  on  the  size  of  the  equivalent
+
+system fonts:
+
+1. System font size - the truetype font will have the same size as a small, medium or large system
+
+font. This allows the developer to size the font based on the device DPI
+
+2. Millimeter size - allows sizing the font in a more DPI aware size
+
+3. Pixels - useful for some unique cases, but highly problematic in multi-DPI scenarios
+
+ You  should  notice  that  font  sizing  is  very  inconsistent  between  platforms  we
+
+recommend using millimeters for sizing
+
+You can load a truetype font from code using:
+
+if(Font.isTrueTypeFileSupported()) {
+    Font myFont = Font.createTrueTypeFont(fontName, fontFileName);
+    myFont = myFont.derive(sizeInPixels, Font.STYLE_PLAIN);
+    // do something with the font
+}
+
+Notice that, in code, only pixel sizes are supported, so it’s up to you to decide how to convert that.
+We  recommend  using  millimeters  with  the  convertToPixels  method.  You  also  need  to  derive  the
+font with the proper size, unless you want a 0 sized font which isn’t very useful.
+
+The font name is the difficult bit, iOS requires the name of the font in order to load the font. This
+
+font name doesn’t always correlate to the file name making this task rather "tricky". The actual font
+
+name is sometimes viewable within a font viewer. It isn’t always intuitive, so be sure to test that on
+
+the device to make sure you got it right.
+
+118
+
+
+
+due  to  copyright  restrictions  we  cannot  distribute  Helvetica  and  thus  can’t
+
+simulate it. In the simulator you will see Roboto and not the device font unless you
+
+are running on a Mac
+
+The code below demonstrates all the major fonts available in Codename One with the handlee ttf
+
+file posing as a standin for arbitrary TTF:
+
+private Label createForFont(Font fnt, String s) {
+  Label l = new Label(s);
+  l.getUnselectedStyle().setFont(fnt);
+  return l;
+}
+
+public void showForm() {
+  GridLayout gr = new GridLayout(5);
+  gr.setAutoFit(true);
+  Form hi = new Form("Fonts", gr);
+
+  int fontSize = Display.getInstance().convertToPixels(3);
+
+  // requires Handlee-Regular.ttf in the src folder root!
+  Font ttfFont = Font.createTrueTypeFont("Handlee", "Handlee-Regular.ttf").
+                      derive(fontSize, Font.STYLE_PLAIN);
+
+  Font smallPlainSystemFont = Font.createSystemFont(Font.FACE_SYSTEM, Font.STYLE_PLAIN, Font.SIZE_SMALL);
+  Font mediumPlainSystemFont = Font.createSystemFont(Font.FACE_SYSTEM, Font.STYLE_PLAIN, Font.SIZE_MEDIUM);
+  Font largePlainSystemFont = Font.createSystemFont(Font.FACE_SYSTEM, Font.STYLE_PLAIN, Font.SIZE_LARGE);
+  Font smallBoldSystemFont = Font.createSystemFont(Font.FACE_SYSTEM, Font.STYLE_BOLD, Font.SIZE_SMALL);
+  Font mediumBoldSystemFont = Font.createSystemFont(Font.FACE_SYSTEM, Font.STYLE_BOLD, Font.SIZE_MEDIUM);
+  Font largeBoldSystemFont = Font.createSystemFont(Font.FACE_SYSTEM, Font.STYLE_BOLD, Font.SIZE_LARGE);
+  Font smallItalicSystemFont = Font.createSystemFont(Font.FACE_SYSTEM, Font.STYLE_ITALIC, Font.SIZE_SMALL);
+  Font mediumItalicSystemFont = Font.createSystemFont(Font.FACE_SYSTEM, Font.STYLE_ITALIC, Font.SIZE_MEDIUM);
+  Font largeItalicSystemFont = Font.createSystemFont(Font.FACE_SYSTEM, Font.STYLE_ITALIC, Font.SIZE_LARGE);
+
+  Font smallPlainMonospaceFont = Font.createSystemFont(Font.FACE_MONOSPACE, Font.STYLE_PLAIN, Font.SIZE_SMALL);
+  Font mediumPlainMonospaceFont = Font.createSystemFont(Font.FACE_MONOSPACE, Font.STYLE_PLAIN, Font.SIZE_MEDIUM);
+  Font largePlainMonospaceFont = Font.createSystemFont(Font.FACE_MONOSPACE, Font.STYLE_PLAIN, Font.SIZE_LARGE);
+  Font smallBoldMonospaceFont = Font.createSystemFont(Font.FACE_MONOSPACE, Font.STYLE_BOLD, Font.SIZE_SMALL);
+  Font mediumBoldMonospaceFont = Font.createSystemFont(Font.FACE_MONOSPACE, Font.STYLE_BOLD, Font.SIZE_MEDIUM);
+  Font largeBoldMonospaceFont = Font.createSystemFont(Font.FACE_MONOSPACE, Font.STYLE_BOLD, Font.SIZE_LARGE);
+  Font smallItalicMonospaceFont = Font.createSystemFont(Font.FACE_MONOSPACE, Font.STYLE_ITALIC, Font.SIZE_SMALL);
+  Font mediumItalicMonospaceFont = Font.createSystemFont(Font.FACE_MONOSPACE, Font.STYLE_ITALIC, Font.SIZE_MEDIUM);
+  Font largeItalicMonospaceFont = Font.createSystemFont(Font.FACE_MONOSPACE, Font.STYLE_ITALIC, Font.SIZE_LARGE);
+
+  Font smallPlainProportionalFont = Font.createSystemFont(Font.FACE_PROPORTIONAL, Font.STYLE_PLAIN, Font.SIZE_SMALL);
+  Font mediumPlainProportionalFont = Font.createSystemFont(Font.FACE_PROPORTIONAL, Font.STYLE_PLAIN, Font.SIZE_MEDIUM);
+  Font largePlainProportionalFont = Font.createSystemFont(Font.FACE_PROPORTIONAL, Font.STYLE_PLAIN, Font.SIZE_LARGE);
+  Font smallBoldProportionalFont = Font.createSystemFont(Font.FACE_PROPORTIONAL, Font.STYLE_BOLD, Font.SIZE_SMALL);
+  Font mediumBoldProportionalFont = Font.createSystemFont(Font.FACE_PROPORTIONAL, Font.STYLE_BOLD, Font.SIZE_MEDIUM);
+  Font largeBoldProportionalFont = Font.createSystemFont(Font.FACE_PROPORTIONAL, Font.STYLE_BOLD, Font.SIZE_LARGE);
+  Font smallItalicProportionalFont = Font.createSystemFont(Font.FACE_PROPORTIONAL, Font.STYLE_ITALIC, Font.SIZE_SMALL);
+  Font mediumItalicProportionalFont = Font.createSystemFont(Font.FACE_PROPORTIONAL, Font.STYLE_ITALIC, Font.SIZE_MEDIUM);
+  Font largeItalicProportionalFont = Font.createSystemFont(Font.FACE_PROPORTIONAL, Font.STYLE_ITALIC, Font.SIZE_LARGE);
+
+  String[] nativeFontTypes = {
+      "native:MainThin", "native:MainLight",
+      "native:MainRegular", "native:MainBold",
+      "native:MainBlack", "native:ItalicThin",
+      "native:ItalicLight", "native:ItalicRegular",
+      "native:ItalicBold", "native:ItalicBlack"};
+
+  for(String s : nativeFontTypes) {
+      Font tt  = Font.createTrueTypeFont(s, s).derive(fontSize, Font.STYLE_PLAIN);
+
+119
+
+      hi.add(createForFont(tt, s));
+  }
+
+  hi.add(createForFont(ttfFont, "Handlee TTF Font")).
+          add(createForFont(smallPlainSystemFont, "smallPlainSystemFont")).
+          add(createForFont(mediumPlainSystemFont, "mediumPlainSystemFont")).
+          add(createForFont(largePlainSystemFont, "largePlainSystemFont")).
+          add(createForFont(smallBoldSystemFont, "smallBoldSystemFont")).
+          add(createForFont(mediumBoldSystemFont, "mediumBoldSystemFont")).
+          add(createForFont(largeBoldSystemFont, "largeBoldSystemFont")).
+          add(createForFont(smallPlainSystemFont, "smallItalicSystemFont")).
+          add(createForFont(mediumItalicSystemFont, "mediumItalicSystemFont")).
+          add(createForFont(largeItalicSystemFont, "largeItalicSystemFont")).
+
+          add(createForFont(smallPlainMonospaceFont, "smallPlainMonospaceFont")).
+          add(createForFont(mediumPlainMonospaceFont, "mediumPlainMonospaceFont")).
+          add(createForFont(largePlainMonospaceFont, "largePlainMonospaceFont")).
+          add(createForFont(smallBoldMonospaceFont, "smallBoldMonospaceFont")).
+          add(createForFont(mediumBoldMonospaceFont, "mediumBoldMonospaceFont")).
+          add(createForFont(largeBoldMonospaceFont, "largeBoldMonospaceFont")).
+          add(createForFont(smallItalicMonospaceFont, "smallItalicMonospaceFont")).
+          add(createForFont(mediumItalicMonospaceFont, "mediumItalicMonospaceFont")).
+          add(createForFont(largeItalicMonospaceFont, "largeItalicMonospaceFont")).
+
+          add(createForFont(smallPlainProportionalFont, "smallPlainProportionalFont")).
+          add(createForFont(mediumPlainProportionalFont, "mediumPlainProportionalFont")).
+          add(createForFont(largePlainProportionalFont, "largePlainProportionalFont")).
+          add(createForFont(smallBoldProportionalFont, "smallBoldProportionalFont")).
+          add(createForFont(mediumBoldProportionalFont, "mediumBoldProportionalFont")).
+          add(createForFont(largeBoldProportionalFont, "largeBoldProportionalFont")).
+          add(createForFont(smallItalicProportionalFont, "smallItalicProportionalFont")).
+          add(createForFont(mediumItalicProportionalFont, "mediumItalicProportionalFont")).
+          add(createForFont(largeItalicProportionalFont, "largeItalicProportionalFont"));
+
+  hi.show();
+}
+
+Figure 136. The fonts running on the ipad simulator on a Mac, notice that this will look different on a PC
+
+120
+
+Figure 137. The same demo running on a OnePlus One device with Android 5.1
+
+Font Effects
+
+You can define an effect to be applied to a specific font, specifically:
+
+• Underline
+
+• Strike thru
+
+• 3d text raised/lowered
+
+• 3d shadow north
+
+The "3d" effects effectively just draw the text twice, with a sligh offest and two different colors to
+
+create a "3d" feel.
+
+All of the effects are relatively simple and performant.
+
+[1] Languages that are written from right to left such as Hebrew, Arabic etc.
+
+121
+
+122
+
+4. Advanced Theming
+
+Before we go into CSS there are a few advanced theme concepts. Notice this still applies to CSS as
+
+features such as theme constants are used there as well…
+
+4.1. Working With UIID’s
+
+UIID’s (User Interface IDentifier) are unique qualifiers given to UI components that associate a set
+of theme definitions with a specific set of components. E.g. we can associate the Button UIID with a
+component and then define the look for the Button in the theme.
+
+One of the biggest advantages with UIID’s is the ability to change the UIID of a component. E.g. to
+
+create a multiline label, one can use something like:
+
+TextArea t = …;
+t.setUIID("Label");
+t.setEditable(false);
+
+
+
+This 
+
+is 
+
+pretty  much 
+
+how 
+
+components 
+
+such 
+
+as 
+
+SpanLabel
+
+[https://www.codenameone.com/javadoc/com/codename1/components/SpanLabel.html] 
+
+are
+
+implemented internally
+
+UIID’s  can  be  customized  via  the  GUI  builder  and  allow  for  powerful  customization  of  individual
+
+components.
+
+ The class name of the component is commonly the same as the UIID, but they are
+
+in essence separate entities
+
+4.2. Theme Layering
+
+There are two use cases in which you would want to use layering:
+
+• You want a slightly different theme in one platform
+
+• You want the ability to customize your theme for a specific use case, e.g. let a user select larger
+
+fonts
+
+This  is  actually  pretty  easy  to  do  and  doesn’t  require  re-doing  the  entire  theme.  You  can  do
+
+something very similar to the cascading effect of CSS where a theme is applied "on top" of another
+
+theme. To do that just add a new theme using the Add Theme button.
+
+ Make sure to remove the includeNativeBool constant in the new theme!
+
+In  the  new  theme  define  the  changes  e.g.  if  you  just  want  a  larger  default  font  define  only  that
+
+property for all the relevant UIID’s and ignore all other properties!
+
+For a non-gui builder app the theme loading looks like this by default:
+
+123
+
+theme = UIManager.initFirstTheme("/theme");
+
+You should fix it to look like this:
+
+theme = UIManager.initNamedTheme("/theme", "Theme");
+
+ This  assumes  the  name  of  your  main  theme  is  "Theme"  (not  the  layer  theme  you
+
+just added).
+
+The original code relies on the theme being in the 0 position in the theme name array which might
+
+not be the case!
+
+When you want to add the theme layer use:
+
+UIManager.getInstance().addThemeProps(theme.getTheme("NameOfLayerTheme"));
+
+The addThemeProps call will layer the secondary theme on top of the primary "Theme" and keep the
+original UIID’s defined in the "Theme" intact.
+
+If you apply theme changes to a running application you can use Form’s `refreshTheme() to update
+the UI instantly and provide visual feedback for the theme changes.
+
+4.3. Override Resources In Platform
+
+When we want to adapt the look of an application to different OS conventions one of the common
+
+requirements is to use different icons. Sometimes we want to change behavior based on device type
+
+e.g. have a different UI structure for a Tablet.
+
+Codename One allows you to override a resource for a specific platform when doing this you can
+
+redefine a resource differently for that specific platform and also add platform specific resources.
+
+Figure 138. Override resources for specific platform
+
+Overriden resources take precedence over embedded resources thus allowing us to change the look
+or even behavior (when overriding a GUI builder element) for a specific platform/OS.
+
+124
+
+ Overriding  the  theme  is  dangerous  as  a  theme  has  external  dependencies  (e.g.
+
+image borders). The solution is to use theme layering and override the layer!
+
+To override select the platform where overriding is applicable
+
+Figure 139. Override for platform, allows us to override the checked resources and replace them with
+
+another resource
+
+You  can  then  click  the  green  checkbox  to  define  that  this  resource  is  specific  to  this  platform.  All
+
+resources  added  when  the  platform  is  selected  will  only  apply  to  the  selected  platform.  If  you
+
+change your mind and are no longer interested in a particular override just delete it in the override
+
+mode and it will no longer be overridden.
+
+4.4. Theme Constants
+
+The  Codename  One  Designer  has  a  tab  for  creating  constants  which  can  be  used  to  add  global
+
+values  of  various  types  and  behavior  hints  to  Codename  One  and  its  components.  Constants  are
+
+always  strings.  There  are  some  conventions  that  allow  the  UI  to  adapt  to  input  types  e.g.  if  a
+
+constant  ends  with  the  word  Bool  it  is  treated  as  a  boolean  (true/false)  value.  Such  a  value  will
+display as a checkbox. Similarly an Int suffix will display a numeric picker and an Image suffix will
+show a combo box to pick an image.
+
+ The  combo  box  in  the  designer  for  adding  a  theme  constant  is  editable,  you  can
+
+just type in any value you want!
+
+To  use  a  constant  one  can  use  the  UIManager  [https://www.codenameone.com/javadoc/com/codename1/ui/
+
+plaf/UIManager.html]'s methods to get the appropriate constant type specifically:
+
+• getThemeConstant
+
+• isThemeConstant
+
+• getThemeImageConstant
+
+Internally,  Codename  One  has  several  built  in  constants  and  the  list  is  constantly  growing.  As  we
+
+add  features  to  Codename  One,  we  try  to  keep  this  list  up  to  date  but  the  very  nature  of  theme
+
+constants is "adhoc" and some might not make it here.
+
+Table 3. Theme Constants
+
+Constant
+
+alwaysTensileBool
+
+Description/Argument
+
+Enables tensile drag even when there is no
+
+scrolling in the container (only for scrollable
+
+containers)
+
+backGestureThresholdInt
+
+The threshold for the back gesture in the
+
+SwipeBackSupport [https://www.codenameone.com/
+
+javadoc/com/codename1/ui/util/SwipeBackSupport.html]
+
+class, defaults to 5
+
+125
+
+Constant
+
+backUsesTitleBool
+
+buttonRippleBool
+
+capsButtonTextBool
+
+capsButtonUiids
+
+Description/Argument
+
+Indicates to the GUI builder that the back
+
+command should use the title of the previous
+
+form and not just the word "Back"
+
+true to activate the material design ripple effect
+on the buttons. This effect draws a growing
+
+circle from the point of touch onwards. This is
+false by default except for Android where it
+defaults to true. This is equivalent to
+setButtonRippleEffectDefault(bool) in the Button
+class
+
+true to activate the caps text mode in the
+buttons. When activated setText on Button and
+all the constructors will invoke upcase() on all
+the strings effectively making the application
+buttons use uppercase exclusively. This is false
+by default except for Android where it defaults
+to true. It’s equivalent to
+Button.setCapsTextDefault(boolean) and can be
+tuned to an individual Component via
+Component.setRippleEffect(boolean)
+
+A list of the UIID’s that should be capitalized by
+
+default (in supported platforms) other than the
+Button and RaisedButton which are already
+capitalized. This list can be separated by spaces
+
+or commas e.g.
+capsButtonUiids=UpcaseButton,OtherCustomButton
+
+defaultCommandImage
+
+Image to give a command with no icon
+
+dialogButtonCommandsBool
+
+Place commands in the dialogs as buttons
+
+dialogBlurRadiusInt
+
+dialogPosition
+
+Sets the default Gaussian blur radius for the
+
+background of the dialogs. The default value is
+
+-1 indicating no blur
+
+Place the dialog in an arbitrary border layout
+
+position (e.g. North, South, Center, etc.)
+
+centeredPopupBool
+
+Popup of the combo box will appear in the
+
+center of the screen
+
+changeTabOnFocusBool
+
+Useful for feature phones, allows changing the
+
+tab when the focus changes immediately,
+
+without pressing a key
+
+checkBoxCheckDisImage
+
+CheckBox image to use instead of Codename
+
+One drawing it on its own
+
+checkBoxCheckedImage
+
+CheckBox image to use instead of Codename
+
+One drawing it on its own
+
+126
+
+Constant
+
+Description/Argument
+
+checkBoxOppositeSideBool
+
+Indicates the check box should be drawn on the
+
+opposite side to the text and not next to the text
+
+checkBoxUncheckDisImage
+
+CheckBox image to use instead of Codename
+
+One drawing it on its own
+
+checkBoxUncheckedImage
+
+CheckBox image to use instead of Codename
+
+One drawing it on its own
+
+comboImage
+
+Combo image to use instead of Codename One
+
+commandBehavior
+
+drawing it on its own
+
+Deprecated: Don’t use this constant as it conflicts
+with the Toolbar. Indicates how commands
+should act, as a touch menu, native menu etc.
+
+Possible values: SoftKey, Touch, Bar, Title, Right,
+
+Native
+
+ComponentGroupBool
+
+Enables component group, which allows
+
+components to be logically grouped together, so
+
+the UIID’s of components would be modified
+
+based on their group placement. This allows for
+
+some unique styling effects where the first/last
+
+elements have different styles from the rest of
+
+the elements. It’s disabled by default, thus
+
+leaving its usage up to the designer
+
+dialogTransitionIn
+
+Default transition for dialog
+
+dialogTransitionInImage
+
+Default transition Image
+
+dialogTransitionOut
+
+defaultCommandImage
+
+[https://www.codenameone.com/javadoc/com/
+
+codename1/ui/Image.html] for dialog, causes a
+
+Timeline [https://www.codenameone.com/javadoc/com/
+
+codename1/ui/animations/Timeline.html] transition
+
+effect
+
+Default transition for dialog
+
+An image to place on a command if none is
+
+defined, only applies to touch commands
+
+defaultEmblemImage
+
+The emblem painted on the side of the
+
+multibutton, by default this is an arrow on some
+
+platforms
+
+dialogTransitionOutImage
+
+Default transition Image
+
+[https://www.codenameone.com/javadoc/com/
+
+codename1/ui/Image.html] for dialog, causes a
+
+Timeline [https://www.codenameone.com/javadoc/com/
+
+codename1/ui/animations/Timeline.html] transition
+
+effect
+
+disabledColor
+
+Color to use when disabling entries by default
+
+127
+
+Constant
+
+Description/Argument
+
+dlgButtonCommandUIID
+
+The UIID used for dialog button commands
+
+dlgCommandButtonSizeInt
+
+Minimum size to give to command buttons in
+
+the dialog
+
+dlgCommandGridBool
+
+Places the dialog commands in a grid for
+
+dlgInvisibleButtons
+
+dlgSlideDirection
+
+dlgSlideInDirBool
+
+dlgSlideOutDirBool
+
+uniform sizes
+
+Includes an RRGGBB color for the line
+
+separating dialog buttons, as is the case with
+
+Android 4 and iOS 7 buttons in dialogs
+
+Slide hints
+
+Slide hints
+
+Slide hints
+
+drawMapPointerBool
+
+Indicates whether a pointer should appear in
+
+the center of the map component
+
+fadeScrollBarBool
+
+Boolean indicating if the scrollbar should fade
+
+fadeScrollEdgeBool
+
+fadeScrollEdgeInt
+
+firstCharRTLBool
+
+noTextModeBool
+
+fixedSelectionInt
+
+when there is inactivity
+
+Places a fade effect at the edges of the screen to
+
+indicate that it’s possible to scroll until we reach
+
+the edge (common on Android)
+
+Amount of pixels to fade out at the edge
+
+Indicates to the GenericListCellRenderer
+
+[https://www.codenameone.com/javadoc/com/
+
+codename1/ui/list/GenericListCellRenderer.html] that it
+
+should determine RTL status based on the first
+
+character in the sentence
+
+Indicates that the on/off switch in iOS shouldn’t
+
+draw text on top of the switch, which is the case
+
+for iOS 7+ but not for prior versions
+
+Number corresponding to the fixed selection
+
+constants in List [https://www.codenameone.com/
+
+javadoc/com/codename1/ui/List.html]
+
+formTransitionIn
+
+Default transition for form
+
+formTransitionInImage
+
+Default transition Image
+
+[https://www.codenameone.com/javadoc/com/
+
+codename1/ui/Image.html] for form, causes a
+
+Timeline [https://www.codenameone.com/javadoc/com/
+
+codename1/ui/animations/Timeline.html] transition
+
+effect
+
+formTransitionOut
+
+Default transition for form
+
+128
+
+Constant
+
+Description/Argument
+
+formTransitionOutImage
+
+Default transition Image
+
+[https://www.codenameone.com/javadoc/com/
+
+codename1/ui/Image.html] for form, causes a
+
+Timeline [https://www.codenameone.com/javadoc/com/
+
+codename1/ui/animations/Timeline.html] transition
+
+effect
+
+globalToobarBool
+
+Indicates that the Toolbar API should be on/off
+
+hasRaisedButtonBool
+
+by default for all forms
+
+Is true in platforms where the theme has the
+RaisedButton UIID defined. This is currently only
+true in the native Android theme to allow some
+
+material design guidelines
+
+hideBackCommandBool
+
+Hides the back command from the side menu
+
+hideEmptyTitleBool
+
+when possible
+
+Indicates that a title with no content should be
+
+hidden even if the border for the title occupies
+
+space
+
+hideLeftSideMenuBool
+
+Hides the side menu icon that appears on the
+
+left side of the UI
+
+ignorListFocusBool
+
+Hide the focus component of the list when the
+
+infiniteImage
+
+includeNativeBool
+
+labelGap
+
+listItemGapInt
+
+list doesn’t have focus
+
+The image used by the infinite progress
+
+component, the component will rotate it as
+
+needed
+
+True to derive from the platform native theme,
+
+false to create a blank theme that only uses the
+
+basic defaults
+
+Positive floating point value representing the
+
+default gap value between the label text and the
+
+icon in millimeters
+
+Built-in item gap in the list, this defaults to 2,
+
+which predated padding/margin in Codename
+
+One
+
+listLongPressBool
+
+Indicates whether a list should handle long press
+
+events, defaults to true
+
+mapTileLoadingImage
+
+An image to preview while loading the
+
+MapComponent [https://www.codenameone.com/
+
+javadoc/com/codename1/maps/MapComponent.html]
+
+tile
+
+129
+
+Constant
+
+mapTileLoadingText
+
+Description/Argument
+
+The text of the tiles in the MapComponent
+
+[https://www.codenameone.com/javadoc/com/
+
+codename1/maps/MapComponent.html] during
+
+loading, defaults to "Loading…"
+
+mapZoomButtonsBool
+
+Indicates whether buttons should be drawn on
+
+mediaBackImage
+
+mediaFwdImage
+
+mediaPauseImage
+
+mediaPlayImage
+
+the map component
+
+Media icon used by the media player class
+
+Media icon used by the media player class
+
+Media icon used by the media player class
+
+Media icon used by the media player class
+
+menuButtonBottomBool
+
+When set to true this flag aligns the menu button
+
+menuButtonTopBool
+
+menuHeightPercent
+
+menuImage
+
+menuImageSize
+
+menuPrefSizeBool
+
+menuSlideDirection
+
+menuSlideInDirBool
+
+menuSlideOutDirBool
+
+menuTransitionIn
+
+to the bottom portion of the title. Defaults to
+
+false
+
+When set to true this flag aligns the menu button
+
+to the top portion of the title. Defaults to false
+
+Allows positioning and sizing the menu
+
+The three dot menu image used in Android and
+
+the Toolbar [https://www.codenameone.com/javadoc/
+
+com/codename1/ui/Toolbar.html] to show additional
+
+command entries
+
+The size in millimeters (floating point value) of
+
+the generated side menu image, this is only used
+
+if you don’t supply a custom image. The default
+
+value is 4.5.
+
+Allows positioning and sizing the menu
+
+Defines menu entrance effect
+
+Defines menu entrance effect
+
+Defines menu entrance effect
+
+Defines menu entrance effect
+
+menuTransitionInImage
+
+Defines menu entrance effect
+
+menuTransitionOut
+
+Defines menu exit effect
+
+menuTransitionOutImage
+
+Defines menu entrance effect
+
+menuWidthPercent
+
+minimizeOnBackBool
+
+130
+
+Allows positioning and sizing the menu
+
+Indicates whether the form should minimize the
+
+entire application when the physical back
+
+button is pressed (if available) and no command
+
+is defined as the back command. Defaults to true
+
+Constant
+
+onOffIOSModeBool
+
+Description/Argument
+
+Indicates whether the on/off switch should use
+
+the iOS or Android mode
+
+otherPopupRendererBool
+
+Indicates that a separate renderer UIID/instance
+
+PackTouchMenuBool
+
+paintsTitleBarBool
+
+should be used to the list within the combo box
+
+popup
+
+Enables preferred sized packing of the touch
+
+menu (true by default), when set to false this
+
+allows manually determining the touch menu
+
+size using percentages
+
+Indicates that the StatusBar UIID should be
+
+added to the top of the form to space down the
+
+title area, as is the case on iOS 7+ where the
+
+status bar is painted on top of the UI
+
+popupCancelBodyBool
+
+Indicates that a cancel button should appear
+
+PopupDialogArrowBool
+
+within the combo box popup
+
+Indicates whether the popup dialog has an
+
+arrow, notice that this constant will change if
+
+you change UIID of the popup dialog
+
+PopupDialogArrowBottomImage
+
+Image of the popup dialog arrow, notice that this
+
+constant will change if you change UIID of the
+
+popup dialog
+
+PopupDialogArrowTopImage
+
+Image of the popup dialog arrow, notice that this
+
+constant will change if you change UIID of the
+
+popup dialog
+
+PopupDialogArrowLeftImage
+
+Image of the popup dialog arrow, notice that this
+
+constant will change if you change UIID of the
+
+popup dialog
+
+PopupDialogArrowRightImage
+
+Image of the popup dialog arrow, notice that this
+
+constant will change if you change UIID of the
+
+popup dialog
+
+popupNoTitleAddPaddingInt
+
+Adds padding to a popup when no title is present
+
+popupTitleBool
+
+Indicates that a title should appear within the
+
+pullToRefreshImage
+
+pureTouchBool
+
+radioOppositeSideBool
+
+combo box popup
+
+The arrow image used to draw the pullToRefresh
+animation
+
+Indicates the pure touch mode
+
+Indicates the radio button should be drawn on
+
+the opposite side to the text and not next to the
+
+text
+
+radioSelectedDisImage
+
+Radio button image
+
+131
+
+Constant
+
+radioSelectedImage
+
+radioUnselectedDisImage
+
+radioUnselectedImage
+
+radioSelectedDisFocusImage
+
+radioSelectedFocusImage
+
+Description/Argument
+
+Radio button image
+
+Radio button image
+
+Radio button image
+
+Radio button image
+
+Radio button image
+
+radioUnselectedDisFocusImage
+
+Radio button image
+
+radioUnselectedFocusImage
+
+Radio button image
+
+releaseRadiusInt
+
+Indicates the distance from the button with
+
+dragging, in which the button should be
+
+released, defaults to 0
+
+rendererShowsNumbersBool
+
+Indicates whether renderers should render the
+
+entry number
+
+reverseSoftButtonsBool
+
+Swaps the softbutton positions
+
+rightSideMenuImage
+
+Same as sideMenuImage only for the right side,
+
+optional and defaults to sideMenuImage
+
+rightSideMenuPressImage
+
+Same as sideMenuPressImage only for the right
+
+scrollVisibleBool
+
+side, optional and defaults to
+
+sideMenuPressImage
+
+true/false default is platform dependent.
+Toggles whether the scroll bar is visible
+
+showBackCommandOnTitleBool
+
+Used by the Toolbar [https://www.codenameone.com/
+
+javadoc/com/codename1/ui/Toolbar.html] API to
+
+indicate whether the back button should appear
+
+on the title
+
+shrinkPopupTitleBool
+
+Indicates the title of the popup should be set to 0
+
+if it’s missing
+
+sideMenuAnimSpeedInt
+
+The speed at which a sidemenu moves defaults
+
+to 300 milliseconds
+
+sideMenuFoldedSwipeBool
+
+Indicates the side menu could be opened via
+
+swiping
+
+sideMenuImage
+
+The image representing the side menu, three
+
+lines (Hamburger menu)
+
+sideMenuPressImage
+
+Optional pressed version of the sideMenuImage
+
+sideMenuScrollVisibleBool
+
+Indicates whether the scroll bar on the side
+
+menu should be visible or not, defaults to
+
+hidden
+
+sideMenuShadowBool
+
+Indicates whether the shadow for the side menu
+
+should be drawn
+
+132
+
+Constant
+
+Description/Argument
+
+sideMenuShadowImage
+
+The image used when drawing the shadow (a
+
+default is used if this isn’t supplied)
+
+sideMenuSizeTabPortraitInt
+
+The size of the side menu when expanded in a
+
+tablet in portrait mode
+
+sideMenuSizePortraitInt
+
+The size of the side menu when expanded in a
+
+phone in portrait mode
+
+sideMenuSizeTabLandscapeInt
+
+The size of the side menu when expanded in a
+
+tablet in landscape mode
+
+sideMenuSizeLandscapeInt
+
+The size of the side menu when expanded in a
+
+phone in landscape mode
+
+sideMenuTensileDragBool
+
+Enables/disables the tensile drag behavior
+
+sideSwipeActivationInt
+
+sideSwipeSensitiveInt
+
+slideDirection
+
+slideInDirBool
+
+slideOutDirBool
+
+sliderThumbImage
+
+snapGridBool
+
+statusBarScrollsUpBool
+
+within the opened side menu
+
+Indicates the threshold in the side menu bar at
+
+which a swipe should trigger activation, defaults
+
+to 15 (percent)
+
+Indicates the region of the screen that is
+
+sensitive to side swipe in the side menu bar,
+
+defaults to 10 (percent)
+
+Default slide transition settings
+
+Default slide transition settings
+
+Default slide transition settings
+
+The thumb image that can appear on the sliders
+
+Snap to grid toggle
+
+Indicates that a tap on the status bar should
+
+scroll up the UI, only relevant in OS’s where
+
+paintsTitleBarBool is true
+
+switchButtonPadInt
+
+Indicates the padding in the on/off switch,
+
+defaults to 16
+
+switchMaskImage
+
+Indicates the mask image used in iOS mode to
+
+draw on top of the switch
+
+switchOnImage
+
+Indicates the on image used in iOS mode to draw
+
+the on/off switch
+
+switchOffImage
+
+Indicates the off image used in iOS mode to
+
+draw the on/off switch
+
+TabEnableAutoImageBool
+
+Indicates images should be filled by default for
+
+TabSelectedImage
+
+tabs
+
+Default selected image for tabs (if
+
+TabEnableAutoImageBool=true)
+
+133
+
+Constant
+
+TabUnselectedImage
+
+tabPlacementInt
+
+tabsSlideSpeedInt
+
+Description/Argument
+
+Default unselected image for tabs (if
+
+TabEnableAutoImageBool=true)
+
+The placement of the tabs in the Tabs
+
+[https://www.codenameone.com/javadoc/com/
+
+codename1/ui/Tabs.html] component: TOP = 0, LEFT
+
+= 1, BOTTOM = 2, RIGHT = 3
+
+The time of the animation that occurs (in
+
+milliseconds) between between releasing a
+
+swiped tab and reaching the next tab. Currently
+
+defaults to 200
+
+tabsFillRowsBool
+
+Indicates if the tabs should fill the row using
+
+tabsGridBool
+
+tabsOnTopBool
+
+flow layout
+
+Indicates whether tabs should use a grid layout
+
+thus forcing all tabs to have identical sizes
+
+Indicates the tabs should be drawn on top of
+
+their content in a layered UI, this allows a tab to
+
+intrude into the content of the tabs
+
+textCmpVAlignInt
+
+The vertical alignment of the text component:
+
+TOP = 0, CENTER = 4, BOTTOM = 2
+
+textComponentErrorColor
+
+A hex RGB color which defaults to null in which
+
+case this has no effect. When defined this will
+
+change the color of the border and label to the
+
+given color to match the material design styling.
+
+This implements the red border underline in
+
+cases of error and the label text color change
+
+Toggles the on top mode which makes things
+
+look like they do on Android. This defaults to
+
+true on Android and false on other OS’s. This
+
+can also be manipulated via the
+onTopMode(boolean) method in InputComponent
+however the layout will only use the theme
+
+constant
+
+toggles the animation mode which again can be
+manipulated by a method in InputComponent. If
+you want to keep the UI static without the
+
+floating hint effect set this to false. Notice this
+
+defaults to true only on Android
+
+textComponentOnTopBool
+
+textComponentAnimBool
+
+134
+
+Constant
+
+Description/Argument
+
+textComponentFieldUIID
+
+sets the UIID of the text field to something other
+than TextField this is useful for platforms such
+as iOS where the look of the text field is different
+
+within the text component. This allows us to
+
+make the background of the text field
+transparent when it’s within the TextComponent
+and make it different from the regular text field
+
+textFieldCursorColorInt
+
+The color of the cursor as an integer (not hex)
+
+tickerSpeedInt
+
+tintColor
+
+The speed of label/button etc. (in milliseconds)
+
+The aarrggbb hex color to tint the screen when a
+
+dialog is shown
+
+topMenuSizeTabPortraitInt
+
+The size of the side menu when expanded and
+
+topMenuSizePortraitInt
+
+attached to the top in a tablet in portrait mode
+
+The size of the side menu when expanded and
+
+attached to the top in a phone in portrait mode
+
+topMenuSizeTabLandscapeInt
+
+The size of the side menu when expanded and
+
+attached to the top in a tablet in landscape mode
+
+topMenuSizeLandscapeInt
+
+The size of the side menu when expanded and
+
+attached to the top in a phone in landscape
+
+mode
+
+touchCommandFillBool
+
+Indicates how the touch menu should layout the
+
+commands within
+
+touchCommandFlowBool
+
+Indicates how the touch menu should layout the
+
+transitionSpeedInt
+
+treeFolderImage
+
+commands within
+
+Indicates the default speed for transitions
+
+Picture of a folder for the Tree
+
+[https://www.codenameone.com/javadoc/com/
+
+codename1/ui/tree/Tree.html] class
+
+treeFolderOpenImage
+
+Picture of a folder expanded for the Tree class
+
+treeNodeImage
+
+tensileDragBool
+
+Picture of a file node for the Tree class
+
+Indicates that tensile drag should be
+
+enabled/disabled. This is usually set by platform
+
+themes
+
+135
+
+Dynamic Theme Swapping & Theme Constants
+
+Once  a  theme  constant  is  set  by  a  theme,  it  isn’t  removed  on  a  refresh  when  replacing  the
+
+theme.
+
+E.g. if one would set the comboImage constant to a specific value in theme A and then switch to
+theme B, that doesn’t define the comboImage, the original theme A comboImage might remain!
+
+The  reason  for  this  is  simple:  when  extracting  the  constant  values,  components  keep  the
+
+values  in  cache  locally  and  just  don’t  track  the  change  in  value.  Furthermore,  since  the
+
+components allow manually setting values, it’s impractical for them to track whether a value
+
+was set by a constant or explicitly by the user.
+
+The  solution  for  this  is  to  either  manually  reset  undesired  values  before  replacing  a  theme
+
+(e.g.  for  the  case,  above  by  calling  the  default  look  and  feel  method  for  setting  the  combo
+
+image with a null value), or defining a constant value to replace the existing value.
+
+4.5. Native Theming
+
+Codename  One  uses  a  theme  constant  called  includeNativeBool,  when  that  constant  is  set  to  true
+Codename  One  starts  by  loading  the  native  theme  first  and  then  applying  all  the  theme  settings.
+
+This  effectively  means  your  theme  "derives"  the  style  of  the  native  theme  first,  similar  to  the
+
+cascading effect of CSS. Internally this is exactly what the theme layering section covered.
+
+By avoiding this flag you can create themes that look EXACTLY the same on all platforms.
+
+
+
+If  you  avoid  the  native  theming  you  might  be  on  your  own.  A  few  small  device
+
+oddities such as the iOS status bar are abstracted by native theming. Without it you
+
+will need to do everything from scratch
+
+You can simulate different OS platforms by using the native theme menu option
+
+Figure 140. The native theme menu option
+
+Developers  can  pick  the  platform  of  their  liking  and  see  how  the  theme  will  appear  in  that
+
+particular platform by selecting it and having the preview update on the fly.
+
+4.6. Under the Hood of the Theme Engine
+
+To truly understand a theme we need to understand what it is. Internally a theme is just a Hashtable
+key/value pair between UIID based keys and their respective values. E.g. the key:
+
+136
+
+Button.fgColor=ffffff
+
+Will  set  the  foreground  color  of  the  Button  [https://www.codenameone.com/javadoc/com/codename1/ui/
+
+Button.html] UIID to white.
+
+When 
+
+a  Codename  One  Component 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/
+
+Component.html]  is  instantiated  it  requests  a  Style  [https://www.codenameone.com/javadoc/com/codename1/
+
+ui/plaf/Style.html] object from the UIManager [https://www.codenameone.com/javadoc/com/codename1/ui/plaf/
+UIManager.html] class. The Style object is based on the settings within the theme and can be modified
+thru code or by using the theme.
+
+We  can  replace  the  theme  dynamically  in  runtime  and  refresh  the  styles  assigned  to  the  various
+
+components  using 
+
+the 
+
+refreshTheme() 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/
+
+Component.html#refreshTheme--] method.
+
+
+
+It’s  a  common  mistake  to  invoke  refreshTheme()  without  actually  changing  the
+theme.  We  see  developers  doing  it  when  all  they  need  is  a  repaint()  or
+revalidate(). Since refreshTheme() is very expensive we recommend that you don’t
+use it unless you really need to…
+
+A theme Hashtable key is comprised of:
+
+[UIID.][type#]attribute
+
+The  UIID,  corresponds  to  the  component’s  UIID  e.g.  Button,  CheckBox  [https://www.codenameone.com/
+javadoc/com/codename1/ui/CheckBox.html]  etc.  It  is  optional  and  may  be  omitted  to  address  the  global
+
+default style.
+
+The  type  is  omitted  for  the  default  unselected  type,  and  may  be  one  of  sel  (selected  type),  dis
+
+(disabled type) or press (pressed type). The attribute should be one of:
+
+• derive - the value for this attribute should be a string representing the base component.
+
+• bgColor - represents the background color for the component, if applicable, in a web hex string
+
+format RRGGBB e.g. ff0000 for red.
+
+• fgColor - represents the foreground color, if applicable.
+
+• border - an instance of the border class, used to display the border for the component.
+
+• bgImage - an Image [https://www.codenameone.com/javadoc/com/codename1/ui/Image.html] object used in
+
+the background of a component.
+
+• transparency  -  a  String  containing  a  number  between  0-255  representing  the  alpha  value  for
+
+the background. This only applies to the bgColor.
+
+• margin  -  the  margin  of  the  component  as  a  String  containing  4  comma  separated  numbers  for
+
+top,bottom,left,right.
+
+• padding - the padding of the component, it has an identical format to the margin attribute.
+
+• font - A Font [https://www.codenameone.com/javadoc/com/codename1/ui/Font.html] object instance.
+
+• alignment  -  an  Integer  object  containing  the  LEFT/RIGHT/CENTER  constant  values  defined  in
+
+137
+
+Component.
+
+• textDecoration  -  an  Integer  value  containing  one  of  the  TEXT_DECORATION_*  constant  values
+
+defined in Style.
+
+• backgroundType - a Byte object containing one of the constants for the background type defined in
+Style [https://www.codenameone.com/javadoc/com/codename1/ui/plaf/Style.html] under BACKGROUND_*.
+
+• backgroundGradient  -  contains  an  Object  array  containing  2  integers  for  the  colors  of  the
+gradient.  If  the  gradient  is  radial  it  contains  3  floating  points  defining  the  x,  y  &  size  of  the
+
+gradient.
+
+So to set the foreground color of a selected button to red, a theme will define a property like:
+
+Button.sel#fgColor=ff0000
+
+This information is mostly useful for understanding how things work within Codename One, but it
+
+can also be useful in runtime.
+
+E.g. to increase the size of all fonts in the application, we can do something like:
+
+Hashtable h = new Hashtable();
+h.put("font", largeFont);
+UIManager.getInstance().addThemeProps(h);
+Display.getInstance().getCurrent().refreshTheme();
+
+4.7. Understanding Images and Multi-Images
+
+
+
+This  section  provides  a  very  high  level  overview  of  images.  We  dive  deeper  into
+
+the  various  types  of  images  in  the  graphics  section  [https://www.codenameone.com/
+
+manual/graphics.html#deep-into-images-section].
+
+When working with a theme, we often use images for borders or backgrounds. We also use images
+
+within the GUI for various purposes and most such images will be extracted from the resource file.
+
+Adding a standard JPEG/PNG image to the resource file is straight forward, and the resulting image
+
+can  be  viewed  within  the  images  section.  However,  due  to  the  wide  difference  between  device
+
+types,  an  image  that  would  be  appropriate  in  size  for  an  iPhone  3gs  would  not  be  appropriate  in
+
+size for a Nexus device or an iPhone 4 (but perhaps, surprisingly, it will be just right for iPad 1 and
+
+iPad 2).
+
+The  density  of  the  devices  varies  significantly  and  Codename  One  tries  to  simplify  the  process  by
+
+unifying  everything  into  one  set  of  values  to  indicate  density.  For  simplicity’s  sake,  density  is
+
+sometimes  expressed  in  terms  of  pixels,  however  it  is  mapped  internally  to  actual  screen
+
+measurements where possible.
+
+A multi-image is an image that has multiple varieties for different densities, and thus looks sharp in
+
+all  the  densities.  Since  scaling  on  the  device  can’t  interpolate  the  data  (due  to  performance
+
+considerations), significant scaling on the device becomes impractical. However, a multi-image will
+
+just provide the “right” resolution image for the given device type.
+
+138
+
+From  the  programming  perspective  this  is  mostly  seamless,  a  developer  just  accesses  one  image
+
+and has no ability to access the images in the different resolutions. Within the designer, however,
+
+we  can  explicitly  define  images  for  multiple  resolutions  and  perform  high  quality  scaling  so  the
+
+“right” image is available.
+
+We can use two basic methods to add a multi-image: quick add and standard add.
+
+Both methods rely on understanding the source resolution of the image, e.g. if you have an icon that
+
+you expect to be 128x128 pixels on iPhone 4, 102x102 on nexus one and 64x64 on iPhone 3gs. You
+
+can  provide  the  source  image  as  the  128  pixel  image  and  just  perform  a  quick  add  option  while
+
+picking the Very High density option.
+
+This  will  indicate  to  the  algorithm  that  your  source  image  is  designed  for  the  "very  high"  density
+
+and it will scale for the rest of the densities accordingly.
+
+
+
+This relies on the common use case of asking your designer to design for one high
+
+end device (e.g. iPhone X) then you can take the resources and add them as "HD"
+
+resources. They will automatically adapt to the lower resolutions
+
+Alternatively, you can use the standard add multi-image dialog and set it like this:
+
+Notice that we selected the square image option, essentially eliminating the height option. Setting
+
+values to 0 prevents the system from generating a multi-image entry for that resolution, which will
+
+mean a device in that category will fall on the closest alternative.
+
+The percentage value will change the entire column, and it means the percentage of the screen. E.g.
+
+We  know  the  icon  is  128  for  the  very  high  resolution,  we  can  just  move  the  percentage  until  we
+
+reach something close to 128 in the “Very High” row and the other rows will represent a size that
+
+should be pretty close in terms of physical size to the 128 figure.
+
+At  runtime,  you  can  always  find  the  host  device’s  approximate  pixel  density  using  the
+Display.getDeviceDensity() method. This will return one of:
+
+Table 4. Densities
+
+139
+
+Constant
+
+Display.DENSITY_VERY_LOW
+
+Display.DENSITY_LOW
+
+Display.DENSITY_MEDIUM
+
+Display.DENSITY_HIGH
+
+Display.DENSITY_VERY_HIGH
+
+Display.DENSITY_HD
+
+Display.DENSITY_560
+
+Density.DENSITY_2HD
+
+Density.DENSITY_4K
+
+Density
+
+~ 88 ppi
+
+~ 120 ppi
+
+~ 160 ppi
+
+~ 240 ppi
+
+~ 320 ppi
+
+~ 540 ppi
+
+~ 750 ppi
+
+~ 1000 ppi
+
+~ 1250ppi
+
+Example Device
+
+Android ldpi devices
+
+iPhone 3GS, iPad, Android mdpi
+
+devices
+
+Android hdpi devices
+
+iPhone 4, iPad Air 2, Android
+
+xhdpi devices
+
+iPhone 6+, Android xxhdpi
+
+devices
+
+Android xxxhdpi devices
+
+4.8. Use Millimeters for Padding/Margin and Font Sizes
+
+When  configuring  your  styles,  you  should  almost  never  use  "Pixels"  as  the  unit  for  padding,
+
+margins,  font  size,  and  border  thickness  because  the  results  will  be  inconsistent  on  different
+
+densities. Instead, you should use millimeters for all non-zero units of measurement.
+
+As we now understand the complexities of DPI it should be clear why this is important.
+
+4.8.1. Fractions of Millimeters
+
+Sometimes  millimeters  don’t  give  you  enough  precision  for  what  you  want  to  do.  Currently  the
+
+designer only allows you to specify integer values for most units. However, you can achieve more
+precise results when working directly in Java. The Display.convertToPixels() method will allow you
+to convert millimeters (or DIPS) to pixels. It also only takes an integer input, but you can use it to
+
+obtain a multiplier that you can then use to convert any millimeter value you want into pixels.
+
+E.g.
+
+double pixelsPerMM = ((double)Display.getInstance().convertToPixels(10, true)) / 10.0;
+
+And now you can set the padding on an element to 1.5mm. E.g.
+
+myButton.getAllStyles().setPaddingUnit(Style.UNIT_TYPE_PIXELS);
+int pixels = (int)(1.5 * pixelsPerMM);
+myButton.getAllStyles().setPadding(pixels, pixels, pixels, pixels);
+
+140
+
+4.9. Creating a Great Looking Side Menu
+
+Figure 141. Side Menu final result
+
+A side menu is a crucial piece of an elegant application. We’ll explain how one creates a simple side
+
+menu  that’s  elegant,  portable  and  easy  to  build.  This  is  a  good  "starting  point"  side  menu  from
+
+which you can build more elaborate designs.
+
+To  get  this  result  we  will  start  from  a  native  theme  and  a  bare  bones  application  to  keep  things
+
+simple.
+
+The code for the side menu is this:
+
+141
+
+Form hi = new Form("Hi World");
+
+Toolbar tb = hi.getToolbar();
+Image icon = theme.getImage("icon.png"); ①
+Container topBar = BorderLayout.east(new Label(icon));
+topBar.add(BorderLayout.SOUTH, new Label("Cool App Tagline...", "SidemenuTagline")); ②
+topBar.setUIID("SideCommand");
+tb.addComponentToSideMenu(topBar);
+
+tb.addMaterialCommandToSideMenu("Home", FontImage.MATERIAL_HOME, e -> {}); ③
+tb.addMaterialCommandToSideMenu("Website", FontImage.MATERIAL_WEB, e -> {});
+tb.addMaterialCommandToSideMenu("Settings", FontImage.MATERIAL_SETTINGS, e -> {});
+tb.addMaterialCommandToSideMenu("About", FontImage.MATERIAL_INFO, e -> {});
+
+hi.addComponent(new Label("Hi World"));
+hi.show();
+
+① This is the icon which was used in lieu of a logo it appears in the top right of the side menu
+
+② This is the top bar containing the tagline and the icon it’s styled as if it’s a command but you can
+
+put anything here e.g. an image etc.
+
+③ The commands are added as usual to the side menu with no styling or functionality, the entire
+
+look is determined by the theme
+
+Next we’ll open the designer tool to style the UI
+
+Figure 142. Open the side menu so we will get the right values in the combo box on add
+
+Now when we press  Add the side menu entries will appear in the combo box (you can type them
+
+but this is more convenient). We’ll start with the SideNavigationPanel style:
+
+Figure 143. The SideNavigationPanel has an opaque white background
+
+The  SideCommand style is a bit more elaborate, we start with a white foreground and an opaque
+
+bluish/purple color:
+
+142
+
+Figure 144. The SideCommand has a white foreground and opaque bluish background
+
+We’ll set padding to 3 millimeters which gives everything a good feel and spacing. This is important
+
+for finger touch sensitivity.
+
+Figure 145. Padding is 3mm so it will feel spacious and touch friendly
+
+We’ll set margin to 0 except for the bottom one pixel which will leave a nice white line by showing
+
+off the background. This means the commands will have a space between them and the white style
+
+we gave to the SideNavigationPanel will appear thru that space.
+
+Figure 146. Margin is 0 except for a thin line below each command
+
+Setting the border to empty is crucial!
+
+The iOS version of the side command inherits a border style so we must "remove" it by defining a
+
+different border in this case an empty border. Since borders take precedence over color this would
+
+have prevented the color changes we made from appearing.
+
+Figure 147. Border must be defined as Empty
+
+143
+
+Next we need to pick a good looking font and make sure it’s large enough. We use millimeters size it
+
+correctly for all OS’s and override the derived text decoration which has a value in the iOS native
+
+theme so it can impact the final look.
+
+Figure 148. Pick a good looking font for the side command
+
+Next we need to move to the selected tab and add a new side command entry that derives from the
+
+unselected  version.  We’ll  pick  a  new  color  that’s  slightly  deeper  and  will  make  the  selected  style
+
+appear selected. We’ll also copy and paste this selected style to the pressed style.
+
+Figure 149. Selected & Pressed SideCommand
+
+Figure 150. Color for the Selected/Pressed SideCommand
+
+The  SidemenuTagline  is  just  a  SideCommand  style  that  was  slightly  adapted.  We’ll  remove  the
+
+padding and margin because the whole section is wrapped in a side command and we don’t want
+
+double padding. We’ll leave 1mm padding at the top for a bit of spacing from the logo.
+
+Figure 151. Padding of the SidemenuTagline
+
+We’ll also update the font to a smaller size and italic styling so it will feel like a tagline.
+
+144
+
+Figure 152. Font for the SideMenuTagline is slightly smaller and italic
+
+The last change for the theme is for the  StatusBarSideMenu UIID which is a spacing on the top of
+
+the  sidemenu.  This  spacing  is  there  for  iOS  devices  which  render  the  clock/battery/reception
+
+symbols on top of the app. We’ll set the padding to 0.
+
+Figure 153. StatusBarSideMenu padding for the top of the side menu
+
+Finally, we’ll add the icon image (or a logo if you have it) into the theme as a multi image so we can
+
+use  it  within  the  side  menu  as  a  good  looking  logo.  A  relatively  large  icon  image  works  as  a  2HD
+
+multi-image but you can use many strategies to get a fitting image for this spot.
+
+
+
+Rounded  images  work  well  here,  you  can  round  images  dynamically  using
+
+masking
+
+These steps produce the UI above as a side menu, they might seem like a long set of steps but each
+
+step  is  pretty  simple  as  you  walk  thru  each  one.  This  does  show  off  the  versatility  and  power  of
+
+Codename One as a change to one step can create a radically different UI design.
+
+4.10. Converting a PSD To A Theme
+
+Codename  One  provides  extensive  support  for  designing  beautiful  user  interfaces,  but  it  isn’t
+
+necessarily  obvious  to  new  developers  how  to  achieve  their  desired  results.  A  common  workflow
+
+for app design includes a PSD file with mock-ups of the UI, created by a professional designer.
+
+
+
+PSD  is  the  Adobe  Photoshop  file  format,  it’s  the  most  common  format  for  UI
+
+designs in the industry
+
+For  this  tutorial  we  adapt  a  very  slick  looking  sign-up  form  found  online  and  convert  it  to  a
+
+Codename One component that can be used inside an application.
+
+The process we followed was:
+
+1. Find the PSD design we want to use: this PSD file [http://freebiesbug.com/psd-freebies/iphone-6-ui-kit/]
+
+created  by  Adrian  Chiran 
+
+[https://dribbble.com/adrianchiran] 
+
+(we  mirrored 
+
+it  here
+
+[https://www.codenameone.com/files/iOS_UI-Kit.psd] in case it goes offline):
+
+145
+
+Figure 154. Sign Up form Design
+
+2. Re-create the general structure and layout of the design in a Codename One Form using nested
+components and layout managers. Here is a break-down of how we structured the component
+hierarchy in the Form:
+
+Figure 155. Component hierarchy and layouts
+
+3. Extract the images we needed using Photoshop - this process is often referred to as "cutting"
+
+4. Extract the fonts, colors, and styles we needed to reproduce the design in Codename One
+
+5. Import images into the Codename one project, and define theme styles so that our components
+
+match the look of the original design
+
+Here is a screenshot of the resulting component running inside the Codename One simulator:
+
+146
+
+Figure 156. Resulting app in the Codename One simulator
+
+4.10.1. Breaking Down the PSD
+
+Open the PSD you are interested in using Photoshop.
+
+
+
+You might be missing fonts in your system so you can either install them or ignore
+
+that.  Keep  in  mind  that  some  fonts  might  not  be  redistributable  with  your
+
+application
+
+In this PSD we want only one of the screen designs so initially we want to remove everything that
+
+isn’t related so we can get our bearings more effectively:
+
+• Select the drag tool (the top left tool)
+
+• In the toolbar for the tool (top bar area) check the Auto Select mode
+
+• Select the  Layer Mode for auto selection (in some cases group would actually be better so feel
+
+free to experiment)
+
+• Click on the portion in the PSD that you are interested in
+
+You should end up with something like this where a layer is selected in the layers window:
+
+147
+
+Figure 157. Selecting a layer from the region you are interested in
+
+Scroll up the hierarchy a bit and uncheck/recheck the eye icon on the left until you locate the right
+
+element layer.
+
+Figure 158. Selecting a layer from the region you are interested in
+
+Right click the layer and select Convert To Smart Object.
+
+ The right click menu will present different options when you click different areas
+
+of the layer, clicking on the left area of the layer works
+
+148
+
+Figure 159. In the right click menu option select "Convert To Smart Object"
+
+Once  the  layer  hierarchy  is  a  smart  object  you  can  just  double  click  it  which  will  open  the  sub
+
+hierarchy in a new tab and you now only have the pieces of the image you care about.
+
+Figure 160. Double clicking the smart object allows us to edit only the form we need
+
+Removing the Noise
+
+The first thing we need to do is remove from the image all of the things that we don’t really need.
+
+The status bar area on the top is redundant as if is a part of the phones UI. We can select it using the
+
+select tool and click the eye icon next to the layer to hide it.
+
+Normally we’d want to have the back arrow but thanks to the material design icons that are a part
+
+of Codename One we don’t need that icon so we can hide that too.
+
+We don’t need the "Sign Up" or "Done" strings in the title either but before removing them we’d like
+
+to know the font that is used.
+
+149
+
+To discover that I can click them to select the layer then switch to the text tool:
+
+Figure 161. The text tool allows us to inspect the font used
+
+Then I can double click the text area layer to find out the font in the top of the UI like this:
+
+Figure 162. The Done toolbar entry uses SourceSansPro Regular
+
+
+
+Notice  that  I  don’t  actually  need  to  have  the  font  installed  in  this  case  I  don’t
+
+(hence the square brackets)
+
+Also notice that the color of the font is accessible in that toolbar, by clicking the color element we
+
+get this dialog which shows the color value to be f73267, this is something we will use later
+
+Figure 163. The color dialog lists the hex color at the bottom, we can paste that directly to the designer tool
+
+We can now hide both text layers so they won’t pose a problem later.
+
+The Camera Button
+
+The  camera  button  includes  an  icon  and  the  button  background  itself.  You  can  just  use  that  as  a
+
+single image and be done with it, but for the purpose of this tutorial I will take the harder route of
+
+separating this into a button background and a foreground image.
+
+When  you  click  on  the  camera  icon  you  will  notice  that  the  camera  icon  is  comprised  of  two
+
+separate layers: the camera and the "x" symbol above it. We can select both layers using  ctrl-click
+
+(command click on the Mac) and convert both to a smart object together using the same method as
+
+before:
+
+150
+
+Figure 164. The camera smart object
+
+Since the image is used as an icon we want it to be completely square which isn’t the situation here!
+
+This is important as a non-square image can trigger misalignment when dealing with icons and the
+
+background. So we need to use the  Image →  Canvas Size menu and set the values to be the same
+
+(the higher value of the two).
+
+Figure 165. The canvas size dialog for the camera.png file
+
+We  can  now  use  File  →  Export  and  save  the  first  image  resource  we  will  need  into  a  temporary
+
+directory. Make sure to save a PNG file to preserve quality and transparency!
+
+
+
+Use File → Export and never use File → Save As . The latter can produce a huge size
+
+difference as it retains image meta-data
+
+For convenience we’ll refer to the file as camera.png when we need it later.
+
+Figure 166. The camera icon image
+
+We can follow the exact same procedure with the parent button layer (the white portion) which we
+can convert to a smart object and export camera-button.png.
+
+151
+
+Figure 167. The camera button image set to a gray background so it will be visible
+
+Now we can hide both of these elements and proceed to get the background image for the title.
+
+Here  the  "smart  object  trick"  won’t  work…  There  is  an  effects  layer  in  place  and  the  smart  object
+
+will  provide  us  with  the  real  underlying  image  instead  of  the  look  we  actually  want.  However,
+
+solving this is trivial now that we hid all of the elements on top of the image!
+
+We need to switch to the rectangular select tool:
+
+Figure 168. The select tool and the clean image we want to select
+
+Now drag the select tool to select the image don’t cross into the white pixels below the image. You
+
+can use the zoom value and set it to a very high value to get the selection right.
+
+When the selection is right click  Edit →  Copy Merged. Normally  Copy would only copy a specific
+
+layer but in this case we want to copy what we see on the screen!
+
+Now click  File →  New it should have the  Presets set to  Clipboard which means the newly created
+
+image is based on what we just copied (that is seriously great UX). Just accept that dialog and paste
+
+(Ctrl-V or Command-V).
+
+You  can  now  save  the  image,  since  it’s  just  a  background  using  JPEG  is  totally  acceptable  in  this
+case. We named it background.jpg.
+
+152
+
+Figure 169. The background image
+
+The last thing we need is the colors used in the UI. We can use the "eye drop" tool in a high zoom
+level to discover the colors of various elements e.g. the text color is 4d606f and the separator color is
+f5f5f5:
+
+Figure 170. The eye drop tool can be pointed at an area of the image to get the color in that region
+
+4.10.2. The Code
+
+While  that  was  verbose  it  was  relatively  simple.  We’ll  create  a  simple  barebones  manual
+
+application with the native theme.
+
+ The reason for this is to avoid "noise", if we use a more elaborate theme it would
+
+have some existing settings. This can make the tutorial harder to follow
+
+153
+
+Figure 171. Simple bare bones app settings
+
+Once the project is created double click the theme.res file and within the designer select  Images →
+Quick Add Multi Images. Select the 3 images we created above: background.jpg, camera.png & camera-
+button.png. Leave the default setting on Very High and press OK.
+
+Then save the resource file so we can use these images from code.
+
+Here  is  the  source  code  we  used  to  work  with  the  UI  above  there  are  comments  within  the  code
+
+explaining some of the logic:
+
+private Label createSeparator() {
+    Label sep = new Label();
+    sep.setUIID("Separator");
+    // the separator line  is implemented in the theme using padding and background color, by default labels
+    // are hidden when they have no content, this method disables that behavior
+    sep.setShowEvenIfBlank(true);
+    return sep;
+}
+
+public void start() {
+    if(current != null){
+        current.show();
+        return;
+    }
+    // The toolbar uses the layered mode so it resides on top of the background image, the theme makes
+    // it transparent so we will see the image below it, we use border layout to place the background image on
+    // top and the "Get started" button in the south
+    Form psdTutorial = new Form("Signup", new BorderLayout());
+    Toolbar tb = new Toolbar(true);
+    psdTutorial.setToolbar(tb);
+
+    // we create 4mm material arrow images for the back button and the Get started button
+
+154
+
+    Style iconStyle = psdTutorial.getUIManager().getComponentStyle("Title");
+    FontImage leftArrow = FontImage.createMaterial(FontImage.MATERIAL_ARROW_BACK, iconStyle, 4);
+    FontImage rightArrow = FontImage.createMaterial(FontImage.MATERIAL_ARROW_FORWARD, iconStyle, 4);
+
+    // we place the back and done commands in the toolbar, we need to change UIID of the "Done" command
+    // so we can color it in Red
+    tb.addCommandToLeftBar("", leftArrow, (e) -> Log.p("Back pressed"));
+    Command doneCommand = tb.addCommandToRightBar("Done", null, (e) -> Log.p("Done pressed"));
+    tb.findCommandComponent(doneCommand).setUIID("RedCommand");
+
+    // The camera button is comprised of 3 pieces. A label containing the image and the transparent button
+    // with the camera icon on top. This is all wrapped in the title container where the title background image
+    // is placed using the theme. We chose to use a Label rather than a background using the cameraLayer so
+    // the label will preserve the original size of the image without scaling it and take up the space it needs
+    Button cameraButton = new Button(theme.getImage("camera.png"));
+    Container cameraLayer = LayeredLayout.encloseIn(
+            new Label(theme.getImage("camera-button.png")),
+            cameraButton);
+    cameraButton.setUIID("CameraButton");
+    Container titleContainer = Container.encloseIn(
+            new BorderLayout(BorderLayout.CENTER_BEHAVIOR_CENTER),
+            cameraLayer, BorderLayout.CENTER);
+    titleContainer.setUIID("TitleContainer");
+
+    TextField firstName = new TextField("", "First Name");
+    TextField lastName = new TextField("", "Last Name");
+    TextField email = new TextField("", "Email Address", 20, TextField.EMAILADDR);
+    TextField password = new TextField("", "Choose a Password", 20, TextField.PASSWORD);
+    TextField phone = new TextField("", "Phone Number", 20, TextField.PHONENUMBER);
+    Label phonePrefix = new Label("+1");
+    phonePrefix.setUIID("TextField");
+
+    // The phone and full name have vertical separators, we use two table layouts to arrange them correctly
+    // so the vertical separator will be in the right place
+    TableLayout fullNameLayout = new TableLayout(1, 3);
+    Container fullName = new Container(fullNameLayout);
+    fullName.add(fullNameLayout.createConstraint().widthPercentage(49), firstName).
+        add(fullNameLayout.createConstraint().widthPercentage(1), createSeparator()).
+        add(fullNameLayout.createConstraint().widthPercentage(50), lastName);
+    Container fullPhone = TableLayout.encloseIn(3, phonePrefix, createSeparator(), phone);
+
+    // The button in the south portion needs the arrow icon to be on the right side so we place the text on the left
+    Button southButton = new Button("Get started", rightArrow);
+    southButton.setTextPosition(Component.LEFT);
+    southButton.setUIID("SouthButton");
+
+    // we add the components and the separators the center portion contains all of the elements in a box
+    // Y container which we allow to scroll. BorderLayout Containers implicitly disable scrolling
+    Container by = BoxLayout.encloseY(
+                    fullName,
+                    createSeparator(),
+                    email,
+                    createSeparator(),
+                    password,
+                    createSeparator(),
+                    fullPhone,
+                    createSeparator()
+            );
+    by.setScrollableY(true);
+    psdTutorial.add(BorderLayout.NORTH, titleContainer).
+            add(BorderLayout.SOUTH, southButton).
+            add(BorderLayout.CENTER, by);
+
+155
+
+    psdTutorial.show();
+}
+
+4.10.3. Styling The UI
+
+So the code above is most of the work but we still need to put everything together using the theme.
+
+This is what we have so far:
+
+Figure 172. Before applying the changes to the theme this is what we have
+
+Figure 173. This is what we are aiming at with no additional code changes
+
+This looks like a major set of changes but it requires exactly 10 UIID definitions to get to this look!
+
+Open the designer and select the theme. Press the  Add button and type in  TitleContainer. Uncheck
+
+derive  for  the  background  and  select  IMAGE_SCALED_FILL  for  the  Type  and  the  background.jpg
+
+image.
+
+Define the padding as:
+
+• Left - 3 millimeter
+
+• Right - 3 millimeter
+
+• Top - 8 millimeter
+
+• Bottom - 2 millimeter
+
+This will allow enough space for the title. Define margin as 0 on all sides. Then press OK.
+
+Add the "Title" UIID. In the  Color tab define the foreground as ffffff define transparency as 0 (fully
+transparent  so  we  will  see  the  TitleContainer).  Define  padding  as  1  millimeter  on  all  sides  and
+
+156
+
+margin as 0 on all sides.
+
+In the Border tab press the … button and select [Empty].
+
+In the  Font tab select the  True Type as  native:MainThin. Select the  True Type Size as millimeters
+and set the value to 3.5.
+
+Press OK to save the changes.
+
+Copy  the  Title  UIID  and  paste  it,  change  the  name  to  "TitleCommand"  and  press  OK  to  save  the
+changes.
+
+Copy the Title UIID again and paste it, change the name to "RedCommand". In the  Color tab set the
+foreground color to f73267. In the Font tab set the  True Type to native:MainLight and set the size to
+3. Press OK to save the changes.
+
+Add the "TitleArea" UIID. In the  Color tab define transparency as 0 (fully transparent so we will see
+the TitleContainer). Define padding and margin as 0 on all sides.
+In the Border tab press the … button and select [Empty]. Press OK to save the changes.
+
+Add  the  "TextField"  UIID.  In  the  Color  tab  define  transparency  as  255  (fully  opaque)  and  the
+background  as  ffffff  (white).  Define  padding  as  2  millimeter  on  all  sides  and  margin  as  0  on  all
+sides.
+
+In  the  Border  tab  press  the  …  button  and  select  [Empty].  In  the  Font  tab  set  the  True Type  to
+
+native:MainLight and set the size to 2. Press OK to save the changes.
+
+Copy the TextField UIID again and paste it, change the name to "TextHint". In the  Color tab set the
+foreground color to 4d606f. Press OK to save the changes.
+
+Add  the  "SouthButton"  UIID.  In  the  Color  tab  define  transparency  as  255  (fully  opaque)  and  the
+background as f73267 (red) and the foreground as ffffff (white). Define Alignment as Center.
+
+Define padding as:
+
+• Left - 1 millimeter
+
+• right - 1 millimeter
+
+• top - 2 millimeters
+
+• bottom - 2 millimeters
+
+Define margin as 0 on all sides. In the Font tab set the True Type  to native:MainThin and set the size
+
+to 3. Press OK to save the changes.
+
+Add the "CameraButton" UIID. In the  Color tab define transparency as 0 (fully transparent). Define
+Alignment as Center.
+
+Define padding as:
+
+• Left - 1 millimeter
+
+• right - 1 millimeter
+
+• top - 3 millimeters
+
+157
+
+• bottom - 1 millimeter
+
+ This helps spacing away from the title
+
+Define margin as 1 millimeter on all sides. Press OK to save the changes.
+
+You can now save the theme and the app should look like the final result!
+
+Not Quite There Yet
+
+There is one last piece that you would notice if you actually try to run this code. When pressing the
+
+buttons/text  fields  you  would  see  their  look  change  completely  due  to  the  different  styles  for
+
+focus/press behavior.
+
+You can derive the regular styles from the selected/pressed styles but one of the simplest ways is to
+just  copy  &  paste  the  styles  to  the  pressed/selected  tabs.  We  can  copy  CameraButton,  RedCommand,
+SouthButton  &  TextField  to  the  selected  state.  Then  copy  CameraButton,  RedCommand  &  SouthButton  to
+the pressed state to get the complete app running!
+
+158
+
+5. CSS
+
+In this chapter we’ll discuss theming with CSS in Codename One.
+
+
+
+CSS Changes Don’t Require a Recompile
+
+You can change the CSS values while the simulator is running and the changes will
+
+reflect in the simulator within a few seconds
+
+5.1. Activating CSS
+
+Codename  One  applications  always  use  the  resource  file.  The  CSS  support  compiles  a  file  in  CSS
+
+syntax to a Codename One resource file and adds it to the application. In runtime the CSS no longer
+
+exists and the file acts like a regular theme file.
+
+To enable CSS support in Codename One you need to flip a switch in Codename One Settings.
+
+Figure 174. The CSS Option in Codename One Settings Part I
+
+159
+
+Figure 175. The CSS Option in Codename One Settings Part II
+
+Once  enabled  your  theme.res  file  will  regenerate  from  a  CSS  file  that  resides  under  the  css
+directory.  Changes  you  make  to  the  CSS  file  will  instantly  update  the  simulator  as  you  save.
+
+However,  there  are  some  limits  to  this  live  update  so  in  some  cases  a  simulator  restart  would  be
+
+necessary.
+
+5.2. Supported CSS Selectors
+
+Since Codename One stylesheets are meant to be used with Codename One component hierarchies
+
+instead of XML/HTML documents, selectors work a little differently.
+
+1. All selectors (with some specific exceptions discussed below) are interpreted as UIIDs.
+
+2. Only 4 predefined CSS classes are supported:
+
+◦ .pressed — Targets the component when in "Pressed" state.
+
+◦ .selected — Targets the component when in "Selected" state.
+
+◦ .unselected — Targets the component when in "Unselected" state.
+
+◦ .disabled — Targets the component when in "Disabled" state.
+
+If no class is specified, then the selector targets "all" states of the given component.
+
+The following are a few possible selectors you can include in your stylesheet.
+
+1. Button — Defines styles for the "Button" UIID.
+
+160
+
+2. Button.pressed — Defines styles for the "Button" UIID’s "pressed" state.
+
+3. Button, TextField, Form — Defines styles for the "Button", "TextField", and "Form" UIIDs.
+
+The  following  example  creates  a  simple  button  with  a  border,  and  text  aligned  center.  By  default
+
+the  button  will  have  a  transparent  background,  but  when  it  is  pressed,  it  will  have  a  gray
+
+background:
+
+Button {
+    text-align: center;
+    border: 1pt solid gray;
+    background-color: transparent;
+}
+
+Button.pressed {
+    background-color: gray;
+}
+
+5.2.1. Inheriting properties using cn1-derive
+
+The  following  example  defines  a  custom  Button  style  named  "MyButton"  that  inherits  all  of  the
+
+styles of Button but changes the background color to blue.
+
+MyButton {
+   cn1-derive: Button;
+   background-color: blue;
+}
+
+5.3. Special Selectors
+
+5.3.1. #Device
+
+The #Device selector allows you to define which device resolutions this CSS file should target. Mutli-
+images  generated  from  this  style-sheet  will  only  be  include  variants  for  device  resolutions  in  the
+range  (min-resolution,  max-resolution)  as  defined  in  this  section.  By  default  all  resolutions  are
+generated.
+
+#Device {
+    min-resolution: 120dpi;
+    max-resolution: 480dpi;
+    resolution: 480dpi;
+}
+
+5.3.2. #Constants
+
+The #Constants selector allows you to specify theme constants.
+
+161
+
+e.g.
+
+#Constants {
+    PopupDialogArrowBool: false;
+    calTitleDayStyleBool: true;
+    calTransitionVertBool: false;
+    calendarLeftImage: "calendar-arrow-left.png";
+    calendarRightImage: "calendar-arrow-right.png";
+    centeredPopupBool: false;
+    checkBoxCheckDisFocusImage: "Check-Box_Normal.png";
+    checkBoxCheckedFocusImage: "Check-Box_Press.png";
+    checkBoxCheckedImage: "Check-Box_Press.png";
+    checkBoxOppositeSideBool: true;
+    checkBoxUncheckedFocusImage: "Check-Box_Normal.png";
+    checkBoxUncheckedImage: "Check-Box_Normal.png";
+    comboImage: "combo.png";
+    commandBehavior: "Side";
+    dialogTransitionIn: "fade";
+    dialogTransitionOut: "fade";
+    dlgButtonCommandUIID: "DialogButton";
+    dlgCommandGridBool: true;
+    dlgInvisibleButtons: #1a1a1a;
+    formTransitionIn: "empty";
+    formTransitionOut: "slide";
+    includeNativeBool: true;
+    menuImage: "of_menu.png";
+    noTextModeBool: true;
+    onOffIOSModeBool: true;
+    otherPopupRendererBool: false;
+    pureTouchBool: true;
+    radioSelectedFocusImage: "Radio_btn_Press.png";
+    radioSelectedImage: "Radio_btn_Press.png";
+    radioUnselectedFocusImage: "Radio_btn_Normal.png";
+    radioUnselectedImage: "Radio_btn_Normal.png";
+    sideMenuImage: "menu.png";
+    switchMaskImage: "switch-mask-3.png";
+    switchOffImage: "switch-off-3.png";
+    switchOnImage: "switch-on-3.png";
+    tabPlacementInt: 0;
+    backIconImage: "Back-icon.png";
+    articleSourceIconImage: "Source-icon.png";
+    articleDateIconImage: "Date-icon.png";
+    articleArrowRightImage: "Arrow-right.png";
+    articleShareIconImage: "Share-icon.png";
+    articleBookmarkIconImage: "Bookmark-icon.png";
+    articleTextIconImage: "Text-icon.png";
+    articleCommentsIconImage: "Comments-icon.png";
+    newsIconImage: "News-icon.png";
+    channelsIconImage: "Channels-icon.png";
+    bookmarksIconImage: "Bookmarks-icon.png";
+
+162
+
+    overviewIconImage: "Overview-icon.png";
+    calendarIconImage: "Calendar-icon.png";
+    timelineIconImage: "Timeline-icon.png";
+    profileIconImage: "Profile-icon.png";
+    widgetsIconImage: "Widgets-icon.png";
+    settingsIconImage: "Settings-icon.png";
+    SubmitIconImage: "Submit-icon.png";
+    SubmitIconDarkImage: "SubmitButtonLight-icon.png";
+
+}
+
+In the above example, the constants referring to an image name as a string requires that the image
+
+exists in one of the following locations:
+
+• res/<cssfilename>/<imageName>
+
+• ../res/<cssfilename>/<imageName>
+
+• ../../res/<cssfilename>/<imageName>
+
+or that it has been defined as a background image in some selector in this CSS file.
+
+5.3.3. Default
+
+The  Default  selector  is  special  in  that  it  will  set  properties  on  the  theme’s  "default"  element.  The
+default element is a special UIID in Codename One from which all other UIIDs in the same theme
+
+are derived. This is a good place to set things like default fonts or background-colors.
+
+5.4. Standard CSS Properties
+
+• padding (and variants)
+
+• margin (and variants)
+
+• border (and variants)
+
+• border-radius
+
+• background (Usage below)
+
+• background-color
+
+• background-repeat
+
+• background-image
+
+• border-image
+
+• border-image-slice
+
+• font (Usage is covered in the following font section)
+
+• font-family (Usage is covered in the following font section)
+
+• font-style (Usage is covered in the following font section)
+
+• font-size (Usage is covered in the following font section)
+
+163
+
+• @font-face (Usage is covered in the following font section)
+
+• color
+
+• text-align
+
+• text-decoration(Usage below)
+
+• opacity
+
+• box-shadow
+
+• width (only used for generating background-images and borders)
+
+• height (only used for generating background-images and borders)
+
+5.5. Custom Properties
+
+• cn1-source-dpi — Used to specify source DPI for multi-image generation of background images.
+Accepted values: 0 (Not multi-image), 120 (Low res), 160 (Medium Res), 320 (Very High Res), 480
+(HD), Higher than 480 (2HD)
+
+• cn1-background-type — Used to explicitly specify the background-type that should be used for the
+
+class.
+
+• cn1-9patch — Used  to  explicitly  specify  the  slices  used  when  generating  9-piece  borders.
+
+Deprecated - Use border-image and border-image-slice for 9-piece borders.
+
+• cn1-derive — Used to specify that this UIID should derive from an existing UIID.
+
+5.6. CSS Variables
+
+As of CodenameOne 7.0, you can use variables in your CSS file via the var() CSS function. E.g.
+
+var(--header-color, blue);
+
+The var() function can only be used inside property values. I.e. You cannot use it in property names
+or selectors.
+
+Syntax:
+
+var(<custom-property-name>, <declaration-value>?)
+
+The <custom-property-name> must begin with two dashes (--).
+
+The <declaration-value> is the fallback value that will be used if the variable hasn’t been defined in
+the CSS file. The fallback value may include commas.
+
+Examples
+
+164
+
+Listing 13. Example defining and using a CSS variable
+
+#Constants {
+    --main-bg-color: red;
+}
+
+MyContainer {
+    background-color: var(--main-bg-color);
+}
+
+Listing 14. Example using a fallback value
+
+#Constants {
+    --main-bg-color: red;
+}
+
+MyContainer {
+    background-color: var(--main-bg-color, blue);
+}
+
+See  the  MDN  docs  [https://developer.mozilla.org/en-US/docs/Web/CSS/var]  for  more  details  about  the  CSS
+
+variable spec.
+
+5.7. CSS Properties
+
+This section isn’t as comprehensive as it should be due to the breadth of CSS.
+
+5.7.1. text-decoration
+
+underline
+
+overline
+
+line-through
+
+none
+
+cn1-3d
+
+cn1-3d-lowered
+
+Underlines text. E.g. text-decoration: underline;
+
+Overlines text. E.g. text-decoration: overline;
+
+Strikes through text. E.g. text-decoration: line-
+through;
+
+No text decoration. E.g. text-decoration: none;
+
+3D 
+
+text. 
+
+E.g. 
+
+text-decoraton: 
+
+cn1-3d;
+
+3D  lowered  text.  E.g.  text-decoration:  cn1-3d-
+lowered;
+
+cn1-3d-shadow-north
+
+3D text with north shadow. E.g. text-decoration:
+cn1-3d-shadow-north;
+
+165
+
+For other CSS font settings see the Fonts section [Fonts]
+
+5.7.2. border
+
+This  library  supports  the  border  property  [https://developer.mozilla.org/en-US/docs/Web/CSS/border]  and
+
+most  of  its  variants  (e.g.  border-width  [https://developer.mozilla.org/en-US/docs/Web/CSS/border-width],
+
+border-style 
+
+[https://developer.mozilla.org/en-US/docs/Web/CSS/border-style], 
+
+and 
+
+border-color
+
+[https://developer.mozilla.org/en-US/docs/Web/CSS/border-color].  It  will  try  to  use  native  Codename  One
+
+styles for generating borders if possible. If the border definition is too complex, it will fall-back to
+
+generating  a  9-piece  image  border  at  compile-time.  This  has  the  effect  of  making  the  resulting
+
+resource file larger, but will produce good runtime performance, and a look that is faithful to the
+
+provided CSS.
+
+The algorithm used to determine whether to use a native border or to generate a 9-piece image, is
+
+complex,  but  the  following  guidelines  may  help  you  if  you  wish  to  design  borders  that  can  be
+
+rendered natively in CN1:
+
+• Non-pixel units border-width. (Except with the cn1-round-border and cn1-pill-border styles)
+
+• Using the border-radius directive.
+
+• Using box-shadow (Except when using cn1-round-border or cn1-pill-border styles)
+
+• Using a background gradient in combination with a border or any kind
+
+• Using a different border-width, border-style, or border-color for different sides of the border
+
+• Using a filter
+
+
+
+You  can  open  the  resulting  theme  file  in  the  designer  and  inspect  it  to  see  if  an
+
+image was generated
+
+Generating  the  image  triggers  slower  CSS  compilation  and  a  larger  binary  so  we  generally
+
+recommend tuning the CSS so it avoids this fallback.
+
+Round Borders
+
+Rounded borders can be achieved in a few different ways. The easiest methods are:
+
+• The  cn1-round-border  style.  This  will  render  a  circular  round  border  in  the  background
+
+natively. I.e. this doesn’t require generation of an image border
+
+• The  cn1-pill-border  style.  This  will  render  a  pill-shaped  border  in  the  background  natively.
+
+This also doesn’t require generation of an image border
+
+• The  border-radius  property.  This  will  round  the  corners  of  the  border.  If  the  style  can  be
+achieved using the RoundRectBorder in CodenameOne, then it will use that border. If not, this will
+cause the style to be generated as an image border
+
+Examples using cn1-round-border
+
+166
+
+RoundBorder {
+    border: 1px #3399ff  cn1-round-border;
+    text-align:center;
+    margin:2mm;
+    padding:3mm;
+}
+
+RoundBorderFilled {
+    background: cn1-round-border;
+    background-color: #ccc;
+    text-align:center;
+    margin:2mm;
+    padding:3mm;
+}
+
+Examples using cn1-pill-border
+
+PillBorder {
+    border: 1pt #3399ff cn1-pill-border;
+    text-align:center;
+}
+
+PillBorderFilled {
+    background: cn1-pill-border;
+    background-color: #3399ff;
+    color:white;
+    text-align:center;
+}
+
+Examples using border-radius
+
+RoundRectLabel {
+    background-color: red;
+    border-radius: 2mm;
+}
+
+cn1-pill-border  and  cn1-round-border  don’t  support  the  standard  CSS  box-shadow  property.  This  is
+because the box-shadow property parameters don’t map nicely onto the shadow parameters for the
+Codename  One  RoundBorder  class.  To  get  shadows  on  the  cn1-pill-border,  you  should  use  one  or
+more of the following CSS properties:
+
+• cn1-box-shadow-spread — Accepts  values  in  any  scalar  unit  (e.g.  px,  mm,  cm,  etc…).  This  maps
+directly  to  the  border’s  shadowSpread  [https://www.codenameone.com/javadoc/com/codename1/ui/plaf/
+
+RoundBorder.html#shadowSpread-int-boolean-] property.
+
+• cn1-box-shadow-h — Accepts  values  in  real  values  or  integers  (not  a  scalar  unit).  This  maps
+[https://www.codenameone.com/javadoc/com/codename1/ui/plaf/
+
+the  border’s  shadowX 
+
+directly 
+
+to 
+
+167
+
+RoundBorder.html#shadowX-float-] property.
+
+• cn1-box-shadow-v — Accepts  values  in  real  values  or  integers  (not  a  scalar  unit).  This  maps
+[https://www.codenameone.com/javadoc/com/codename1/ui/plaf/
+
+the  border’s  shadowY 
+
+directly 
+
+to 
+
+RoundBorder.html#shadowY-float-] property.
+
+• cn1-box-shadow-blur — Scalar 
+
+value. 
+
+Maps 
+
+to 
+
+the 
+
+border’s 
+
+shadowBlur
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/plaf/RoundBorder.html#shadowBlur-float-]
+
+property.
+
+• cn1-box-shadow-color — The shadow color
+
+Currently  using  the  regular  CSS  box-shadow  in  conjunction  with  border-radius  will  cause  a  9-piece
+border  to  be  generated  rather  than  mapping  to  the  RoundRectBorder.  If,  however,  you  use  the  cn1-
+box-* properties for the shadow instead, it will use the RoundRectBorder — assuming that no other
+styles are specified that trigger an image border to be generated.
+
+5.7.3. background
+
+The background property supports most standard CSS values [https://developer.mozilla.org/en-US/docs/Web/
+CSS/background] for setting the background color, or background image.
+
+
+
+9-piece  Image  borders  always  take  precedence  over  background  settings  in
+
+Codename  One.  If  your  background  directive  seems  to  have  no  effect,  it  is  likely
+
+because  the  theme  has  specified  a  9-piece  image  border  for  the  UIID.  You  can
+disable the image border using a directive like border: none
+
+Background Images
+
+See Images [Images]
+
+Gradients
+
+Both  the  linear-gradient  and  radial-gradient  CSS  functions  are  fully  supported  by  this  library.  If
+Codename One is capable of rendering the gradient natively then the theme resource file generated
+
+will  only  include  encoded  parameters  for  the  gradients.  If  the  gradient  is  not  supported  by
+
+Codename  One,  then  the  module  will  fall  back  to  an  image  background  which  it  generates  at
+
+compile-time.  It  is  generally  preferable  to  try  to  stick  to  gradients  that  Codename  One  supports
+
+natively.  This  will  result  in  a  smaller  theme  resource  file  since  it  doesn’t  need  to  generate  any
+
+images for the gradient.
+
+Natively Supported linear-gradient Syntax
+
+In order for a linear gradient to be natively supported by Codename One, the following properties
+
+must be met:
+
+1. The gradient function has exactly two color stops, and these colors have the same opacity.
+
+2. The gradient is either perfectly horizontal or perfectly vertical. (e.g Direction can be 0deg, 90deg,
+
+180deg, or 270deg.
+
+Examples
+
+168
+
+MyContainer {
+   background: linear-gradient(0deg, #ccc, #666);
+}
+
+Figure 176. Native linear gradient 0 degrees
+
+MyContainer {
+    background: linear-gradient(to top, #ccc, #666);
+}
+
+Figure 177. Native linear gradient to top
+
+169
+
+MyContainer {
+    background: linear-gradient(90deg, #ccc, #666);
+}
+
+Figure 178. Native linear gradient 90deg
+
+MyContainer {
+    background: linear-gradient(to left, #ccc, #666);
+}
+
+Figure 179. Native linear gradient to left
+
+Unsupported linear-gradient syntax
+
+The  following  are  some  examples  of  linear  gradients  that  aren’t  supported  natively  by  Codename
+
+170
+
+One, and will result in a background image to be generated at compile-time:
+
+MyComponent {
+    background: linear-gradient(45deg, #eaeaea, #666666);
+}
+
+Figure 180. 45deg gradient rendered at compile-time — uses background image
+
+The  above  example  is  not  supported  natively  because  the  gradient  direction  is  45  degrees.
+
+Codename One only supports 0, 90, 180, and 270 degrees natively. Therefore this would result in a
+
+background image being generated at compile-time with the appropriate gradient.
+
+MyComponent {
+    background: linear-gradient(90deg, rgba(255, 0, 0, 0.6), blue);
+}
+
+171
+
+Figure 181. Linear gradient with different alpha
+
+The  above  linear-gradient  is  not  supported  natively  because  the  stop  colors  have  different
+
+transparencies. The first color has an opacity of 0.5, and the second as an opacity of 1.0 (implicitly).
+
+Therefore, this would result in the gradient being generated as an image at compile-time.
+
+Natively Supported radial-gradient Syntax
+
+The following syntax is supported natively for radial gradients. Other syntaxes are also supported
+
+by  the  CSS  library,  but  they  will  use  compile-time  image  generation  for  the  gradients  rather  than
+
+generating them at runtime.
+
+background: radial-gradient(circle [closest-side] [at <position>], <color stop>, <color stop>)
+
+• <position> — The position using either offset keywords or percentages.
+
+• <color stop> — Either a color alone, or a color followed by a percentage. 0% indicates that color
+begins  at  center  of  the  circle.  100%  indicates  that  the  color  begins  at  the  closest  edge  of  the
+
+bounding box. Higher/lower values (>0%) will shift the color further or closer to circle’s center.
+
+If  the  first  color  stop  is  set  to  a  non-zero  value,  the  gradient  cannot  be  rendered  natively  by
+
+Codename One, and an image of the gradient will instead be generated at compile-time.
+
+More complex gradients are supported by this library, but they will be generated at compile-time.
+For  more  information  about  the  radial-gradient  CSS  function  see  its  MDN  Wiki  page
+[https://developer.mozilla.org/en-US/docs/Web/CSS/radial-gradient].
+
+Examples
+
+MyContainer {
+    background: radial-gradient(circle, gray, white);
+}
+
+172
+
+Figure 182. Radial gradient 0 to 100
+
+MyContainer {
+    background: radial-gradient(circle, gray, white 200%);
+}
+
+Figure 183. Radial gradient 0 to 200
+
+MyContainer {
+    background: radial-gradient(circle at left, gray, white);
+}
+
+173
+
+Figure 184. Radial gradient at left
+
+MyContainer {
+    background: radial-gradient(circle at right, gray, white);
+}
+
+Figure 185. Radial gradient at right
+
+5.7.4. cn1-background-type
+
+It also supports some special Codename One values, which are identifiers with a "cn1-" prefix. The
+
+following  special  values  are  available.  They  map  to  the  standard  Codename  One  values  we
+
+discussed in the theming chapter:
+
+• cn1-image-scaled
+
+• cn1-image-scaled-fill
+
+• cn1-image-scaled-fit
+
+• cn1-image-tile-both
+
+• cn1-image-tile-valign-left
+
+• cn1-image-tile-valign-center
+
+174
+
+• cn1-image-tile-valign-right
+
+• cn1-image-tile-halign-top
+
+• cn1-image-tile-halign-center
+
+• cn1-image-tile-halign-bottom
+
+• cn1-image-align-bottom
+
+• cn1-image-align-left
+
+• cn1-image-align-right
+
+• cn1-image-align-center
+
+• cn1-image-align-top-left
+
+• cn1-image-align-top-right
+
+• cn1-image-align-bottom-left
+
+• cn1-image-align-bottom-right
+
+• cn1-image-border
+
+• cn1-none
+
+• cn1-round-border
+
+• cn1-pill-border
+
+5.8. Images
+
+Images  are  supported  as  both  "inputs"  of  the  stylesheet,  and  as  outputs  to  the  compiled  resource
+file.  "Input"  images  are  usually  specified  via  the  background-image  property  in  a  selector.  "Output"
+images are always saved as multi-images inside the resource file.
+
+5.8.1. Image DPI and Device Densities
+
+In order to appropriately size the image, the CSS compiler needs to know what the source density of
+
+the image is. E.g. if an image is 160x160 pixels with a source density of 160dpi (i.e. medium density -
+
+or the same as an iPhone 3G), then the resulting multi-image will be sized at 160x160 for medium
+
+density devices and 320x320 on very high density devices (e.g. iPhone 4S Retina) - which will result
+
+in the same perceived size to the user of 1x1 inch.
+
+However  if  the  image  has  a  source  density  of  320dpi,  then  the  resulting  multi-image  would  be
+
+80x80 pixels on medium density devices and 160x160 pixels on very high density devices.
+
+Some images have this density information embedded in the image itself so that the CSS processor
+
+will  know  how  to  resize  the  image  properly.  However,  it  is  usually  better  to  explicitly  document
+your intentions by including the cn1-source-dpi property as follows:
+
+175
+
+SomeStyle {
+    background-image: url(images/my-image.png);
+    cn1-source-dpi: 160;
+}
+
+cn1-source-dpi  values  are  meant  to  fall  into  threshold  ranges.  Values  less  than  or
+equal to 120, are interpreted as low density. 121 - 160 are medium density (iPhone
+
+
+
+3GS). 161 - 320, very high density (iPhone 4S). 321 - 480 == HD. 481 and higher ==
+
+2HD.  In  general,  you  should  try  to  use  images  that  are  one  of  these  DPIs  exactly:
+
+160,  320,  or  480,  then  images  will  be  scaled  up  or  down  to  the  other  densities
+
+accordingly.
+
+5.8.2. Multi-Images vs Regular Images
+
+By default all images are imported as multi-images. If you want to import an image as a "regular"
+image, you can simply set cn1-source-dpi to 0. E.g.
+
+SomeStyle {
+    background-image: url(images/my-image.png);
+    cn1-source-dpi: 0;
+}
+
+5.8.3. Multi-Images as Inputs
+
+If  you  have  already  generated  images  in  all  of  the  appropriate  sizes  for  all  densities,  you  can
+
+provide them in the same file structure used by the Codename One XML resource files: The image
+
+path is a directory that contains images named after the density that they are intended to be used
+
+for. The possible names include:
+
+• verylow.png
+
+• low.png
+
+• medium.png
+
+• high.png
+
+• veryhigh.png
+
+• 560.png
+
+• hd.png
+
+• 2hd.png
+
+• 4k.png
+
+E.g. Given the CSS directives:
+
+176
+
+MyStyle {
+    background-image: url(images/mymultiimage.png);
+}
+
+The files would look like:
+
+css/
+ +--- mycssfile.css
+ +--- images/
+       +--- mymultiimage.png/
+             +--- verylow.png
+             +--- low.png
+             +--- medium.png
+              ... etc...
+
+ Multi-image inputs are only supported for local URLs. You cannot use remote (e.g.
+
+http://) urls with multi-image inputs
+
+5.8.4. Image Constants
+
+Theme constants can be images. The convention is to suffix the constant name with "Image" so that
+it will be treated as an image. In addition to the standard url() notation for specifying a constant
+image, you can provide a simple string name of the image, and the CSS processor will try to find an
+
+image by that name specified as a background image for one of the styles. If it cannot find one, it
+
+will look inside a special directory named "res" (located in the same directory as the CSS stylesheet),
+
+inside which it will look for a directory named the same as the stylesheet, inside which it will look
+
+for  a  directory  with  the  specified  multi-image.  This  directory  structure  is  the  same  as  used  for
+
+Codename One’s XML resources directory.
+
+E.g. In the CSS file "mycssfile.css":
+
+radioSelectedFocusImage: "Radio_btn_Press.png";
+
+Will  look  for  a  directory  located  at  res/mycssfile.css/Radio_btn_Press.png/  with  the  following
+images:
+
+• verylow.png
+
+• low.png
+
+• medium.png
+
+• high.png
+
+• veryhigh.png
+
+• 560.png
+
+• hd.png
+
+177
+
+• 2hd.png
+
+• 4k.png
+
+It will then create a multi-image from these images and include them in the resource file.
+
+5.9. Image Recipes
+
+5.9.1. Import Multiple Images In Single Selector
+
+It is quite useful to be able to embed images inside the resource file that is generated from the CSS
+stylesheet so that you can access the images using the Resources.getImage() method in your app and
+set it as an icon on a button or label. In this case, it is easier to simply create a dummy style that you
+
+don’t intend to use and include multiple images in the background-image property like so:
+
+Images {
+    background-image: url(images/NowLogo.png),
+        url(images/Username-icon.png),
+        url(images/Password-icon.png),
+        url(images/Name-icon.png),
+        url(images/Email-icon.png),
+        url(images/SeaIce.png),
+        url(images/Back-icon.png),
+        url(images/Source-icon.png),
+        url(images/Date-icon.png),
+        url(images/Arrow-right.png),
+        url(images/Share-icon.png),
+        url(images/Text-icon.png),
+        url(images/Comments-icon.png),
+        url(images/RedPlanet.png),
+        url(images/News-icon.png),
+        url(images/Channels-icon.png),
+        url(images/Bookmarks-icon.png),
+        url(images/Overview-icon.png),
+        url(images/Calendar-icon.png),
+        url(images/Timeline-icon.png),
+        url(images/Profile-icon.png),
+        url(images/Widgets-icon.png),
+        url(images/Settings-icon.png),
+        url(images/Bookmark-icon.png);
+}
+
+Then in Java, I might do something like:
+
+Resources theme = Resources.openLayered("/theme.css.res");
+
+Label bookmark = new Label(theme.getImage("Bookmark-icon.png"));
+
+178
+
+5.9.2. Loading Images from URLs
+
+You can also load images from remote URLs. E.g.
+
+Images {
+    background-image: url(http://solutions.weblite.ca/logo.png);
+}
+
+5.9.3. Generating 9-Piece Image Borders
+
+9-Piece image borders can be created using the image-border and image-border-slice properties.
+
+E.g.
+
+NinePiece {
+    border-image:url('dashbg_landscape.png');
+}
+
+In  the  above  example  we  omitted  the  border-image-slice  property,  so  it  defaults  to  "40%",  which
+means that the image is sliced 40% from the top, 40% from the bottom, 40% from the left, and 40%
+
+from the right.
+
+If you want more specific "slice" points, you can add the border-image-slice property. E.g.
+
+179
+
+NinePiece {
+    border-image:url('dashbg_landscape.png');
+    border-image-slice:10% 49%;  /*vertical horizontal*/
+}
+
+NinePiece2 {
+    border-image:url('dashbg_landscape.png');
+    border-image-slice:10% 49% 20%;  /*top horizontal bottom*/
+}
+
+NinePiece3 {
+    border-image:url('dashbg_landscape.png');
+    border-image-slice:10% 30% 40% 20%;  /*top right bottom left*/
+}
+
+NinePiece4 {
+    border-image:url('dashbg_landscape.png');
+    border-image-slice:10%;  /*all*/
+}
+
+5.9.4. Image Backgrounds
+
+Component  backgrounds  in  Codename  One  are  a  common  source  of  confusion  for  newcomers
+
+because there are 3 different properties that can be used to define what a component’s background
+
+looks like, and they have priorities:
+
+1. Background Color - You can specify an RGB color to be used as the background for a component.
+
+2. Background Image - You can specify an image to be used as the background for a component.
+
+Codename  One  includes  settings  to  define  how  the  image  is  treated,  e.g.  scale/fill,  tile,  etc.  If  a
+
+background image is specified, it will override the background color setting - unless the image
+
+has transparent regions.
+
+3. Image  Border  -  You  can  define  a  9-piece  image  border  which  will  effectively  cover  the  entire
+
+background of the component. If an image border is specified, it will override the background
+
+image of the component.
+
+A common scenario that I run into is trying to set the background color of a component and see no
+
+change  when  I  preview  my  form  because  the  style  had  an  image  background  defined  -  which
+
+overrides my background color change.
+
+The  potential  for  confusion  is  mitigated  somewhat,  but  still  exists  when  using  CSS.  You  can  make
+your  intentions  explicit  by  adding  the  cn1-background-type  property  to  your  style.  Possible  values
+include:
+
+• cn1-image-scaled
+
+• cn1-image-scaled-fill
+
+• cn1-image-scaled-fit
+
+• cn1-image-tile-both
+
+180
+
+• cn1-image-tile-valign-left
+
+• cn1-image-tile-valign-center
+
+• cn1-image-tile-valign-right
+
+• cn1-image-tile-halign-top
+
+• cn1-image-tile-halign-center
+
+• cn1-image-tile-halign-bottom
+
+• cn1-image-align-bottom
+
+• cn1-image-align-left
+
+• cn1-image-align-right
+
+• cn1-image-align-center
+
+• cn1-image-align-top-left
+
+• cn1-image-align-top-right
+
+• cn1-image-align-bottom-left
+
+• cn1-image-align-bottom-right
+
+• cn1-image-border
+
+• cn1-none
+
+• none
+
+Example Setting Background Image to Scale Fill
+
+MyContainer {
+    background-image: url(myimage.png);
+    cn1-background-type: cn1-image-scaled-fill;
+}
+
+5.10. Image Compression
+
+CN1 resource files support both PNG and JPEG images, but PNG is the default. Multi-images that are
+
+generated by the CSS compiler will be PNG if they include alpha transparency, and JPEG otherwise.
+
+This is to try to reduce the file size as much as possible while not sacrificing quality.
+
+5.11. Fonts
+
+This 
+
+library 
+
+supports 
+
+the 
+
+font 
+
+[https://developer.mozilla.org/en/docs/Web/CSS/font], 
+
+font-size
+
+[https://developer.mozilla.org/en/docs/Web/CSS/font-size],  font-family  [https://developer.mozilla.org/en/docs/Web/
+
+CSS/font-family], 
+
+font-style 
+
+[https://developer.mozilla.org/en/docs/Web/CSS/font-style], 
+
+font-weight
+
+[https://developer.mozilla.org/en/docs/Web/CSS/font-weight],  and  text-decoration  [https://developer.mozilla.org/
+
+en/docs/Web/CSS/text-decoration]  properties,  as  well  at  the  @font-face  [https://developer.mozilla.org/en/docs/
+
+Web/CSS/@font-face] CSS "at" rule for including TTF/OTF fonts.
+
+181
+
+5.11.1. font-family
+
+By  default,  CN1’s  native  fonts  [https://www.codenameone.com/blog/good-looking-by-default-native-fonts-
+
+simulator-detection-more.html] are used. The appropriate native font is selected for the provided font-
+
+weight and font-style properties. You can also explicitly specify the native font you wish to use in
+the font-family property. E.g.
+
+SideCommand {
+    font-family:  "native:MainThin";
+}
+
+If you omit the font-family directive altogether, it will use native:MainRegular. The following native
+fonts are available:
+
+1. native:MainThin
+
+2. native:MainLight
+
+3. native:MainRegular
+
+4. native:MainBold
+
+5. native:MainBlack
+
+6. native:ItalicThin
+
+7. native:ItalicLight
+
+8. native:ItalicRegular
+
+9. native:ItalicBold
+
+10. native:ItalicBlack
+
+Using TTF Fonts
+
+If you want to use a font other than the built-in fonts, you’ll need to define the font using the @font-
+face rule. E.g.
+
+@font-face {
+    font-family: "Montserrat";
+    src: url(res/Montserrat-Regular.ttf);
+}
+
+Then you’ll be able to reference the font using the specified font-family in any CSS element. E.g.
+
+MyLabel {
+    font-family: "Montserrat";
+}
+
+The @font-face directive’s src property will accept both local and remote URLs. E.g.
+
+182
+
+@font-face {
+    font-family: "MyFont";
+    src: url(http://example.com/path/to/myfont.ttf);
+}
+
+In this case, it will download the myfont.ttf file to the same directory as the CSS file. From then on
+it  will  use  that  locally  downloaded  version  of  the  font  so  that  it  doesn’t  have  to  make  a  network
+
+request for each build.
+
+Fonts are automatically copied to the project’s "src" directory when the CSS file is compiled so that
+
+they will be distributed with the app and available at runtime.
+
+Github URLs
+
+Fonts hosted on GitHub are accessible using a special github: protocol to make it easier to reference
+such fonts. E.g. the following directive includes the "FontAwesome" font directly from Github
+
+@font-face {
+    font-family: "FontAwesome";
+    src: url(github://FontAwesome/Font-Awesome/blob/master/fonts/fontawesome-webfont.ttf);
+}
+
+ Apparently FontAwesome has removed its public repositories from Github so this
+
+URL no longer works.
+
+5.11.2. font-size
+
+It  is  best  practice  to  size  your  fonts  using  millimetres  (mm)  (or  another  "real-world"  measurement
+unit  such  as  inches  (in),  centimetres  (cm).  This  will  allow  the  font  to  be  sized  appropriate  for  all
+display densities. If you specify size in pixels (px), it will treat it the same as if you sized it in points
+(pt), where 1pt == 1/72 inches (one seventy-second of an inch).
+
+If  you  size  your  font  in  percentage  units  (e.g.  150%)  it  will  set  the  font  size  relative  to  the  medium
+font  size  of  the  platform.  This  is  different  than  the  standard  behaviour  of  a  web  browser,  which
+
+would size it relative to the parent element’s font size.
+
+You can use system fonts, true type fonts, and native fonts in your CSS stylesheet. True Type fonts
+need  to  be  defined  in  a  @font-face  directive  before  they  can  be  referenced.  True-type  fonts  and
+native fonts have the advantage that you can specify their sizes in generic terms (e.g. small, medium,
+large) and in more specific units such as millimeters (mm) or pixels (px).
+
+5.11.3. text-decoration
+
+See  the  text-decoration  section  [Supported-Properties#text-decoration]  in  the  "Supported  Properties"
+
+page.
+
+183
+
+5.11.4. Some Sample CSS Directives
+
+@font-face {
+    font-family: "Montserrat";
+    src: url(res/Montserrat-Regular.ttf);
+}
+
+@font-face {
+    font-family: "Montserrat-Bold";
+    src: url(res/Montserrat-Bold.ttf);
+}
+
+@font-face {
+    font-family: "FontAwesome";
+    src: url(github://FontAwesome/Font-Awesome/blob/master/fonts/fontawesome-webfont.ttf);
+}
+
+PlainText0p5mm {
+    font-size: 0.5mm;
+}
+
+PlainText1mm {
+    font-size: 1mm;
+}
+
+PlainText2mm {
+    font-size: 2mm;
+}
+
+PlainText5mm {
+    font-size: 5mm;
+}
+
+PlainText10mm {
+    font-size: 10mm;
+}
+
+PlainText50mm {
+    font-size: 50mm;
+}
+
+PlainTextSmall {
+    font-size: small;
+}
+
+PlainTextMedium {
+    font-size: medium;
+}
+
+PlainTextLarge {
+    font-size: large;
+}
+
+184
+
+PlainText3pt {
+    font-size: 3pt;
+}
+
+PlainText6pt {
+    font-size: 6pt;
+}
+
+PlainText12pt {
+    font-size: 12pt;
+}
+
+PlainText20pt {
+    font-size: 20pt;
+}
+
+PlainText36pt {
+    font-size: 36pt;
+}
+
+BoldText {
+    font-weight: bold;
+}
+
+BoldText1mm {
+    font-weight: bold;
+    font-size: 1mm;
+}
+
+BoldText2mm {
+    font-weight: bold;
+    font-size: 2mm;
+}
+
+BoldText3mm {
+    font-weight: bold;
+    font-size: 3mm;
+}
+
+BoldText5mm {
+    font-weight: bold;
+    font-size: 5mm;
+}
+
+ItalicText {
+    font-style: italic;
+}
+
+ItalicText3mm {
+    font-style: italic;
+    font-size: 3mm;
+}
+
+185
+
+ItalicBoldText {
+    font-style: italic;
+    font-weight: bold;
+}
+
+PlainTextUnderline {
+    text-decoration: underline;
+}
+
+BoldTextUnderline {
+    text-decoration: underline;
+    font-weight: bold;
+}
+
+ItalicTextUnderline {
+    text-decoration: underline;
+    font-style: italic;
+}
+
+PlainText3d {
+    text-decoration: cn1-3d;
+    color:white;
+    background-color: #3399ff
+}
+
+BoldText3d {
+    text-decoration: cn1-3d;
+    font-weight: bold;
+    color:white;
+    background-color: #3399ff;
+}
+
+ItalicText3d {
+    text-decoration: cn1-3d;
+    font-style: italic;
+    color:white;
+    background-color: #3399ff;
+}
+
+PlainText3dLowered {
+    text-decoration: cn1-3d-lowered;
+    color:black;
+    background-color: #3399ff;
+}
+
+BoldText3dLowered {
+    text-decoration: cn1-3d-lowered;
+    font-weight: bold;
+    color:black;
+    background-color: #3399ff;
+}
+
+186
+
+ItalicText3dLowered {
+    text-decoration: cn1-3d-lowered;
+    font-style: italic;
+    color:black;
+    background-color: #3399ff;
+}
+
+PlainText3dShadow {
+    text-decoration: cn1-3d-shadow-north;
+    color:white;
+    background-color: #3399ff;
+}
+
+BoldText3dShadow {
+    text-decoration: cn1-3d-shadow-north;
+    font-weight: bold;
+    color:white;
+    background-color: #3399ff;
+}
+
+ItalicText3dShadow {
+    text-decoration: cn1-3d-shadow-north;
+    font-style: italic;
+    color:white;
+    background-color: #3399ff;
+}
+
+MainThin {
+
+    font-size: 200%;
+    background: radial-gradient(circle at top left, yellow, blue 100%);
+}
+
+MainRegular0001 {
+    font-family: "native:MainRegular";
+    /*background: cn1-pill-border;
+    background-color: red;*/
+    color: blue;
+    border: 1px cn1-pill-border blue;
+    /*box-shadow: 1mm 1mm 0 2mm rgba(0,0,0,1.0);*/
+    padding: 2mm;
+}
+
+MainRegular0001.pressed {
+    font-family: "native:MainRegular";
+    background: cn1-pill-border blue;
+    /*background-color: red;*/
+    color: white;
+    border: 1px solid white;
+    /*box-shadow: 1mm 1mm 0 2mm rgba(0,0,0,1.0);*/
+    padding: 2mm;
+}
+
+187
+
+Heading {
+    font-size: 4mm;
+    font-family: "Montserrat-Bold";
+    color: black;
+    padding: 2mm;
+    text-align: center;
+}
+
+XMLVIewIcon {
+    font-family: "FontAwesome";
+}
+
+5.12. Media Queries
+
+You  can  use  media  queries  to  target  styles  to  specific  platforms,  devices,  and  device  densities.
+
+Currently the following media queries are supported:
+
+1. platform-xxx - Target a specific platform. E.g. platform-and, platform-ios, platform-mac, platform-
+
+win.
+
+2. density-xxx - Target a specific device density. E.g. density-very-low, density-low, density-medium,
+
+density-high, density-very-high, density-hd, density-2hd, and density-560.
+
+3. device-xxx - Target a specific device type. E.g. device-desktop, device-tablet, device-phone.
+
+Listing 15. Example: Different font colors on Android and iOS.  On Android, labels will appear green.  On
+
+iOS, they will appear red.  On all other platforms, they will appear black.
+
+Label {
+    color: black;
+}
+
+@media platform-and {
+    Label {
+        color: green;
+    }
+}
+
+@media platform-ios {
+    Label {
+        color: red;
+    }
+}
+
+188
+
+Listing 16. Example: Different font colors based on device density.  On lower densities, labels will be green.
+
+On higher densities, labels will be red.
+
+Label {
+    color: black;
+}
+
+@media density-very-low, density-low, density-medium, density-high {
+    Label {
+        color: green;
+    }
+}
+
+@media density-very-high, density-h2, density-2hd, density-560 {
+    Label {
+        color: red;
+    }
+}
+
+Listing 17. Example: Different label colors based on device type.
+
+Label {
+    color: black;
+}
+
+@media device-desktop {
+    Label {
+        color: green;
+    }
+}
+
+@media device-tablet, device-phone {
+    Label {
+        color: red;
+    }
+}
+
+When  deploying  your  app  using  the  Javascript  port,  it  will  use  a  platform  name
+
+
+
+derived  from  the  "UserAgent"  string  in  the  browser,  rather  than  the  result  of
+Display.getPlatformName(),  which  is  used  for  other  ports.  When  running  on
+Android, then, the platform will be "and". When running on iOS, the platform will
+
+be "ios". Etc…
+
+5.12.1. Compound Media Queries
+
+You can combine multiple media queries together, separated by a comma. Queries of the same type
+
+are  "OR"ed  together.  Queries  of  different  types  are  "AND"ed  together.  For  example  if  you  have  a
+media  query  that  specifies  two  different  device  densities  (e.g.  density-low  and  density-high)  the
+
+189
+
+query will match both devices with low density and high density. However, if the query specifies a
+device density and a platform (e.g. density-low and platform-and), then it will only match a device if
+it matches the platform and the density.
+
+Listing 18. Example: Targeting styles to only Android devices with high density
+
+@media platform-and, density-high {
+    ....
+}
+
+Listing 19. Example: Targeting styles to iOS devices with high or low density
+
+@media platform-ios, density-high, density-low {
+    ....
+}
+
+Listing 20. Example: Targeting only Mac Desktop.
+
+@media device-desktop, platform-mac {
+    ....
+}
+
+5.12.2. Order or Precedence
+
+The  order  of  precendence  when  applying  styles  differs  slightly  from  the  way  styles  would  be
+
+applied in standard CSS. The order of precendence is as follows:
+
+1. Styles defined inside @media blocks will always take precendence over styles defined outside of
+
+@media blocks.
+
+2. @media  blocks  with  more  query  matches  will  take  precendence  over  blocks  with  fewer  query
+matches. E.g. A media block matching density, platform, and device will take precendence over
+
+a block that only matches the density and platform.
+
+3. If  the  same  style  is  defined  in  two  media  blocks  which  contain  the  same  number  of  query
+matches,  then  the  order  precedence  is  platform,  device,  density  in  decreasing  order.  I.e.  the
+block that matches on platform will take precedence over the block that matches on density.
+
+4. If the same style is defined in two media blocks with identical query matches, then the order of
+
+precedence is undefined.
+
+5.12.3. Font Scaling Constants
+
+In  some  cases  you  may  find  that  fonts  are  coming  out  too  large  or  too  small  across  the  board  on
+
+certain types of devices. You can use standard media queries to customize font sizes, but you can
+also  use  font-scaling  constants  to  scale  font  sizes  for  the  entires  stylesheet  based  on  platform,
+device, and/or density. In some cases you may find this approach easier.
+
+For example, consider the following simple stylesheet that defines a font size of 2mm on labels:
+
+190
+
+Label {
+    font-size: 3mm;
+}
+
+During testing, perhaps you find that, on desktop, the fonts are a little bit too small. In this case, you
+
+can apply a font-scale constant that only applies to the desktop.
+
+#Constants {
+    device-desktop-font-scale: "1.5";
+}
+
+Label {
+    font-size: 3mm;
+}
+
+Now, on most devices the Label style will have 3mm fonts. But on desktop, it will have 4.5mm fonts.
+
+The above would be roughly equivalent to:
+
+Label {
+    font-size: 3mm;
+}
+
+@media device-desktop {
+    Label {
+        font-size: 4.5mm;
+    }
+}
+
+Listing 21. Example: Font-scaling based on device, platform, and density
+
+#Constants {
+    device-phone-font-scale: "1.5";
+    device-tablet-font-scale: "1.2";
+    device-desktop-font-scale: "1.4";
+    platform-ios-font-scale: "0.9";
+    density-low-font-scale: "1.2";
+    platform-ios-density-low-font-scale: "1.3";
+}
+
+
+
+All matching font-scale constants will be applied to the styles. If you define 3 font-
+scale  constants  that  all  match  the  current  runtime  environment,  they  will  all  be
+
+applied. E.g. If there are 3 matching font-scale constants with "2.0", "3.0", and "4.0",
+
+then fonts will be scaled by 2*3*4=24!
+
+191
+
+192
+
+6. The Components of Codename One
+
+This chapter covers the components of Codename One. Not all components are covered, but it tries
+
+to go deeper than the JavaDocs [https://www.codenameone.com/javadoc/].
+
+6.1. Container
+
+The  Codename  One  container  is  a  base  class  for  many  high  level  components;  a  container  is  a
+
+component that can contain other components.
+
+Every  component  has  a  parent  container  that  can  be  null  if  it  isn’t  within  a  container  at  the
+
+moment or is a top-level container. A container can have many children.
+
+Figure 186. Component-Container relationship expressed as UML
+
+Components  are  arranged  in  containers  using  layout  managers  which  are  algorithms  that
+
+determine the arrangement of components within the container.
+
+You can read more about layout managers in the basics section [https://www.codenameone.com/manual/
+
+basics.html#component-container-hierarchy].
+
+6.1.1. Composite Components
+
+Codename  One  components  share  a  very  generic  hierarchy  of 
+
+inheritance  e.g.  Button
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/Button.html] 
+
+derives 
+
+from 
+
+Label
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/Label.html] and thus receives all its abilities.
+
+However, 
+
+some 
+
+components 
+
+are 
+
+composites 
+
+and 
+
+derive 
+
+from 
+
+the 
+
+Container
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/Container.html]  class.  E.g. 
+
+the  MultiButton
+
+[https://www.codenameone.com/javadoc/com/codename1/components/MultiButton.html]  is  a  composite  button
+that  derives  from  Container  but  acts/looks  like  a  Button.  Normally  this  is  pretty  seamless  for  the
+developer, with a few things to keep in mind.
+
+• You  should  not  use  the  Container  derived  methods  on  such  a  composite  component  (e.g.  add
+
+/remove etc.).
+
+• You can’t cast it to the type that it relates to e.g. you can’t cast MultiButton to Button.
+
+• Events  might  be  more  nuanced.  E.g. 
+
+if  you 
+
+rely  on  ActionEvent.getSource()
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/events/ActionEvent.html#getSource--] 
+
+or
+
+ActionEvent.getComponent() 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/events/
+
+ActionEvent.html#getComponent--] notice that they might not behave the way you would expect. For
+a  MultiButton  they  will  return  the  underlying  Button.  To  workaround  this  we  have
+[https://www.codenameone.com/javadoc/com/codename1/ui/events/
+ActionEvent.getActualComponent() 
+
+193
+
+ActionEvent.html#getActualComponent--].
+
+Lead Component
+
+Codename  One  has  a  rather  unique  feature  for  creating  composite  components:  "lead
+components". This feature effectively allows components like MultiButton to act as if they are
+a single component while really being comprised of multiple components.
+
+Lead components work by setting a single component within as the "leader" it determines the
+style state for all the components in the hierarchy so if we have a Container that is lead by a
+Button  the  button  will  determine  if  the  selected/pressed  state  is  returned  for  the  entire
+container hierarchy.
+
+This creates a case where a single Component has multiple nested UIID’s e.g. `MultiButton has
+UIID’s  such  as  `MultiLine1  that  can  be  customized  via  API’s  such  as  setUIIDLine1
+[https://www.codenameone.com/javadoc/com/codename1/components/MultiButton.html#setUIIDLine1-
+
+java.lang.String-].
+
+The  lead  component  also  handles  the  events  from  a  single  source  so  clicking  in  one  of  the
+other components within the hierarchy will send the event to the leading Button resulting in
+action events that behave "oddly" (hence the need for getActualComponent);
+
+You  can  learn  more  about  lead  components  in  here  [https://www.codenameone.com/manual/misc-
+
+features.html#lead-component-section].
+
+6.2. Form
+
+Form  [https://www.codenameone.com/javadoc/com/codename1/ui/Form.html]  is  the  top-level  container  of
+Codename One, Form derives from Container and is the element we “show”. Only one form can be
+visible at any given time. We can get the currently visible Form using the code:
+
+Form currentForm = Display.getInstance().getCurrent();
+
+A  form  is  a  unique  container  in  the  sense  that  it  has  a  title,  a  content  area  and  optionally  a
+menu/menu  bar  area.  When  invoking  methods  such  as  add/remove  on  a  form,  you  are  in  fact
+invoking something that maps to this:
+
+myForm.getContentPane().add(...);
+
+Form  is  in  effect  just  a  Container  [https://www.codenameone.com/javadoc/com/codename1/ui/Container.html]
+that has a border layout, its north section is occupied by the title area and its south section by the
+
+optional menu bar. The center (which stretches) is the content pane. The content pane is where you
+
+place all your components.
+
+194
+
+Figure 187. Form layout graphic
+
+You can see that every Form has space allocated for the title area. If you don’t set the title it won’t
+show up (its size will be zero), but it will still be there. The same isn’t always true for the case of the
+
+menu bar, which can vary significantly. Effectively, the section that matters is the content pane, so
+
+the  form  tries  to  do  the  “right  thing”  by  pretending  to  be  the  content  pane.  However,  this  isn’t
+always  seamless  and  sometimes  code  needs  to  just  invoke  getContentPane()  in  order  to  work
+directly with the container.
+
+
+
+A  good  example  for  such  a  case  is  with  layout  animations.  Animating  the  form
+
+might  not  produce  the  right  results.  When  in  doubt  its  pretty  easy  to  just  use
+getContentPane instead of working with the Form directly.
+
+As you can see from the graphic, Form has two layers that reside on top of the content pane/title. The
+first is the layered pane which allows you to place "always on top" components. The layered pane
+added implicitly when you invoke getLayeredPane().
+
+ You still need to place components using layout managers in order to get them to
+
+appear in the right place when using the layered pane.
+
+The second layer is the glass pane which allows you to draw arbitrary things on top of everything.
+
+The order in the image is indeed accurate:
+
+1. ContentPane is lowest
+
+2. LayeredPane is second
+
+3. GlassPane is painted last
+
+
+
+Its  important  to  notice  that  a  layered  pane  is  on  top  of  the  ContentPane  only  and
+doesn’t stretch to the title. A GlassPane usually stretches all the way but only with a
+"lightweight" title area e.g. the Toolbar API [https://www.codenameone.com/javadoc/com/
+
+codename1/ui/Toolbar.html].
+
+The GlassPane allows developers to overlay UI on top of existing UI and paint as they see fit. This is
+useful for things that provide notification but don’t want to intrude with application functionality.
+
+In earlier versions of Codename One (pre-3.6), LayeredPane & GlassPane didn’t work
+with "native" peer components such as media, browser, native maps etc, because
+
+
+
+peer components were always rendered "in front" of the Codename One UI canvas.
+
+However, current versions now allow for proper layering of peer components and
+
+light-weight  components  so  that  LayeredPane  and  GlassPane  can  be  used
+
+seamlessly with peer components.
+
+195
+
+6.3. Dialog
+
+A Dialog [https://www.codenameone.com/javadoc/com/codename1/ui/Dialog.html] is a special kind of Form that
+can  occupy  only  a  portion  of  the  screen,  it  also  has  the  additional  functionality  of  the  modal  show
+method.
+
+When showing a dialog we have two basic options: modeless and modal:
+
+• Modal  dialogs  (the  default)  block  the  current  EDT  thread  until  the  dialog  is  dismissed  (to
+
+understand how they do it, read about invokeAndBlock).
+Modal  dialogs  are  an  extremely  useful  way  to  prompt  the  user  since  the  code  can  assume  the
+
+user responded in the next line of execution. This promotes a linear & intuitive way of writing
+
+code.
+
+• Modless dialogs return immediately so a call to show such a dialog can’t assume anything in the
+
+next  line  of  execution.  This  is  useful  for  features  such  as  progress  indicators  where  we  aren’t
+
+waiting for user input.
+
+E.g. a modal dialog can be expressed as such:
+
+if(Dialog.show("Click Yes Or No", "Select one", "Yes", "No")) {
+    // user clicked yes
+} else {
+    // user clicked no
+}
+
+Notice  that  during  the  show  call  above  the  execution  of  the  next  line  was  "paused"  until  we  got  a
+response from the user and once the response was returned we could proceed directly.
+
+
+
+All usage of Dialog must be within the Event Dispatch Thread (the default thread of
+Codename One). This is especially true for modal dialogs. The Dialog class knows
+how to "block the EDT" without blocking it.
+
+To learn more about invokeAndBlock which is the workhorse behind the modal dialog functionality
+check out the EDT section [https://www.codenameone.com/manual/edt.html].
+
+The Dialog class contains multiple static helper methods to quickly show user notifications, but also
+allows  a  developer  to  create  a  Dialog  instance,  add  information  to  its  content  pane  and  show  the
+dialog.
+
+
+
+Dialogs contain a ContentPane just like Form.
+
+When  showing  a  dialog  in  this  way,  you  can  either  ask  Codename  One  to  position  the  dialog  in  a
+
+specific  general  location  (taken  from  the  BorderLayout  [https://www.codenameone.com/javadoc/com/
+
+codename1/ui/layouts/BorderLayout.html]  concept  for  locations)  or  position  it  by  spacing  it  (in  pixels)
+
+from the 4 edges of the screen.
+
+E.g. you could do something like this to show a simple modal Dialog:
+
+196
+
+Dialog d = new Dialog("Title");
+d.setLayout(new BorderLayout());
+d.add(BorderLayout.CENTER, new SpanLabel("Dialog Body", "DialogBody"));
+d.showPacked(BorderLayout.SOUTH, true);
+
+Figure 188. Custom modal Dialog in the south position
+
+
+
+You  can  turn  the  code  above  to  a  modless  Dialog  by  flipping  the  boolean  true
+argument to false.
+
+We can position a Dialog absolutely by determining the space from the edges e.g. with this code we
+can occupy the bottom portion of the screen:
+
+Dialog d = new Dialog("Title");
+d.setLayout(new BorderLayout());
+d.add(BorderLayout.CENTER, new SpanLabel("Dialog Body", "DialogBody"));
+d.show(hi.getHeight() / 2, 0, 0, 0);
+
+Figure 189. Custom Dialog positioned absolutely
+
+ hi is the name of the parent Form in the sample above.
+
+6.3.1. Styling Dialogs
+
+It’s  important  to  style  a  Dialog  using  getDialogStyle()  [https://www.codenameone.com/javadoc/com/
+[https://www.codenameone.com/javadoc/com/
+codename1/ui/Dialog.html#getDialogStyle--]  or 
+
+setDialogUIID 
+
+197
+
+codename1/ui/Dialog.html#setDialogUIID-java.lang.String-]  methods  rather  than  styling  the  dialog  object
+
+directly.
+
+The reason for this is that the Dialog is really a Form that takes up the whole screen. The Form that is
+visible behind the Dialog is rendered as a screenshot. So customizing the actual UIID of the Dialog
+won’t produce the desired results.
+
+6.3.2. Tint and Blurring
+
+By default a Dialog uses a platform specific tint color when it is showing e.g. notice the background
+in the image below is tinted:
+
+Form hi = new Form("Tint Dialog", new BoxLayout(BoxLayout.Y_AXIS));
+Button showDialog = new Button("Tint");
+showDialog.addActionListener((e) -> Dialog.show("Tint", "Is On....", "OK", null));
+hi.add(showDialog);
+hi.show();
+
+Figure 190. Dialog with tinted background
+
+The tint color can be manipulated on the parent form, you can set it to any AARRGGBB value to set
+any color using the setTintColor method. Notice that this is invoked on the parent form and not on
+the Dialog!
+
+ This is an AARRGGBB value and not an RRGGBB value! This means that 0 will be
+
+transparent.
+
+You can also manipulate this default value globally using the theme constant tintColor. The sample
+below tints the background in green:
+
+Form hi = new Form("Tint Dialog", new BoxLayout(BoxLayout.Y_AXIS));
+hi.setTintColor(0x7700ff00);
+Button showDialog = new Button("Tint");
+showDialog.addActionListener((e) -> Dialog.show("Tint", "Is On....", "OK", null));
+hi.add(showDialog);
+hi.show();
+
+198
+
+Figure 191. Dialog with green tinted background
+
+We can apply Gaussian blur to the background of a dialog to highlight the foreground further and
+produce  a  very  attractive  effect.  We  can  use  the  setDefaultBlurBackgroundRadius  to  apply  this
+globally, we can use the theme constant dialogBlurRadiusInt to do the same or we can do this on a
+per Dialog basis using setBlurBackgroundRadius.
+
+
+
+Not  all  device  types  support  blur  you  can  test  if  your  device  supports  it  using
+Display.getInstnace().isGaussianBlurSupported().  If  blur  isn’t  supported  the  blur
+setting will be ignored.
+
+Form hi = new Form("Blur Dialog", new BoxLayout(BoxLayout.Y_AXIS));
+Dialog.setDefaultBlurBackgroundRadius(8);
+Button showDialog = new Button("Blur");
+showDialog.addActionListener((e) -> Dialog.show("Blur", "Is On....", "OK", null));
+hi.add(showDialog);
+hi.show();
+
+Figure 192. The blur effect coupled with the OS default tint
+
+It might be a bit hard to notice the blur effect with the tinting so here is the same code with tinting
+
+disabled:
+
+hi.setTintColor(0);
+
+199
+
+Figure 193. The blur effect is more pronounced when the tint is disabled
+
+6.3.3. Popup Dialog
+
+A popup dialog is a common mobile paradigm showing a Dialog that points at a specific component.
+It’s just a standard Dialog that is shown in a unique way:
+
+Dialog d = new Dialog("Title");
+d.setLayout(new BorderLayout());
+d.add(BorderLayout.CENTER, new SpanLabel("Dialog Body", "DialogBody"));
+d.showPopupDialog(showDialog);
+
+Figure 194. Popup Dialog
+
+The  popup  dialog  accepts  a  Component  [https://www.codenameone.com/javadoc/com/codename1/ui/
+
+Component.html]  or  Rectangle  [https://www.codenameone.com/javadoc/com/codename1/ui/geom/Rectangle.html]
+
+to point at and handles the rest.
+
+Styling The Arrow Of The Popup Dialog
+
+When  Codename  One  was  young  we  needed  a  popup  arrow  implementation  but  our  low  level
+
+graphics API was pretty basic. As a workaround we created a version of the 9-piece image border
+
+that supported pointing arrows at a component.
+
+Today  Codename  One  supports  pointing  an  arrow  from  the  RoundRectBorder  class.  This  is  implicit
+for  the  PopupDialog  UI.  This  allows  for  better  customization  of  the  border  (color  etc.)  and  it  looks
+better on newer displays. It also works on all OSs. Right now only the iOS theme has the old image
+
+border approach.
+
+200
+
+ This will change with a future update where all OS’s will align and iOS will use the
+
+lightweight popup too
+
+
+
+You  can  make  all  OS’s  act  the  same  way  by  overriding  the  PopupDialog  UIID  and
+defining its style to RoundRectBorder
+
+The new RoundRectBorder support works by setting the track component property on border. When
+that’s done the border implicitly points to the right location.
+
+If  you  still  need  deeper  customization  of  the  arrow  you  can  still  use  the  old  9-piece  border
+
+functionality illustrated below.
+
+Legacy 9-Piece Border Arrow
+
+One of the harder aspects of a popup dialog is the construction of the theme elements required for
+
+arrow  styling.  To  get  that  sort  of  behavior  you  will  need  a  custom  image  border  and  4  arrows
+
+pointing in each direction that will be overlaid with the border.
+
+
+
+The sizes of the arrow images should be similarly proportioned and fit within the
+
+image borders whitespace. The block image of the dialog should have empty pixels
+
+in  the  sides  to  reserve  space  for  the  arrow.  E.g.  if  the  arrows  are  all  32x32  pixels
+then the PopupDialog image should have 32 pixels of transparent pixels around it.
+
+You will need to define the following theme constants for the arrow to work:
+
+PopupDialogArrowBool=true
+PopupDialogArrowTopImage=arrow up image
+PopupDialogArrowBottomImage=arrow down image
+PopupDialogArrowLeftImage=arrow left image
+PopupDialogArrowRightImage=arrow right image
+
+Then style the PopupDialog UIID with the image for the Dialog itself.
+
+6.4. InteractionDialog
+
+Dialogs in Codename One can be modal or modeless, the former blocks the calling thread and the
+
+latter does not. However, there is another definition to those terms: A modal dialog blocks access to
+
+the rest of the UI while a modeless dialog "floats" on top of the UI.
+
+In  that  sense,  all  dialogs  in  Codename  One  are  modal;  they  block  the  parent  form  since  they  are
+
+effectively 
+
+just 
+
+forms 
+
+that  show 
+
+the  "parent" 
+
+in 
+
+their  background. 
+
+InteractionDialog
+
+[https://www.codenameone.com/javadoc/com/codename1/components/InteractionDialog.html]  has  an  API  that  is
+
+very  similar  to  the  Dialog  [https://www.codenameone.com/javadoc/com/codename1/ui/Dialog.html]  API  but,
+
+unlike dialog, it never blocks anything. Neither the calling thread nor the UI.
+
+201
+
+
+
+InteractionDialog  isn’t  a  Dialog  since  it  doesn’t  share  the  same  inheritance
+hierarchy. However, it acts and "feels" like a Dialog despite the fact that it’s just a
+Container in the LayeredPane.
+
+InteractionDialog  is  really  just  a  container  that  is  positioned  within  the  layered  pane.  Notice  that
+because of that design, you can have only one such dialog at the moment and, if you add something
+
+else to the layered pane, you might run into trouble.
+
+Using the interaction dialog is pretty trivial and very similar to dialog:
+
+InteractionDialog dlg = new InteractionDialog("Hello");
+dlg.setLayout(new BorderLayout());
+dlg.add(BorderLayout.CENTER, new Label("Hello Dialog"));
+Button close = new Button("Close");
+close.addActionListener((ee) -> dlg.dispose());
+dlg.addComponent(BorderLayout.SOUTH, close);
+Dimension pre = dlg.getContentPane().getPreferredSize();
+dlg.show(0, 0, Display.getInstance().getDisplayWidth() - (pre.getWidth() + pre.getWidth() / 6), 0);
+
+Figure 195. Interaction Dialog
+
+This will show the dialog on the right hand side of the screen, which is pretty useful for a floating in
+
+place dialog.
+
+
+
+The  InteractionDialog  can  only  be  shown  at  absolute  or  popup  locations.  This  is
+inherent to its use case which is "non-blocking". When using this component you
+
+need to be very aware of its location.
+
+6.5. Label
+
+Label [https://www.codenameone.com/javadoc/com/codename1/ui/Label.html] represents a text, icon or both.
+Label is also the base class of Button which in turn is the base class for RadioButton & CheckBox. Thus
+the functionality of the Label class extends to all of these components.
+
+Label text can be positioned in one of 4 locations as such:
+
+202
+
+Label left = new Label("Left", icon);
+left.setTextPosition(Component.LEFT);
+Label right = new Label("Right", icon);
+right.setTextPosition(Component.RIGHT);
+Label bottom = new Label("Bottom", icon);
+bottom.setTextPosition(Component.BOTTOM);
+Label top = new Label("Top", icon);
+top.setTextPosition(Component.TOP);
+hi.add(left).add(right).add(bottom).add(top);
+
+Figure 196. Label positions
+
+Label allows only a single line of text, line breaking is a very expensive operation on mobile devices
+[2] and so the Label class doesn’t support it.
+
+
+
+SpanLabel  supports  multiple  lines  with  a  single  label,  notice  that  it  does  carry  a
+
+performance penalty for this functionality.
+
+Labels  support  tickering  and  the  ability  to  end  with  “…”  if  there  isn’t  enough  space  to  render  the
+
+label.  Developers  can  determine  the  placement  of  the  label  relatively  to  its  icon  in  quite  a  few
+
+powerful ways.
+
+6.5.1. Label Gap
+
+The  gap  between  the  label  text  &  the  icon  defaults  to  2  pixels  due  to  legacy  settings.  The  setGap
+method of Label accepts a gap size in pixels.
+
+Two pixels is low for most cases & it’s hard to customize for each Label.
+
+You  can  use  the  theme  constant  labelGap  which  is  a  floating  point  value  you  can  specify  in
+millimeters that will allow you to determine the default gap for a label. You can also customize this
+manually using the method Label.setDefaultGap(int) which determines the default gap in pixels.
+
+6.5.2. Autosizing Labels
+
+One of the common requests we received over the years is a way to let text "fit" into the allocated
+
+space  so  the  font  will  match  almost  exactly  the  width  available.  In  some  designs  this  is  very
+
+important  but  it’s  also  very  tricky.  Measuring  the  width  of  a  String  is  a  surprisingly  expensive
+
+203
+
+operation  on  some  OS’s.  Unfortunately,  there  is  no  other  way  other  than  trial  &  error  to  find  the
+
+"best size".
+
+Still despite the fact that something is "slow" we might still want to use it for some cases, this isn’t
+
+something  you  should  use  in  a  renderer,  infinite  scroll  etc.  and  we  recommend  minimizing  the
+
+usage of this feature as much as possible.
+
+This  feature  is  only  applicable  to  Label  and  its  subclasses  (e.g.  Button),  with  components  such  as
+TextArea (e.g. SpanButton) the choice between shrinking and line break would require some complex
+logic.
+
+To activate this feature just use setAutoSizeMode(true) e.g.:
+
+Form hi = new Form("AutoSize", BoxLayout.y());
+
+Label a = new Label("Short Text");
+a.setAutoSizeMode(true);
+Label b = new Label("Much Longer Text than the previous line...");
+b.setAutoSizeMode(true);
+Label c = new Label("MUCH MUCH MUCH Much Longer Text than the previous line by a pretty big margin...");
+c.setAutoSizeMode(true);
+
+Label a1 = new Button("Short Text");
+a1.setAutoSizeMode(true);
+Label b1 = new Button("Much Longer Text than the previous line...");
+b1.setAutoSizeMode(true);
+Label c1 = new Button("MUCH MUCH MUCH Much Longer Text than the previous line by a pretty big margin...");
+c1.setAutoSizeMode(true);
+hi.addAll(a, b, c, a1, b1, c1);
+
+hi.show();
+
+Figure 197. Automatically sizes the fonts of the buttons/labels based on text and available space
+
+6.6. TextField and TextArea
+
+The  TextField  [https://www.codenameone.com/javadoc/com/codename1/ui/TextField.html]  class  derives  from
+
+the  TextArea  [https://www.codenameone.com/javadoc/com/codename1/ui/TextArea.html]  class,  and  both  are
+
+used for text input in Codename One.
+
+TextArea defaults to multi-line input and TextField defaults to single line input but both can be used
+
+204
+
+in both cases. The main differences between TextField and TextArea are:
+
+• Blinking cursor is rendered on TextField only
+
+• DataChangeListener 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/events/
+DataChangedListener.html] is only available in TextField. This is crucial for character by character
+input event tracking
+
+• Done 
+
+listener  [https://www.codenameone.com/javadoc/com/codename1/ui/TextField.html#setDoneListener-
+
+com.codename1.ui.events.ActionListener-] is only available in the TextField
+
+• Different UIID
+
+
+
+The semantic difference between TextField & TextArea dates back to the ancestor
+of  Codename  One:  LWUIT.  Feature  phones  don’t  have  “proper”  in-place  editing
+capabilities & thus TextField was introduced to allow such input.
+
+Because  it  lacks  the  blinking  cursor  capability  TextArea  is  often  used  as  a  multi-line  label  and  is
+used internally in SpanLabel, SpanButton etc.
+
+
+
+A  common  use  case  is  to  have  an  important  text  component  in  edit  mode
+immediately as we enter a Form. Codename One forms support this exact use case
+thru  the  Form.setEditOnShow(TextArea)  [https://www.codenameone.com/javadoc/com/
+
+codename1/ui/Form.html#setEditOnShow-com.codename1.ui.TextArea-] method.
+
+TextField & TextArea support constraints for various types of input such as NUMERIC, EMAIL, URL, etc.
+Those usually affect the virtual keyboard used, but might not limit input in some platforms. E.g. on
+iOS even with NUMERIC constraint you would still be able to input characters.
+
+
+
+If you need to prevent specific types of input check out the validation section.
+
+The following sample shows off simple text field usage:
+
+205
+
+TableLayout tl;
+int spanButton = 2;
+if(Display.getInstance().isTablet()) {
+    tl = new TableLayout(7, 2);
+} else {
+    tl = new TableLayout(14, 1);
+    spanButton = 1;
+}
+tl.setGrowHorizontally(true);
+hi.setLayout(tl);
+
+TextField firstName = new TextField("", "First Name", 20, TextArea.ANY);
+TextField surname = new TextField("", "Surname", 20, TextArea.ANY);
+TextField email = new TextField("", "E-Mail", 20, TextArea.EMAILADDR);
+TextField url = new TextField("", "URL", 20, TextArea.URL);
+TextField phone = new TextField("", "Phone", 20, TextArea.PHONENUMBER);
+
+TextField num1 = new TextField("", "1234", 4, TextArea.NUMERIC);
+TextField num2 = new TextField("", "1234", 4, TextArea.NUMERIC);
+TextField num3 = new TextField("", "1234", 4, TextArea.NUMERIC);
+TextField num4 = new TextField("", "1234", 4, TextArea.NUMERIC);
+
+Button submit = new Button("Submit");
+TableLayout.Constraint cn = tl.createConstraint();
+cn.setHorizontalSpan(spanButton);
+cn.setHorizontalAlign(Component.RIGHT);
+hi.add("First Name").add(firstName).
+        add("Surname").add(surname).
+        add("E-Mail").add(email).
+        add("URL").add(url).
+        add("Phone").add(phone).
+        add("Credit Card").
+                add(GridLayout.encloseIn(4, num1, num2, num3, num4)).
+        add(cn, submit);
+
+Figure 198. Simple text component sample
+
+
+
+The  Toolbar  section  contains  a  very  elaborate  TextField  search  sample  with
+DataChangeListener and rather unique styling.
+
+206
+
+6.6.1. Masking
+
+A  common  use  case  when  working  with  text  components  is  the  ability  to  "mask"  input  e.g.  in  the
+
+credit card number above we would want 4 digits for each text field and don’t want the user to tap
+
+Next 3 times.
+
+Masking allows us to accept partial input in one field and implicitly move to the next, this can be
+
+used to all types of complex input thanks to the text component API. E.g with the code above we can
+
+mask the credit card input so the cursor jumps to the next field implicitly using this code:
+
+automoveToNext(num1, num2);
+automoveToNext(num2, num3);
+automoveToNext(num3, num4);
+
+Then implement the method automoveToNext as:
+
+private void automoveToNext(final TextField current, final TextField next) {
+    current.addDataChangedListener((type, index) -> {
+        if(current.getText().length() == 5) {
+            current.stopEditing();
+            current.setText(val.substring(0, 4));
+            next.setText(val.substring(4));
+            next.startEditingAsync();
+        }
+    });
+}
+
+Notice we can invoke stopEditing(Runnable) where we receive a callback as editing is stopped.
+
+6.6.2. The Virtual Keyboard
+
+A  common  misconception  for  developers  is  assuming  the  virtual  keyboard  represents  "keys".  E.g.
+
+developers often override the "keyEvent" callbacks which are invoked for physical keyboard typing
+
+and expect those to occur with a virtual keyboard.
+
+This  isn’t  the  case  since  a  virtual  keyboard  is  a  very  different  beast.  With  a  virtual  keyboard
+
+characters typed might produce a completely different output due to autocorrect. Some keyboards
+
+don’t  even  have  "keys"  in  the  traditional  sense  or  don’t  type  them  in  the  traditional  sense  (e.g.
+
+swiping).
+
+
+
+
+
+The constraint property for the TextField/TextArea is crucial for a virtual keyboard.
+
+When working with a virtual keyboard it’s important that the parent Container for
+the TextField/TextArea is scrollable. Otherwise the component won’t be reachable
+or the UI might be distorted when the keyboard appears.
+
+207
+
+Action Button Client Property
+
+By  default,  the  virtual  keyboard  on  Android  has  a  "Done"  button,  you  can  customize  it  to  be  a
+
+search icon, a send icon, or a go icon using a hint such as this:
+
+searchTextField.putClientProperty("searchField", Boolean.TRUE);
+sendTextField.putClientProperty("sendButton", Boolean.TRUE);
+goTextField.putClientProperty("goButton", Boolean.TRUE);
+
+This will adapt the icon for the action on the keys.
+
+Next and Done on iOS
+
+We try to hide a lot of the platform differences in Codename One, input is very different between
+
+OS’s.  A  common  reliance  is  the  ability  to  send  the  "Done"  event  when  the  user  presses  the  Done
+
+button.  Unfortunately  this  button  doesn’t  always  exist  e.g.  if  there  is  an  Enter  button  (due  to
+
+multiline input) or if there is a Next button in that place.
+
+To make the behavior more uniform we slightly customized the iOS keyboard as such:
+
+Figure 199. Next virtual keyboard with toolbar
+
+Figure 200. Done virtual keyboard without toolbar
+
+ This works with 3rd party keyboards too…
+
+However, this behavior might not be desired so to block that we can do:
+
+tf.putClientProperty("iosHideToolbar", Boolean.TRUE);
+
+This will hide the toolbar for that given field.
+
+
+
+You  can  customize  the  color  of  the  Done  button  in  the  toolbar  by  setting  the
+ios.doneButtonColor display property. E.g. To change the color to red, you could do
+Display.getInstance().setProperty("ios.doneButtonColor",
+String.valueOf(0xff0000)). @since 5.0
+
+208
+
+6.6.3. Clearable Text Field
+
+iOS has a convention where an X can be placed after the text field to clear it. Some Android apps
+
+have it but there is no native support for that as of this writing.
+
+You can wrap a TextField with a clearable wrapper to get this effect on all platforms. E.g. replace
+this:
+
+cnt.add(myTextField);
+
+With this:
+
+cnt.add(ClearableTextField.wrap(myTextField));
+
+You can also specify the size of the clear icon if you wish. This is technically just a Container with
+the text field style and a button to clear the text at the edge.
+
+6.7. TextComponent
+
+When building input forms we sometimes want to adapt to the native OS behavior and create a UI
+that’s a bit more distinct to the native OS. TextField and TextArea are very low level, you can create
+an Android style UI with such components but it might look out of place in iOS.
+
+E.g. this is how most of us would expect the UI to look on iOS and Android respectively:
+
+Figure 201. Text Input on iOS
+
+Figure 202. Text Input on Android
+
+Doing  this  with  text  fields  is  possible  but  would  require  code  that  looks  a  bit  different  and  jumps
+through  hoops.  TextComponent  allows  this  exact  UI  without  forcing  developers  to  write  OS  specific
+code:
+
+209
+
+TextModeLayout tl = new TextModeLayout(3, 2);
+Form f = new Form("Pixel Perfect", tl);
+TextComponent title = new TextComponent().label("Title");
+TextComponent price = new TextComponent().label("Price");
+TextComponent location = new TextComponent().label("Location");
+TextComponent description = new TextComponent().label("Description").multiline(true);
+
+f.add(tl.createConstraint().horizontalSpan(2), title);
+f.add(tl.createConstraint().widthPercentage(30), price);
+f.add(tl.createConstraint().widthPercentage(70), location);
+f.add(tl.createConstraint().horizontalSpan(2), description);
+f.setEditOnShow(title.getField());
+f.show();
+
+
+
+This code uses the TextModeLayout which is discussed in the layouts section
+
+The text component uses a builder approach to set various values e.g.:
+
+TextComponent t = new TextComponent().
+    text("This appears in the text field").
+    hint("This is the hint").
+    label("This is the label").
+    multiline(true);
+
+The  code  is  pretty  self  explanatory  and  more  convenient  than  typical  setters/getters.  It
+
+automatically handles the floating hint style of animation when running on Android.
+
+6.7.1. Error Handling
+
+The validator class supports text component and it should "just work". But the cool thing is that it
+
+uses the material design convention for error handling!
+
+So if we add to the sample above a Validator:
+
+Validator val = new Validator();
+val.addConstraint(title, new LengthConstraint(2));
+val.addConstraint(price, new NumericConstraint(true));
+
+You would see something that looks like this on Android:
+
+210
+
+Figure 203. Error handling when the text is blank
+
+Figure 204. Error handling when there is some input (notice red title label)
+
+Figure 205. On iOS the situation hasn’t changed much yet
+
+The underlying system is the errorMessage method which you can chain like the other methods on
+TextComponent as such:
+
+TextComponent tc = new TextComponent().
+    label("Input Required").
+    errorMessage("Input is essential in this field");
+
+6.7.2. InputComponent and PickerComponent
+
+To keep the code common and generic we use the InputComponent abstract base class and derive the
+other classes from that. PickerComponent is currently the only other option.
+
+A picker can work with our existing sample using code like this:
+
+211
+
+TextModeLayout tl = new TextModeLayout(3, 2);
+Form f = new Form("Pixel Perfect", tl);
+TextComponent title = new TextComponent().label("Title");
+TextComponent price = new TextComponent().label("Price");
+TextComponent location = new TextComponent().label("Location");
+PickerComponent date = PickerComponent.createDate(new Date()).label("Date");
+TextComponent description = new TextComponent().label("Description").multiline(true);
+Validator val = new Validator();
+val.addConstraint(title, new LengthConstraint(2));
+val.addConstraint(price, new NumericConstraint(true));
+f.add(tl.createConstraint().widthPercentage(60), title);
+f.add(tl.createConstraint().widthPercentage(40), date);
+f.add(location);
+f.add(price);
+f.add(tl.createConstraint().horizontalSpan(2), description);
+f.setEditOnShow(title.getField());
+f.show();
+
+This produces the following which looks pretty standard:
+
+Figure 206. Picker component taking place in iOS
+
+Figure 207. And in Android
+
+The one tiny thing you should notice with the PickerComponent is that we don’t construct the picker
+component  using  new  PickerComponent(). 
+such  as
+PickerComponent.createDate(new Date()). The reason for that is that we have many types of pickers
+and it wouldn’t make sense to have one constructor.
+
+Instead  we  use  create  methods 
+
+6.7.3. Underlying Theme Constants and UIID’s
+
+These varying looks are implemented via a combination of layouts, theme constants and UIID’s. The
+most important UIID’s are: TextComponent, FloatingHint & TextHint.
+
+212
+
+There are several theme constants related that can manipulate some pieces of this functionality:
+
+• textComponentErrorColor a hex RGB color which defaults to null in which case this has no effect.
+When defined this will change the color of the border and label to the given color to match the
+
+material  design  styling.  This  implements  the  red  border  underline  in  cases  of  error  and  the
+
+label text color change
+
+• textComponentOnTopBool  toggles  the  on  top  mode  which  makes  things  look  like  they  do  on
+Android. This defaults to true on Android and false on other OS’s. This can also be manipulated
+via the onTopMode(boolean) method in InputComponent however the layout will only use the theme
+constant
+
+• textComponentAnimBool  toggles  the  animation  mode  which  again  can  be  manipulated  by  a
+method  in  InputComponent.  If  you  want  to  keep  the  UI  static  without  the  floating  hint  effect  set
+this to false. Notice this defaults to true only on Android
+
+• textComponentFieldUIID  sets  the  UIID  of  the  text  field  to  something  other  than  TextField  this  is
+useful  for  platforms  such  as  iOS  where  the  look  of  the  text  field  is  different  within  the  text
+
+component. This allows us to make the background of the text field transparent when it’s within
+the TextComponent and make it different from the regular text field
+
+6.8. Button
+
+Button [https://www.codenameone.com/javadoc/com/codename1/ui/Button.html] is a subclass of Label and as a
+result it inherits all of its functionality, specifically icon placement, tickering, etc.
+
+Button adds to the mix some additional states such as a pressed UIID state and pressed icon.
+
+ There are additional icon states in Button such as rollover and disabled icon.
+
+Button also exposes some functionality for subclasses specifically the setToggle method call which
+has no meaning when invoked on a Button but has a lot of implications for CheckBox & RadioButton.
+
+Button  event  handling  can  be  performed  via  an  ActionListener  [https://www.codenameone.com/javadoc/
+com/codename1/ui/events/ActionListener.html] or via a Command [https://www.codenameone.com/javadoc/com/
+
+codename1/ui/Command.html].
+
+ Changes in a Command won’t be reflected into the Button after the command was set
+
+to the Button.
+
+Here is a trivial hello world style Button:
+
+Form hi = new Form("Button");
+Button b = new Button("My Button");
+hi.add(b);
+b.addActionListener((e) -> Log.p("Clicked"));
+
+213
+
+Figure 208. Simple button in the iOS styling, notice iOS doesn’t have borders on buttons…
+
+Such a button can be styled to look like a link using code like this or simply by making these settings
+in the theme and using code such as btn.setUIID("Hyperlink").
+
+Form hi = new Form("Button");
+Button b = new Button("Link Button");
+b.getAllStyles().setBorder(Border.createEmpty());
+b.getAllStyles().setTextDecoration(Style.TEXT_DECORATION_UNDERLINE);
+hi.add(b);
+b.addActionListener((e) -> Log.p("Clicked"));
+
+Figure 209. Button styled to look like a link
+
+6.8.1. Uppercase Buttons
+
+Buttons on Android’s material design UI use upper case styling which isn’t the case for iOS. To solve
+this  we  have  the  method  setCapsText(boolean)  in  Button  which  has  the  corresponding  isCapsText,
+isCapsTextDefault & setCapsTextDefault(boolean). This is pretty core to Codename One so to prevent
+this from impacting everything unless you explicitly invoke setCapsText(boolean) the default value
+of true will only apply when the UIID is Button, RaisedButton or for the builtin Dialog buttons.
+
+We also have a theme constant: capsButtonTextBool. This constant controls caps text behavior from
+the theme and is set to true in the Android native theme.
+
+6.8.2. Raised Button
+
+Raised  button  is  a  style  of  button  that’s  available  on  Android  and  used  to  highlight  an  important
+
+action within a form. To confirm with the material design UI guidelines you might want to leverage
+
+a raised button UI element on Android but use a regular button everywhere else.
+
+First we need to know whether a raised button exists in the theme. So on Android this will return
+
+true but on other OS’s it will return false. A potential future update might make another platform
+
+true based on UI guidelines in other OS’s.
+
+For  this  purpose  we’ve  got  the  theme  constant  hasRaisedButtonBool  which  will  return  true  on
+Android but will be false elsewhere. You can use it like this:
+
+214
+
+if(UIManager.getInstance().isThemeConstant("hasRaisedButtonBool", false)) {
+    // that means we can use a raised button
+}
+
+To enable this we have the RaisedButton UIID that derives from Button and will act like it except for
+the places where hasRaisedButtonBool is true in which case it will look like this:
+
+Figure 210. Raised and flat button in simulator
+
+Notice that you can easily customize the colors of these buttons now since the border respects user
+
+colors…
+
+In this case I just set the background color to purple and the foreground to white:
+
+Figure 211. Purple raised button
+
+Form f = new Form("Pixel Perfect", BoxLayout.y());
+Button b = new Button("Raised Button", "RaisedButton");
+Button r = new Button("Flat Button");
+f.add(b);
+f.add(r);
+f.show();
+
+6.8.3. Ripple Effect
+
+The  ripple  effect  in  material  design  highlights  the  location  of  the  finger  and  grows  as  a  circle  to
+
+occupy the full area of the component as the user presses the button.
+
+We have the ability to perform a ripple effect by darkening the touched area and growing that in a
+
+quick animation.
+
+Ripple effect can be applied to any component but we currently only have it turned on for buttons
+
+on Android which also applies to things like title commands, side menu elements etc. This might not
+
+apply at this moment to lead components like multi-buttons but that might change in the future.
+
+Component has a property to enable the ripple effect setRippleEffect(boolean) and the corresponding
+isRippleEffect(). You can turn it on or off individually in the component level. However, Button has
+static setButtonRippleEffectDefault(boolean) and isButtonRippleEffectDefault(). These allow us to
+define the default behavior for all the buttons and that can be configured via the theme constant
+buttonRippleBool which is currently on by default on the native Android theme.
+
+215
+
+6.9. CheckBox/RadioButton
+
+CheckBox 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/CheckBox.html]  & 
+
+RadioButton
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/RadioButton.html]  are  subclasses  of  button  that
+
+allow for either a toggle state or exclusive selection state.
+
+Both CheckBox & RadioButton have a selected state that allows us to determine their selection.
+
+
+
+RadioButton  doesn’t  allow  us  to  "deselect"  it,  the  only  way  to  "deselect"  a
+RadioButton is by selecting another RadioButton.
+
+The  CheckBox  can  be  added  to  a  Container  like  any  other  Component  but  the  RadioButton  must  be
+associated with a ButtonGroup otherwise if we have more than one set of RadioButton’s in the form
+we might have an issue.
+
+Notice  in  the  sample  below  that  we  associate  all  the  radio  buttons  with  a  group  but  don’t  do
+
+anything  with  the  group  as  the  radio  buttons  keep  the  reference  internally.  We  also  show  the
+
+opposite side functionality and icon behavior:
+
+CheckBox cb1 = new CheckBox("CheckBox No Icon");
+cb1.setSelected(true);
+CheckBox cb2 = new CheckBox("CheckBox With Icon", icon);
+CheckBox cb3 = new CheckBox("CheckBox Opposite True", icon);
+CheckBox cb4 = new CheckBox("CheckBox Opposite False", icon);
+cb3.setOppositeSide(true);
+cb4.setOppositeSide(false);
+RadioButton rb1 = new RadioButton("Radio 1");
+RadioButton rb2 = new RadioButton("Radio 2");
+RadioButton rb3 = new RadioButton("Radio 3", icon);
+new ButtonGroup(rb1, rb2, rb3);
+rb2.setSelected(true);
+hi.add(cb1).add(cb2).add(cb3).add(cb4).add(rb1).add(rb2).add(rb3);
+
+Figure 212. RadioButton & CheckBox usage
+
+Both of these components can be displayed as toggle buttons (see the toggle button section below),
+
+or just use the default check mark/filled circle appearance based on the type/OS.
+
+216
+
+6.9.1. Toggle Button
+
+A toggle button is a button that is pressed and stays pressed. When a toggle button is pressed again
+
+it’s released from the pressed state. Hence the button has a selected state to indicate if it’s pressed
+or not exactly like the CheckBox/RadioButton components in Codename One.
+
+To  turn  any  CheckBox  or  RadioButton  to  a  toggle  button  just  use  the  setToggle(true)  method.
+Alternatively you can use the static createToggle method on both CheckBox and RadioButton to create
+a toggle button directly.
+
+ Invoking setToggle(true) implicitly converts the UIID to ToggleButton unless it was
+
+changed by the user from its original default value.
+
+We can easily convert the sample above to use toggle buttons as such:
+
+CheckBox cb1 = CheckBox.createToggle("CheckBox No Icon");
+cb1.setSelected(true);
+CheckBox cb2 = CheckBox.createToggle("CheckBox With Icon", icon);
+CheckBox cb3 = CheckBox.createToggle("CheckBox Opposite True", icon);
+CheckBox cb4 = CheckBox.createToggle("CheckBox Opposite False", icon);
+cb3.setOppositeSide(true);
+cb4.setOppositeSide(false);
+ButtonGroup bg = new ButtonGroup();
+RadioButton rb1 = RadioButton.createToggle("Radio 1", bg);
+RadioButton rb2 = RadioButton.createToggle("Radio 2", bg);
+RadioButton rb3 = RadioButton.createToggle("Radio 3", icon, bg);
+rb2.setSelected(true);
+hi.add(cb1).add(cb2).add(cb3).add(cb4).add(rb1).add(rb2).add(rb3);
+
+Figure 213. Toggle button converted sample
+
+That’s  half  the  story  though,  to  get  the  full  effect  of  some  cool  toggle  button  UI’s  we  can  use  a
+
+ComponentGroup 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/ComponentGroup.html].  This
+
+allows us to create a button bar effect with the toggle buttons.
+
+E.g.  lets  enclose  the  CheckBox  components  in  a  vertical  ComponentGroup  and  the  RadioButton’s  in  a
+horizontal group. We can do this by changing the last line of the code above as such:
+
+217
+
+hi.add(ComponentGroup.enclose(cb1, cb2, cb3, cb4)).
+        add(ComponentGroup.encloseHorizontal(rb1, rb2, rb3));
+
+Figure 214. Toggle button converted sample wrapped in ComponentGroup
+
+6.10. ComponentGroup
+
+ComponentGroup 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/ComponentGroup.html] 
+
+is  a
+
+special  container  that  can  be  either  horizontal  or  vertical  (BoxLayout  [https://www.codenameone.com/
+javadoc/com/codename1/ui/layouts/BoxLayout.html] X_AXIS or Y_AXIS respectively).
+
+ComponentGroup  "restyles"  the  elements  within  the  group  to  have  a  UIID  that  allows  us  to  create  a
+"round border" effect that groups elements together.
+
+The  following  code  adds  4  component  groups  to  a  Container  to  demonstrate  the  various  UIID
+changes:
+
+hi.add("Three Labels").
+        add(ComponentGroup.enclose(new Label("GroupElementFirst UIID"), new Label("GroupElement UIID"), new
+Label("GroupElementLast UIID"))).
+        add("One Label").
+        add(ComponentGroup.enclose(new Label("GroupElementOnly UIID"))).
+        add("Three Buttons").
+        add(ComponentGroup.enclose(new Button("ButtonGroupFirst UIID"), new Button("ButtonGroup UIID"), new
+Button("ButtonGroupLast UIID"))).
+        add("One Button").
+        add(ComponentGroup.enclose(new Button("ButtonGroupOnly UIID")));
+
+218
+
+Figure 215. ComponentGroup adapts the UIID’s of the components added so we can style them
+
+Notice the following about the code above and the resulting image:
+
+• Buttons have a different UIID than other element types. Their styling is slightly different in such
+
+UI’s so you need to pay attention to that.
+
+• When an element is placed alone within a ComponentGroup its a special case UIID.
+
+
+
+By  default,  ComponentGroup  does  nothing.  You  need  to  explicitly  activate  it  in  the
+theme  by  setting  a  theme  property  to  true.  Specifically  you  need  to  set
+ComponentGroupBool to true for ComponentGroup to do something otherwise its just a
+box  layout  container!  The  ComponentGroupBool  flag  is  true  by  default  in  the  iOS
+native theme.
+
+When  ComponentGroupBool  is  set  to  true,  the  component  group  will  modify  the  styles  of  all
+components placed within it to match the element UIID given to it (GroupElement by default) with
+
+special caveats to the first/last/only elements. E.g.
+
+1. If I have one element within a component group it will have the UIID: GroupElementOnly
+
+2. If  I  have  two  elements  within  a  component  group  they  will  have  the  UIID’s  GroupElementFirst,
+
+GroupElementLast
+
+3. If I have three elements within a component group they will have the UIID’s GroupElementFirst,
+
+GroupElement, GroupElementLast
+
+4. If I have four elements within a component group they will have the UIID’s GroupElementFirst,
+
+GroupElement, GroupElement, GroupElementLast
+
+This allows you to define special styles for the edges.
+
+You can customize the UIID set by the component group by calling setElementUIID in the component
+group e.g. setElementUIID("ToggleButton") for three elements result in the following UIID’s:
+
+ToggleButtonFirst, ToggleButton, ToggleButtonLast
+
+6.11. MultiButton
+
+MultiButton 
+
+[https://www.codenameone.com/javadoc/com/codename1/components/MultiButton.html] 
+
+is 
+
+a
+
+219
+
+composite 
+
+component 
+
+(lead 
+
+component) 
+
+that 
+
+acts 
+
+like 
+
+a 
+
+versatile 
+
+Button
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/Button.html].  It  supports  up  to  4  lines  of  text  (it
+
+doesn’t automatically wrap the text), an emblem (usually navigational arrow, or check box) and an
+
+icon.
+
+MultiButton can be used as a button, a CheckBox or a RadioButton for creating rich UI’s.
+
+ The MultiButton was inspired by the aesthetics of the UITableView iOS component.
+
+A  common  source  of  confusion  in  the  MultiButton  is  the  difference  between  the  icon  and  the
+emblem,  since  both  may  have  an  icon  image  associated  with  them.  The  icon  is  an  image
+
+representing the entry while the emblem is an optional visual representation of the action that will
+
+be  undertaken  when  the  element  is  pressed.  Both  may  be  used  simultaneously  or  individually  of
+
+one another.
+
+MultiButton twoLinesNoIcon = new MultiButton("MultiButton");
+twoLinesNoIcon.setTextLine2("Line 2");
+MultiButton oneLineIconEmblem = new MultiButton("Icon + Emblem");
+oneLineIconEmblem.setIcon(icon);
+oneLineIconEmblem.setEmblem(emblem);
+MultiButton twoLinesIconEmblem = new MultiButton("Icon + Emblem");
+twoLinesIconEmblem.setIcon(icon);
+twoLinesIconEmblem.setEmblem(emblem);
+twoLinesIconEmblem.setTextLine2("Line 2");
+
+MultiButton twoLinesIconEmblemHorizontal = new MultiButton("Icon + Emblem");
+twoLinesIconEmblemHorizontal.setIcon(icon);
+twoLinesIconEmblemHorizontal.setEmblem(emblem);
+twoLinesIconEmblemHorizontal.setTextLine2("Line 2 Horizontal");
+twoLinesIconEmblemHorizontal.setHorizontalLayout(true);
+
+MultiButton twoLinesIconCheckBox = new MultiButton("CheckBox");
+twoLinesIconCheckBox.setIcon(icon);
+twoLinesIconCheckBox.setCheckBox(true);
+twoLinesIconCheckBox.setTextLine2("Line 2");
+
+MultiButton fourLinesIcon = new MultiButton("With Icon");
+fourLinesIcon.setIcon(icon);
+fourLinesIcon.setTextLine2("Line 2");
+fourLinesIcon.setTextLine3("Line 3");
+fourLinesIcon.setTextLine4("Line 4");
+
+hi.add(oneLineIconEmblem).
+        add(twoLinesNoIcon).
+        add(twoLinesIconEmblem).
+        add(twoLinesIconEmblemHorizontal).
+        add(twoLinesIconCheckBox).
+        add(fourLinesIcon);
+
+220
+
+Figure 216. Multiple usage scenarios for the MultiButton
+
+6.11.1. Styling The MultiButton
+
+Since the MultiButton is a composite component setting its UIID will only impact the top level UI.
+
+To  customize  everything  you  need  to  customize  the  UIID’s  for  MultiLine1,  MultiLine2,  MultiLine3,
+MultiLine4 & Emblem.
+
+You  can  customize  the  individual  UIID’s  thru  the  API  directly  using  the  setIconUIID,  setUIIDLine1,
+setUIIDLine2, setUIIDLine3, setUIIDLine4 & setEmblemUIID.
+
+6.12. SpanButton
+
+[https://www.codenameone.com/javadoc/com/codename1/components/SpanButton.html] 
+
+SpanButton 
+a
+composite component (lead component) that looks/acts like a Button but can break lines rather than
+crop them when the text is very long.
+
+is 
+
+Unlike the MultiButton it uses the TextArea internally to break lines seamlessly. The SpanButton is far
+simpler than the MultiButton and as a result isn’t as configurable.
+
+SpanButton sb = new SpanButton("SpanButton is a composite component (lead component) that looks/acts like a Button but
+can break lines rather than crop them when the text is very long.");
+sb.setIcon(icon);
+hi.add(sb);
+
+Figure 217. The SpanButton Component
+
+
+
+SpanButton  is  slower  than  both  Button  and  MultiButton.  We  recommend  using  it
+only when there is a genuine need for its functionality.
+
+6.13. SpanLabel
+
+SpanLabel 
+
+[https://www.codenameone.com/javadoc/com/codename1/components/SpanLabel.html] 
+
+is 
+
+a
+
+composite  component  (lead  component)  that  looks/acts  like  a  Label  [https://www.codenameone.com/
+
+221
+
+javadoc/com/codename1/ui/Label.html] but can break lines rather than crop them when the text is very
+
+long.
+
+SpanLabel  uses  the  TextArea  internally  to  break  lines  seamlessly  and  so  doesn’t  provide  all  the
+elaborate configuration options of Label.
+
+One of the features of label that moved into SpanLabel to some extent is the ability to position the
+icon.  However,  unlike  a  Label  the  icon  position  is  determined  by  the  layout  manager  of  the
+composite so setIconPosition accepts a BorderLayout constraint.
+
+SpanLabel d = new SpanLabel("Default SpanLabel that can seamlessly line break when the text is really long.");
+d.setIcon(icon);
+SpanLabel l = new SpanLabel("NORTH Positioned Icon SpanLabel that can seamlessly line break when the text is really
+long.");
+l.setIcon(icon);
+l.setIconPosition(BorderLayout.NORTH);
+SpanLabel r = new SpanLabel("SOUTH Positioned Icon SpanLabel that can seamlessly line break when the text is really
+long.");
+r.setIcon(icon);
+r.setIconPosition(BorderLayout.SOUTH);
+SpanLabel c = new SpanLabel("EAST Positioned Icon SpanLabel that can seamlessly line break when the text is really
+long.");
+c.setIcon(icon);
+c.setIconPosition(BorderLayout.EAST);
+hi.add(d).add(l).add(r).add(c);
+
+Figure 218. The SpanLabel Component
+
+
+
+SpanLabel  is  significantly  slower  than  Label.  We  recommend  using  it  only  when
+there is a genuine need for its functionality.
+
+6.14. OnOffSwitch
+
+The  OnOffSwitch 
+
+[https://www.codenameone.com/javadoc/com/codename1/components/OnOffSwitch.html]
+
+allows you to write an application where the user can swipe a switch between two states (on/off).
+
+This  is  a  common  UI  paradigm  in  Android  and  iOS,  although  it’s  implemented  in  a  radically
+
+different way in both platforms.
+
+This is a rather elaborate component because of its very unique design on iOS, but we we’re able to
+
+accommodate  most  of  the  small  behaviors  of  the  component  into  our  version,  and  it  seamlessly
+
+adapts between the Android style and the iOS style.
+
+222
+
+The image below was generated based on the default use of the OnOffSwitch:
+
+OnOffSwitch onOff = new OnOffSwitch();
+hi.add(onOff);
+
+Figure 219. The OnOffSwitch component as it appears on/off on iOS (top) and on Android (bottom)
+
+As you can understand the difference between the way iOS and Android render this component has
+
+triggered  two  very  different 
+
+implementations  within  a  single  component.  The  Android
+
+implementation just uses standard buttons and is the default for non-iOS platforms.
+
+
+
+You  can  force  the  Android  or  iOS  mode  by  using  the  theme  constant
+onOffIOSModeBool.
+
+6.14.1. Validation
+
+Validation  is  an  inherent  part  of  text  input,  and  the  Validator  [https://www.codenameone.com/javadoc/
+
+com/codename1/ui/validation/Validator.html]  class  allows  just  that.  You  can  enable  validation  thru  the
+Validator class to add constraints for a specific component. It’s also possible to define components
+that  would  be  enabled/disabled  based  on  validation  state  and  the  way  in  which  validation  errors
+are  rendered  (change  the  components  UIID,  paint  an  emblem  on  top,  etc.).  A  Constraint
+interface  that
+[https://www.codenameone.com/javadoc/com/codename1/ui/validation/Constraint.html] 
+
+is  an 
+
+represents validation requirements. You can define a constraint in Java or use some of the builtin
+
+constraints  such  as  LengthConstraint  [https://www.codenameone.com/javadoc/com/codename1/ui/validation/
+
+LengthConstraint.html],  RegexConstraint  [https://www.codenameone.com/javadoc/com/codename1/ui/validation/
+
+RegexConstraint.html], etc.
+
+This sample below continues from the place where the TextField sample above stopped by adding
+
+validation to that code.
+
+223
+
+Validator v = new Validator();
+v.addConstraint(firstName, new LengthConstraint(2)).
+        addConstraint(surname, new LengthConstraint(2)).
+        addConstraint(url, RegexConstraint.validURL()).
+        addConstraint(email, RegexConstraint.validEmail()).
+        addConstraint(phone, new RegexConstraint(phoneRegex, "Must be valid phone number")).
+        addConstraint(num1, new LengthConstraint(4)).
+        addConstraint(num2, new LengthConstraint(4)).
+        addConstraint(num3, new LengthConstraint(4)).
+        addConstraint(num4, new LengthConstraint(4));
+
+v.addSubmitButtons(submit);
+
+Figure 220. Validation & Regular Expressions
+
+6.15. InfiniteProgress
+
+The 
+
+InfiniteProgress 
+
+[https://www.codenameone.com/javadoc/com/codename1/components/
+
+InfiniteProgress.html] indicator spins an image infinitely to indicate that a background process is still
+
+working.
+
+
+
+This style of animation is often nicknamed "washing machine" as it spins endlessly.
+
+InfiniteProgress  can  be  used  in  one  of  two  ways  either  by  embedding  the  component  into  the  UI
+thru something like this:
+
+myContainer.add(new InfiniteProgress());
+
+InfiniteProgress  can  also  appear  over  the  entire  screen,  thus  blocking  all  input.  This  tints  the
+background while the infinite progress rotates:
+
+Dialog ip = new InfiniteProgress().showInifiniteBlocking();
+
+// do some long operation here using invokeAndBlock or do something in a separate thread and callback later
+// when you are done just call
+
+ip.dispose();
+
+224
+
+Figure 221. Infinite progress
+
+The image used in the InfiniteProgress animation is defined by the native theme. You can override
+that definition either by defining the theme constant infiniteImage or by invoking the setAnimation
+[https://www.codenameone.com/javadoc/com/codename1/components/InfiniteProgress.html#setAnimation-
+
+com.codename1.ui.Image-] method.
+
+ Despite  the  name  of  the  method  setAnimation  expects  a  static  image  that  will  be
+
+rotated internally. Don’t use an animated image.
+
+6.16. InfiniteScrollAdapter and InfiniteContainer
+
+InfiniteScrollAdapter 
+
+[https://www.codenameone.com/javadoc/com/codename1/components/
+
+InfiniteScrollAdapter.html]  &  InfiniteContainer  [https://www.codenameone.com/javadoc/com/codename1/ui/
+InfiniteContainer.html] allow us to create a scrolling effect that "never" ends with the typical Container
+/Component paradigm.
+
+The  motivation  behind  these  classes  is  simple,  say  we  have  a  lot  of  data  to  fetch  from  storage  or
+
+from the internet. We can fetch the data in batches and show progress indication while we do this.
+
+Infinite  scroll  fetches  the  next  batch  of  data  dynamically  as  we  reach  the  end  of  the  Container.
+InfiniteScrollAdapter  &  InfiniteContainer  represent  two  similar  ways  to  accomplish  that  task
+relatively easily.
+
+Let start by exploring how we can achieve this UI that fetches data from a webservice:
+
+Figure 222. InfiniteScrollAdapter demo code fetching property cross data
+
+The first step is creating the webservice call, we won’t go into too much detail here as webservices
+
+& IO are discussed later in the guide:
+
+225
+
+int pageNumber = 1;
+java.util.List<Map<String, Object>> fetchPropertyData(String text) {
+    try {
+        ConnectionRequest r = new ConnectionRequest();
+        r.setPost(false);
+        r.setUrl("http://api.nestoria.co.uk/api");
+        r.addArgument("pretty", "0");
+        r.addArgument("action", "search_listings");
+        r.addArgument("encoding", "json");
+        r.addArgument("listing_type", "buy");
+        r.addArgument("page", "" + pageNumber);
+        pageNumber++;
+        r.addArgument("country", "uk");
+        r.addArgument("place_name", text);
+        NetworkManager.getInstance().addToQueueAndWait(r);
+        Map<String,Object> result = new JSONParser().parseJSON(new InputStreamReader(new
+ByteArrayInputStream(r.getResponseData()), "UTF-8"));
+        Map<String, Object> response = (Map<String, Object>)result.get("response");
+        return (java.util.List<Map<String, Object>>)response.get("listings");
+    } catch(Exception err) {
+        Log.e(err);
+        return null;
+    }
+}
+
+
+
+The demo code here doesn’t do any error handling! This is a very bad practice and
+
+it is taken here to keep the code short and readable. Proper error handling is used
+
+in the Property Cross demo.
+
+The  fetchPropertyData  is  a  very  simplistic  tool  that  just  fetches  the  next  page  of  listings  for  the
+nestoria  webservice.  Notice  that  this  method  is  synchronous  and  will  block  the  calling  thread
+
+(legally) until the network operation completes.
+
+Now that we have a webservice lets proceed to create the UI. Check out the code annotations below:
+
+226
+
+Form hi = new Form("InfiniteScrollAdapter", new BoxLayout(BoxLayout.Y_AXIS));
+
+Style s = UIManager.getInstance().getComponentStyle("MultiLine1");
+FontImage p = FontImage.createMaterial(FontImage.MATERIAL_PORTRAIT, s);
+EncodedImage placeholder = EncodedImage.createFromImage(p.scaled(p.getWidth() * 3, p.getHeight() * 3), false); ①
+
+InfiniteScrollAdapter.createInfiniteScroll(hi.getContentPane(), () -> { ②
+    java.util.List<Map<String, Object>> data = fetchPropertyData("Leeds"); ③
+    MultiButton[] cmps = new MultiButton[data.size()];
+    for(int iter = 0 ; iter < cmps.length ; iter++) {
+        Map<String, Object> currentListing = data.get(iter);
+        if(currentListing == null) { ④
+            InfiniteScrollAdapter.addMoreComponents(hi.getContentPane(), new Component[0], false);
+            return;
+        }
+        String thumb_url = (String)currentListing.get("thumb_url");
+        String guid = (String)currentListing.get("guid");
+        String summary = (String)currentListing.get("summary");
+        cmps[iter] = new MultiButton(summary);
+        cmps[iter].setIcon(URLImage.createToStorage(placeholder, guid, thumb_url));
+    }
+    InfiniteScrollAdapter.addMoreComponents(hi.getContentPane(), cmps, true); ⑤
+}, true); ⑥
+
+① Placeholder  is  essential  for  the  URLImage  [https://www.codenameone.com/javadoc/com/codename1/ui/
+
+URLImage.html] class which we will discuss at a different place.
+
+② The InfiniteScrollAdapter accepts a runnable which is invoked every time we reach the edge of
+
+the scrolling. We used a closure instead of the typical run() method override.
+
+③ This is a blocking call, after the method completes we’ll have all the data we need. Notice that
+
+this method doesn’t block the EDT illegally.
+
+④ If  there  is  no  more  data  we  call  the  addMoreComponents  method  with  a  false  argument.  This
+
+indicates that there is no additional data to fetch.
+
+⑤ Here we add the actual components to the end of the form. Notice that we must not invoke the
+add/remove method of Container. Those might conflict with the work of the InfiniteScrollAdapter.
+
+⑥ We  pass  true  to  indicate  that  the  data  isn’t  "prefilled"  so  the  method  should  be  invoked
+
+immediately when the Form is first shown
+
+ Do not violate the EDT in the callback. It is invoked on the event dispatch thread
+
+and it is crucial
+
+6.16.1. The InfiniteContainer
+
+InfiniteContainer 
+[https://www.codenameone.com/javadoc/com/codename1/ui/InfiniteContainer.html]  was
+introduced to simplify and remove some of the boilerplate of the InfiniteScrollAdapter. It takes a
+more traditional approach of inheriting the Container class to provide its functionality.
+
+Unlike the InfiniteScrollAdapter the InfiniteContainer accepts an index and amount to fetch. This
+is useful for tracking your position but also important since the InfiniteContainer also implements
+Pull To Refresh as part of its functionality.
+
+Converting the code above to an InfiniteContainer is pretty simple we just moved all the code into
+
+227
+
+the callback fetchComponents method and returned the array of Component’s as a response.
+
+Unlike  the  InfiniteScrollAdapter  we  can’t  use  the  ContentPane  directly  so  we  have  to  use  a
+BorderLayout and place the InfiniteContainer there:
+
+Form hi = new Form("InfiniteContainer", new BorderLayout());
+
+Style s = UIManager.getInstance().getComponentStyle("MultiLine1");
+FontImage p = FontImage.createMaterial(FontImage.MATERIAL_PORTRAIT, s);
+EncodedImage placeholder = EncodedImage.createFromImage(p.scaled(p.getWidth() * 3, p.getHeight() * 3), false);
+
+InfiniteContainer ic = new InfiniteContainer() {
+    @Override
+    public Component[] fetchComponents(int index, int amount) {
+        java.util.List<Map<String, Object>> data = fetchPropertyData("Leeds");
+        MultiButton[] cmps = new MultiButton[data.size()];
+        for(int iter = 0 ; iter < cmps.length ; iter++) {
+            Map<String, Object> currentListing = data.get(iter);
+            if(currentListing == null) {
+                return null;
+            }
+            String thumb_url = (String)currentListing.get("thumb_url");
+            String guid = (String)currentListing.get("guid");
+            String summary = (String)currentListing.get("summary");
+            cmps[iter] = new MultiButton(summary);
+            cmps[iter].setIcon(URLImage.createToStorage(placeholder, guid, thumb_url));
+        }
+        return cmps;
+    }
+};
+hi.add(BorderLayout.CENTER, ic);
+
+6.17. List, MultiList, Renderers & Models
+
+6.17.1. InfiniteContainer/InfiniteScrollAdapter vs. List/ContainerList
+
+Our recommendation is to always go with Container, InfiniteContainer or InfiniteScrollAdapter.
+
+We  recommend  avoiding  List  or  its  subclasses/related  classes  specifically  ContainerList  &
+MultiList.
+
+ We  recommend  replacing  ComboBox  with  Picker  but  that’s  a  completely  different
+
+discussion.
+
+A  Container  with  ~5000  nested  containers  within  it  can  perform  on  par  with  a  List  and  probably
+exceed its performance when used correctly.
+
+Larger sets of data are rarely manageable on phones or tablets so the benefits for lists are dubious.
+
+In terms of API we found that even experienced developers experienced a great deal of pain when
+
+wrangling the Swing styled lists and their stateless approach.
+
+Since  animation,  swiping  and  other  capabilities  that  are  so  common  in  mobile  are  so  hard  to
+
+228
+
+accomplish with lists we see no actual reason to use them.
+
+6.17.2. Why Isn’t List Deprecated?
+
+We  deprecated  ContainerList  which  performs  really  badly  and  has  some  inherent  complexity
+issues. List has some unique use cases and is still used all over Codename One.
+
+MultiList is a reasonable version of List that is far easier to use without most of the pains related to
+renderer configuration.
+
+There are cases where using List or MultiList is justified, they are just rarer than usual hence our
+recommendation.
+
+6.17.3. MVC In Lists
+
+A  Codename  One  List  [https://www.codenameone.com/javadoc/com/codename1/ui/List.html]  doesn’t  contain
+
+components, but rather arbitrary data; this seems odd at first but makes sense. If you want a list to
+
+contain components, just use a Container.
+
+The  advantage  of  using  a  List  in  this  way  is  that  we  can  display  it  in  many  ways  (e.g.  fixed  focus
+positions, horizontally, etc.), and that we can have more than a million entries without performance
+
+overhead.  We  can  also  do  some  pretty  nifty  things,  like  filtering  the  list  on  the  fly  or  fetching  it
+
+dynamically from the Internet as the user scrolls down the list. To achieve these things the list uses
+
+two  interfaces:  ListModel  [https://www.codenameone.com/javadoc/com/codename1/ui/list/ListModel.html]  and
+
+ListCellRenderer. 
+
+List 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/List.html]  model
+
+represents  the  data;  its  responsibility  is  to  return  the  arbitrary  object  within  the  list  at  a  given
+
+offset. Its second responsibility is to notify the list when the data changes, so the list can refresh.
+
+
+
+Think of the model as an array of objects that can notify you when it changes.
+
+The  list  renderer  is  like  a  rubber  stamp  that  knows  how  to  draw  an  object  from  the  model,  it’s
+
+called many times per entry in an animated list and must be very fast. Unlike standard Codename
+
+One components, it is only used to draw the entry in the model and is immediately discarded, hence
+
+it  has  no  memory  overhead,  but  if  it  takes  too  long  to  process  a  model  value  it  can  be  a  big
+
+bottleneck!
+
+
+
+Think of the render as a translation layer that takes the "data" from the model and
+
+translates it to a visual representation.
+
+This  is  all  very  generic,  but  a  bit  too  much  for  most,  doing  a  list  "properly"  requires  some
+
+understanding. The main source of confusion for developers is the stateless nature of the list and
+
+the transfer of state to the model (e.g. a checkbox list needs to listen to action events on the list and
+
+update  the  model,  in  order  for  the  renderer  to  display  that  state).  Once  you  understand  that  it’s
+
+easy.
+
+6.17.4. Understanding MVC
+
+Let’s recap, what is MVC:
+
+229
+
+• Model  -  Represents  the  data  for  the  component  (list),  the  model  can  tell  us  exactly  how  many
+
+items  are  in  it  and  which  item  resides  at  a  given  offset  within  the  model.  This  differs  from  a
+simple Vector (or array), since all access to the model is controlled (the interface is simpler), and
+unlike a Vector/Array, the model can notify us of changes that occur within it.
+
+• View - The view draws the content of the model. It is a "dumb" layer that has no notion of what
+
+is  displayed  and  only  knows  how  to  draw.  It  tracks  changes  in  the  model  (the  model  sends
+
+events) and redraws itself when it changes.
+
+• Controller - The controller accepts user input and performs changes to the model, which in turn
+
+cause the view to refresh.
+
+Figure 223. Typical MVC Diagram [3]
+
+Codename  One’s  List  [https://www.codenameone.com/javadoc/com/codename1/ui/List.html]  component  uses
+the MVC paradigm in its implementation. List itself is the  Controller (with a bit of the  View mixed
+in). The ListCellRenderer [https://www.codenameone.com/javadoc/com/codename1/ui/list/ListCellRenderer.html]
+
+interface is the rest of the View and the ListModel [https://www.codenameone.com/javadoc/com/codename1/
+
+ui/list/ListModel.html] is (you guessed it by now) the Model.
+
+When the list is painted, it iterates over the visible elements in the model and asks the model for
+
+the data, it then draws them using the renderer. Notice that because of this both the model and the
+
+renderer must be REALLY fast and that’s hard.
+
+Why is this useful?
+
+Since the model is a lightweight interface, it can be implemented by you and replaced in runtime if
+
+so desired, this allows several use cases:
+
+1. A  list  can  contain  thousands  of  entries  but  only  load  the  portion  visible  to  the  user.  Since  the
+
+model will only be queried for the elements that are visible to the user, it won’t need to load the
+
+large data set into memory until the user starts scrolling down (at which point other elements
+
+may be offloaded from memory).
+
+2. A  list  can  cache  efficiently.  E.g.  a  list  can  mirror  data  from  the  server  into  local  RAM  without
+
+actually  downloading  all  the  data.  Data  can  also  be  mirrored  from  storage  for  better
+
+performance and discarded for better memory utilization.
+
+3. The  is  no  need  for  state  copying.  Since  renderers  allow  us  to  display  any  object  type,  the  list
+
+model 
+
+interface  can  be 
+
+implemented  by 
+
+the  application’s  data 
+
+structures 
+
+(e.g.
+
+persistence/network  engine),  which  would  return  internal  application  data  structures  saving
+
+you  the  need  of  copying  application  state  into  a  list  specific  data  structure.  Note  that  this
+
+230
+
+advantage only applies with a custom renderer which is pretty difficult to get right.
+
+4. Using  the  proxy  pattern  we  can  layer  logic  such  as  filtering,  sorting,  caching,  etc.  on  top  of
+
+existing models without changing the model source code.
+
+5. We  can  reuse  generic  models  for  several  views,  e.g.  a  model  that  fetches  data  from  the  server
+
+can  be  initialized  with  different  arguments,  to  fetch  different  data  for  different  views.  View
+
+objects in different Forms can display the same model instance in different view instances, thus
+
+they would update automatically when we change one global model.
+
+Most  of  these  use  cases  work  best  for  lists  that  grow  to  a  larger  size,  or  represent  complex  data,
+
+which is what the list object is designed to do.
+
+6.17.5. Important - Lists & Layout Managers
+
+Usually when working with lists, you want the list to handle the scrolling (otherwise it will perform
+
+badly).  This  means  you  should  place  the  list  in  a  non-scrollable  container  (no  parent  can  be
+
+scrollable), notice that the content pane is scrollable by default, so you should disable that.
+
+It 
+
+is  also  recommended  to  place  the 
+
+list 
+
+in  the  CENTER 
+
+location  of  a  BorderLayout
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/layouts/BorderLayout.html]  to  produce  the  most
+
+effective results. e.g.:
+
+form.setScrollable(false);
+form.setLayout(new BorderLayout());
+form.add(BorderLayout.CENTER, myList);
+
+6.17.6. MultiList & DefaultListModel
+
+So  after  this  long  start  lets  show  the  first  sample  of  creating  a  list  using  the  MultiList
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/list/MultiList.html].
+
+The MultiList is a preconfigured list that contains a ready made renderer with defaults that make
+sense  for  the  most  common  use  cases.  It  still  retains  most  of  the  power  available  to  the  List
+component  but  reduces  the  complexity  of  one  of  the  hardest  things  to  grasp  for  most  developers:
+
+rendering.
+
+The  full  power  of  the  ListModel  is  still  available  and  allows  you  to  create  a  million  entry  list  with
+just a few lines of code. However the objects that the model returns should always be in the form of
+Map objects and not an arbitrary object like the standard List allows.
+
+Here is a simple example of a MultiList containing a highly popular subject matter:
+
+231
+
+Form hi = new Form("MultiList", new BorderLayout());
+
+ArrayList<Map<String, Object>> data = new ArrayList<>();
+
+data.add(createListEntry("A Game of Thrones", "1996"));
+data.add(createListEntry("A Clash Of Kings", "1998"));
+data.add(createListEntry("A Storm Of Swords", "2000"));
+data.add(createListEntry("A Feast For Crows", "2005"));
+data.add(createListEntry("A Dance With Dragons", "2011"));
+data.add(createListEntry("The Winds of Winter", "2016 (please, please, please)"));
+data.add(createListEntry("A Dream of Spring", "Ugh"));
+
+DefaultListModel<Map<String, Object>> model = new DefaultListModel<>(data);
+MultiList ml = new MultiList(model);
+hi.add(BorderLayout.CENTER, ml);
+
+Figure 224. Basic usage of the MultiList & DefaultListModel]
+
+createListEntry is relatively trivial:
+
+private Map<String, Object> createListEntry(String name, String date) {
+    Map<String, Object> entry = new HashMap<>();
+    entry.put("Line1", name);
+    entry.put("Line2", date);
+    return entry;
+}
+
+There  is  one  major  piece  missing  here  and  that  is  the  cover  images  for  the  books.  A  simple
+
+approach would be to just place the image objects into the entries using the "icon" property as such:
+
+private Map<String, Object> createListEntry(String name, String date, Image cover) {
+    Map<String, Object> entry = new HashMap<>();
+    entry.put("Line1", name);
+    entry.put("Line2", date);
+    entry.put("icon", cover);
+    return entry;
+}
+
+232
+
+Figure 225. With cover images in place
+
+
+
+Since  the  MultiList  uses  the  GenericListCellRenderer  internally  we  can  use
+to
+URLImage 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/URLImage.html] 
+
+dynamically fetch the data. This is discussed in the graphics section of this guide.
+
+Going Further With the ListModel
+
+Lets assume that GRRM [http://www.georgerrmartin.com/] was really prolific and wrote 1 million books.
+
+The  default  list  model  won’t  make  much  sense  in  that  case  but  we  would  still  be  able  to  render
+
+everything in a list model.
+
+We’ll fake it a bit but notice that 1M components won’t be created even if we somehow scroll all the
+
+way down…
+
+The ListModel [https://www.codenameone.com/javadoc/com/codename1/ui/list/ListModel.html] interface can be
+
+implemented by anyone in this case we just did a really stupid simple implementation:
+
+class GRMMModel implements ListModel<Map<String,Object>> {
+    @Override
+    public Map<String, Object> getItemAt(int index) {
+        int idx = index % 7;
+        switch(idx) {
+            case 0:
+                return createListEntry("A Game of Thrones " + index, "1996");
+            case 1:
+                return createListEntry("A Clash Of Kings " + index, "1998");
+            case 2:
+                return createListEntry("A Storm Of Swords " + index, "2000");
+            case 3:
+                return createListEntry("A Feast For Crows " + index, "2005");
+            case 4:
+                return createListEntry("A Dance With Dragons " + index, "2011");
+            case 5:
+                return createListEntry("The Winds of Winter " + index, "2016 (please, please, please)");
+            default:
+                return createListEntry("A Dream of Spring " + index, "Ugh");
+        }
+    }
+
+    @Override
+    public int getSize() {
+        return 1000000;
+
+233
+
+    }
+
+    @Override
+    public int getSelectedIndex() {
+        return 0;
+    }
+
+    @Override
+    public void setSelectedIndex(int index) {
+    }
+
+    @Override
+    public void addDataChangedListener(DataChangedListener l) {
+    }
+
+    @Override
+    public void removeDataChangedListener(DataChangedListener l) {
+    }
+
+    @Override
+    public void addSelectionListener(SelectionListener l) {
+    }
+
+    @Override
+    public void removeSelectionListener(SelectionListener l) {
+    }
+
+    @Override
+    public void addItem(Map<String, Object> item) {
+    }
+
+    @Override
+    public void removeItem(int index) {
+    }
+}
+
+We can now replace the existing model by removing all the model related logic and changing the
+
+constructor call as such:
+
+MultiList ml = new MultiList(new GRMMModel());
+
+Figure 226. It took ages to scroll this far… This goes to a million…
+
+234
+
+6.17.7. List Cell Renderer
+
+The Renderer is a simple interface with 2 methods:
+
+public interface ListCellRenderer {
+   //This method is called by the List for each item, when the List paints itself.
+   public Component getListCellRendererComponent(List list, Object value, int index, boolean isSelected);
+
+   //This method returns the List animated focus which is animated when list selection changes
+   public Component getListFocusComponent(List list);
+}
+
+The most simple/naive implementation may choose to implement the renderer as follows:
+
+public Component getListCellRendererComponent(List list, Object value, int index, boolean isSelected){
+     return new Label(value.toString());
+}
+
+public Component getListFocusComponent(List list){
+     return null;
+}
+
+This will compile and work, but won’t give you much, notice that you won’t see the List selection
+move  on  the  List,  this  is  just  because  the  renderer  returns  a  Label  [https://www.codenameone.com/
+
+javadoc/com/codename1/ui/Label.html] with the same style regardless if it’s selected or not.
+
+Now Let’s try to make it a bit more useful.
+
+public Component getListCellRendererComponent(List list, Object value, int index, boolean isSelected){
+      Label l = new Label(value.toString());
+if (isSelected) {
+             l.setFocus(true);
+             l.getAllStyles().setBgTransparency(100);
+         } else {
+             l.setFocus(false);
+             l.getAllStyles().setBgTransparency(0);
+        }
+        return l;
+}   public Component getListFocusComponent(List list){
+      return null;
+}
+
+In this renderer we set the Label.setFocus(true) if it’s selected, calling to this method doesn’t really
+give the focus to the Label, it simply renders the label as selected.
+
+Then  we 
+transparency, and 0 for full transparency if not selected.
+
+invoke  Label.getAllStyles().setBgTransparency(100) 
+
+to  give 
+
+the  selection  semi
+
+That is still not very efficient because we create a new Label each time the method is invoked.
+
+To make the code tighter, keep a reference to the Component or extend it as DefaultListCellRenderer
+
+235
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/list/DefaultListCellRenderer.html] does.
+
+class MyRenderer extends Label implements ListCellRenderer {
+    public Component getListCellRendererComponent(List list, Object value, int index, boolean isSelected){
+        setText(value.toString());
+        if (isSelected) {
+            setFocus(true);
+            getAllStyles().setBgTransparency(100);
+        } else {
+            setFocus(false);
+            getAllStyles().setBgTransparency(0);
+        }
+        return this;
+        }
+    }
+}
+
+Now Let’s have a look at a more advanced Renderer.
+
+class ContactsRenderer extends Container implements ListCellRenderer {
+
+ private Label name = new Label("");
+ private Label email = new Label("");
+ private Label pic = new Label("");
+
+ private Label focus = new Label("");
+
+ public ContactsRenderer() {
+     setLayout(new BorderLayout());
+     addComponent(BorderLayout.WEST, pic);
+     Container cnt = new Container(new BoxLayout(BoxLayout.Y_AXIS));
+     name.getAllStyles().setBgTransparency(0);
+     name.getAllStyles().setFont(Font.createSystemFont(Font.FACE_SYSTEM, Font.STYLE_BOLD, Font.SIZE_MEDIUM));
+     email.getAllStyles().setBgTransparency(0);
+     cnt.addComponent(name);
+     cnt.addComponent(email);
+     addComponent(BorderLayout.CENTER, cnt);
+
+     focus.getStyle().setBgTransparency(100);
+ }
+
+ public Component getListCellRendererComponent(List list, Object value, int index, boolean isSelected) {
+
+     Contact person = (Contact) value;
+     name.setText(person.getName());
+     email.setText(person.getEmail());
+     pic.setIcon(person.getPic());
+     return this;
+ }
+
+ public Component getListFocusComponent(List list) {
+     return focus;
+ }
+}
+
+In  this  renderer  we  want  to  render  a  Contact  object  to  the  Screen,  we  build  the  Component  in  the
+
+236
+
+constructor and in the getListCellRendererComponent we simply update the Labels' texts according
+to the Contact object.
+
+Notice that in this renderer we return a focus Label with semi transparency, as mentioned before,
+the focus component can be modified within this method.
+
+For example, I can modify the focus Component to have an icon.
+
+focus.getAllStyles().setBgTransparency(100);
+try {
+    focus.setIcon(Image.createImage("/duke.png"));
+    focus.setAlignment(Component.RIGHT);
+} catch (IOException ex) {
+    ex.printStackTrace();
+}
+
+6.17.8. Generic List Cell Renderer
+
+As  part  of  the  GUI  builder  work,  we  needed  a  way  to  customize  rendering  for  a  List,  but  the
+
+renderer/model  approach  seemed  impossible  to  adapt  to  a  GUI  builder  (it  seems  the  Swing  GUI
+builders  had  a  similar  issue).  Our  solution  was  to  introduce  the  GenericListCellRenderer,  which
+while introducing limitations and implementation requirements still manages to make life easier,
+
+both in the GUI builder and outside of it.
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/list/
+GenericListCellRenderer 
+GenericListCellRenderer.html]  is  a  renderer  designed  to  be  as  simple  to  use  as  a  Component-Container
+hierarchy, we effectively crammed most of the common renderer use cases into one class. To enable
+that, we need to know the content of the objects within the model, so the GenericListCellRenderer
+assumes the model contains only Map objects. Since Maps can contain arbitrary data the list model is
+still  quite  generic  and  allows  storing  application  specific  data.  Furthermore  a  Map  can  still  be
+derived and extended to provide domain specific business logic.
+
+The GenericListCellRenderer accepts two container instances (more later on why at least two, and
+not  one),  which  it  maps  to  individual  Map  entries  within  the  model,  by  finding  the  appropriate
+components within the given container hierarchy. Components are mapped to the Map entries based
+on the name property of the component (getName/setName) and the key/value within the Map, e.g.:
+
+For a model that contains a Map entry like this:
+
+"Foo": "Bar"
+"X": "Y"
+"Not": "Applicable"
+"Number": Integer(1)
+
+A  renderer  will  loop  over  the  component  hierarchy  in  the  container,  searching  for  components
+
+whose name matches Foo, X, Not, and Number, and assigning the appropriate value to them.
+
+237
+
+You  can  also  use  image  objects  as  values,  and  they  will  be  assigned  to  labels  as
+
+
+
+expected.  However,  you  can’t  assign  both  an  image  and  a  text  to  a  single  label,
+
+since the key will be taken. That isn’t a big problem, since two labels can be used
+
+quite easily in such a renderer.
+
+To  make  matters  even  more  attractive  the  renderer  seamlessly  supports  list  tickering  when
+
+appropriate,  and  if  a  CheckBox  [https://www.codenameone.com/javadoc/com/codename1/ui/CheckBox.html]
+appears within the renderer, it will toggle a boolean flag within the Map seamlessly.
+
+One issue that crops up with this approach is that, if a value is missing from the Map, it is treated as
+empty and the component is reset.
+
+This can pose an issue if we hardcode an image or text within the renderer and we don’t want them
+replaced (e.g. an arrow graphic on a Label within the renderer). The solution for this is to name the
+component with Fixed in the end of the name, e.g. HardcodedIconFixed.
+
+Naming  a  component  within  the  renderer  with  $number  will  automatically  set  it  as  a  counter
+
+component for the offset of the component within the list.
+
+Styling the GenericListCellRenderer is slightly different, the renderer uses the UIID of the Container
+passed to the generic list cell renderer, and the background focus uses that same UIID with the word
+"Focus" appended to it.
+
+It is important to notice that the generic list cell renderer will grant focus to the child components
+
+of the selected entry if they are focusable, thus changing the style of said entries. E.g. a Container
+[https://www.codenameone.com/javadoc/com/codename1/ui/Container.html] might have a child Label that has
+one style when the parent container is unselected and another when it’s selected (focused), this can
+
+be easily achieved by defining the label as focusable. Notice that the component will never receive
+
+direct focus, since it is still part of a renderer.
+
+Last but not least, the generic list cell renderer accepts two or four instances of a Container, rather
+
+than  the  obvious  choice  of  accepting  only  one  instance.  This  allows  the  renderer  to  treat  the
+
+selected entry differently, which is especially important to tickering, although it’s also useful for the
+fisheye effect [4]. Since it might not be practical to seamlessly clone the Container for the renderer’s
+needs,  Codename  One  expects  the  developer  to  provide  two  separate  instances,  they  can  be
+
+identical  in  all  respects,  but  they  must  be  separate  instances  for  tickering  to  work.  The  renderer
+
+also  allows  for  a  fisheye  effect,  where  the  selected  entry  is  actually  different  from  the  unselected
+
+entry in its structure, it also allows for a pinstripe effect, where odd/even rows have different styles
+
+(this is accomplished by providing 4 instances of the containers selected/unselected for odd/even).
+
+The best way to learn about the generic list cell renderer and the Map model is by playing with them
+in the old GUI builder. Notice they can be used in code without any dependency on the GUI builder
+
+and can be quite useful at that.
+
+Here is a simple example of a list with checkboxes that gets updated automatically:
+
+238
+
+com.codename1.ui.List list = new com.codename1.ui.List(createGenericListCellRendererModelData());
+list.setRenderer(new GenericListCellRenderer(createGenericRendererContainer(), createGenericRendererContainer()));
+
+private Container createGenericRendererContainer() {
+    Label name = new Label();
+    name.setFocusable(true);
+    name.setName("Name");
+    Label surname = new Label();
+    surname.setFocusable(true);
+    surname.setName("Surname");
+    CheckBox selected = new CheckBox();
+    selected.setName("Selected");
+    selected.setFocusable(true);
+    Container c = BorderLayout.center(name).
+            add(BorderLayout.SOUTH, surname).
+            add(BorderLayout.WEST, selected);
+    c.setUIID("ListRenderer");
+    return c;
+}
+
+private Object[] createGenericListCellRendererModelData() {
+    Map<String,Object>[] data = new HashMap[5];
+    data[0] = new HashMap<>();
+    data[0].put("Name", "Shai");
+    data[0].put("Surname", "Almog");
+    data[0].put("Selected", Boolean.TRUE);
+    data[1] = new HashMap<>();
+    data[1].put("Name", "Chen");
+    data[1].put("Surname", "Fishbein");
+    data[1].put("Selected", Boolean.TRUE);
+    data[2] = new HashMap<>();
+    data[2].put("Name", "Ofir");
+    data[2].put("Surname", "Leitner");
+    data[3] = new HashMap<>();
+    data[3].put("Name", "Yaniv");
+    data[3].put("Surname", "Vakarat");
+    data[4] = new HashMap<>();
+    data[4].put("Name", "Meirav");
+    data[4].put("Surname", "Nachmanovitch");
+    return data;
+}
+
+Figure 227. GenericListCellRenderer demo code
+
+239
+
+Custom UIID Of Entry in GenenricListCellRenderer/MultiList
+
+MultiList 
+
+With 
+[https://www.codenameone.com/javadoc/com/codename1/ui/list/MultiList.html
+]/GenenricListCellRenderer  one  of  the  common  issues  is  making  a  UI  where  a  specific  component
+within the list renderer has a different UIID style based on data. E.g. this can be helpful to mark a
+
+label within the list as red, for instance, in the case of a list of monetary transactions.
+
+This can be achieved with a custom renderer, but that is a pretty difficult task.
+GenericListCellRenderer (MultiList uses GenericListCellRenderer internally) has another option.
+
+Normally, to build the model for a renderer of this type, we use something like:
+
+map.put("componentName", "Component Value");
+
+What if we want componentName to be red? Just use:
+
+map.put("componentName_uiid", "red");
+
+This will apply the UIID "red" to the component, which you can then style in the theme. Notice that
+
+once you start doing this, you need to define this entry for all entries, e.g.:
+
+map.put("componentName_uiid", "blue");
+
+Otherwise  the  component  will  stay  red  for  the  next  entry  (since  the  renderer  acts  like  a  rubber
+
+stamp).
+
+Rendering Prototype
+
+Because of the rendering architecture of a List its pretty hard to calculate the right preferred size
+for such a component. The default behavior includes querying a few entries from the model then
+
+constructing their renderers to get a "sample" of the preferred size value.
+
+As you might guess this triggers a performance penalty that is paid with every reflow of the UI. The
+solution is to use setRenderingPrototype.
+
+setRenderingPrototype accepts a "fake" value that represents a reasonably large amount of data and
+it will be used to calculate the preferred size. E.g. for a multiList that should render 2 lines of text
+
+with 20 characters and a 5mm square icon I can do something like this:
+
+Map<String, Object> proto = new HashMap<>();
+map.put("Line1", "WWWWWWWWWWWWWWWWWWWW");
+map.put("Line2", "WWWWWWWWWWWWWWWWWWWW");
+int mm5 = Display.getInstance().convertToPixels(5, true);
+map.put("icon", Image.create(mm5, mm5));
+myMultiList.setRenderingPrototype(map);
+
+240
+
+6.17.9. ComboBox
+
+ComboBox 
+
+a
+The 
+specialization  of  List  that  displays  a  single  selected  entry.  When  clicking  that  entry  a  popup  is
+presented allowing the user to pick an entry from the full list of entries.
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/ComboBox.html] 
+
+is 
+
+
+
+The ComboBox UI paradigm isn’t as common on OS’s such as iOS where there is no
+the  Picker
+native 
+
+recommend  using 
+
+equivalent 
+
+it.  We 
+
+either 
+
+to 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/spinner/Picker.html]  class  or  the
+
+AutoCompleteTextField 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/
+
+AutoCompleteTextField.html].
+
+ComboBox is notoriously hard to style properly as it relies on a complex dynamic of popup renderer
+and  instantly  visible  renderer.  The  UIID  for  the  ComboBox  is  ComboBox  however  if  you  set  it  to
+something  else  all  the  other  UIID’s  will  also  change  their  prefix.  E.g.  the  ComboBoxPopup  UIID  will
+become MyNewUIIDPopup.
+
+The combo box defines the following UIID’s by default:
+
+• ComboBox
+
+• ComboBoxItem
+
+• ComboBoxFocus
+
+• PopupContentPane
+
+• PopupItem
+
+• PopupFocus
+
+The  ComboBox  also  defines  theme  constants  that  allow  some  native  themes  to  manipulate  its
+behavior e.g.:
+
+• popupTitleBool - shows the "label for" value as the title of the popup dialog
+
+• popupCancelBodyBool - Adds a cancel button into the popup dialog
+
+• centeredPopupBool  -  shows  the  popup  dialog  in  the  center  of  the  screen  instead  of  under  the
+
+popup
+
+• otherPopupRendererBool - Uses a different list cell render for the popup than the one used for the
+ComboBox  itself.  When  this  is  false  PopupItem  &  PopupFocus  become  irrelevant.  Notice  that  the
+Android native theme defines this to true.
+
+Since a ComboBox is really a List you can use everything we learned about a List to build a ComboBox
+including models, GenericListCellRenderer etc.
+
+E.g. the demo below uses the GRRM demo data from above to build a ComboBox:
+
+241
+
+Form hi = new Form("ComboBox", new BoxLayout(BoxLayout.Y_AXIS));
+ComboBox<Map<String, Object>> combo = new ComboBox<> (
+        createListEntry("A Game of Thrones", "1996"),
+        createListEntry("A Clash Of Kings", "1998"),
+        createListEntry("A Storm Of Swords", "2000"),
+        createListEntry("A Feast For Crows", "2005"),
+        createListEntry("A Dance With Dragons", "2011"),
+        createListEntry("The Winds of Winter", "2016 (please, please, please)"),
+        createListEntry("A Dream of Spring", "Ugh"));
+
+combo.setRenderer(new GenericListCellRenderer<>(new MultiButton(), new MultiButton()));
+
+Figure 228. GRRM ComboBox
+
+6.18. Slider
+
+A Slider [https://www.codenameone.com/javadoc/com/codename1/ui/Slider.html] is an empty component that
+
+can  be  filled  horizontally  or  vertically  to  allow  indicating  progress,  setting  volume  etc.  It  can  be
+
+editable to allow the user to determine its value or none editable to just relay that information to
+
+the user. It can have a thumb on top to show its current position.
+
+Figure 229. Slider
+
+The interesting part about the slider is that it has two separate style UIID’s, Slider & SliderFull. The
+Slider  UIID  is  always  painted  and  SliderFull  is  rendered  on  top  based  on  the  amount  the  Slider
+should be filled.
+
+Slider  is  highly  customizable  e.g.  a  slider  can  be  used  to  replicate  a  5  star  rating  widget  as  such.
+Notice  that  this  slider  will  only  work  when  its  given  its  preferred  size  otherwise  additional  stars
+will appear. That’s why we place it within a FlowLayout:
+
+Form hi = new Form("Star Slider", new BoxLayout(BoxLayout.Y_AXIS));
+hi.add(FlowLayout.encloseCenter(createStarRankSlider()));
+hi.show();
+
+The slider itself is initialized in the code below. Notice that you can achieve almost the same result
+using a theme by setting the Slider & SliderFull UIID’s (both in selected & unselected states).
+
+In fact doing this in the theme might be superior as you could use one image that contains 5 stars
+
+already and that way you won’t need the preferred size hack below:
+
+242
+
+private void initStarRankStyle(Style s, Image star) {
+    s.setBackgroundType(Style.BACKGROUND_IMAGE_TILE_BOTH);
+    s.setBorder(Border.createEmpty());
+    s.setBgImage(star);
+    s.setBgTransparency(0);
+}
+
+private Slider createStarRankSlider() {
+    Slider starRank = new Slider();
+    starRank.setEditable(true);
+    starRank.setMinValue(0);
+    starRank.setMaxValue(10);
+    Font fnt = Font.createTrueTypeFont("native:MainLight", "native:MainLight").
+            derive(Display.getInstance().convertToPixels(5, true), Font.STYLE_PLAIN);
+    Style s = new Style(0xffff33, 0, fnt, (byte)0);
+    Image fullStar = FontImage.createMaterial(FontImage.MATERIAL_STAR, s).toImage();
+    s.setOpacity(100);
+    s.setFgColor(0);
+    Image emptyStar = FontImage.createMaterial(FontImage.MATERIAL_STAR, s).toImage();
+    initStarRankStyle(starRank.getSliderEmptySelectedStyle(), emptyStar);
+    initStarRankStyle(starRank.getSliderEmptyUnselectedStyle(), emptyStar);
+    initStarRankStyle(starRank.getSliderFullSelectedStyle(), fullStar);
+    initStarRankStyle(starRank.getSliderFullUnselectedStyle(), fullStar);
+    starRank.setPreferredSize(new Dimension(fullStar.getWidth() * 5, fullStar.getHeight()));
+    return starRank;
+}
+private void showStarPickingForm() {
+  Form hi = new Form("Star Slider", new BoxLayout(BoxLayout.Y_AXIS));
+  hi.add(FlowLayout.encloseCenter(createStarRankSlider()));
+  hi.show();
+}
+
+Figure 230. Star Slider set to 5 (its between 0 - 10)
+
+
+
+This slider goes all the way to 0 stars which is less common. You can use a Label to
+represent the first star and have the slider work between 0 - 8 values to provide 4
+
+additional stars.
+
+6.19. Table
+
+Table  [https://www.codenameone.com/javadoc/com/codename1/ui/table/Table.html]  is  a  composite  component
+
+(but it isn’t a lead component), this means it is a subclass of Container [https://www.codenameone.com/
+
+javadoc/com/codename1/ui/Container.html]. It’s effectively built from multiple components.
+
+243
+
+
+
+Table  is  heavily  based  on  the  TableLayout  [https://www.codenameone.com/javadoc/com/
+codename1/ui/table/TableLayout.html]  class.  It’s  important  to  be  familiar  with  that
+layout manager when working with Table.
+
+Here is a trivial sample of using the standard table component:
+
+Form hi = new Form("Table", new BorderLayout());
+TableModel model = new DefaultTableModel(new String[] {"Col 1", "Col 2", "Col 3"}, new Object[][] {
+    {"Row 1", "Row A", "Row X"},
+    {"Row 2", "Row B", "Row Y"},
+    {"Row 3", "Row C", "Row Z"},
+    {"Row 4", "Row D", "Row K"},
+    }) {
+        public boolean isCellEditable(int row, int col) {
+            return col != 0;
+        }
+    };
+Table table = new Table(model);
+hi.add(BorderLayout.CENTER, table);
+hi.show();
+
+Figure 231. Simple Table usage
+
+ In the sample above the title area and first column aren’t editable. The other two
+
+columns are editable.
+
+The more "interesting" capabilities of the Table class can be utilized via the TableLayout. You can use
+the layout constraints (also exposed in the table class) to create spanning and elaborate UI’s.
+
+E.g.:
+
+244
+
+Form hi = new Form("Table", new BorderLayout());
+TableModel model = new DefaultTableModel(new String[] {"Col 1", "Col 2", "Col 3"}, new Object[][] {
+    {"Row 1", "Row A", "Row X"},
+    {"Row 2", "Row B can now stretch", null},
+    {"Row 3", "Row C", "Row Z"},
+    {"Row 4", "Row D", "Row K"},
+    }) {
+        public boolean isCellEditable(int row, int col) {
+            return col != 0;
+        }
+    };
+Table table = new Table(model) {
+    @Override
+    protected TableLayout.Constraint createCellConstraint(Object value, int row, int column) {
+        TableLayout.Constraint con =  super.createCellConstraint(value, row, column);
+        if(row == 1 && column == 1) {
+            con.setHorizontalSpan(2);
+        }
+        con.setWidthPercentage(33);
+        return con;
+    }
+};
+hi.add(BorderLayout.CENTER, table);
+
+Figure 232. Table with spanning & fixed widths to 33%
+
+In  order  to  customize  the  table  cell  behavior  you  can  derive  the  Table  to  create  a  "renderer  like"
+widget,  however  unlike  the  list  this  component  is  "kept"  and  used  as  is.  This  means  you  can  bind
+
+listeners to this component and work with it as you would with any other component in Codename
+
+One.
+
+So lets fix the example above to include far more capabilities:
+
+245
+
+Table table = new Table(model) {
+    @Override
+    protected Component createCell(Object value, int row, int column, boolean editable) { ①
+        Component cell;
+        if(row == 1 && column == 1) {  ②
+            Picker p = new Picker();
+            p.setType(Display.PICKER_TYPE_STRINGS);
+            p.setStrings("Row B can now stretch", "This is a good value", "So Is This", "Better than text field");
+            p.setSelectedString((String)value);  ③
+            p.setUIID("TableCell");
+            p.addActionListener((e) -> getModel().setValueAt(row, column, p.getSelectedString()));  ④
+            cell = p;
+        } else {
+            cell = super.createCell(value, row, column, editable);
+        }
+        if(row > -1 && row % 2 == 0) {  ⑤
+            // pinstripe effect
+            cell.getAllStyles().setBgColor(0xeeeeee);
+            cell.getAllStyles().setBgTransparency(255);
+        }
+        return cell;
+    }
+
+    @Override
+    protected TableLayout.Constraint createCellConstraint(Object value, int row, int column) {
+        TableLayout.Constraint con =  super.createCellConstraint(value, row, column);
+        if(row == 1 && column == 1) {
+            con.setHorizontalSpan(2);
+        }
+        con.setWidthPercentage(33);
+        return con;
+    }
+};
+
+① The  createCell  method  is  invoked  once  per  component  but  is  similar  conceptually  to  the  List
+renderer. Notice that it doesn’t return a "rubber stamp" though, it returns a full component.
+
+② We only apply the picker to one cell for simplicities sake.
+
+③ We need to set the value of the component manually, this is crucial since the Table doesn’t "see"
+
+this.
+
+④ We need to track the event and update the model in this case as the Table isn’t aware of the data
+
+change.
+
+⑤ We set the "pinstripe" effect by coloring even rows. Notice that unlike renderers we only need to
+
+apply the coloring once as the Components are stateful.
+
+246
+
+Figure 233. Table with customize cells using the pinstripe effect
+
+Figure 234. Picker table cell during edit
+
+To  line  wrap  table  cells  we  can  just  override  the  createCell  method  and  return  a  TextArea
+TextField
+[https://www.codenameone.com/javadoc/com/codename1/ui/TextArea.html] 
+[https://www.codenameone.com/javadoc/com/codename1/ui/TextField.html]  since  the  TextArea  defaults  to  the
+multi-line behavior this should work seamlessly. E.g.:
+
+instead 
+
+of 
+
+a 
+
+247
+
+Form hi = new Form("Table", new BorderLayout());
+TableModel model = new DefaultTableModel(new String[] {"Col 1", "Col 2", "Col 3"}, new Object[][] {
+    {"Row 1", "Row A", "Row X"},
+    {"Row 2", "Row B can now stretch very long line that should span multiple rows as much as possible", "Row Y"},
+    {"Row 3", "Row C", "Row Z"},
+    {"Row 4", "Row D", "Row K"},
+    }) {
+        public boolean isCellEditable(int row, int col) {
+            return col != 0;
+        }
+    };
+Table table = new Table(model) {
+    @Override
+    protected Component createCell(Object value, int row, int column, boolean editable) {
+        TextArea ta = new TextArea((String)value);
+        ta.setUIID("TableCell");
+        return ta;
+    }
+
+    @Override
+    protected TableLayout.Constraint createCellConstraint(Object value, int row, int column) {
+        TableLayout.Constraint con =  super.createCellConstraint(value, row, column);
+        con.setWidthPercentage(33);
+        return con;
+    }
+};
+hi.add(BorderLayout.CENTER, table);
+hi.show();
+
+
+
+Notice  that  we  don’t  really  need  to  do  anything  else  as  binding  to  the  TextArea  is
+builtin to the Table.
+
+
+
+We  must  set  the  column  width  constraint  when  we  want  multi-line  to  work.
+
+Otherwise the preferred size of the column might be too wide and the remaining
+
+columns might not have space left.
+
+Figure 235. Multiline table cell in portrait mode
+
+Figure 236. Multiline table cell in landscape mode. Notice the cell row count adapts seamlessly
+
+248
+
+6.19.1. Sorting Tables
+
+Sorting tables by clicking the titles is something that should generally work out of the box by using
+an API like setSortSupported(true).
+
+Form hi = new Form("Table", new BorderLayout());
+TableModel model = new DefaultTableModel(new String[] {"Col 1", "Col 2", "Col 3"}, new Object[][] {
+    {"Row 1", "Row A", 1},
+    {"Row 2", "Row B", 4},
+    {"Row 3", "Row C", 7.5},
+    {"Row 4", "Row D", 2.24},
+    });
+Table table = new Table(model);
+table.setSortSupported(true);
+hi.add(BorderLayout.CENTER, table);
+hi.add(NORTH, new Button("Button"));
+hi.show();
+
+Notice this works with numbers, Strings and might work with dates but you can generally support
+any  object  type  by  overriding  the  method  protected  Comparator  createColumnSortComparator(int
+column) which should return a comparator for your custom object type in the column.
+
+6.20. Tree
+
+Tree 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/tree/Tree.html] 
+
+allows 
+
+displaying
+
+hierarchical  data  such  as  folders  and  files  in  a  collapsible/expandable  UI.  Like  the  Table  it  is  a
+composite  component  (but  it  isn’t  a  lead  component).  Like  the  Table  it  works  in  consort  with  a
+model to construct its user interface on the fly but doesn’t use a stateless renderer (as List does).
+
+The data of the Tree arrives from a model model e.g. this:
+
+249
+
+class StringArrayTreeModel implements TreeModel {
+    String[][] arr = new String[][] {
+            {"Colors", "Letters", "Numbers"},
+            {"Red", "Green", "Blue"},
+            {"A", "B", "C"},
+            {"1", "2", "3"}
+        };
+
+    public Vector getChildren(Object parent) {
+        if(parent == null) {
+            Vector v = new Vector();
+            for(int iter = 0 ; iter < arr[0].length ; iter++) {
+                v.addElement(arr[0][iter]);
+            }
+            return v;
+        }
+        Vector v = new Vector();
+        for(int iter = 0 ; iter < arr[0].length ; iter++) {
+            if(parent == arr[0][iter]) {
+                if(arr.length > iter + 1 && arr[iter + 1] != null) {
+                    for(int i = 0 ; i < arr[iter + 1].length ; i++) {
+                        v.addElement(arr[iter + 1][i]);
+                    }
+                }
+            }
+        }
+        return v;
+    }
+
+    public boolean isLeaf(Object node) {
+        Vector v = getChildren(node);
+        return v == null || v.size() == 0;
+    }
+}
+
+Tree dt = new Tree(new StringArrayTreeModel());
+
+Will result in this:
+
+Figure 237. Tree
+
+250
+
+ Since  Tree  is  hierarchy  based  we  can’t  have  a  simple  model  like  we  have  for  the
+
+Table as deep hierarchy is harder to represent with arrays.
+
+A  more  practical  "real  world"  example  would  be  working  with  XML  data.  We  can  use  something
+like this to show an XML Tree:
+
+Form hi = new Form("XML Tree", new BorderLayout());
+InputStream is = Display.getInstance().getResourceAsStream(getClass(), "/build.xml");
+try(Reader r = new InputStreamReader(is, "UTF-8");) {
+    Element e = new XMLParser().parse(r);
+    Tree xmlTree = new Tree(new XMLTreeModel(e)) {
+        @Override
+        protected String childToDisplayLabel(Object child) {
+            if(child instanceof Element) {
+                return ((Element)child).getTagName();
+            }
+            return child.toString();
+        }
+    };
+    hi.add(BorderLayout.CENTER, xmlTree);
+} catch(IOException err) {
+    Log.e(err);
+}
+
+ The  try(Stream)  syntax  is  a  try  with  resources  clogic  that  implicitly  closes  the
+
+stream.
+
+Figure 238. XML Tree
+
+The model for the XML hierarchy is implemented as such:
+
+251
+
+class XMLTreeModel implements TreeModel {
+    private Element root;
+    public XMLTreeModel(Element e) {
+        root = e;
+    }
+
+    public Vector getChildren(Object parent) {
+        if(parent == null) {
+            Vector c = new Vector();
+            c.addElement(root);
+            return c;
+        }
+        Vector result = new Vector();
+        Element e = (Element)parent;
+        for(int iter = 0 ; iter < e.getNumChildren() ; iter++) {
+            result.addElement(e.getChildAt(iter));
+        }
+        return result;
+    }
+
+    public boolean isLeaf(Object node) {
+        Element e = (Element)node;
+        return e.getNumChildren() == 0;
+    }
+}
+
+6.21. ShareButton
+
+ShareButton 
+
+[https://www.codenameone.com/javadoc/com/codename1/components/ShareButton.html] 
+
+is  a
+
+button you can add into the UI to let a user share an image or block of text.
+
+The  ShareButton  uses  a  set  of  predefined  share  options  on  the  simulator.  On  Android  &  iOS  the
+ShareButton is mapped to the OS native sharing functionality and can share the image/text with the
+services configured on the device (e.g. Twitter, Facebook etc.).
+
+
+
+Sharing  text  is  trivial  but  to  share  an  image  we  need  to  save  it  to  the
+
+FileSystemStorage 
+
+[https://www.codenameone.com/javadoc/com/codename1/io/
+
+FileSystemStorage.html]. Notice that saving to Storage won’t work!
+
+In  the  sample  code  below  we  take  a  screenshot  which  is  saved  to  FileSystemStorage
+
+[https://www.codenameone.com/javadoc/com/codename1/io/FileSystemStorage.html] for sharing:
+
+252
+
+Form hi = new Form("ShareButton");
+ShareButton sb = new ShareButton();
+sb.setText("Share Screenshot");
+hi.add(sb);
+
+Image screenshot = Image.createImage(hi.getWidth(), hi.getHeight());
+hi.revalidate();
+hi.setVisible(true);
+hi.paintComponent(screenshot.getGraphics(), true);
+
+String imageFile = FileSystemStorage.getInstance().getAppHomePath() + "screenshot.png";
+try(OutputStream os = FileSystemStorage.getInstance().openOutputStream(imageFile);) {
+    ImageIO.getImageIO().save(screenshot, os, ImageIO.FORMAT_PNG, 1);
+} catch(IOException err) {
+    Log.e(err);
+}
+sb.setImageToShare(imageFile, "image/png");
+
+Figure 239. The share button running on the simulator
+
+ ShareButton behaves very differently on the device…
+
+Figure 240. The share button running on the Android device and screenshot sent into twitter
+
+253
+
+
+
+The ShareButton features some share service classes to allow plugging in additional
+share services. However, this functionality is only relevant to devices where native
+
+sharing isn’t supported. So this code isn’t used on iOS/Android…
+
+6.22. Tabs
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/Tabs.html] 
+
+The  Tabs 
+arranges
+components  into  groups  within  "tabbed"  containers.  Tabs  is  a  container  type  that  allows  leafing
+through its children using labeled toggle buttons. The tabs can be placed in multiple different ways
+
+Container 
+
+(top, bottom, left or right) with the default being determined by the platform. This class also allows
+
+swiping  between  components  to  leaf  between  said  tabs  (for  this  purpose  the  tabs  themselves  can
+
+also be hidden).
+
+Since  Tabs  are  a  Container  its  a  common  mistake  to  try  and  add  a  Tab  using  the  add  method.  That
+method won’t work since a Tab can have both an Image and text String associated with it.
+
+Form hi = new Form("Tabs", new BorderLayout());
+
+Tabs t = new Tabs();
+Style s = UIManager.getInstance().getComponentStyle("Tab");
+FontImage icon1 = FontImage.createMaterial(FontImage.MATERIAL_QUESTION_ANSWER, s);
+
+Container container1 = BoxLayout.encloseY(new Label("Label1"), new Label("Label2"));
+t.addTab("Tab1", icon1, container1);
+t.addTab("Tab2", new SpanLabel("Some text directly in the tab"));
+
+hi.add(BorderLayout.CENTER, t);
+
+Figure 241. Simple usage of Tabs
+
+A  common  usage  for  Tabs  is  the  the  swipe  to  proceed  effect  which  is  very  common  in  iOS
+applications.  In  the  code  below  we  use  RadioButton  [https://www.codenameone.com/javadoc/com/
+
+codename1/ui/RadioButton.html]  and  LayeredLayout  [https://www.codenameone.com/javadoc/com/codename1/
+
+ui/layouts/LayeredLayout.html] with hidden tabs to produce that effect:
+
+254
+
+Form hi = new Form("Swipe Tabs", new LayeredLayout());
+Tabs t = new Tabs();
+t.hideTabs();
+
+Style s = UIManager.getInstance().getComponentStyle("Button");
+FontImage radioEmptyImage = FontImage.createMaterial(FontImage.MATERIAL_RADIO_BUTTON_UNCHECKED, s);
+FontImage radioFullImage = FontImage.createMaterial(FontImage.MATERIAL_RADIO_BUTTON_CHECKED, s);
+((DefaultLookAndFeel)UIManager.getInstance().getLookAndFeel()).setRadioButtonImages(radioFullImage, radioEmptyImage,
+radioFullImage, radioEmptyImage);
+
+Container container1 = BoxLayout.encloseY(new Label("Swipe the tab to see more"),
+        new Label("You can put anything here"));
+t.addTab("Tab1", container1);
+t.addTab("Tab2", new SpanLabel("Some text directly in the tab"));
+
+RadioButton firstTab = new RadioButton("");
+RadioButton secondTab = new RadioButton("");
+firstTab.setUIID("Container");
+secondTab.setUIID("Container");
+new ButtonGroup(firstTab, secondTab);
+firstTab.setSelected(true);
+Container tabsFlow = FlowLayout.encloseCenter(firstTab, secondTab);
+
+hi.add(t);
+hi.add(BorderLayout.south(tabsFlow));
+
+t.addSelectionListener((i1, i2) -> {
+    switch(i2) {
+        case 0:
+            if(!firstTab.isSelected()) {
+                firstTab.setSelected(true);
+            }
+            break;
+        case 1:
+            if(!secondTab.isSelected()) {
+                secondTab.setSelected(true);
+            }
+            break;
+     }
+});
+
+Figure 242. Swipeable Tabs with an iOS carousel effect page 1
+
+255
+
+Figure 243. Swipeable Tabs with an iOS carousel effect page 2
+
+ Notice that we used setRadioButtonImages to explicitly set the radio button images
+
+to the look we want for the carousel.
+
+6.23. MediaManager & MediaPlayer
+
+
+
+MediaPlayer is a peer component, understanding this is crucial if your application
+depends  on  such  a  component.  You  can  learn  about  peer  components  and  their
+
+issues 
+
+here 
+
+[https://www.codenameone.com/manual/advanced-topics.html#native-peer-
+
+components].
+
+The  MediaPlayer 
+[https://www.codenameone.com/javadoc/com/codename1/components/MediaPlayer.html]
+allows you to control video playback. To use the MediaPlayer we need to first load the Media object
+from the MediaManager [https://www.codenameone.com/javadoc/com/codename1/media/MediaManager.html].
+
+The MediaManager is the core class responsible for media interaction in Codename One.
+
+
+
+You  should  also  check  out  the  Capture  [https://www.codenameone.com/javadoc/com/
+
+codename1/capture/Capture.html]  class  for 
+MediaManager.
+
+things 
+
+that  aren’t  covered  by 
+
+the
+
+In  the  demo  code  below  we  use  the  gallery  functionality  to  pick  a  video  from  the  device’s  video
+
+gallery.
+
+256
+
+final Form hi = new Form("MediaPlayer", new BorderLayout());
+hi.setToolbar(new Toolbar());
+Style s = UIManager.getInstance().getComponentStyle("Title");
+FontImage icon = FontImage.createMaterial(FontImage.MATERIAL_VIDEO_LIBRARY, s);
+hi.getToolbar().addCommandToRightBar("", icon, (evt) -> {
+    Display.getInstance().openGallery((e) -> {
+        if(e != null && e.getSource() != null) {
+            String file = (String)e.getSource();
+            try {
+                Media video = MediaManager.createMedia(file, true);
+                hi.removeAll();
+                hi.add(BorderLayout.CENTER, new MediaPlayer(video));
+                hi.revalidate();
+            } catch(IOException err) {
+                Log.e(err);
+            }
+        }
+    }, Display.GALLERY_VIDEO);
+});
+hi.show();
+
+Figure 244. Video playback running on the simulator
+
+Figure 245. Video playback running on an Android device. Notice the native playback controls that appear
+
+when the video is tapped
+
+257
+
+ Video  playback  in  the  simulator  will  only  work  with  JavaFX  enabled.  This  is  the
+
+default for Java 8 or newer so we recommend using that.
+
+6.24. ImageViewer
+
+The 
+
+ImageViewer 
+
+[https://www.codenameone.com/javadoc/com/codename1/components/ImageViewer.html]
+
+allows  us  to  inspect,  zoom  and  pan  into  an  image.  It  also  allows  swiping  between  images  if  you
+
+have a set of images (using an image list model).
+
+
+
+The ImageViewer is a complex rich component designed for user interaction. If you
+just  want  to  display  an  image  use  Label  [https://www.codenameone.com/javadoc/com/
+
+codename1/ui/Label.html] 
+
+if  you  want 
+
+the 
+
+image 
+
+to  scale  seamlessly  use
+
+ScaleImageLabel 
+
+[https://www.codenameone.com/javadoc/com/codename1/components/
+
+ScaleImageLabel.html].
+
+You can use the ImageViewer as a tool to view a single image which allows you to zoom in/out to that
+image as such:
+
+Form hi = new Form("ImageViewer", new BorderLayout());
+ImageViewer iv = new ImageViewer(duke);
+hi.add(BorderLayout.CENTER, iv);
+
+
+
+You  can  simulate  pinch  to  zoom  on  the  simulator  by  dragging  the  right  button
+
+away from the top left corner to zoom in and towards the top left corner to zoom
+
+out. On Mac touchpads you can drag two fingers to achieve that.
+
+Figure 246. ImageViewer as the demo loads with the image from the default icon
+
+258
+
+Figure 247. ImageViewer zoomed in
+
+We can work with a list of images to produce a swiping effect for the image viewer where you can
+
+swipe from one image to the next and also zoom in/out on a specific image:
+
+Form hi = new Form("ImageViewer", new BorderLayout());
+
+Image red = Image.createImage(100, 100, 0xffff0000);
+Image green = Image.createImage(100, 100, 0xff00ff00);
+Image blue = Image.createImage(100, 100, 0xff0000ff);
+Image gray = Image.createImage(100, 100, 0xffcccccc);
+
+ImageViewer iv = new ImageViewer(red);
+iv.setImageList(new DefaultListModel<>(red, green, blue, gray));
+hi.add(BorderLayout.CENTER, iv);
+
+Figure 248. An ImageViewer with multiple elements is indistinguishable from a single ImageViewer with
+
+the exception of swipe
+
+Notice that we use a ListModel [https://www.codenameone.com/javadoc/com/codename1/ui/list/ListModel.html]
+
+to allow swiping between images.
+
+
+
+EncodedImage’s aren’t always fully loaded and so when you swipe if the images are
+really large you might see delays!
+
+You  can  dynamically  download  images  directly  into  the  ImageViewer  with  a  custom  list  model  like
+this:
+
+259
+
+Form hi = new Form("ImageViewer", new BorderLayout());
+final EncodedImage placeholder = EncodedImage.createFromImage(
+        FontImage.createMaterial(FontImage.MATERIAL_SYNC, s).
+                scaled(300, 300), false);
+
+class ImageList implements ListModel<Image> {
+    private int selection;
+    private String[] imageURLs = {
+        "http://awoiaf.westeros.org/images/thumb/9/93/AGameOfThrones.jpg/300px-AGameOfThrones.jpg",
+        "http://awoiaf.westeros.org/images/thumb/3/39/AClashOfKings.jpg/300px-AClashOfKings.jpg",
+        "http://awoiaf.westeros.org/images/thumb/2/24/AStormOfSwords.jpg/300px-AStormOfSwords.jpg",
+        "http://awoiaf.westeros.org/images/thumb/a/a3/AFeastForCrows.jpg/300px-AFeastForCrows.jpg",
+        "http://awoiaf.westeros.org/images/7/79/ADanceWithDragons.jpg"
+    };
+    private Image[] images;
+    private EventDispatcher listeners = new EventDispatcher();
+
+    public ImageList() {
+        this.images = new EncodedImage[imageURLs.length];
+    }
+
+    public Image getItemAt(final int index) {
+        if(images[index] == null) {
+            images[index] = placeholder;
+            Util.downloadUrlToStorageInBackground(imageURLs[index], "list" + index, (e) -> {
+                    try {
+                        images[index] = EncodedImage.create(Storage.getInstance().createInputStream("list" + index));
+                        listeners.fireDataChangeEvent(index, DataChangedListener.CHANGED);
+                    } catch(IOException err) {
+                        err.printStackTrace();
+                    }
+            });
+        }
+        return images[index];
+    }
+
+    public int getSize() {
+        return imageURLs.length;
+    }
+
+    public int getSelectedIndex() {
+        return selection;
+    }
+
+    public void setSelectedIndex(int index) {
+        selection = index;
+    }
+
+    public void addDataChangedListener(DataChangedListener l) {
+        listeners.addListener(l);
+    }
+
+    public void removeDataChangedListener(DataChangedListener l) {
+        listeners.removeListener(l);
+    }
+
+    public void addSelectionListener(SelectionListener l) {
+    }
+
+    public void removeSelectionListener(SelectionListener l) {
+    }
+
+    public void addItem(Image item) {
+    }
+
+260
+
+    public void removeItem(int index) {
+    }
+};
+
+ImageList imodel = new ImageList();
+
+ImageViewer iv = new ImageViewer(imodel.getItemAt(0));
+iv.setImageList(imodel);
+hi.add(BorderLayout.CENTER, iv);
+
+Figure 249. Dynamically fetching an image URL from the internet [5]
+
+This  fetches  the  images  in  the  URL  asynchronously  and  fires  a  data  change  event  when  the  data
+arrives to automatically refresh the ImageViewer when that happens.
+
+6.25. ScaleImageLabel & ScaleImageButton
+
+ScaleImageLabel [https://www.codenameone.com/javadoc/com/codename1/components/ScaleImageLabel.html] &
+
+ScaleImageButton  [https://www.codenameone.com/javadoc/com/codename1/components/ScaleImageButton.html]
+
+allow us to position an image that will grow/shrink to fit available space. In that sense they differ
+
+from Label & Button which keeps the image at the same size.
+
+
+
+The  default  UIID  of  ScaleImageLabel  is  “Label”,  however  the  default  UIID  of
+ScaleImageButton  is  “ScaleImageButton”.  The  reasoning  for  the  difference  is  that
+the “Button” UIID includes a border and a lot of legacy.
+
+You can use ScaleImageLabel/ScaleImageButton interchangeably. The only major difference between
+these components is the buttons ability to handle click events/focus.
+
+Here  is  a  simple  example  that  also  shows  the  difference  between  the  scale  to  fill  and  scale  to
+fit modes:
+
+261
+
+TableLayout tl = new TableLayout(2, 2);
+Form hi = new Form("ScaleImageButton/Label", tl);
+Style s = UIManager.getInstance().getComponentStyle("Button");
+Image icon = FontImage.createMaterial(FontImage.MATERIAL_WARNING, s);
+ScaleImageLabel fillLabel = new ScaleImageLabel(icon);
+fillLabel.setBackgroundType(Style.BACKGROUND_IMAGE_SCALED_FILL);
+ScaleImageButton fillButton = new ScaleImageButton(icon);
+fillButton.setBackgroundType(Style.BACKGROUND_IMAGE_SCALED_FILL);
+hi.add(tl.createConstraint().widthPercentage(20), new ScaleImageButton(icon)).
+        add(tl.createConstraint().widthPercentage(80), new ScaleImageLabel(icon)).
+        add(fillLabel).
+        add(fillButton);
+hi.show();
+
+Figure 250. ScaleImageLabel/Button, the top row includes scale to fit versions (the default) whereas the
+
+bottom row includes the scale to fill versions
+
+
+
+When  styling  these  components  keep  in  mind  that  changing  attributes  such  as
+
+background  behavior  might  cause  an  issue  with  their  functionality  or  might  not
+
+work.
+
+6.26. Toolbar
+
+The  Toolbar  [https://www.codenameone.com/javadoc/com/codename1/ui/Toolbar.html]  API  provides  deep
+
+customization  of 
+
+the 
+
+title  bar  area  with  more 
+
+flexibility  e.g.  placing  a  TextField
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/TextField.html] for search or buttons in arbitrary
+title  area  positions.  The  Toolbar  API  replicates  some  of  the  native  functionality  available  on
+Android/iOS  and  integrates  with  features  such  as  the  side  menu  to  provide  very  fine  grained
+
+control over the title area behavior.
+
+The Toolbar needs to be installed into the Form in order for it to work. You can setup the Toolbar in
+one of these three ways:
+
+1. form.setToolbar(new  Toolbar());  -  allows  you  to  activate  the  Toolbar  to  a  specific  Form  and  not
+
+for the entire application
+
+2. Toolbar.setGlobalToolbar(true); - enables the Toolbar for all the forms in the app
+
+3. Theme constant globalToobarBool - this is equivalent to Toolbar.setGlobalToolbar(true);
+
+The  basic  functionality  of  the  Toolbar  includes  the  ability  to  add  a  command  to  the  following  4
+places:
+
+• Left side of the title - addCommandToLeftBar
+
+• Right side of the title - addCommandToRightBar
+
+262
+
+• Side  menu  bar  (the  drawer  that  opens  when  you  click  the  icon  on  the  top  left  or  swipe  the
+
+screen from left to right) - addCommandToSideMenu
+
+• Overflow menu (the menu that opens when you tap the 3 vertical dots in the top right corner) -
+
+addCommandToOverflowMenu
+
+The code below provides a brief overview of these options:
+
+Toolbar.setGlobalToolbar(true);
+
+Form hi = new Form("Toolbar", new BoxLayout(BoxLayout.Y_AXIS));
+hi.getToolbar().addCommandToLeftBar("Left", icon, (e) -> Log.p("Clicked"));
+hi.getToolbar().addCommandToRightBar("Right", icon, (e) -> Log.p("Clicked"));
+hi.getToolbar().addCommandToOverflowMenu("Overflow", icon, (e) -> Log.p("Clicked"));
+hi.getToolbar().addCommandToSideMenu("Sidemenu", icon, (e) -> Log.p("Clicked"));
+hi.show();
+
+Figure 251. The Toolbar
+
+Figure 252. The default sidemenu of the Toolbar
+
+Figure 253. The overflow menu of the Toolbar
+
+Normally  you  can  just  set  a  title  with  a  String  but  if  you  would  want  the  component  to  be  a  text
+field or a multi line label you can use setTitleComponent(Component) which allows you to install any
+component into the title area.
+
+
+
+The  code  below  demonstrates  searching  using  custom  code  however  the  Toolbar
+
+also has builtin support for search covered in the next section
+
+The  customization  of  the  title  area  allows  for  some  pretty  powerful  UI  effects  e.g.  the  code  below
+
+allows searching dynamically within a set of entries and uses some very neat tricks:
+
+263
+
+Toolbar.setGlobalToolbar(true);
+Style s = UIManager.getInstance().getComponentStyle("Title");
+
+Form hi = new Form("Toolbar", new BoxLayout(BoxLayout.Y_AXIS));
+TextField searchField = new TextField("", "Toolbar Search"); ①
+searchField.getHintLabel().setUIID("Title");
+searchField.setUIID("Title");
+searchField.getAllStyles().setAlignment(Component.LEFT);
+hi.getToolbar().setTitleComponent(searchField);
+FontImage searchIcon = FontImage.createMaterial(FontImage.MATERIAL_SEARCH, s);
+searchField.addDataChangeListener((i1, i2) -> { ②
+    String t = searchField.getText();
+    if(t.length() < 1) {
+        for(Component cmp : hi.getContentPane()) {
+            cmp.setHidden(false);
+            cmp.setVisible(true);
+        }
+    } else {
+        t = t.toLowerCase();
+        for(Component cmp : hi.getContentPane()) {
+            String val = null;
+            if(cmp instanceof Label) {
+                val = ((Label)cmp).getText();
+            } else {
+                if(cmp instanceof TextArea) {
+                    val = ((TextArea)cmp).getText();
+                } else {
+                    val = (String)cmp.getPropertyValue("text");
+                }
+            }
+            boolean show = val != null && val.toLowerCase().indexOf(t) > -1;
+            cmp.setHidden(!show); ③
+            cmp.setVisible(show);
+        }
+    }
+    hi.getContentPane().animateLayout(250);
+});
+hi.getToolbar().addCommandToRightBar("", searchIcon, (e) -> {
+    searchField.startEditingAsync(); ④
+});
+
+hi.add("A Game of Thrones").
+        add("A Clash Of Kings").
+        add("A Storm Of Swords").
+        add("A Feast For Crows").
+        add("A Dance With Dragons").
+        add("The Winds of Winter").
+        add("A Dream of Spring");
+hi.show();
+
+264
+
+① We use a TextField the whole time and just style it to make it (and its hint) look like a regular
+
+title. An alternative way is to replace the title component dynamically.
+
+② We use the DataChangeListener to update the search results as we type them.
+
+③ Hidden  &  Visible  use  the  opposite  flag  values  to  say  similar  things  (e.g.  when  hidden  is  set  to
+
+false you would want to set visible to true).
+
+Visible indicates whether a component can be seen. It will still occupy the physical space on the
+
+screen even when it isn’t visible. Hidden will remove the space occupied by the component from
+
+the screen, but some code might still try to paint it. Normally, visible is redundant but we use it
+
+with hidden for good measure.
+
+④ The search button is totally unnecessary here. We can just click the TextField!
+
+However, that isn’t intuitive to most users so we added the button to start editing.
+
+Figure 254. Search field within the toolbar
+
+Figure 255. Search field after typing a couple of letters
+
+6.26.1. Search Mode
+
+While  you  can  implement  search  manually  using  the  builtin  search  offers  a  simpler  and  more
+
+uniform UI.
+
+Figure 256. Builtin toolbar search functionality
+
+265
+
+You  can  customize  the  appearance  of  the  search  bar  by  using  the  UIID’s:  ToolbarSearch,
+TextFieldSearch & TextHintSearch.
+
+In the sample below we fetch all the contacts from the device and enable search thru them, notice it
+expects and image called duke.png which is really just the default Codename One icon renamed and
+placed in the src folder:
+
+Image duke = null;
+try {
+    duke = Image.createImage("/duke.png");
+} catch(IOException err) {
+    Log.e(err);
+}
+int fiveMM = Display.getInstance().convertToPixels(5);
+final Image finalDuke = duke.scaledWidth(fiveMM);
+Toolbar.setGlobalToolbar(true);
+Form hi = new Form("Search", BoxLayout.y());
+hi.add(new InfiniteProgress());
+Display.getInstance().scheduleBackgroundTask(()-> {
+    // this will take a while...
+    Contact[] cnts = Display.getInstance().getAllContacts(true, true, true, true, false, false);
+    Display.getInstance().callSerially(() -> {
+        hi.removeAll();
+        for(Contact c : cnts) {
+            MultiButton m = new MultiButton();
+            m.setTextLine1(c.getDisplayName());
+            m.setTextLine2(c.getPrimaryPhoneNumber());
+            Image pic = c.getPhoto();
+            if(pic != null) {
+                m.setIcon(fill(pic, finalDuke.getWidth(), finalDuke.getHeight()));
+            } else {
+                m.setIcon(finalDuke);
+            }
+            hi.add(m);
+        }
+        hi.revalidate();
+    });
+});
+
+hi.getToolbar().addSearchCommand(e -> {
+    String text = (String)e.getSource();
+    if(text == null || text.length() == 0) {
+        // clear search
+        for(Component cmp : hi.getContentPane()) {
+            cmp.setHidden(false);
+            cmp.setVisible(true);
+        }
+        hi.getContentPane().animateLayout(150);
+    } else {
+        text = text.toLowerCase();
+        for(Component cmp : hi.getContentPane()) {
+            MultiButton mb = (MultiButton)cmp;
+            String line1 = mb.getTextLine1();
+            String line2 = mb.getTextLine2();
+
+266
+
+            boolean show = line1 != null && line1.toLowerCase().indexOf(text) > -1 ||
+                    line2 != null && line2.toLowerCase().indexOf(text) > -1;
+            mb.setHidden(!show);
+            mb.setVisible(show);
+        }
+        hi.getContentPane().animateLayout(150);
+    }
+}, 4);
+
+hi.show();
+
+6.26.2. South Component
+
+A common feature in side menu bar is the ability to add a component to the "south" part of the side
+
+menu.
+
+Notice that this feature only works with the on-top and permanent versions of the side menu and
+
+not with the legacy versions:
+
+toolbar.setComponentToSideMenuSouth(myComponent);
+
+This places the component below the side menu bar. Notice that this component controls its entire
+UIID & is separate from the SideNavigationPanel UIID so if you set that component you might want
+to place it within a container that has the SideNavigationPanel UIID so it will blend with the rest of
+the UI.
+
+6.26.3. Title Animations
+
+Modern  UI’s  often  animate  the  title  upon  scrolling  to  balance  the  highly  functional  smaller  title
+
+advantage with the gorgeous large image based title. This is pretty easy to do with the Toolbar API
+
+thru the Title animation API.
+
+The  code  below  shows  off  an  attractive  title  based  on  a  book  by  GRRM  on  top  of  text  [6]  that  is
+scrollable. As the text is scrolled the title fades out.
+
+267
+
+Toolbar.setGlobalToolbar(true);
+
+Form hi = new Form("Toolbar", new BoxLayout(BoxLayout.Y_AXIS));
+EncodedImage placeholder = EncodedImage.createFromImage(Image.createImage(hi.getWidth(), hi.getWidth() / 5, 0xffff0000),
+true);
+URLImage background = URLImage.createToStorage(placeholder, "400px-AGameOfThrones.jpg",
+        "http://awoiaf.westeros.org/images/thumb/9/93/AGameOfThrones.jpg/400px-AGameOfThrones.jpg");
+background.fetch();
+Style stitle = hi.getToolbar().getTitleComponent().getUnselectedStyle();
+stitle.setBgImage(background);
+stitle.setBackgroundType(Style.BACKGROUND_IMAGE_SCALED_FILL);
+stitle.setPaddingUnit(Style.UNIT_TYPE_DIPS, Style.UNIT_TYPE_DIPS, Style.UNIT_TYPE_DIPS, Style.UNIT_TYPE_DIPS);
+stitle.setPaddingTop(15);
+SpanButton credit = new SpanButton("This excerpt is from A Wiki Of Ice And Fire. Please check it out by clicking here!");
+credit.addActionListener((e) -> Display.getInstance().execute("http://awoiaf.westeros.org/index.php/A_Game_of_Thrones"));
+hi.add(new SpanLabel("A Game of Thrones is the first of seven planned novels in A Song of Ice and Fire, an epic fantasy
+series by American author George R. R. Martin. It was first published on 6 August 1996. The novel was nominated for the
+1998 Nebula Award and the 1997 World Fantasy Award,[1] and won the 1997 Locus Award.[2] The novella Blood of the Dragon,
+comprising the Daenerys Targaryen chapters from the novel, won the 1997 Hugo Award for Best Novella. ")).
+        add(new Label("Plot introduction", "Heading")).
+        add(new SpanLabel("A Game of Thrones is set in the Seven Kingdoms of Westeros, a land reminiscent of Medieval
+Europe. In Westeros the seasons last for years, sometimes decades, at a time.\n\n" +
+            "Fifteen years prior to the novel, the Seven Kingdoms were torn apart by a civil war, known alternately as
+\"Robert's Rebellion\" and the \"War of the Usurper.\" Prince Rhaegar Targaryen kidnapped Lyanna Stark, arousing the ire
+of her family and of her betrothed, Lord Robert Baratheon (the war's titular rebel). The Mad King, Aerys II Targaryen,
+had Lyanna's father and eldest brother executed when they demanded her safe return. Her second brother, Eddard, joined
+his boyhood friend Robert Baratheon and Jon Arryn, with whom they had been fostered as children, in declaring war against
+the ruling Targaryen dynasty, securing the allegiances of House Tully and House Arryn through a network of dynastic
+marriages (Lord Eddard to Catelyn Tully and Lord Arryn to Lysa Tully). The powerful House Tyrell continued to support the
+King, but House Lannister and House Martell both stalled due to insults against their houses by the Targaryens. The civil
+war climaxed with the Battle of the Trident, when Prince Rhaegar was killed in battle by Robert Baratheon. The Lannisters
+finally agreed to support King Aerys, but then brutally... ")).
+        add(credit);
+
+ComponentAnimation title = hi.getToolbar().getTitleComponent().createStyleAnimation("Title", 200);
+hi.getAnimationManager().onTitleScrollAnimation(title);
+hi.show();
+
+Figure 257. The Toolbar starts with the large URLImage fetched from the web
+
+268
+
+Figure 258. As we scroll down the image fades and the title shrinks in size returning to the default UIID look
+
+Figure 259. As scrolling continues the title reaches standard size
+
+Almost all of the code above just creates the "look" of the application. The key piece of code above is
+
+this:
+
+ComponentAnimation title = hi.getToolbar().getTitleComponent().createStyleAnimation("Title", 200);
+hi.getAnimationManager().onTitleScrollAnimation(title);
+
+In the first line we create a style animation that will translate the style from the current settings to
+
+the destination UIID (the first argument) within 200 pixels of scrolling. We then bind this animation
+
+to the title scrolling animation event.
+
+6.27. BrowserComponent & WebBrowser
+
+
+
+BrowserComponent  is  a  peer  component,  understanding  this  is  crucial  if  your
+application depends on such a component. You can learn about peer components
+
+and  their  issues  here  [https://www.codenameone.com/manual/advanced-topics.html#native-
+
+peer-components].
+
+The  WebBrowser 
+
+[https://www.codenameone.com/javadoc/com/codename1/components/WebBrowser.html]
+
+component  shows  the  native  device  web  browser  when  supported  by  the  device  and  the
+
+HTMLComponent 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/html/HTMLComponent.html]
+
+when  the  web  browser  isn’t  supported  on  the  given  device.  If  you  only  intend  to  target
+
+smartphones  you  should  use  the  BrowserComponent  [https://www.codenameone.com/javadoc/com/
+codename1/ui/BrowserComponent.html] directly instead of the WebBrowser.
+
+269
+
+The BrowserComponent can point at an arbitrary URL to load it:
+
+Form hi = new Form("Browser", new BorderLayout());
+BrowserComponent browser = new BrowserComponent();
+browser.setURL("https://www.codenameone.com/");
+hi.add(BorderLayout.CENTER, browser);
+
+Figure 260. Browser Component showing the Codename One website on the simulator
+
+ The  scrollbars  only  appear  in  the  simulator,  device  versions  of  the  browser
+
+component act differently and support touch scrolling.
+
+
+
+A  BrowserComponent  should  be  in  the  center  of  a  BorderLayout.  Otherwise  its
+preferred size might be zero before the HTML finishes loading/layout in the native
+
+layer and layout might be incorrect as a result.
+
+You can use WebBrowser and BrowserComponent interchangeably for most basic usage. However, if you
+need access to JavaScript or native browser functionality then there is really no use in going thru
+the WebBrowser abstraction.
+
+The BrowserComponent has full support for executing local web pages from within the jar. The basic
+support uses the jar:/// URL as such:
+
+BrowserComponent wb = new BrowserComponent();
+wb.setURL("jar:///Page.html");
+
+
+
+On Android a native indicator might show up when the web page is loading. This
+can  be  disabled  using  the  Display.getInstance().setProperty("WebLoadingHidden",
+"true"); call. You only need to invoke this once.
+
+270
+
+6.27.1. BrowserComponent Hierarchy
+
+When  Codename  One  packages  applications  into  native  apps  it  hides  a  lot  of  details  to  make  the
+
+process simpler. One of the things hidden is the fact that we aren’t dealing with a JAR anymore, so
+getResource/getResourceAsStream  are  problematic…  Both  of  these  API’s  support  hierarchies  and  a
+concept of package relativity both of which might not be supported on all OS’s.
+
+Codename One has its own getResourceAsSteam in the Display [https://www.codenameone.com/javadoc/
+
+com/codename1/ui/Display.html] class and that works just fine, but it requires that all files be in the src
+
+root directory.
+
+
+
+That’s  why  we  recommend  that  you  place  files  inside  res  files.  A  resource  file
+
+allows you to add arbitrary data files and you can have as many resource files as
+
+you need.
+
+For  web  developers  this  isn’t  enough  since  hierarchies  are  used  often  to  represent  the  various
+
+dependencies, this means that many links & references are relative. To work with such hierarchies
+
+just  place  all  of  your  resources  in  a  hierarchy  under  the  html  package  in  the  project  source
+directory  (src/html).  The  build  server  will  tar  the  entire  content  of  that  package  and  add  an
+html.tar  file  into  the  native  package.  This  tar  is  seamlessly  extracted  on  the  device  when  you
+actually  need  the  resources  and  only  with  new  application  versions  (not  on  every  launch).  So
+
+assuming the resources are under the html root package they can be displayed with code like this:
+
+try {
+    browserComponent.setURLHierarchy("/htmlFile.html");
+} catch(IOException err) {
+    ...
+}
+
+Notice that the path is relative to the html directory and starts with / but inside the HTML files you
+should use relative (not absolute) paths.
+
+Also  notice  that  an  IOException  can  be  thrown  due  to  the  process  of  untarring.  Its  unlikely  to
+happen but is entirely possible.
+
+6.27.2. NavigationCallback
+
+At 
+
+the 
+
+core 
+
+of 
+
+the 
+
+BrowserComponent  we 
+
+have 
+
+the  BrowserNavigationCallback
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/events/BrowserNavigationCallback.html]. It might not
+
+seem  like  the  most  important  interface  within  the  browser  but  it  is  the  "glue"  that  allows  the
+
+JavaScript code to communicate back into the Java layer.
+
+You  can  bind  a  BrowserNavigationCallback  by  invoking  setBrowserNavigationCallback  on  the
+BrowserComponent.  At  that  point  with  every  navigation  within  the  browser  the  callback  will  get
+invoked.
+
+271
+
+
+
+The  shouldNavigate  method  from  the  BrowserNavigationCallback  is  invoked  in  a
+native thread and NOT ON THE EDT!
+
+It is crucial that this method returns immediately and that it won’t do any changes
+
+on the UI.
+
+The shouldNavigate indicates to the native code whether navigation should proceed or not. E.g. if a
+user clicks a specific link we might choose to do something in the Java code so we can just return
+
+false  and  block  the  navigation.  We  can  invoke  callSerially  [https://www.codenameone.com/javadoc/com/
+
+codename1/ui/Display.html#callSerially-java.lang.Runnable-] to do the actual task in the Java side.
+
+Form hi = new Form("BrowserComponent", new BorderLayout());
+BrowserComponent bc = new BrowserComponent();
+bc.setPage( "<html lang=\"en\">\n" +
+            "    <head>\n" +
+            "        <meta charset=\"utf-8\">\n" +
+            "        <script>\n" +
+            "          function  fnc(message) {\n" +
+            "         document.write(message);\n" +
+            "            };\n" +
+            "        </script>\n" +
+            "    </head>\n" +
+            "    <body >\n" +
+            "        <p><a href=\"http://click\">Demo</a></p>\n" +
+            "    </body>\n" +
+            "</html>", null);
+hi.add(BorderLayout.CENTER, bc);
+bc.setBrowserNavigationCallback((url) -> {
+    if(url.startsWith("http://click")) {
+        Display.getInstance().callSerially(() -> bc.execute("fnc('<p>You clicked!</p>')"));
+        return false;
+    }
+    return true;
+});
+
+Figure 261. Before the link is clicked for the "shouldNavigate" call
+
+Figure 262. After the link is clicked for the "shouldNavigate" call
+
+ The JavaScript Bridge is implemented on top of the BrowserNavigationCallback.
+
+6.27.3. JavaScript
+
+272
+
+
+
+The  JavaScript  bridge  is  sometimes  confused  with  the  JavaScript  Port.  The
+
+JavaScript  bridge  allows  us  to  communicate  with  JavaScript  from  Java  (and  visa
+
+versa).  The  JavaScript  port  allows  you  to  compile  the  Codename  One  application
+
+into  a  JavaScript  application  that  runs  in  a  standard  web  browser  without  code
+
+changes  (think  GWT  without  source  changes  and  with  thread  support).+  We
+
+discuss the JavaScript port further later in the guide.
+
+Codename One 4.0 introduced a new API for interacting with Javascript in Codename One. This API
+is part of the BrowserComponent class, and effectively replaces the com.codename1.javascript package
+is  now
+[https://www.codenameone.com/javadoc/com/codename1/javascript/package-summary.html],  which 
+
+deprecated.
+
+So what was wrong with the old API?
+
+The  old  API  provided  a  synchronous  wrapper  around  an  inherently  asynchronous  process,  and
+made  extensive  use  of  invokeAndBlock()  underneath  the  covers.  This  resulted  in  a  very  nice  API
+with  high-level  abstractions  that  played  nicely  with  a  synchronous  programming  model,  but  it
+
+came  with  a  price-tag  in  terms  of  performance,  complexity,  and  predictability.  Let’s  take  a  simple
+
+example, getting a reference to the “window” object:
+
+JSObject window = ctx.get("window");
+
+This  code  looks  harmless  enough,  but  this  is  actually  quite  expensive.  It  issues  a  command  to  the
+BrowserComponent, and uses invokeAndBlock() to wait for the command to go through and send back
+a response. invokeAndBlock() is a magical tool that allows you to “block” without blocking the EDT,
+but  it  has  its  costs,  and  shouldn’t  be  overused.  Most  of  the  Codename  One  APIs  that  use
+invokeAndBlock() indicate this in their name. E.g. Component.animateLayoutAndWait(). This gives you
+the expectation that this call could take some time, and helps to alert you to the underlying cost.
+
+The  problem  with  the  ctx.get("window")  call  is  that  it  looks  the  same  as  a  call  to  Map.get(key).
+There’s no indication that this call is expensive and could take time. One call like this probably isn’t
+
+a big deal, but it doesn’t take long before you have dozens or even hundreds of calls like this littered
+
+throughout your codebase, and they can be hard to pick out.
+
+The New API
+
+The  new  API  fully  embraces  the  asynchronous  nature  of  Javascript.  It  uses  callbacks  instead  of
+
+return  values,  and  provides  convenience  wrappers  with  the  appropriate  “AndWait()”  naming
+
+convention to allow for synchronous usage. Let’s look at a simple example:
+
+
+
+In all of the sample code below, you can assume that variables named bc represent
+[https://www.codenameone.com/javadoc/com/
+an 
+
+instance  of  BrowserComponent 
+
+codename1/ui/BrowserComponent.html].
+
+273
+
+bc.execute(
+    "callback.onSuccess(3+4)",
+    res -> Log.p("The result was "+res.getInt())
+);
+
+This  code  should  output  “The  result  was  7”  to  the  console.  It  is  fully  asynchronous,  so  you  can
+
+include  this  code  anywhere  without  worrying  about  it  “bogging  down”  your  code.  The  full
+
+signature  of  this  form  of  the  execute()  [https://www.codenameone.com/javadoc/com/codename1/ui/
+
+BrowserComponent.html#execute-java.lang.String-com.codename1.util.SuccessCallback-] method is:
+
+public void execute(String js, SuccessCallback<JSRef> callback)
+
+The  first  parameter 
+javascript  MUST  call  either
+callback.onSuccess(result) or callback.onError(message, errCode) at some point in order for your
+callback to be called.
+
+javascript  expression.  This 
+
+just  a 
+
+is 
+
+The  second  parameter  is  your  callback  that  is  executed  from  the  javascript  side,  when
+callback.onSuccess(res) 
+[https://www.codenameone.com/javadoc/com/codename1/ui/BrowserComponent.JSRef.html]  which  is  a  generic
+
+is  called.  The  callback  takes  a  single  parameter  of  type  JSRef
+
+wrapper  around  a  javascript  variable.  JSRef  has  accessors  to  retrieve  the  value  as  some  of  the
+primitive  types.  E.g.  getBoolean(),  getDouble(),  getInt(),  toString(),  and  it  provides  some
+introspection via the getType() method.
+
+
+
+It is worth noting that the callback method can only take a single parameter. If you
+
+need  to  pass  multiple  parameters,  you  may  consider  including  them  in  a  single
+
+string which you parse in your callback.
+
+Synchronous Wrappers
+
+As  mentioned  before,  the  new  API  also  provides  an  executeAndWait()  wrapper  for  execute()  that
+will work synchronously. It, as its name suggests, uses invokeAndBlock under the hood so as not to
+block the EDT while it is waiting.
+
+E.g.
+
+JSRef res = bc.executeAndWait("callback.onSuccess(3+4)");
+Log.p("The result was "+res.Int());
+
+Prints “The result was 7”.
+
+
+
+When using the andWait() variant, it is extremely important that your Javascript
+calls your callback method at some point - otherwise it will block indefinitely. We
+
+provide  variants  of  executeAndWait()  that  include  a  timeout  in  case  you  want  to
+
+hedge against this possibility.
+
+274
+
+Multi-use Callbacks
+
+The  callbacks  you  pass  to  execute()  and  executeAndWait()  are  single-use  callbacks.  You  can’t,  for
+example, store the callback variable on the javascript side for later use (e.g. to respond to a button
+click event). If you need a “multi-use” callback, you should use the addJSCallback() method instead.
+Its usage looks identical to execute(), the only difference is that the callback will life on after its first
+use. E.g. Consider the following code:
+
+bc.execute(
+    "$('#somebutton').click(function(){callback.onSuccess('Button was clicked')})",
+    res -> Log.p(res.toString())
+);
+
+The above example, assumes that jQuery is loaded in the webpage that we are interacting with, and
+
+we  are  adding  a  click  handler  to  a  button  with  ID  “somebutton”.  The  click  handler  calls  our
+
+callback.
+
+If you run this example, the first time the button is clicked, you’ll see “Button was clicked” printed
+
+to the console as expected. However, the 2nd time, you’ll just get an exception. This is because the
+callback passed to execute() is only single-use.
+
+We need to modify this code to use the addJSCallback() method as follows:
+
+bc.addJSCallback(
+    "$('#somebutton').click(function(){callback.onSuccess('Button was clicked')})",
+    res -> Log.p(res.toString())
+);
+
+Now it will work no matter how many times the button is clicked.
+
+Passing Parameters to Javascript
+
+In many cases, the javascript expressions that you execute will include parameters from your java
+
+code.  Properly  escaping  these  parameters  is  tricky  at  worst,  and  annoying  at  best.  E.g.  If  you’re
+
+passing  a  string,  you  need  to  make  sure  that  it  escapes  quotes  and  new  lines  properly  or  it  will
+cause  the  javascript  to  have  a  syntax  error.  Luckily  we  provide  variants  of  execute()  and
+[https://www.codenameone.com/javadoc/com/codename1/ui/BrowserComponent.html#
+addJSCallback() 
+
+addJSCallback-java.lang.String-com.codename1.util.SuccessCallback-] that allow you to pass your parameters
+
+and have them automatically escaped.
+
+For example, suppose we want to pass a string with text to set in a textarea within the webpage. We
+
+can do something like:
+
+275
+
+bc.execute(
+    "jQuery('#bio').text(${0}); jQuery('#age').text(${1})",
+    new Object[]{
+       "A multi-line\n string with \"quotes\"",
+       27
+    }
+);
+
+The  gist  is  that  you  embed  placeholders  in  the  javascript  expression  that  are  replaced  by  the
+corresponding entry in an array of parameters. The ${0} placeholder is replaced by the first item in
+the parameters array, the ${1} placeholder is replaced by the 2nd, and so on.
+
+Proxy Objects
+
+The  new  API  also 
+
+includes  a 
+
+JSProxy 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/
+
+BrowserComponent.JSProxy.html]  class  that  encapsulates  a  Javascript  object  simplify  the  getting  and
+
+setting of properties on Javascript objects - and the calling of their methods. It provides essentially
+
+three core methods, along with several variants of each to allow for async or synchronous usages,
+
+parameters, and timeouts.
+
+E.g.  We  might  want  to  create  a  proxy  for  the  window.location  [https://developer.mozilla.org/en-US/docs/
+
+Web/API/Window/location] object so that we can access its properties more easily from Java.
+
+JSProxy location = bc.createJSProxy("window.location");
+
+Then we can retrieve its properties using the get() method:
+
+location.get("href", res -> Log.p("location.href="+res));
+
+Or synchronously:
+
+JSRef href = location.getAndWait("href");
+Log.p("location.href="+href);
+
+We can also set its properties:
+
+location.set("href", "http://www.google.com");
+
+And call its methods:
+
+location.call("replace", new Object[]{"http://www.google.com"},
+    res -> Log.p("Return value was "+res)
+);
+
+276
+
+Legacy JSObject Support
+
+This section describes the now deprecated JSObject approach. It’s here for reference by developers
+working with older code. We suggest using the new API when starting a new project.
+
+BrowserComponent  can  communicate  with  the  HTML  code  using  JavaScript  calls.  E.g.  we  can  create
+HTML like this:
+
+Form hi = new Form("BrowserComponent", new BorderLayout());
+BrowserComponent bc = new BrowserComponent();
+bc.setPage( "<html lang=\"en\">\n" +
+            "    <head>\n" +
+            "        <meta charset=\"utf-8\">\n" +
+            "        <script>\n" +
+            "          function  fnc(message) {\n" +
+            "         document.write(message);\n" +
+            "            };\n" +
+            "        </script>\n" +
+            "    </head>\n" +
+            "    <body >\n" +
+            "        <p>Demo</p>\n" +
+            "    </body>\n" +
+            "</html>", null);
+TextField tf = new TextField();
+hi.add(BorderLayout.CENTER, bc).
+        add(BorderLayout.SOUTH, tf);
+bc.addWebEventListener("onLoad", (e) ->  bc.execute("fnc('<p>Hello World</p>')"));
+tf.addActionListener((e) -> bc.execute("fnc('<p>" + tf.getText() +"</p>')"));
+hi.show();
+
+Figure 263. JavaScript code was invoked to append text into the browser image above
+
+ Notice that opening an alert in an embedded native browser might not work
+
+We  use  the  execute  method  above  to  execute  custom  JavaScript  code.  We  also  have  an
+executeAndReturnString method that allows us to receive a response value from the JavaScript side.
+
+Coupled with shouldNavigate we can effectively do everything which is exactly what the JavaScript
+Bridge tries to do.
+
+277
+
+The JavaScript Bridge
+
+While  it’s  possible  to  just  build  everything  on  top  of  execute  and  shouldNavigate,  both  of  these
+methods  have  their  limits.  That  is  why  we  introduced  the  javascript  package,  it  allows  you  to
+
+communicate with JavaScript using intuitive code/syntax.
+
+The 
+
+JavascriptContext 
+
+[https://www.codenameone.com/javadoc/com/codename1/javascript/
+
+JavascriptContext.html] class lays the foundation by enabling you to call JavaScript code directly from
+
+Java. It provides automatic type conversion between Java and JavaScript types as follows:
+
+Table 5. Java to JavaScript
+
+Java Type
+
+String
+
+Double/Integer/Float/Long
+
+Boolean
+
+JSObject
+
+null
+
+Other
+
+Table 6. JavaScript to Java
+
+Javascript Type
+
+String
+
+Number
+
+Boolean
+
+Object
+
+Function
+
+Array
+
+null
+
+undefined
+
+Javascript Type
+
+String
+
+Number
+
+Boolean
+
+Object
+
+null
+
+Not Allowed
+
+Java Type
+
+String
+
+Double
+
+Boolean
+
+JSObject
+
+JSObject
+
+JSObject
+
+null
+
+null
+
+This  conversion  table  is  more  verbose  than  necessary,  since  JavaScript  functions
+
+
+
+and  arrays  are,  in  fact  Objects  themselves,  so  those  rows  are  redundant.  All
+
+JavaScript  objects  are  converted  to  JSObject  [https://www.codenameone.com/javadoc/
+
+com/codename1/javascript/JSObject.html].
+
+We can access JavaScript variables easily from the context by using code like this:
+
+278
+
+Form hi = new Form("BrowserComponent", new BorderLayout());
+BrowserComponent bc = new BrowserComponent();
+bc.setPage( "<html lang=\"en\">\n" +
+            "    <head>\n" +
+            "        <meta charset=\"utf-8\">\n" +
+            "    </head>\n" +
+            "    <body >\n" +
+            "        <p>This will appear twice...</p>\n" +
+            "    </body>\n" +
+            "</html>", null);
+hi.add(BorderLayout.CENTER, bc);
+bc.addWebEventListener("onLoad", (e) -> {
+    // Create a Javascript context for this BrowserComponent
+    JavascriptContext ctx = new JavascriptContext(bc);
+
+    String pageContent = (String)ctx.get("document.body.innerHTML");
+    hi.add(BorderLayout.SOUTH, pageContent);
+    hi.revalidate();
+});
+hi.show();
+
+Figure 264. The contents was copied from the DOM and placed in the south position of the form
+
+Notice that when you work with numeric values or anything related to the types mentioned above
+your code must be aware of the typing. E.g. in this case the type is Double and not String:
+
+Double outerWidth = (Double)ctx.get("window.outerWidth");
+
+You can also query the context for objects and modify their value e.g.
+
+279
+
+Form hi = new Form("BrowserComponent", new BorderLayout());
+BrowserComponent bc = new BrowserComponent();
+bc.setPage( "<html lang=\"en\">\n" +
+            "    <head>\n" +
+            "        <meta charset=\"utf-8\">\n" +
+            "    </head>\n" +
+            "    <body >\n" +
+            "        <p>Please Wait...</p>\n" +
+            "    </body>\n" +
+            "</html>", null);
+hi.add(BorderLayout.CENTER, bc);
+bc.addWebEventListener("onLoad", (e) -> {
+    // Create a Javascript context for this BrowserComponent
+    JavascriptContext ctx = new JavascriptContext(bc);
+
+    JSObject jo = (JSObject)ctx.get("window");
+    jo.set("location", "https://www.codenameone.com/");
+});
+
+This  code  effectively  navigates  to  the  Codename  One  home  page  by  fetching  the  DOM’s  window
+
+object 
+
+and 
+
+setting 
+
+its 
+
+location 
+
+property 
+
+to 
+
+https://www.codenameone.com/
+
+[https://www.codenameone.com/].
+
+6.27.4. Cordova/PhoneGap Integration
+
+PhoneGap was one of the first web app packager tools in the market. It’s a tool that is effectively a
+
+browser component within a native wrapper coupled with native access API’s. Cordova is the open
+
+source extension of this popular project.
+
+Codename  One  supports  embedding  PhoneGap/Cordova  applications  directly  into  Codename  One
+applications. This is relatively easy to do with the BrowserComponent and JavaScript integration. The
+main aspect that this integration requires is support for Cordova plugins & its JavaScript API’s.
+
+The  effort  to  integrate  Cordova/PhoneGap  support  into  Codename  One  is  handled  within  an  open
+
+source  github  project  here  [https://github.com/codenameone/CN1Cordova].  The  chief  benefits  of  picking
+
+Codename One rather than using Cordova directly are:
+
+• Build Cloud
+
+• Better Native Code Support
+
+• Better Protection Of IP
+
+• IDE Integration Java - JavaScript - HTML
+
+• Easy, Doesn’t Require A Mac, Automates Certificates/Signing
+
+• Migration To Java
+
+This  is  discussed  further  in  the  original  announcement  [https://www.codenameone.com/blog/phonegap-
+
+cordova-compatibility-for-codename-one.html].
+
+280
+
+6.28. AutoCompleteTextField
+
+The 
+
+AutoCompleteTextField 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/
+
+AutoCompleteTextField.html] allows us to write text into a text field and select a completion entry from
+
+the list in a similar way to a search engine.
+
+This  is  really  easy  to  incorporate  into  your  code,  just  replace  your  usage  of  TextField
+[https://www.codenameone.com/javadoc/com/codename1/ui/TextField.html]  with  AutoCompleteTextField  and
+define  the  data  that  the  autocomplete  should  work  from.  There  is  a  default  implementation  that
+accepts  a  String  array  or  a  ListModel  [https://www.codenameone.com/javadoc/com/codename1/ui/list/
+ListModel.html]  for  completion  strings,  this  can  work  well  for  a  "small"  set  of  thousands  (or  tens  of
+
+thousands) of entries.
+
+E.g. This is a trivial use case that can work well for smaller sample sizes:
+
+Form hi = new Form("Auto Complete", new BoxLayout(BoxLayout.Y_AXIS));
+AutoCompleteTextField ac = new AutoCompleteTextField("Short", "Shock", "Sholder", "Shrek");
+ac.setMinimumElementsShownInPopup(5);
+hi.add(ac);
+
+Figure 265. Autocomplete Text Field
+
+However,  if  you  wish  to  query  a  database  or  a  web  service  you  will  need  to  derive  the  class  and
+perform more advanced filtering by overriding the filter method:
+
+281
+
+public void showForm() {
+  final DefaultListModel<String> options = new DefaultListModel<>();
+  AutoCompleteTextField ac = new AutoCompleteTextField(options) {
+      @Override
+      protected boolean filter(String text) {
+          if(text.length() == 0) {
+              return false;
+          }
+          String[] l = searchLocations(text);
+          if(l == null || l.length == 0) {
+              return false;
+          }
+
+          options.removeAll();
+          for(String s : l) {
+              options.addItem(s);
+          }
+          return true;
+      }
+
+  };
+  ac.setMinimumElementsShownInPopup(5);
+  hi.add(ac);
+  hi.add(new SpanLabel("This demo requires a valid google API key to be set below "
+           + "you can get this key for the webservice (not the native key) by following the instructions here: "
+           + "https://developers.google.com/places/web-service/get-api-key"));
+  hi.add(apiKey);
+  hi.getToolbar().addCommandToRightBar("Get Key", null, e ->
+Display.getInstance().execute("https://developers.google.com/places/web-service/get-api-key"));
+  hi.show();
+}
+
+TextField apiKey = new TextField();
+
+String[] searchLocations(String text) {
+    try {
+        if(text.length() > 0) {
+            ConnectionRequest r = new ConnectionRequest();
+            r.setPost(false);
+            r.setUrl("https://maps.googleapis.com/maps/api/place/autocomplete/json");
+            r.addArgument("key", apiKey.getText());
+            r.addArgument("input", text);
+            NetworkManager.getInstance().addToQueueAndWait(r);
+            Map<String,Object> result = new JSONParser().parseJSON(new InputStreamReader(new
+ByteArrayInputStream(r.getResponseData()), "UTF-8"));
+            String[] res = Result.fromContent(result).getAsStringArray("//description");
+            return res;
+        }
+    } catch(Exception err) {
+        Log.e(err);
+    }
+    return null;
+}
+
+Figure 266. Autocomplete Text Field with a webservice
+
+282
+
+6.28.1. Using Images In AutoCompleteTextField
+
+One question I got a few times is "How do you customize the results of the auto complete field"?
+
+This  sounds  difficult  to  most  people  as  we  can  only  work  with  Strings  so  how  do  we  represent
+
+additional data or format the date correctly?
+
+The  answer  is  actually  pretty  simple,  we  still  need  to  work  with  Strings  because  auto-complete  is
+
+first and foremost a text field. However, that doesn’t preclude our custom renderer from fetching
+
+data that might be placed in a different location and associated with the result.
+
+The  following  source  code  presents  an  auto-complete  text  field  with  images  in  the  completion
+
+popup and two lines for every entry:
+
+283
+
+final String[] characters = { "Tyrion Lannister", "Jaime Lannister", "Cersei Lannister", "Daenerys Targaryen",
+    "Jon Snow", "Petyr Baelish", "Jorah Mormont", "Sansa Stark", "Arya Stark", "Theon Greyjoy"
+    // snipped the rest for clarity
+};
+
+Form current = new Form("AutoComplete", BoxLayout.y());
+
+AutoCompleteTextField ac = new AutoCompleteTextField(characters);
+
+final int size = Display.getInstance().convertToPixels(7);
+final EncodedImage placeholder = EncodedImage.createFromImage(Image.createImage(size, size, 0xffcccccc), true);
+
+final String[] actors = { "Peter Dinklage", "Nikolaj Coster-Waldau", "Lena Headey"}; ①
+final Image[] pictures = {
+    URLImage.createToStorage(placeholder, "tyrion","http://i.lv3.hbo.com/assets/images/series/game-of-
+thrones/character/s5/tyrion-lannister-512x512.jpg"),
+    URLImage.createToStorage(placeholder, "jaime","http://i.lv3.hbo.com/assets/images/series/game-of-
+thrones/character/s5/jamie-lannister-512x512.jpg"),
+    URLImage.createToStorage(placeholder, "cersei","http://i.lv3.hbo.com/assets/images/series/game-of-
+thrones/character/s5/cersei-lannister-512x512.jpg")
+};
+
+ac.setCompletionRenderer(new ListCellRenderer() {
+    private final Label focus = new Label(); ②
+    private final Label line1 = new Label(characters[0]);
+    private final Label line2 = new Label(actors[0]);
+    private final Label icon = new Label(pictures[0]);
+    private final Container selection = BorderLayout.center(
+            BoxLayout.encloseY(line1, line2)).add(BorderLayout.EAST, icon);
+
+    @Override
+    public Component getListCellRendererComponent(com.codename1.ui.List list, Object value, int index, boolean
+isSelected) {
+        for(int iter = 0 ; iter < characters.length ; iter++) {
+            if(characters[iter].equals(value)) {
+                line1.setText(characters[iter]);
+                if(actors.length > iter) {
+                    line2.setText(actors[iter]);
+                    icon.setIcon(pictures[iter]);
+                } else {
+                    line2.setText(""); ③
+                    icon.setIcon(placeholder);
+                }
+                break;
+            }
+        }
+        return selection;
+    }
+
+    @Override
+    public Component getListFocusComponent(com.codename1.ui.List list) {
+        return focus;
+    }
+});
+current.add(ac);
+
+current.show();
+
+① We have duplicate arrays that are only partial for clarity. This is a separate list of data element
+
+but you can fetch the additional data from anywhere
+
+② We create the renderer UI instantly in the fields with the helper methods for wrapping elements
+
+which is pretty cool & terse
+
+284
+
+③ In a renderer it’s important to always set the value especially if you don’t have a value in place
+
+Figure 267. Auto complete with images
+
+6.29. Picker
+
+Picker  [https://www.codenameone.com/javadoc/com/codename1/ui/spinner/Picker.html]  occupies  the  limbo
+between native widget and lightweight widget. Picker is more like TextField/TextArea in the sense
+that it’s a Codename One widget that calls the native code only during editing.
+
+The  reasoning  for  this  is  the  highly  native  UX  and  functionality  related  to  this  widget  type  which
+
+should be quite obvious from the screenshots below.
+
+At this time there are 4 types of pickers:
+
+• Time
+
+• Date & Time
+
+• Date
+
+• Strings
+
+If a platform doesn’t support native pickers an internal fallback implementation is used. This is the
+
+implementation we always use in the simulator so assume different behavior when building for the
+
+device.
+
+
+
+While  Android  supports  Date,  Time  native  pickers  it  doesn’t  support  the  Date  &
+
+Time native picker UX and will fallback in that case.
+
+The sample below includes al picker types:
+
+285
+
+Form hi = new Form("Picker", new BoxLayout(BoxLayout.Y_AXIS));
+Picker datePicker = new Picker();
+datePicker.setType(Display.PICKER_TYPE_DATE);
+Picker dateTimePicker = new Picker();
+dateTimePicker.setType(Display.PICKER_TYPE_DATE_AND_TIME);
+Picker timePicker = new Picker();
+timePicker.setType(Display.PICKER_TYPE_TIME);
+Picker stringPicker = new Picker();
+stringPicker.setType(Display.PICKER_TYPE_STRINGS);
+Picker durationPicker = new Picker();
+durationPicker.setType(Display.PICKER_TYPE_DURATION);
+Picker minuteDurationPicker = new Picker();
+minuteDurationPicker.setType(Display.PICKER_TYPE_DURATION_MINUTES);
+Picker hourDurationPicker = new Picker();
+hourDurationPicker.setType(Display.PICKER_TYPE_DURATION_HOURS);
+
+datePicker.setDate(new Date());
+dateTimePicker.setDate(new Date());
+timePicker.setTime(10 * 60); // 10:00AM = Minutes since midnight
+stringPicker.setStrings("A Game of Thrones", "A Clash Of Kings", "A Storm Of Swords", "A Feast For Crows",
+        "A Dance With Dragons", "The Winds of Winter", "A Dream of Spring");
+stringPicker.setSelectedString("A Game of Thrones");
+
+hi.add(datePicker).add(dateTimePicker).add(timePicker)
+  .add(stringPicker).add(durationPicker)
+  .add(minuteDurationPicker).add(hourDurationPicker);
+hi.show();
+
+Figure 268. The various picker components
+
+Figure 269. The date & time picker on the simulator
+
+286
+
+Figure 270. The date picker component on the Android device
+
+Figure 271. Date & time picker on Android. Notice it didn’t use a builtin widget since there is none
+
+Figure 272. String picker on the native Android device
+
+287
+
+Figure 273. Time picker on the Android device
+
+Figure 274. Duration picker on Android device
+
+Figure 275. Hours Duration picker on Android device
+
+Figure 276. Minutes Duration picker on Android device
+
+The  text  displayed  by  the  picker  on  selection  is  generated  automatically  by  the  updateValue()
+method. You can override it to display a custom formatted value and call setText(String) with the
+correct display string.
+
+A common use case is to format date values based on a specific appearance and Picker has builtin
+support for a custom display formatter. Just use the setFormatter(SimpleDateFormat) method and set
+the appearance for the field.
+
+288
+
+6.30. SwipeableContainer
+
+The  SwipeableContainer  [https://www.codenameone.com/javadoc/com/codename1/ui/SwipeableContainer.html]
+
+allows  us  to  place  a  component  such  as  a  MultiButton  [https://www.codenameone.com/javadoc/com/
+
+codename1/components/MultiButton.html] on top of additional "options" that can be exposed by swiping
+
+the component to the side.
+
+This swipe gesture is commonly used in touch interfaces to expose features such as delete, edit etc.
+
+It’s trivial to use this component by just determining the components placed on top and bottom (the
+
+revealed component).
+
+SwipeableContainer swip = new SwipeableContainer(bottom, top);
+
+We can combine some of the demos above including the Slider stars demo to rank GRRM’s books in
+
+an interactive way:
+
+Form hi = new Form("Swipe", new BoxLayout(BoxLayout.Y_AXIS));
+hi.add(createRankWidget("A Game of Thrones", "1996")).
+    add(createRankWidget("A Clash Of Kings", "1998")).
+    add(createRankWidget("A Storm Of Swords", "2000")).
+    add(createRankWidget("A Feast For Crows", "2005")).
+    add(createRankWidget("A Dance With Dragons", "2011")).
+    add(createRankWidget("The Winds of Winter", "TBD")).
+    add(createRankWidget("A Dream of Spring", "TBD"));
+hi.show();
+
+public SwipeableContainer createRankWidget(String title, String year) {
+    MultiButton button = new MultiButton(title);
+    button.setTextLine2(year);
+    return new SwipeableContainer(FlowLayout.encloseCenterMiddle(createStarRankSlider()),
+            button);
+}
+
+Figure 277. SwipableContainer showing a common use case of ranking on swipe
+
+289
+
+6.31. EmbeddedContainer
+
+EmbeddedContainer  [https://www.codenameone.com/javadoc/com/codename1/ui/util/EmbeddedContainer.html]
+
+solves a problem that exists only within the GUI builder and the class makes no sense outside of the
+context of the GUI builder. The necessity for EmbeddedContainer came about due to iPhone inspired
+designs that relied on tabs (iPhone style tabs at the bottom of the screen) where different features
+
+of the application are within a different tab.
+
+This didn’t mesh well with the GUI builder navigation logic and so we needed to rethink some of it.
+
+We wanted to reuse GUI as much as possible while still enjoying the advantage of navigation being
+
+completely managed for me.
+
+Android does this with Activities and the iPhone itself has a view controller, both approaches are
+
+problematic for Codename One. The problem is that you have what is effectively two incompatible
+
+hierarchies to mix and match.
+
+The  Component/Container  hierarchy  is  powerful  enough  to  represent  such  a  UI  but  we  needed  a
+
+"marker"  to  indicate  to  the  UIBuilder  [https://www.codenameone.com/javadoc/com/codename1/ui/util/
+
+UIBuilder.html]  where  a  "root"  component  exists  so  navigation  occurs  only  within  the  given  "root".
+Here  EmbeddedContainer  comes  into  play,  its  a  simple  container  that  can  only  contain  another  GUI
+from the GUI builder. Nothing else. So we can place it in any form of UI and effectively have the UI
+
+change appropriately and navigation would default to "sensible values".
+
+Navigation replaces the content of the embedded container; it finds the embedded container based
+
+on  the  component  that  broadcast  the  event.  If  you  want  to  navigate  manually  just  use  the
+
+showContainer()  method  which  accepts  a  component,  you  can  give  any  component  that  is  under
+the EmbeddedContainer you want to replace and Codename One will be smart enough to replace only
+that component.
+
+The nice part about using the EmbeddedContainer is that the resulting UI can be very easily refactored
+to provide a more traditional form based UI without duplicating effort and can be easily adapted to
+
+a more tablet oriented UI (with a side bar) again without much effort.
+
+6.32. MapComponent
+
+The  MapComponent  uses  a  somewhat  outdated  tiling  API  which  is  not  as  rich  as
+
+
+
+modern  native  maps.  We  recommend  using  the  GoogleMap’s  Native  cn1lib
+
+[https://github.com/codenameone/codenameone-google-maps/]  to  integrate  native  mapping
+
+functionality into the Codename One app.
+
+The  MapComponent  [https://www.codenameone.com/javadoc/com/codename1/maps/MapComponent.html]  uses
+
+the OpenStreetMap webservice by default to display a navigatable map.
+
+The code was contributed by Roman Kamyk and was originally used for a LWUIT application.
+
+290
+
+Figure 278. Map Component
+
+The screenshot above was produced using the following code:
+
+Form map = new Form("Map");
+map.setLayout(new BorderLayout());
+map.setScrollable(false);
+final MapComponent mc = new MapComponent();
+
+try {
+   //get the current location from the Location API
+   Location loc = LocationManager.getLocationManager().getCurrentLocation();
+
+  Coord lastLocation = new Coord(loc.getLatitude(), loc.getLongtitude());
+   Image i = Image.createImage("/blue_pin.png");
+   PointsLayer pl = new PointsLayer();
+   pl.setPointIcon(i);
+   PointLayer p = new PointLayer(lastLocation, "You Are Here", i);
+   p.setDisplayName(true);
+   pl.addPoint(p);
+   mc.addLayer(pl);
+} catch (IOException ex) {
+   ex.printStackTrace();
+}
+mc.zoomToLayers();
+
+map.addComponent(BorderLayout.CENTER, mc);
+map.addCommand(new BackCommand());
+map.setBackCommand(new BackCommand());
+map.show();
+
+The example below shows how to integrate the MapComponent [https://www.codenameone.com/javadoc/
+
+com/codename1/maps/MapComponent.html] with the Google Location [https://www.codenameone.com/javadoc/
+
+com/codename1/location/Location.html]  API.  make  sure  to  obtain  your  secret  api  key  from  the  Google
+
+291
+
+Location 
+
+[https://www.codenameone.com/javadoc/com/codename1/location/Location.html]  data  API  at:
+
+https://developers.google.com/maps/documentation/places/
+
+Figure 279. MapComponent with Google Location API
+
+          final Form map = new Form("Map");
+           map.setLayout(new BorderLayout());
+           map.setScrollable(false);
+           final MapComponent mc = new MapComponent();
+           Location loc = LocationManager.getLocationManager().getCurrentLocation();
+           //use the code from above to show you on the map
+           putMeOnMap(mc);
+           map.addComponent(BorderLayout.CENTER, mc);
+           map.addCommand(new BackCommand());
+           map.setBackCommand(new BackCommand());
+
+           ConnectionRequest req = new ConnectionRequest() {
+
+               protected void readResponse(InputStream input) throws IOException {
+                   JSONParser p = new JSONParser();
+                   Hashtable h = p.parse(new InputStreamReader(input));
+                   // "status" : "REQUEST_DENIED"
+                   String response = (String)h.get("status");
+                   if(response.equals("REQUEST_DENIED")){
+                       System.out.println("make sure to obtain a key from "
+                               + "https://developers.google.com/maps/documentation/places/");
+                       progress.dispose();
+                       Dialog.show("Info", "make sure to obtain an application key from "
+                               + "google places api's"
+                               , "Ok", null);
+                       return;
+                   }
+
+                   final Vector v = (Vector) h.get("results");
+
+                   Image im = Image.createImage("/red_pin.png");
+                   PointsLayer pl = new PointsLayer();
+                   pl.setPointIcon(im);
+                   pl.addActionListener(new ActionListener() {
+
+                       public void actionPerformed(ActionEvent evt) {
+                           PointLayer p = (PointLayer) evt.getSource();
+                           System.out.println("pressed " + p);
+
+292
+
+                           Dialog.show("Details", "" + p.getName(), "Ok", null);
+                       }
+                   });
+
+                   for (int i = 0; i < v.size(); i++) {
+                       Hashtable entry = (Hashtable) v.elementAt(i);
+                       Hashtable geo = (Hashtable) entry.get("geometry");
+                       Hashtable loc = (Hashtable) geo.get("location");
+                       Double lat = (Double) loc.get("lat");
+                       Double lng = (Double) loc.get("lng");
+                       PointLayer point = new PointLayer(new Coord(lat.doubleValue(), lng.doubleValue()),
+                               (String) entry.get("name"), null);
+                       pl.addPoint(point);
+                   }
+                   progress.dispose();
+
+                   mc.addLayer(pl);
+                   map.show();
+                   mc.zoomToLayers();
+
+               }
+           };
+           req.setUrl("https://maps.googleapis.com/maps/api/place/search/json");
+           req.setPost(false);
+           req.addArgument("location", "" + loc.getLatitude() + "," + loc.getLongtitude());
+           req.addArgument("radius", "500");
+           req.addArgument("types", "food");
+           req.addArgument("sensor", "false");
+
+           //get your own key from https://developers.google.com/maps/documentation/places/
+           //and replace it here.
+           String key = "yourAPIKey";
+
+           req.addArgument("key", key);
+
+           NetworkManager.getInstance().addToQueue(req);
+       }
+       catch (IOException ex) {
+           ex.printStackTrace();
+       }
+   }
+
+6.33. Chart Component
+
+The  charts  package  enables  Codename  One  developers  to  add  charts  and  visualizations  to  their
+apps  without  having  to  include  external  libraries  or  embedding  web  views.  We  also  wanted  to
+
+harness the new features in the graphics pipeline to maximize performance.
+
+6.33.1. Device Support
+
+Since  the  charts  package  makes  use  of  2D  transformations  and  shapes,  it  requires  some  of  the
+
+graphics features that are not yet available on all platforms. Currently the following platforms are
+
+supported:
+
+293
+
+1. Simulator
+
+2. Android
+
+3. iOS
+
+6.33.2. Features
+
+1. Built-in support for many common types of charts including bar charts, line charts, stacked
+
+charts, scatter charts, pie charts and more.
+
+2. Pinch  Zoom  -  The  ChartComponent  [https://www.codenameone.com/javadoc/com/codename1/charts/
+
+ChartComponent.html] class includes optional pinch zoom support.
+
+3. Panning  Support  -  The  ChartComponent  [https://www.codenameone.com/javadoc/com/codename1/
+
+charts/ChartComponent.html] class includes optional support for panning.
+
+6.33.3. Chart Types
+
+The  com.codename1.charts  package  includes  models  and  renderers  for  many  different  types  of
+charts.  It  is  also  extensible  so  that  you  can  add  your  own  chart  types  if  required.  The  following
+
+screen shots demonstrate a small sampling of the types of charts that can be created.
+
+Figure 280. Line Charts
+
+Figure 281. Cubic Line Charts
+
+Figure 282. Bar Charts
+
+294
+
+Figure 283. Stacked Bar Charts
+
+Figure 284. Range Bar Charts
+
+Figure 285. Pie Charts
+
+Figure 286. Doughnut Charts
+
+Figure 287. Scatter Charts
+
+Figure 288. Dial Charts
+
+Figure 289. Combined Charts
+
+295
+
+Figure 290. Bubble Charts
+
+Figure 291. Time Charts
+
+
+
+The  above  screenshots  were  taken  from  the  ChartsDemo  app  [https://github.com/
+
+codenameone/codenameone-demos/tree/master/ChartsDemo].  You  can  start  playing  with
+
+this app by checking it out from our git repository.
+
+6.33.4. How to Create A Chart
+
+Adding a chart to your app involves four steps:
+
+1. Build the model. You can construct a model (aka data set) for the chart using one of the existing
+model classes in the com.codename1.charts.models package. Essentially, this is just where you add
+the data that you want to display.
+
+2. Set up a renderer. You can create a renderer for your chart using one of the existing renderer
+classes in the com.codename1.charts.renderers package. The renderer allows you to specify how
+the chart should look. E.g. the colors, fonts, styles, to use.
+
+3. Create  the  Chart  View.  Use  one  of  the  existing  view  classes  in  the  com.codename1.charts.views
+
+package.
+
+4. Create 
+
+a 
+
+ChartComponent 
+
+[https://www.codenameone.com/javadoc/com/codename1/charts/
+
+ChartComponent.html].  In  order  to  add  your  chart  to  the  UI,  you  need  to  wrap  it  in  a
+
+ChartComponent 
+
+[https://www.codenameone.com/javadoc/com/codename1/charts/ChartComponent.html]
+
+object.
+
+You  can  check  out  the  ChartsDemo  [https://github.com/codenameone/codenameone-demos/tree/master/
+
+ChartsDemo] app for specific examples, but here is a high level view of some code that creates a Pie
+
+Chart.
+
+/**
+ * Creates a renderer for the specified colors.
+ */
+private DefaultRenderer buildCategoryRenderer(int[] colors) {
+    DefaultRenderer renderer = new DefaultRenderer();
+    renderer.setLabelsTextSize(15);
+    renderer.setLegendTextSize(15);
+    renderer.setMargins(new int[]{20, 30, 15, 0});
+    for (int color : colors) {
+
+296
+
+        SimpleSeriesRenderer r = new SimpleSeriesRenderer();
+        r.setColor(color);
+        renderer.addSeriesRenderer(r);
+    }
+    return renderer;
+}
+
+/**
+ * Builds a category series using the provided values.
+ *
+ * @param titles the series titles
+ * @param values the values
+ * @return the category series
+ */
+protected CategorySeries buildCategoryDataset(String title, double[] values) {
+    CategorySeries series = new CategorySeries(title);
+    int k = 0;
+    for (double value : values) {
+        series.add("Project " + ++k, value);
+    }
+
+    return series;
+}
+
+public Form createPieChartForm() {
+
+    // Generate the values
+    double[] values = new double[]{12, 14, 11, 10, 19};
+
+    // Set up the renderer
+    int[] colors = new int[]{ColorUtil.BLUE, ColorUtil.GREEN, ColorUtil.MAGENTA, ColorUtil.YELLOW, ColorUtil.CYAN};
+    DefaultRenderer renderer = buildCategoryRenderer(colors);
+    renderer.setZoomButtonsVisible(true);
+    renderer.setZoomEnabled(true);
+    renderer.setChartTitleTextSize(20);
+    renderer.setDisplayValues(true);
+    renderer.setShowLabels(true);
+    SimpleSeriesRenderer r = renderer.getSeriesRendererAt(0);
+    r.setGradientEnabled(true);
+    r.setGradientStart(0, ColorUtil.BLUE);
+    r.setGradientStop(0, ColorUtil.GREEN);
+    r.setHighlighted(true);
+
+    // Create the chart ... pass the values and renderer to the chart object.
+    PieChart chart = new PieChart(buildCategoryDataset("Project budget", values), renderer);
+
+    // Wrap the chart in a Component so we can add it to a form
+    ChartComponent c = new ChartComponent(chart);
+
+    // Create a form and show it.
+    Form f = new Form("Budget");
+    f.setLayout(new BorderLayout());
+    f.addComponent(BorderLayout.CENTER, c);
+    return f;
+
+}
+
+6.34. Calendar
+
+The  Calendar  [https://www.codenameone.com/javadoc/com/codename1/ui/Calendar.html]  class  allows  us  to
+
+display a traditional calendar picker and optionally highlight days in various ways.
+
+297
+
+ We  normally  recommend  developers  use  the  Picker  UI  rather  than  use  the
+
+calendar to pick a date. It looks better on the devices.
+
+Simple usage of the Calendar class looks something like this:
+
+Form hi = new Form("Calendar", new BorderLayout());
+Calendar cld = new Calendar();
+cld.addActionListener((e) -> Log.p("You picked: " + new Date(cld.getSelectedDay())));
+hi.add(BorderLayout.CENTER, cld);
+
+Figure 292. The Calendar component
+
+6.35. ToastBar
+
+The ToastBar [https://www.codenameone.com/javadoc/com/codename1/components/ToastBar.html] class allows
+
+us to display none-obtrusive status messages to the user at the bottom of the screen. This is useful
+
+for  such  things  as  informing  the  user  of  a  long-running  task  (like  downloading  a  file  in  the
+
+background), or popping up an error message that doesn’t require a response from the user.
+
+Simple usage of the ToastBar class looks something like this:
+
+Status status = ToastBar.getInstance().createStatus();
+status.setMessage("Downloading your file...");
+status.show();
+
+//  ... Later on when download completes
+status.clear();
+
+298
+
+Figure 293. ToastBar with message
+
+We can show a progress indicator in the ToastBar like this:
+
+Status status = ToastBar.getInstance().createStatus();
+status.setMessage("Hello world");
+status.setShowProgressIndicator(true);
+status.show();
+
+Figure 294. Status Message with Progress Bar
+
+We can automatically clear a status message/progress after a timeout using the setExpires method
+as such:
+
+Status status = ToastBar.getInstance().createStatus();
+status.setMessage("Hello world");
+status.setExpires(3000);  // only show the status for 3 seconds, then have it automatically clear
+status.show();
+
+We can also delay the showing of the status message using showDelayed as such:
+
+299
+
+Status status = ToastBar.getInstance().createStatus();
+status.setMessage("Hello world");
+status.showDelayed(300); // Wait 300 ms to show the status
+
+// ... Some time later, clear the status... this may be before it shows at all
+status.clear();
+
+Figure 295. ToastBar with a multiline message
+
+6.35.1. Actions In ToastBar
+
+Probably  the  best  usage  example  for  actions  in  toast  is  in  the  gmail  style  undo.  If  you  are  not  a
+
+gmail user then the gmail app essentially never prompts for confirmation!
+
+It just does whatever you ask and pops a "toast message" with an option to undo. So if you clicked
+
+by mistake you have 3-4 seconds to take that back.
+
+This simple example shows you how you can undo any addition to the UI in a similar way to gmail:
+
+Form hi = new Form("Undo", BoxLayout.y());
+Button add = new Button("Add");
+
+add.addActionListener(e -> {
+    Label l = new Label("Added this");
+    hi.add(l);
+    hi.revalidate();
+    ToastBar.showMessage("Added, click here to undo...", FontImage.MATERIAL_UNDO,
+            ee -> {
+                l.remove();
+                hi.revalidate();
+            });
+});
+hi.add(add);
+hi.show();
+
+300
+
+6.36. SignatureComponent
+
+The 
+
+SignatureComponent 
+
+[https://www.codenameone.com/javadoc/com/codename1/components/
+
+SignatureComponent.html] provides a widget that allows users to draw their signature in the app.
+
+Simple usage of the SignatureComponent class looks like:
+
+Form hi = new Form("Signature Component");
+hi.setLayout(new BoxLayout(BoxLayout.Y_AXIS));
+hi.add("Enter Your Name:");
+hi.add(new TextField());
+hi.add("Signature:");
+SignatureComponent sig = new SignatureComponent();
+sig.addActionListener((evt)-> {
+    System.out.println("The signature was changed");
+    Image img = sig.getSignatureImage();
+    // Now we can do whatever we want with the image of this signature.
+});
+hi.addComponent(sig);
+hi.show();
+
+Figure 296. The signature Component
+
+6.37. Accordion
+
+The  Accordion  [https://www.codenameone.com/javadoc/com/codename1/components/Accordion.html]  displays
+
+collapsible content panels.
+
+Simple usage of the Accordion class looks like:
+
+301
+
+Form f = new Form("Accordion", new BoxLayout(BoxLayout.Y_AXIS));
+f.setScrollableY(true);
+Accordion accr = new Accordion();
+accr.addContent("Item1", new SpanLabel("The quick brown fox jumps over the lazy dog\n"
+        + "The quick brown fox jumps over the lazy dog"));
+accr.addContent("Item2", new SpanLabel("The quick brown fox jumps over the lazy dog\n"
+        + "The quick brown fox jumps over the lazy dog\n "
+        + "The quick brown fox jumps over the lazy dog\n "
+        + "The quick brown fox jumps over the lazy dog\n "
+        + ""));
+
+accr.addContent("Item3", BoxLayout.encloseY(new Label("Label"), new TextField(), new Button("Button"), new
+CheckBox("CheckBox")));
+
+f.add(accr);
+f.show();
+
+Figure 297. The Accordion Component
+
+6.38. Floating Hint
+
+FloatingHint  [https://www.codenameone.com/javadoc/com/codename1/components/FloatingHint.html]  wraps  a
+
+text component with a special container that can animate the hint label into a title label when the
+
+text component is edited or has content within it.
+
+302
+
+Form hi = new Form("Floating Hint", BoxLayout.y());
+TextField first = new TextField("", "First Field");
+TextField second = new TextField("", "Second Field");
+hi.add(new FloatingHint(first)).
+        add(new FloatingHint(second)).
+        add(new Button("Go"));
+hi.show();
+
+Figure 298. The FloatingHint component with one component that contains text and another that doesn’t
+
+6.39. Floating Button
+
+The material design floating action button is a powerful tool for promoting an action within your
+
+application.
+
+FloatingActionButton 
+
+[https://www.codenameone.com/javadoc/com/codename1/components/
+
+FloatingActionButton.html] is a round button that resides on top of the UI typically in the bottom right
+
+hand side.
+
+It  has  a  drop  shadow  to  distinguish  it  from  the  UI  underneath  and  it  can  hide  two  or  more
+
+additional actions under the surface. E.g. we can create a simple single click button such as this:
+
+FloatingActionButton fab = FloatingActionButton.createFAB(FontImage.MATERIAL_ADD);
+fab.addActionListener(e -> ToastBar.showErrorMessage("Not implemented yet..."));
+fab.bindFabToContainer(form.getContentPane());
+
+Which will place a + sign button that will perform the action. Alternatively we can create a nested
+action where a click on the button will produce a submenu for users to pick from e.g.:
+
+FloatingActionButton fab = FloatingActionButton.createFAB(FontImage.MATERIAL_ADD);
+fab.createSubFAB(FontImage.MATERIAL_PEOPLE, "");
+fab.createSubFAB(FontImage.MATERIAL_IMPORT_CONTACTS, "");
+fab.bindFabToContainer(form.getContentPane());
+
+Figure 299. FloatingActionButton with submenu expanded
+
+Those  familiar  with  this  widget  know  that  there  are  many  nuances  to  this  UI  that  we  might
+
+303
+
+implement/expose in the future. At the moment we chose to keep the API simple and minimal for
+
+the common use cases and refine it based on feedback.
+
+6.39.1. Using Floating Button as a Badge
+
+Floating  buttons  can  also  be  used  to  badge  an  arbitrary  component  in  the  style  popularized  by
+
+iOS/Mac OS. A badge appears at the top right corner and includes special numeric details such as
+
+"unread count"..
+
+The code below adds a simple badge to an icon button:
+
+Form hi = new Form("Badge");
+
+Button chat = new Button("");
+FontImage.setMaterialIcon(chat, FontImage.MATERIAL_CHAT, 7);
+
+FloatingActionButton badge = FloatingActionButton.createBadge("33");
+hi.add(badge.bindFabToContainer(chat, Component.RIGHT, Component.TOP));
+
+TextField changeBadgeValue = new TextField("33");
+changeBadgeValue.addDataChangedListener((i, ii) -> {
+    badge.setText(changeBadgeValue.getText());
+    badge.getParent().revalidate();
+});
+hi.add(changeBadgeValue);
+
+hi.show();
+
+The code above results in this, notice you can type into the text field to change the badge value:
+
+Figure 300. Badge floating button in action
+
+6.40. SplitPane
+
+The split pane component is a bit desktop specific but works reasonably well on devices. To get the
+image below we changed SalesDemo.java in the kitchen sink by changing this:
+
+304
+
+private Container encloseInMaximizableGrid(Component cmp1, Component cmp2) {
+    GridLayout gl = new GridLayout(2, 1);
+    Container grid = new Container(gl);
+    gl.setHideZeroSized(true);
+
+    grid.add(encloseInMaximize(grid, cmp1)).
+            add(encloseInMaximize(grid, cmp2));
+    return grid;
+}
+
+To:
+
+private Container encloseInMaximizableGrid(Component cmp1, Component cmp2) {
+    return new SplitPane(SplitPane.VERTICAL_SPLIT, cmp1, cmp2, "25%", "50%", "75%");
+}
+
+Figure 301. Split Pane in the Kitchen Sink Demo
+
+This is mostly self explanatory but only "mostly". We have 5 arguments the first 3 make sense:
+
+• Split orientation
+
+• Components to split
+
+The last 3 arguments seem weird but they also make sense once you understand them, they are:
+
+• The minimum position of the split - 1/4 of available space
+
+• The default position of the split - middle of the screen
+
+• The maximum position of the split - 3/4 of available space
+
+The units don’t have to be percentages they can be mm (millimeters) or px (pixels).
+
+[2] String width is the real expensive part here, the complexity of font kerning and the recursion required to reflow text is a big
+
+305
+
+performance hurdle
+
+[3] Image by RegisFrey - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=10298177
+
+[4] Fisheye is an effect where the selection stays in place as the list moves around it
+
+[5] Image was fetched from http://awoiaf.westeros.org/index.php/Portal:Books
+
+[6] The text below is from A Wiki of Ice & Fire: http://awoiaf.westeros.org/index.php/A_Game_of_Thrones
+
+306
+
+7. Animations
+
+There  are  many  ways  to  animate  and  liven  the  data  within  a  Codename  One  application,  layout
+
+animations  are  probably  chief  among  them.  But  first  we  need  to  understand  some  basics  such  as
+
+layout reflows.
+
+7.1. Layout Reflow
+
+Layout  in  tools  such  as  HTML  is  implicit,  when  you  add  something  into  the  UI  it  is  automatically
+
+placed  correctly.  Other  tools  such  as  Codename  One  use  explicit  layout,  that  means  you  have  to
+
+explicitly request the UI to layout itself after making changes!
+
+ Like many such rules exceptions occur. E.g. if the device is rotated or window size
+
+changes a layout will occur automatically.
+
+When adding a component to a UI that is already visible, the component will not show by default.
+
+
+
+When adding a component to a form which isn’t shown on the screen, there is no
+
+need to tell the UI to repaint or reflow. This happens implicitly.
+
+The chief advantage of explicit layout is performance.
+
+E.g. imagine adding 100 components to a form. If the form was laid out automatically, layout would
+
+have  happened  100  times  instead  of  once  when  adding  was  finished.  In  fact  layout  reflows  are
+
+often considered the #1 performance issue for HTML/JavaScript applications.
+
+
+
+Smart  layout  reflow  logic  can  alleviate  some  of  the  pains  of  the  automatic  layout
+
+reflows  however  since  the  process  is  implicit  it’s  almost  impossible  to  optimize
+
+complex usages across browsers/devices. A major JavaScript performance tip is to
+
+use absolute positioning which is akin to not using layouts at all!
+
+That  is  why,  when  you  add  components  to  a  form  that  is  already  showing,  you  should  invoke
+revalidate() or animate the layout appropriately. This also enables the layout animation behavior
+explained below.
+
+7.2. Layout Animations
+
+To  understand  animations  you  need  to  understand  a  couple  of  things  about  Codename  One
+
+components. When we add a component to a container, it’s generally just added but not positioned
+anywhere. A novice might notice the setX/setY/setWidth/setHeight methods on a component and just
+try to position it absolutely.
+
+This won’t work since these methods are meant for the layout manager, which is implicitly invoked
+
+when  a  form  is  shown  (internally  in  Codename  One).  The  layout  manager  uses  these  methods  to
+
+position/size the components based on the hints given to it.
+
+If  you  add  components  to  a  form  that  is  currently  showing,  it  is  your  responsibility  to  invoke
+
+307
+
+revalidate/layoutContainer to arrange the newly added components (see Layout Reflows).
+
+animateLayout() method is a fancy form of revalidate that animates the components into their laid
+out position. After changing the layout & invoking this method the components move to their new
+
+sizes/positions seamlessly.
+
+This sort of behavior creates a special case where setting the size/position makes sense. When we
+
+set  the  size/position  in  the  demo  code  here  we  are  positioning  the  components  at  the  animation
+
+start position above the frame.
+
+Form hi = new Form("Layout Animations", new BoxLayout(BoxLayout.Y_AXIS));
+Button fall = new Button("Fall"); ①
+fall.addActionListener((e) -> {
+    for(int iter = 0 ; iter < 10 ; iter++) {
+        Label b = new Label ("Label " + iter);
+        b.setWidth(fall.getWidth());
+        b.setHeight(fall.getHeight());
+        b.setY(-fall.getHeight());
+        hi.add(b);
+    }
+    hi.getContentPane().animateLayout(20000); ②
+});
+hi.add(fall);
+
+There are a couple of things that you should notice about this example:
+
+① We used a button to do the animation rather than doing it on show. Since show() implicitly lays
+
+out the components it wouldn’t have worked correctly.
+
+② We used hi.getContentPane().animateLayout(20000); & not hi.animateLayout(20000);. You need to
+
+animate the "actual" container and Form is a special case.
+
+This results in:
+
+308
+
+309
+
+ 
+ 
+310
+
+ 
+7.2.1. Unlayout Animations
+
+While  layout  animations  are  really  powerful  effects  for  adding  elements  into  the  UI  and  drawing
+
+attention  to  them.  The  inverse  of  removing  an  element  from  the  UI  is  often  more  important.  E.g.
+
+when we delete or remove an element we want to animate it out.
+
+Layout  animations  don’t  really  do  that  since  they  will  try  to  bring  the  animated  item  into  place.
+
+What we want is the exact opposite of a layout animation and that is the "unlayout animation".
+
+The "unlayout animation" takes a valid laid out state and shifts the components to an invalid state
+
+that we defined in advance. E.g. we can fix the example above to flip the "fall" button into a "rise"
+
+button when the buttons come into place and this will allow the buttons to float back up to where
+
+they came from in the exact reverse order.
+
+ An unlayout animation always leaves the container in an invalidated state.
+
+Form hi = new Form("Layout Animations", new BoxLayout(BoxLayout.Y_AXIS));
+Button fall = new Button("Fall");
+fall.addActionListener((e) -> {
+    if(hi.getContentPane().getComponentCount() == 1) {
+        fall.setText("Rise");
+        for(int iter = 0 ; iter < 10 ; iter++) {
+            Label b = new Label ("Label " + iter);
+            b.setWidth(fall.getWidth());
+            b.setHeight(fall.getHeight());
+            b.setY(-fall.getHeight());
+            hi.add(b);
+        }
+        hi.getContentPane().animateLayout(20000);
+    } else {
+        fall.setText("Fall");
+        for(int iter = 1 ; iter < hi.getContentPane().getComponentCount() ; iter++) { ①
+            Component c = hi.getContentPane().getComponentAt(iter);
+            c.setY(-fall.getHeight()); ②
+        }
+        hi.getContentPane().animateUnlayoutAndWait(20000, 255); ③
+        hi.removeAll(); ④
+        hi.add(fall);
+        hi.revalidate();
+    }
+});
+hi.add(fall);
+
+You  will  notice  some  similarities  with  the  unlayout  animation  but  the  differences  represent  the
+
+exact opposite of the layout animation:
+
+① We loop over existing components (not newly created ones)
+
+② We set the desired end position not the desired starting position
+
+③ We used the AndWait variant of the animate unlayout call. We could have used the async call as
+
+311
+
+well.
+
+④ After the animation completes we need to actually remove the elements since the UI is now in
+
+an invalid position with elements outside of the screen but still physically there!
+
+7.2.2. Hiding & Visibility
+
+A common trick for animating Components in Codename One is to set their preferred size to 0 and
+then invoke animateLayout() thus triggering an animation to hide said Component. There are several
+issues  with  this  trick  but  one  of  the  biggest  ones  is  the  fact  that  setPreferredSize  has  been
+deprecated for quite a while.
+
+Instead  of  using  that  trick  you  can  use  setHidden/isHidden  who  effectively  encapsulate  this
+functionality and a bit more.
+
+One of the issues setHidden tries to solve is the fact that preferred size doesn’t include the margin in
+the  total  and  thus  a  component  might  still  occupy  space  despite  being  hidden.  To  solve  this  the
+margin  is  set  to  0  when  hiding  and  restored  to  its  original  value  when  showing  the  component
+again by resetting the UIID (which resets all style modifications).
+
+This  functionality  might  be  undesirable  which  is  why  there  is  a  version  of  the  setHidden  method
+that  accepts  a  boolean  flag  indicating  whether  the  margin/UIID  should  be  manipulated.  You  can
+effectively hide/show a component without deprecated code using something like this:
+
+Button toHide = new Button("Will Be Hidden");
+Button hide = new Button("Hide It");
+hide.addActionListener((e) -> {
+    hide.setEnabled(false);
+    boolean t = !toHide.isHidden();
+    toHide.setHidden(t);
+    toHide.getParent().animateLayoutAndWait(200);
+    toHide.setVisible(!t);
+    hide.setEnabled(true);
+});
+
+
+
+Notice  that  the  code  above  uses  setVisible(),  which  shouldn’t  be  confused  with
+setHidden.  setVisible()  just  toggles  the  visibility  of  the  component  it  would  still
+occupy the same amount of space
+
+7.2.3. Synchronicity In Animations
+
+Most animations have two or three variants:
+
+• Standard animation e.g. animateLayout(int)
+
+• And wait variant e.g. animateLayoutAndWait(int)
+
+• Callback variant e.g. animateUnlayout(int, int, Runnable)
+
+The standard animation is invoked when we don’t care about the completion of the animation. We
+
+312
+
+can do this for a standard animation.
+
+
+
+The unlayout animations don’t have a standard variant. Since they leave the UI in
+
+an invalid state we must always do something once the animation completes so a
+
+standard variant makes no sense
+
+The AndWait variant blocks the calling thread until the animation completes. This is really useful for
+sequencing animations one after the other e.g this code from the kitchen sink demo:
+
+arrangeForInterlace(effects);
+effects.animateUnlayoutAndWait(800, 20);
+effects.animateLayoutFade(800, 20);
+
+First the UI goes thru an "unlayout" animation, once that completes the layout itself is performed.
+
+
+
+The AndWait calls needs to be invoked on the Event Dispatch Thread despite being
+"blocking". This is a common convention in Codename One powered by a unique
+capability of Codename One: invokeAndBlock.
+You 
+
+invokeAndBlock 
+
+learn  more 
+
+the  EDT 
+
+section
+
+about 
+
+can 
+
+in 
+
+[https://www.codenameone.com/manual/edt.html].
+
+The callback variant is similar to the invokeAndBlock variant but uses a more conventional callback
+semantic  which  is  more  familiar  to  some  developers.  It  accepts  a  Runnable  callback  that  will  be
+invoked  after  the  fact.  E.g.  we  can  change  the  unlayout  call  from  before  to  use  the  callback
+
+semantics as such:
+
+hi.getContentPane().animateUnlayout(20000, 255, () -> {
+    hi.removeAll();
+    hi.add(fall);
+    hi.revalidate();
+});
+
+Animation Fade and Hierarchy
+
+There are several additional variations on the standard animate methods. Several methods accept a
+numeric fade argument. This is useful to fade out an element in an "unlayout" operation or fade in
+a regular animation.
+
+The  value  for  the  fade  argument  is  a  number  between  0  and  255  where  0  represents  full
+
+transparency and 255 represents full opacity.
+
+Some  animate  layout  methods  are  hierarchy  based.  They  work  just  like  the  regular  animateLayout
+methods  but  recurse  into  the  entire  Container  [https://www.codenameone.com/javadoc/com/codename1/ui/
+
+Container.html]  hierarchy.  These  methods  work  well  when  you  have  components  in  a  nested
+
+hierarchy  that  need  to  animate  into  place.  This  is  demonstrated  in  the  opening  sequence  of  the
+
+kitchen sink demo:
+
+313
+
+for(int iter = 0 ; iter < demoComponents.size() ; iter++) {
+    Component cmp = (Component)demoComponents.elementAt(iter);
+    if(iter < componentsPerRow) {
+        cmp.setX(-cmp.getWidth());
+    } else {
+        if(iter < componentsPerRow * 2) {
+            cmp.setX(dw);
+        } else {
+            cmp.setX(-cmp.getWidth());
+        }
+    }
+}
+boxContainer.setShouldCalcPreferredSize(true);
+boxContainer.animateHierarchyFade(3000, 30);
+
+The demoComponents Vector contains components from separate containers and this code would not
+work with a simple animate layout.
+
+
+
+We  normally  recommend  avoiding  the  hierarchy  version.  Its  slower  but  more
+importantly, it’s flaky. Since the size/position of the Container might be affected by
+the layout the animation could get clipped and skip. These are very hard issues to
+
+debug.
+
+7.2.4. Sequencing Animations Via AnimationManager
+
+All  the  animations  go  thru  a  per-form  queue:  the  AnimationManager  [https://www.codenameone.com/
+
+javadoc/com/codename1/ui/AnimationManager.html].  This  effectively  prevents  two  animations  from
+
+mutating  the  UI  in  parallel  so  we  won’t  have  collisions  between  two  conflicting  sides.  Things  get
+
+more interesting when we try to do something like this:
+
+cnt.add(myButton);
+int componentCount = cnt.getComponentCount();
+cnt.animateLayout(300);
+cnt.removeComponent(myButton);
+if(componentCount == cnt.getComponentCount()) {
+    // this will happen...
+}
+
+The reason this happens is that the second remove gets postponed to the end of the animation so it
+
+won’t  break  the  animation.  This  works  for  remove  and  add  operations  on  a  Container
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/Container.html] as well as other animations.
+
+The simple yet problematic fix would be:
+
+314
+
+cnt.add(myButton);
+int componentCount = cnt.getComponentCount();
+cnt.animateLayoutAndWait(300);
+cnt.removeComponent(myButton);
+if(componentCount == cnt.getComponentCount()) {
+    // this probably won't happen...
+}
+
+So why that might still fail?
+
+Events  come  in  constantly  during  the  run  of  the  EDT  [7],  so  an  event  might  come  in  that  might
+trigger an animation in your code. Even if you are on the EDT keep in mind that you don’t actually
+
+block it and an event might come in.
+
+In those cases an animation might start and you might be unaware of that animation and it might
+
+still be in action when you expect remove to work.
+
+Animation Manager to the Rescue
+
+AnimationManager  [https://www.codenameone.com/javadoc/com/codename1/ui/AnimationManager.html]  has
+
+builtin support to fix this exact issue.
+
+We  can  flush  the  animation  queue  and  run  synchronously  after  all  the  animations  finished  and
+
+before new ones come in by using something like this:
+
+cnt.add(myButton);
+int componentCount = cnt.getComponentCount();
+cnt.animateLayout(300);
+cnt.getAnimationManager().flushAnimation(() -> {
+    cnt.removeComponent(myButton);
+    if(componentCount == cnt.getComponentCount()) {
+        // this shouldn't happen...
+    }
+});
+
+7.3. Low Level Animations
+
+The Codename One event dispatch thread has a special animation “pulse” allowing an animation to
+
+update  its  state  and  draw  itself.  Code  can  make  use  of  this  pulse  to  implement  repetitive  polling
+
+tasks that have very little to do with drawing.
+
+This is helpful since the callback will always occur on the event dispatch thread.
+
+Every  component  in  Codename  One  contains  an  animate()  method  that  returns  a  boolean  value,
+implement  the  Animation  [https://www.codenameone.com/javadoc/com/codename1/ui/
+you  can  also 
+
+animations/Animation.html] interface in an arbitrary component to implement your own animation. In
+
+order  to  receive  animation  events  you  need  to  register  yourself  within  the  parent  form,  it  is  the
+responsibility of the parent for to call animate().
+
+315
+
+If  the  animate  method  returns  true  then  the  animation  will  be  painted  (the  paint  method  of  the
+Animation interface would be invoked).
+
+
+
+It  is  important  to  deregister  animations  when  they  aren’t  needed  to  conserve
+
+battery life.
+
+If  you  derive  from  a  component,  which  has  its  own  animation  logic  you  might  damage  its
+
+animation behavior by deregistering it, so tread gently with the low level API’s.
+
+E.g. you can add additional animation logic using code like this:
+
+myForm.registerAnimated(this);
+
+private int spinValue;
+public boolean animate() {
+   if(userStatusPending) {
+       spinValue++;
+       super.animate();
+       return true;
+   }
+   return super.animate();
+}
+
+7.3.1. Why Not Just Write Code In Paint?
+
+Animations are comprised of two parts, the logic (deciding the position etc) and the painting. The
+
+paint method should be dedicated to painting only, not to the actual moving of the components.
+
+The  separation  of  concerns  allows  us  to  avoid  redundant  painting  e.g.  if  animate  didn’t  trigger  a
+change just return false to avoid the overhead related to animations.
+
+We  discuss  low  level  animations  in  more  details  within  the  animation  section  of  the  clock  demo
+
+[https://www.codenameone.com/manual/graphics.html#clock-animation-section].
+
+7.4. Transitions
+
+Transitions  allow  us  to  replace  one  component  with  another,  most  typically  forms  or  dialogs  are
+
+replaced with a transition however a transition can be applied to replace any arbitrary component.
+
+Developers can implement their own custom transition and install it to components by deriving the
+
+Transition 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/animations/Transition.html] 
+
+class,
+
+although  most  commonly  the  built  in  CommonTransitions  [https://www.codenameone.com/javadoc/com/
+
+codename1/ui/animations/CommonTransitions.html] class is used for almost everything.
+
+You  can  define  transitions  for  forms/dialogs/menus  globally  either  via  the  theme  constants  or  via
+
+the  LookAndFeel 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/plaf/LookAndFeel.html]  class.
+
+Alternatively you can install a transition on top-level components via setter methods.
+
+316
+
+In/Out Transitions
+
+When  defining  a  transition  we  define  the  entering  transition  and  the  exiting  transition.  For
+
+most  cases  only  one  of  those  is  necessary  and  we  default  to  the  exiting  (out  transition)  as  a
+
+convention.
+
+So  for  almost  all  cases  the  method  setFormTransitonIn  should  go  unused.  That  API  exists  for
+some  elaborate  custom  transitions  that  might  need  to  have  a  special  effect  both  when
+
+transitioning  in  and  out  of  a  specific  form.  However,  most  of  these  effects  are  easier  to
+
+achieve with layout animations (e.g. components dropping into place etc.).
+
+In the case of Dialog the transition in shows its appearance and the transition out shows its
+disposal. So in that case both transitions make a lot of sense.
+
+Back/Forward Transitions
+
+Transitions have a direction and can all be played either in incoming or outgoing direction. A
+transition  can  be  flipped  (played  in  reverse)  when  we  use  an  RTL  language  [8]  or  when  we
+simply traverse backwards in the form navigation hierarchy.
+
+Normally Form.show() displays the next Form with an incoming transition based on the current
+RTL mode. If we use Form.showBack() it will play the transition in reverse.
+
+
+
+When  working  with  high  level  animations  you  can  select  Slow Motion  option  in
+
+the simulator to slow down animations and inspect their details
+
+Themes define the default transitions used when showing a form, these differ based on the OS. In
+most platforms the default is Slide whereas in iOS the default is SlideFade which slides the content
+pane and title while fading in/out the content of the title area.
+
+
+
+SlideFade  is  problematic  without  a  title  area.  If  you  have  a  Form  that  lacks  a  title
+area we would recommend to disable SlideFade at least for that Form.
+
+Check  out 
+
+the 
+
+full 
+
+set  of 
+
+theme 
+
+constants 
+
+in 
+
+the  Theme  Constants 
+
+Section
+
+[https://www.codenameone.com/manual/advanced-theming.html#theme-constants-section].
+
+7.4.1. Replace
+
+To apply a transition to a component we can just use the Container.replace() method as such:
+
+317
+
+Form hi = new Form("Replace", new BoxLayout(BoxLayout.Y_AXIS));
+Button replace = new Button("Replace Pending");
+Label replaceDestiny = new Label("Destination Replace");
+hi.add(replace);
+replace.addActionListener((e) -> {
+    replace.getParent().replaceAndWait(replace, replaceDestiny,
+CommonTransitions.createCover(CommonTransitions.SLIDE_VERTICAL, true, 800));
+    replaceDestiny.getParent().replaceAndWait(replaceDestiny, replace,
+CommonTransitions.createUncover(CommonTransitions.SLIDE_VERTICAL, true, 800));
+});
+
+Replace  even  works  when  you  have  a  layout  constraint  in  place  e.g.  replacing  a
+
+
+
+component  in  a  border  layout  will  do  the  "right  thing".  However,  some  layouts
+such  as  TableLayout  might  be  tricky  in  such  cases  so  we  recommend  wrapping  a
+potentially replaceable Component in a border layout and replacing the content.
+
+Container.replace() can also be used with a null transition at which point it replaces instantly with
+no transition.
+
+7.4.2. Slide Transitions
+
+The slide transitions are used to move the Form/Component in a sliding motion to the side or up/down.
+There are 4 basic types of slide transitions:
+
+1. Slide - the most commonly used transition
+
+2. Fast  Slide  -  historically  this  provided  better  performance  for  old  device  types.  It  is  no  longer
+
+recommended for newer devices
+
+3. Slide Fade - the iOS default where the title area features a fade transition
+
+4. Cover/Uncover - a type of slide transition where only the source or destination form slides while
+
+the other remains static in place
+
+The code below demonstrates the usage of all the main transitions:
+
+318
+
+Toolbar.setGlobalToolbar(true);
+Form hi = new Form("Transitions", new BoxLayout(BoxLayout.Y_AXIS));
+Style bg = hi.getContentPane().getUnselectedStyle();
+bg.setBgTransparency(255);
+bg.setBgColor(0xff0000);
+Button showTransition = new Button("Show");
+Picker pick = new Picker();
+pick.setStrings("Slide", "SlideFade", "Cover", "Uncover", "Fade", "Flip");
+pick.setSelectedString("Slide");
+TextField duration = new TextField("10000", "Duration", 6, TextArea.NUMERIC);
+CheckBox horizontal = CheckBox.createToggle("Horizontal");
+pick.addActionListener((e) -> {
+    String s = pick.getSelectedString().toLowerCase();
+    horizontal.setEnabled(s.equals("slide") || s.indexOf("cover") > -1);
+});
+horizontal.setSelected(true);
+hi.add(showTransition).
+    add(pick).
+    add(duration).
+    add(horizontal);
+
+Form dest = new Form("Destination");
+bg = dest.getContentPane().getUnselectedStyle();
+bg.setBgTransparency(255);
+bg.setBgColor(0xff);
+dest.setBackCommand(
+        dest.getToolbar().addCommandToLeftBar("Back", null, (e) -> hi.showBack()));
+
+showTransition.addActionListener((e) -> {
+    int h = CommonTransitions.SLIDE_HORIZONTAL;
+    if(!horizontal.isSelected()) {
+        h = CommonTransitions.SLIDE_VERTICAL;
+    }
+    switch(pick.getSelectedString()) {
+        case "Slide":
+            hi.setTransitionOutAnimator(CommonTransitions.createSlide(h, true, duration.getAsInt(3000)));
+            dest.setTransitionOutAnimator(CommonTransitions.createSlide(h, true, duration.getAsInt(3000)));
+            break;
+        case "SlideFade":
+            hi.setTransitionOutAnimator(CommonTransitions.createSlideFadeTitle(true, duration.getAsInt(3000)));
+            dest.setTransitionOutAnimator(CommonTransitions.createSlideFadeTitle(true, duration.getAsInt(3000)));
+            break;
+        case "Cover":
+            hi.setTransitionOutAnimator(CommonTransitions.createCover(h, true, duration.getAsInt(3000)));
+            dest.setTransitionOutAnimator(CommonTransitions.createCover(h, true, duration.getAsInt(3000)));
+            break;
+        case "Uncover":
+            hi.setTransitionOutAnimator(CommonTransitions.createUncover(h, true, duration.getAsInt(3000)));
+            dest.setTransitionOutAnimator(CommonTransitions.createUncover(h, true, duration.getAsInt(3000)));
+            break;
+        case "Fade":
+            hi.setTransitionOutAnimator(CommonTransitions.createFade(duration.getAsInt(3000)));
+            dest.setTransitionOutAnimator(CommonTransitions.createFade(duration.getAsInt(3000)));
+            break;
+        case "Flip":
+            hi.setTransitionOutAnimator(new FlipTransition(-1, duration.getAsInt(3000)));
+            dest.setTransitionOutAnimator(new FlipTransition(-1, duration.getAsInt(3000)));
+            break;
+    }
+    dest.show();
+});
+hi.show();
+
+319
+
+Figure 302. The slide transition moves both incoming and outgoing forms together
+
+Figure 303. The slide transition can be applied vertically as well
+
+Figure 304. Slide fade fades in the destination title while sliding the content pane it is the default on iOS
+
+
+
+SlideFade  is  problematic  without  a  title  area.  If  you  have  a  Form  that  lacks  a  title
+area we would recommend to disable SlideFade at least for that Form.
+
+Figure 305. With cover transitions the source form stays in place as it is covered by the destination. This
+
+transition can be played both horizontally and vertically
+
+Figure 306. Uncover is the inverse of cover. The destination form stays in place while the departing form
+
+moves away
+
+7.4.3. Fade and Flip Transitions
+
+The fade transition is pretty trivial and only accepts a time value since it has no directional context.
+
+320
+
+Figure 307. Fade transition is probably the simplest one around
+
+The  FlipTransition  [https://www.codenameone.com/javadoc/com/codename1/ui/animations/FlipTransition.html]
+is  also  pretty  simple  but  unlike  the  others  it  isn’t  a  part  of  the  CommonTransitions.  It  has  its  own
+FlipTransition class.
+
+ This  transition  looks  very  different  on  devices  as  it  uses  native  perspective
+
+transforms available only there
+
+Figure 308. Fade transition is probably the simplest one around
+
+7.4.4. Bubble Transition
+
+BubbleTransiton  [https://www.codenameone.com/javadoc/com/codename1/ui/animations/BubbleTransition.html]
+
+morphs a component into another component using a circular growth motion.
+
+The  BubbleTransition  accepts  the  component  that  will  grow  into  the  bubble  effect  as  one  of  its
+arguments. It’s generally designed for Dialog transitions although it could work for more creative
+use cases:
+
+ The code below manipulates styles and look. This is done to make the code more
+
+"self contained". Real world code should probably use the theme
+
+321
+
+Form hi = new Form("Bubble");
+Button showBubble = new Button("+");
+showBubble.setName("BubbleButton");
+Style buttonStyle = showBubble.getAllStyles();
+buttonStyle.setBorder(Border.createEmpty());
+buttonStyle.setFgColor(0xffffff);
+buttonStyle.setBgPainter((g, rect) -> {
+    g.setColor(0xff);
+    int actualWidth = rect.getWidth();
+    int actualHeight = rect.getHeight();
+    int xPos, yPos;
+    int size;
+    if(actualWidth > actualHeight) {
+        yPos = rect.getY();
+        xPos = rect.getX() + (actualWidth - actualHeight) / 2;
+        size = actualHeight;
+    } else {
+        yPos = rect.getY() + (actualHeight - actualWidth) / 2;
+        xPos = rect.getX();
+        size = actualWidth;
+    }
+    g.setAntiAliased(true);
+    g.fillArc(xPos, yPos, size, size, 0, 360);
+});
+hi.add(showBubble);
+hi.setTintColor(0);
+showBubble.addActionListener((e) -> {
+    Dialog dlg = new Dialog("Bubbled");
+    dlg.setLayout(new BorderLayout());
+    SpanLabel sl = new SpanLabel("This dialog should appear with a bubble transition from the button", "DialogBody");
+    sl.getTextUnselectedStyle().setFgColor(0xffffff);
+    dlg.add(BorderLayout.CENTER, sl);
+    dlg.setTransitionInAnimator(new BubbleTransition(500, "BubbleButton"));
+    dlg.setTransitionOutAnimator(new BubbleTransition(500, "BubbleButton"));
+    dlg.setDisposeWhenPointerOutOfBounds(true);
+    dlg.getTitleStyle().setFgColor(0xffffff);
+
+    Style dlgStyle = dlg.getDialogStyle();
+    dlgStyle.setBorder(Border.createEmpty());
+    dlgStyle.setBgColor(0xff);
+    dlgStyle.setBgTransparency(0xff);
+    dlg.showPacked(BorderLayout.NORTH, true);
+});
+
+hi.show();
+
+Figure 309. Bubble transition converting a circular button to a Dialog
+
+322
+
+7.4.5. Morph Transitions
+
+Android’s  material  design  has  a  morphing  effect  where  an  element  from  the  previous  form
+
+(activity) animates into a different component on a new activity. Codename One has a morph effect
+
+in  the  Container  [https://www.codenameone.com/javadoc/com/codename1/ui/Container.html]  class  but  it
+
+doesn’t work as a transition between forms and doesn’t allow for multiple separate components to
+
+transition at once.
+
+Figure 310. Morph Transition
+
+To  support  this  behavior  we  have  the  MorphTransition  [https://www.codenameone.com/javadoc/com/
+
+codename1/ui/animations/MorphTransition.html] class that provides this same effect coupled with a fade
+
+to the rest of the UI (see Figure 310, “Morph Transition”).
+
+Since the transition is created before the form exists we can’t reference explicit components within
+
+the  form  when  creating  the  morph  transition  (in  order  to  indicate  which  component  becomes
+which)  so  we  need  to  refer  to  them  by  name.  This  means  we  need  to  use  setName(String)  on  the
+components in the source/destination forms so the transition will be able to find them.
+
+Form demoForm = new Form(currentDemo.getDisplayName());
+demoForm.setScrollable(false);
+demoForm.setLayout(new BorderLayout());
+Label demoLabel = new Label(currentDemo.getDisplayName());
+demoLabel.setIcon(currentDemo.getDemoIcon());
+demoLabel.setName("DemoLabel");
+demoForm.addComponent(BorderLayout.NORTH, demoLabel);
+demoForm.addComponent(BorderLayout.CENTER, wrapInShelves(n));
+....
+demoForm.setBackCommand(backCommand);
+demoForm.setTransitionOutAnimator(
+    MorphTransition.create(3000).morph(
+        currentDemo.getDisplayName(),
+        "DemoLabel"));
+f.setTransitionOutAnimator(
+    MorphTransition.create(3000).
+        morph(currentDemo.getDisplayName(),
+        "DemoLabel"));
+demoForm.show();
+
+7.4.6. SwipeBackSupport
+
+iOS7+ allows swiping back one form to the previous form, Codenmae One has an API to enable back
+
+swipe transition:
+
+323
+
+SwipeBackSupport.bindBack(Form currentForm, LazyValue<Form> destination);
+
+That 
+
+one 
+
+command  will 
+
+enable 
+
+swiping 
+
+back 
+
+from 
+
+currentForm. 
+
+LazyValue
+
+[https://www.codenameone.com/javadoc/com/codename1/util/LazyValue.html] allows us to pass a value lazily:
+
+public interface LazyValue<T> {
+    public T get(Object... args);
+}
+
+This effectively allows us to pass a form and only create it as necessary (e.g. for a GUI builder app
+
+we  don’t  have  the  actual  previous  form  instance),  notice  that  the  arguments  aren’t  used  for  this
+
+case but will be used in other cases.
+
+The code below should work for the transition sample above. Notice that this API was designed to
+
+work with "Slide Fade" transition and might have issues with other transition types:
+
+SwipeBackSupport.bindBack(dest, (args) -> hi);
+
+[7] Event Dispatch Thread
+
+[8] Right to left/bidi language such as Hebrew or Arabic
+
+324
+
+8. The EDT - Event Dispatch Thread
+
+8.1. What Is The EDT
+
+Codename  One  allows  developers  to  create  as  many  threads  as  they  want;  however  in  order  to
+
+interact with the Codename One user interface components a developer must use the EDT. The EDT
+
+stands for "Event Dispatch Thread" but it handles a lot more than just "events".
+
+The EDT is the main thread of Codename One, by using just one thread Codename One can avoid
+
+complex synchronization code and focus on simple functionality that assumes only one thread.
+
+
+
+This  has  huge  advantages  for  your  code.  You  can  normally  assume  that  all  code
+
+will occur on a single thread and avoid complex synchronization logic.
+
+You can visualize the EDT as a loop such as this:
+
+while(codenameOneRunning) {
+     performEventCallbacks();
+     performCallSeriallyCalls();
+     drawGraphicsAndAnimations();
+     sleepUntilNextEDTCycle();
+}
+
+Normally, every call you receive from Codename One will occur on the EDT. E.g. every event, calls
+
+to paint(), lifecycle calls (start etc.) should all occur on the EDT.
+
+This is pretty powerful, however it means that as long as your code is processing nothing else can
+
+happen in Codename One!
+
+
+
+If  your  code  takes  too  long  to  execute  then  no  painting  or  event  processing
+will  occur  during  that  time,  so  a  call  to  Thread.sleep()  will  actually  stop
+everything!
+
+The solution is pretty simple, if you need to perform something that requires intensive CPU you can
+
+spawn a thread.
+
+Codename  One’s  networking  code  automatically  spawns  its  own  network  thread  (see  the
+
+NetworkManager 
+
+[https://www.codenameone.com/javadoc/com/codename1/io/NetworkManager.html]).
+
+However, this also poses a problem…
+
+Codename One assumes all modifications to the UI are performed on the EDT but if we spawned a
+
+separate thread. How do we force our modifications back into the EDT?
+
+Codename One includes 3 methods in the Display [https://www.codenameone.com/javadoc/com/codename1/
+callSerially(Runnable)  &
+
+situations: 
+
+isEDT(), 
+
+to  help 
+
+these 
+
+class 
+
+in 
+
+ui/Display.html] 
+callSeriallyAndWait(Runnable).
+
+325
+
+isEDT()  is  useful  for  generic  code  that  needs  to  test  whether  the  current  code  is  executing  on  the
+EDT.
+
+8.2. Call Serially (And Wait)
+
+callSerially(Runnable)  should  normally  be  called  off  the  EDT  (in  a  separate  thread),  the  run
+method within the submitted runnable will be invoked on the EDT.
+
+ The Runnable passed to the callSerially and callSeriallyAndWait methods is not a
+
+Thread. We just use the Runnable interface as a convenient callback interface.
+
+// this code is executing in a separate thread
+final String res = methodThatTakesALongTime();
+Display.getInstance().callSerially(new Runnable() {
+     public void run() {
+          // this occurs on the EDT so I can make changes to UI components
+          resultLabel.setText(res);
+     }
+});
+
+
+
+You can write this code more concisely using Java 8 lambda code as such:
+
+// this code is executing in a separate thread
+String res = methodThatTakesALongTime();
+Display.getInstance().callSerially(() -> resultLabel.setText(res));
+
+This allows code to leave the EDT and then later on return to it to perform things within the EDT.
+
+The  callSeriallyAndWait(Runnable)  method  blocks  the  current  thread  until  the  method  completes,
+this is useful for cases such as user notification e.g.:
+
+// this code is executing in a separate thread
+methodThatTakesALongTime();
+Display.getInstance().callSeriallyAndWait(() -> {
+  // this occurs on the EDT so I can make changes to UI components
+  globalFlag = Dialog.show("Are You Sure?", "Do you want to continue?", "Continue", "Stop");
+});
+// this code is executing the separate thread
+// global flag was already set by the call above
+if(!globalFlag) {
+   return;
+}
+otherMethod();
+
+
+
+If you are unsure use callSerially. The use cases for callSeriallyAndWait are very
+rare.
+
+326
+
+8.2.1. callSerially On The EDT
+
+One of the misunderstood topics is why would we ever want to invoke callSerially when we are
+still  on  the  EDT.  This  is  best  explained  by  example.  Say  we  have  a  button  that  has  quite  a  bit  of
+
+functionality tied to its events e.g.:
+
+1. A user added an action listener to show a Dialog.
+
+2. A framework the user installed added some logging to the button.
+
+3. The button repaints a release animation as its being released.
+
+However, this might cause a problem if the first event that we handle (the dialog) might cause an
+issue to the following events. E.g. a dialog will block the EDT (using invokeAndBlock), events will keep
+happening but since the event we are in "already happened" the button repaint and the framework
+
+logging won’t occur. This might also happen if we show a form which might trigger logic that relies
+
+on the current form still being present.
+
+One of the solutions to this problem is to just wrap the action listeners body with a callSerially. In
+this  case  the  callSerially  will  postpone  the  event  to  the  next  cycle  (loop)  of  the  EDT  and  let  the
+other events in the chain complete. Notice that you shouldn’t use this normally since it includes an
+
+overhead and complicates application flow, however when you run into issues in event processing
+
+we suggest trying this to see if its the cause.
+
+
+
+You  should  never  invoke  callSeriallyAndWait  on  the  EDT  since  this  would
+
+effectively mean sleeping on the EDT. We made that method throw an exception if
+
+its invoked from the EDT.
+
+8.3. Debugging EDT Violations
+
+There are two types of EDT violations:
+
+1. Blocking the EDT thread so the UI performance is considerably slower.
+
+2. Invoking UI code on a separate thread
+
+Codename One provides a tool to help you detect some of these violations some caveats may apply
+
+though…
+
+It’s an imperfect tool. It might fire “false positives” meaning it might detect a violation for perfectly
+
+legal  code  and  it  might  miss  some  illegal  calls.  However,  it  is  a  valuable  tool  in  the  process  of
+
+detecting  hard  to  track  bugs  that  are  sometimes  only  reproducible  on  the  devices  (due  to  race
+
+condition behavior).
+
+To  activate  this  tool  just  select  the  Debug  EDT  menu  option  in  the  simulator  and  pick  the  level  of
+
+output you wish to receive:
+
+327
+
+Figure 311. Debug EDT
+
+Full output will include stack traces to the area in the code that is suspected in the violation.
+
+8.4. Invoke And Block
+
+Invoke  and  block  is  the  exact  opposite  of  callSeriallyAndWait(),  it  blocks  the  EDT  and  opens  a
+the  Foxtrot
+separate 
+
+the  runnable  call.  This 
+
+functionality 
+
+inspired  by 
+
+thread 
+
+for 
+
+is 
+
+[http://foxtrot.sourceforge.net/]  API,  which  is  a  remarkably  powerful  tool  most  Swing  developers  don’t
+
+know about.
+
+This  is  best  explained  by  an  example.  When  we  write  typical  code  in  Java  we  like  that  code  is  in
+
+sequence as such:
+
+doOperationA();
+doOperationB();
+doOperationC();
+
+This works well normally but on the EDT it might be a problem, if one of the operations is slow it
+
+might slow the whole EDT (painting, event processing etc.). Normally we can just move operations
+
+into a separate thread e.g.:
+
+doOperationA();
+new Thread() {
+    public void run() {
+         doOperationB();
+    }
+}).start();
+doOperationC();
+
+Unfortunately, this means that operation C will happen in parallel to operation B which might be a
+
+problem…
+
+E.g. instead of using operation names lets use a more "real world" example:
+
+328
+
+updateUIToLoadingStatus();
+readAndParseFile();
+updateUIWithContentOfFile();
+
+Notice  that  the  first  and  last  operations  must  be  conducted  on  the  EDT  but  the  middle  operation
+might  be  really  slow!  Since  updateUIWithContentOfFile  needs  readAndParseFile  to  occur  before  it
+starts doing the new thread won’t be enough.
+
+A simplistic approach is to do something like this:
+
+updateUIToLoadingStatus();
+new Thread() {
+    public void run() {
+          readAndParseFile();
+          updateUIWithContentOfFile();
+    }
+}).start();
+
+But updateUIWithContentOfFile should be executed on the EDT and not on a random thread. So the
+right way to do this would be something like this:
+
+updateUIToLoadingStatus();
+new Thread() {
+    public void run() {
+          readAndParseFile();
+          Display.getInstance().callSerially(new Runnable() {
+               public void run() {
+                     updateUIWithContentOfFile();
+               }
+          });
+    }
+}).start();
+
+This  is  perfectly  legal  and  would  work  reasonably  well,  however  it  gets  complicated  as  we  add
+
+more and more features that need to be chained serially after all these are just 3 methods!
+
+Invoke and block solves this in a unique way you can get almost the exact same behavior by using
+
+this:
+
+updateUIToLoadingStatus();
+Display.getInstance().invokeAndBlock(new Runnable() {
+    public void run() {
+          readAndParseFile();
+    }
+});
+updateUIWithContentOfFile();
+
+329
+
+Or this with Java 8 syntax:
+
+updateUIToLoadingStatus();
+Display.getInstance().invokeAndBlock(() -> readAndParseFile());
+updateUIWithContentOfFile();
+
+Invoke and block effectively blocks the current EDT in a legal way. It spawns a separate thread that
+runs the run() method and when that run method completes it goes back to the EDT.
+
+All  events  and  EDT  behavior  still  work  while  invokeAndBlock  is  running,  this  is  because
+invokeAndBlock() keeps calling the main thread loop internally.
+
+
+
+Notice that invokeAndBlock comes at a slight performance penalty. Also notice that
+nesting invokeAndBlock calls (or over using them) isn’t recommended.
+However, they are very convenient when working with multiple threads/UI.
+
+Even if you never call invokeAndBlock directly you are probably using it indirectly in API’s such as
+Dialog  [https://www.codenameone.com/javadoc/com/codename1/ui/Dialog.html]  that  show  a  dialog  while
+
+blocking the current thread e.g.:
+
+public void actionPerformed(ActionEvent ev) {
+  // will return true if the user clicks "OK"
+  if(!Dialog.show("Question", "How Are You", "OK", "Not OK")) {
+  // ask what went wrong...
+  }
+}
+
+Notice that the dialog show method will block the calling thread until the user clicks OK or Not OK…
+
+
+
+Other  API’s  such  as  NetworkManager.addToQueueAndWait()  also  make  use  of  this
+feature.  Pretty  much  every  "AndWait"  method  or  blocking  method  uses  this  API
+
+internally!
+
+To explain how invokeAndBlock works we can return to the sample above of how the EDT works:
+
+while(codenameOneRunning) {
+     performEventCallbacks();
+     performCallSeriallyCalls();
+     drawGraphicsAndAnimations();
+     sleepUntilNextEDTCycle();
+}
+
+invokeAndBlock() works in a similar way to this pseudo code:
+
+330
+
+void invokeAndBlock(Runnable r) {
+    openThreadForR(r);
+    while(r is still running) {
+         performEventCallbacks();
+         performCallSeriallyCalls();
+         drawGraphicsAndAnimations();
+         sleepUntilNextEDTCycle();
+    }
+}
+
+So the EDT is effectively "blocked" but we "redo it" within the invokeAndBlock method…
+
+As  you  can  see  this  is  a  very  simple  approach  for  thread  programming  in  UI,  you  don’t  need  to
+
+block your flow and track the UI thread. You can just program in a way that seems sequential (top
+
+to bottom) but really uses multi-threading correctly without blocking the EDT.
+
+331
+
+332
+
+9. Monetization
+
+Codename One tries to make the lives of software developers easier by integrating several forms of
+
+built-in monetization solutions such as ad network support, in-app-purchase etc.
+
+A  lot  of  the  monetization  options  are  available  as  3rd  party  cn1lib’s  [https://www.codenameone.com/
+
+cn1libs.html] that you can install thru the Codename One website.
+
+9.1. Google Play Ads
+
+The most effective network is the simplest banner ad support. To enable mobile ads just create an
+
+ad  unit  [https://apps.admob.com/?pli=1#monetize/adunit:create]  in  Admob’s  website,  you  should  end  up
+
+with the key similar to this:
+
+ca-app-pub-8610616152754010/3413603324
+
+this 
+
+enable 
+
+for  Android 
+
+To 
+8610616152754010/3413603324 
+in
+in  the  build  arguments  and  for 
+ios.googleAdUnitId.  The  rest  is  seamless,  the  right  ad  will  be  created  for  you  at  the  bottom  of  the
+screen  and  the  form  should  automatically  shrink  to  fit  the  ad.  This  shrinking  is  implemented
+
+iOS  use  the  same  as 
+
+android.googleAdUnitId=ca-app-pub-
+
+define 
+
+just 
+
+the 
+
+differently between iOS and Android due to some constraints but the result should be similar and
+
+this should work reasonably well with device rotation as well.
+
+Figure 312. Google play ads
+
+special  ad  unit 
+
+specify  ca-app-pub-
+There’s  a 
+3940256099942544/6300978111,  you’ll  get  test  ads  for  your  development  phase.  This  is  important
+because you’re not allowed to click on your own ads. When it’s time to create a production release,
+
+test  ads. 
+
+to  use 
+
+If  you 
+
+for 
+
+id 
+
+you should replace this with the real value you generated in adMob.
+
+9.2. In App Purchase
+
+In-app purchase is a helpful tool for making app development profitable. Codename One supports
+
+in-app  purchases  of  consumable/non-consumable  products  on  Android  &  iOS.  It  also  features
+
+support  for  subscriptions.  For  such  a  seemingly  simple  task,  in-app  purchase  involves  a  lot  of
+
+moving parts - especially when it comes to subscriptions.
+
+9.2.1. The SKU
+
+In-app purchase support centers around your set of SKUs that you want to sell. Each product that
+
+you sell, whether it be a 1-month subscription, an upgrade to the "Pro" version, "10 disco credits",
+
+will  have  a  SKU  (stock-keeping-unit).  Ideally  you  will  be  able  to  use  the  same  SKU  across  all  the
+
+stores that you sell your app in.
+
+333
+
+9.2.2. Types of Products
+
+There are generally 4 classifications for products:
+
+1. Non-consumable  Product  -  This  is  a  product  that  the  user  purchases  once  to  "own".  They
+
+cannot re-purchase it. One example is a product that upgrades your app to a "Pro" version.
+
+2. Consumable Product - This is a product that the user can buy more than once. E.g. You might
+
+have a product for "10 Credits" that allows the user to buy items in a game.
+
+3. Non-Renewable  Subscription  -  A  subscription  that  you  buy  once,  and  will  not  be  "auto-
+
+renewed"  by  the  app  store.  These  are  almost  identical  to  consumable  products,  except  that
+
+subscriptions  need  to  be  transferable  across  all  the  user’s  devices.  This  means  that  non-
+
+renewable subscriptions require that you have a server that keeps track of the subscriptions.
+
+4. Renewable  Subscriptions  -  A  subscription  that  the  app  store  manages.  The  user  will  be
+
+automatically billed when the subscription period ends, and the subscription will renew.
+
+
+
+These subscription categories may not be explicitly supported by a given store, or
+
+they  may  carry  a  different  name.  You  can  integrate  each  product  type  in  a  cross
+
+platform  way  using  Codename  One.  E.g.  In  Google  Play  there  is  no  distinction
+
+between  consumable  products  and  non-renewable  subscriptions,  but  in  iTunes
+
+there is a distinction.
+
+9.2.3. The "Hello World" of In-App Purchase
+
+Let’s start with a simple example of an app that sells "Worlds". The first thing we do is pick the SKU
+
+for our product. I’ll choose "com.codename1.world" for the SKU.
+
+public static final String SKU_WORLD = "com.codename1.world";
+
+
+
+While we chose to use the package name convention for an SKU you can use any
+name you want e.g UA8879
+
+Next, our app’s main class needs to implement the PurchaseCallback interface
+
+334
+
+public class HelloWorldIAP implements PurchaseCallback {
+    ....
+
+    @Override
+    public void itemPurchased(String sku) {
+        ...
+    }
+
+    @Override
+    public void itemPurchaseError(String sku, String errorMessage) {
+        ...
+    }
+
+    @Override
+    public void itemRefunded(String sku) {
+        ...
+    }
+
+    @Override
+    public void subscriptionStarted(String sku) {
+        ...
+    }
+
+    @Override
+    public void subscriptionCanceled(String sku) {
+        ...
+    }
+
+    @Override
+    public void paymentFailed(String paymentCode, String failureReason) {
+       ...
+    }
+
+    @Override
+    public void paymentSucceeded(String paymentCode, double amount, String currency) {
+        ...
+    }
+
+}
+
+Using  these  callbacks,  we’ll  be  notified  whenever  something  changes  in  our  purchases.  For  our
+simple app we’re only interested in itemPurchased() and itemPurchaseError().
+
+Now in the start method, we’ll add a button that allows the user to buy the world:
+
+335
+
+    public void start() {
+        if(current != null){
+            current.show();
+            return;
+        }
+        Form hi = new Form("Hi World");
+        Button buyWorld = new Button("Buy World");
+        buyWorld.addActionListener(e->{
+            if (Purchase.getInAppPurchase().wasPurchased(SKU_WORLD)) {
+                Dialog.show("Can't Buy It", "You already Own It", "OK", null);
+            } else {
+                Purchase.getInAppPurchase().purchase(SKU_WORLD);
+            }
+        });
+
+        hi.addComponent(buyWorld);
+        hi.show();
+    }
+
+At this point, we already have a functional app that will track the sale of the world. To make it more
+interesting, let’s add some feedback with the ToastBar to show when the purchase completes.
+
+    @Override
+    public void itemPurchased(String sku) {
+        ToastBar.showMessage("Thanks.  You now own the world", FontImage.MATERIAL_THUMB_UP);
+    }
+
+    @Override
+    public void itemPurchaseError(String sku, String errorMessage) {
+        ToastBar.showErrorMessage("Failure occurred: "+errorMessage);
+    }
+
+
+
+You can test out this code in the simulator without doing any additional setup and
+
+it will work. If you want the code to work properly on Android and iOS, you’ll need
+
+to set up the app and in-app purchase settings in the Google Play and iTunes stores
+
+respectively as explained below
+
+When the app first opens we see our button:
+
+336
+
+Figure 313. In-app purchase demo app
+
+In the simulator, clicking on the "Buy World" button will bring up a prompt to ask you if you want
+
+to approve the purchase.
+
+Figure 314. Approving the purchase in the simulator
+
+Now if I try to buy the product again, it pops up the dialog to let me know that I already own it.
+
+337
+
+Figure 315. In App purchase already owned
+
+9.2.4. Making it Consumable
+
+In the "Buy World" example above, the "world" product was non-consumable, since we could only
+
+buy  the  world  once. We  could  change  it  to  a  consumable  product  by  disregarding  whether  it  was
+
+purchased before & keeping track of how many times it had been purchased.
+
+We’ll  use  storage  to  keep  track  of  the  number  of  worlds  that  the  user  purchased.  We  need  two
+
+methods to manage this count. One method gets the number of worlds that we own, and another
+
+adds a world to this count.
+
+private static final String NUM_WORLDS_KEY = "NUM_WORLDS.dat";
+public int getNumWorlds() {
+    synchronized (NUM_WORLDS_KEY) {
+        Storage s = Storage.getInstance();
+        if (s.exists(NUM_WORLDS_KEY)) {
+            return (Integer)s.readObject(NUM_WORLDS_KEY);
+        } else {
+            return 0;
+        }
+    }
+}
+
+public void addWorld() {
+    synchronized (NUM_WORLDS_KEY) {
+        Storage s = Storage.getInstance();
+        int count = 0;
+        if (s.exists(NUM_WORLDS_KEY)) {
+            count = (Integer)s.readObject(NUM_WORLDS_KEY);
+        }
+        count++;
+        s.writeObject(NUM_WORLDS_KEY, new Integer(count));
+    }
+}
+
+338
+
+Now we’ll change our purchase code as follows:
+
+buyWorld.addActionListener(e->{
+    if (Dialog.show("Confirm", "You own "+getNumWorlds()+
+           " worlds.  Do you want to buy another one?", "Yes", "No")) {
+        Purchase.getInAppPurchase().purchase(SKU_WORLD);
+    }
+});
+
+And our itemPurchased() callback will need to add a world:
+
+@Override
+public void itemPurchased(String sku) {
+    addWorld();
+    ToastBar.showMessage("Thanks.  You now own "+getNumWorlds()+" worlds", FontImage.MATERIAL_THUMB_UP);
+}
+
+
+
+When we set up the products in the iTunes store we will need to mark the product
+
+as a consumable product or iTunes will prevent us from purchasing it more than
+
+once
+
+9.2.5. Non-Renewable Subscriptions
+
+As we discussed before, there are two types of subscriptions:
+
+1. Non-renewable
+
+2. Auto-renewable
+
+Non-renewable subscriptions are the same as consumable products, except that they are shareable
+
+across  devices.  Auto-renewable  subscriptions  will  continue  as  long  as  the  user  doesn’t  cancel  the
+
+subscription.  They  will  be  re-billed  automatically  by  the  appropriate  app-store  when  the  chosen
+
+period expires, and the app-store handles the management details itself.
+
+
+
+
+
+The  concept  of  an  "Non-renewable"  subscription  is  unique  to  iTunes.  Google  Play
+
+has no formal similar option. In order to create a non-renewable subscription SKU
+
+that  behaves  the  same  in  your  iOS  and  Android  apps  you  would  create  it  as  a
+
+regular product in Google play, and a Non-renewable subscription in the iTunes
+
+store. We’ll learn more about that in a later post when we go into the specifics of
+
+app store setup.
+
+The  Purchase  class  includes  both  a  purchase()  method  and  a  subscribe()  method.
+On  some  platforms  it  makes  no  difference  which  one  you  use,  but  on  Android  it
+
+matters. If the product is set up as a subscription in Google Play, then you must use
+subscribe() to purchase the product. If it is set up as a regular product, then you
+must  use  purchase().  Since  we  enter  "Non-renewable"  subscriptions  as  regular
+products in the play store, we would use the purchase() method.
+
+339
+
+9.2.6. The Server-Side
+
+Since a subscription purchased on one user device needs to be available across the user’s devices
+
+(Apple’s rules for non-renewable subscriptions), our app will need to have a server-component. In
+
+this  section,  we’ll  gloss  over  that  &  "mock"  the  server  interface.  We’ll  go  into  the  specifics  of  the
+
+server-side below.
+
+The Receipts API
+
+Subscriptions, in Codename One use the "Receipts" API. It’s up to you to register a receipt store with
+
+the In-App purchase instance, which allows Codename one to load receipts (from your server), and
+submit new receipts to your server. A Receipt includes information such as:
+
+1. Store code (since you may be dealing with receipts from itunes, google play & Microsoft)
+
+2. SKU
+
+3. Transaction ID (store specific)
+
+4. Expiry Date
+
+5. Cancellation date
+
+6. Purchase date
+
+7. Order  Data  (that  you  can  use  on  the  server-side  to  verify  the  receipt  and  load  receipt  details
+
+directly from the store it originated from).
+
+The Purchase provides a set of methods for interacting with the receipt store, such as:
+
+1. isSubscribed([skus])  -  Checks  to  see  if  the  user  is  currently  subscribed  to  any  of  the  provided
+
+skus.
+
+2. getExpiryDate([skus]) - Checks the expiry date for a set of skus.
+
+3. synchronizeReceipts()  -  Synchronizes  the  receipts  with  the  receipt  store.  This  will  attempt  to
+submit  any  pending  purchase  receipts  to  the  receipt  store,  and  the  reload  receipts  from  the
+
+receipt store.
+
+In order for any of this to work, you must implement the ReceiptStore interface, and register it with
+the Purchase instance. Your receipt store must implement two methods:
+
+1. fetchReceipts(SuccessCallback<Receipt[]>  callback)  -  Loads  all  of  the  receipts  from  your
+
+receipt store for the current user.
+
+2. submitReceipt(Receipt receipt, SuccessCallback<Boolean> callback) - Submits a receipt to your
+receipt store. This gives you an opportunity to add details to the receipt such as an expiry date.
+
+9.2.7. The "Hello World" of Non-Renewable Subscriptions
+
+We’ll expand on the theme of "Buying" the world for this app, except, this time we will "Rent" the
+
+world for a period of time. We’ll have two products:
+
+1. A 1 month subscription
+
+2. A 1 year subscription
+
+340
+
+public static final String SKU_WORLD_1_MONTH = "com.codename1.world.subscribe.1month";
+public static final String SKU_WORLD_1_YEAR = "com.codename1.world.subscribe.1year";
+
+public static final String[] PRODUCTS = {
+    SKU_WORLD_1_MONTH,
+    SKU_WORLD_1_YEAR
+};
+
+Notice  that  we  create  two  separate  SKUs  for  the  1  month  and  1  year  subscription.  Each
+subscription period must have its own SKU. I have created an array (PRODUCTS) that contains both
+of the SKUs. This is handy, as you’ll see in the examples ahead, because the APIs for checking status
+
+and expiry date of a subscription take the SKUs in a "subscription group" as input.
+
+
+
+Different SKUs that sell the same service/product but for different periods form a
+
+"subscription  group".  Conceptually,  customers  are  not  subscribing  to  a  particular
+
+SKU,  they  are  subscribing  to  the  subscription  group  of  which  that  SKU  is  a
+
+member. As an example, if a user purchases a 1 month subscription to "the world",
+
+they are actually subscribing to "the world" subscription group.
+
+It’s  up  to  you  to  know  the  grouping  of  your  SKUs.  Any  methods  in  the  Purchase  class  that  check
+subscription  status  or  expiry  date  of  a  SKU  should  be  passed  all  SKUs  of  that  subscription  group.
+E.g. If you want to know if the user is subscribed to the SKU_WORLD_1_MONTH subscription, it would not
+be sufficient to call iap.isSubscribed(SKU_WORLD_1_MONTH), because that wouldn’t take into account if
+the  user  had  purchased  a  1  year  subscription.  The  correct  way 
+to  always  call
+iap.isSubscribed(SKU_WORLD_1_MONTH, SKU_WORLD_1_YEAR), or simply iap.isSubscribed(PRODUCTS) since
+we have placed both SKUs into our PRODUCTS array.
+
+is 
+
+Implementing the Receipt Store
+
+The  receipt  store  is  intended  to  interface  with  a  server  so  that  the  subscriptions
+
+
+
+can  be  synced  with  multiple  devices,  as  required  by  Apple’s  guidelines.  For  this
+
+post we’ll just store our receipts on device using internal storage. Moving the logic
+
+to a server is a simple matter that we will cover in a future post when we cover the
+
+server-side.
+
+341
+
+Figure 316. The Receipt store is a layer between your server and Codename One
+
+A basic receipt store needs to implement just two methods:
+
+1. fetchReceipts
+
+2. submitReceipt
+
+Generally we’ll register it in our app’s init() method so that it’s always available.
+
+342
+
+public void init(Object context) {
+    ...
+
+    Purchase.getInAppPurchase().setReceiptStore(new ReceiptStore() {
+
+        @Override
+        public void fetchReceipts(SuccessCallback<Receipt[]> callback) {
+            // Fetch receipts from storage and pass them to the callback
+        }
+
+        @Override
+        public void submitReceipt(Receipt receipt, SuccessCallback<Boolean> callback) {
+            // Save a receipt to storage.  Make sure to call callback when done.
+        }
+    });
+}
+
+These methods are designed to be asynchronous since real-world apps will always be connecting to
+
+some  sort  of  network  service.  Therefore,  instead  of  returning  a  value,  both  of  these  methods  are
+
+instances  of 
+
+passed 
+to  call
+callback.onSuccess() ALWAYS when the methods have completed, even if there is an error, or the
+Purchase  class  will  just  assume  that  you’re  taking  a  long  time  to  complete  the  task,  and  will
+
+the  SuccessCallback  class. 
+
+to  make  sure 
+
+important 
+
+It’s 
+
+continue to wait for you to finish.
+
+Once implemented, our fetchReceipts() method will look like:
+
+// static declarations used by receipt store
+
+// Storage key where list of receipts are stored
+private static final String RECEIPTS_KEY = "RECEIPTS.dat";
+
+@Override
+public void fetchReceipts(SuccessCallback<Receipt[]> callback) {
+    Storage s = Storage.getInstance();
+    Receipt[] found;
+    synchronized(RECEIPTS_KEY) {
+        if (s.exists(RECEIPTS_KEY)) {
+            List<Receipt> receipts = (List<Receipt>)s.readObject(RECEIPTS_KEY);
+            found = receipts.toArray(new Receipt[receipts.size()]);
+        } else {
+            found = new Receipt[0];
+        }
+    }
+    // Make sure this is outside the synchronized block
+    callback.onSucess(found);
+}
+
+This is fairly straight forward. We’re checking to see if we already have a list of receipts stored. If so
+
+343
+
+we return that list to the callback. If not we return an empty array of receipts.
+
+ Receipt  implements  Externalizable  so  you  are  able  to  write  instances  directly  to
+
+Storage.
+
+The submitReceipt() method is a little more complex, as it needs to calculate the new expiry date for
+our subscription.
+
+@Override
+public void submitReceipt(Receipt receipt, SuccessCallback<Boolean> callback) {
+    Storage s = Storage.getInstance();
+    synchronized(RECEIPTS_KEY) {
+        List<Receipt> receipts;
+        if (s.exists(RECEIPTS_KEY)) {
+            receipts = (List<Receipt>)s.readObject(RECEIPTS_KEY);
+        } else {
+            receipts = new ArrayList<Receipt>();
+        }
+        // Check to see if this receipt already exists
+        // This probably won't ever happen (that we'll be asked to submit an
+        // existing receipt, but better safe than sorry
+        for (Receipt r : receipts) {
+            if (r.getStoreCode().equals(receipt.getStoreCode()) &&
+                    r.getTransactionId().equals(receipt.getTransactionId())) {
+                // If we've already got this receipt, we'll just this submission.
+                return;
+            }
+        }
+
+        // Now try to find the current expiry date
+        Date currExpiry = new Date();
+        List<String> lProducts = Arrays.asList(PRODUCTS);
+        for (Receipt r : receipts) {
+            if (!lProducts.contains(receipt.getSku())) {
+                continue;
+            }
+            if (r.getCancellationDate() != null) {
+                continue;
+            }
+            if (r.getExpiryDate() == null) {
+                continue;
+            }
+            if (r.getExpiryDate().getTime() > currExpiry.getTime()) {
+                currExpiry = r.getExpiryDate();
+            }
+        }
+
+        // Now set the appropriate expiry date by adding time onto
+        // the end of the current expiry date
+        Calendar cal = Calendar.getInstance();
+
+344
+
+        cal.setTime(currExpiry);
+        switch (receipt.getSku()) {
+            case SKU_WORLD_1_MONTH:
+                cal.add(Calendar.MONTH, 1);
+                break;
+            case SKU_WORLD_1_YEAR:
+                cal.add(Calendar.YEAR, 1);
+        }
+        Date newExpiry = cal.getTime();
+
+        receipt.setExpiryDate(newExpiry);
+        receipts.add(receipt);
+        s.writeObject(RECEIPTS_KEY, receipts);
+
+    }
+    // Make sure this is outside the synchronized block
+    callback.onSucess(Boolean.TRUE);
+}
+
+The  main  logic  of  this  method  involves  iterating  through  all  of  the  existing  receipts  to  find  the
+
+latest current expiry date, so that when the user purchases a subscription, it’s added onto the end
+
+of the current subscription (if one exists) rather than going from today’s date. This enables users to
+
+safely renew their subscription before the subscription has expired.
+
+In the real-world, we would implement this logic on the server-side.
+
+
+
+The iTunes store and Play store have no knowledge of your subscription durations.
+This is why it’s up to you to set the expiry date in the submitReceipt method. Non-
+renewable  subscriptions  are  essentially  no  different  than  regular  consumable
+
+products. It’s up to you to manage the subscription logic - and Apple, in particular,
+
+requires you to do so using a server.
+
+Synchronizing Receipts
+
+In order for your app to provide you with current data about the user’s subscriptions and expiry
+dates,  you  need  to  synchronize  the  receipts  with  your  receipt  store.  Purchase  provides  a  set  of
+methods  for  doing  this.  Generally  I’ll  call  one  of  them  inside  the  start()  method,  and  I  may
+resynchronize at other strategic times if I suspect that the information may have changed.
+
+The following methods can be used for synchronization:
+
+1. synchronizeReceipts() - Asynchronously synchronizes receipts in the background. You won’t be
+
+notified when it’s complete.
+
+2. synchronizeReceiptsSync() - Synchronously synchronizes receipts, and blocks until it’s complete.
+
+This is safe to use on the EDT as it employs invokeAndBlock under the covers.
+
+3. synchronizeReceipts(final  long  ifOlderThanMs,  final  SuccessCallback<Boolean>  callback)  -
+Asynchronously  synchronizes  receipts,  but  only  if  they  haven’t  been  synchronized  in  the
+
+specified  time  period.  E.g.  In  your  start()  method  you  might  decide  that  you  only  want  to
+
+345
+
+synchronize  receipts  once  per  day.  This  also  includes  a  callback  that  will  be  called  when
+
+synchronization is complete.
+
+4. synchronizeReceiptsSync(long  ifOlderThanMs)  -  A  synchronous  version  that  will  only  refetch  if
+
+data is older than given time.
+
+In our hello world app we synchronize the subscriptions in a few places.
+
+At the end of the start() method:
+
+public void start() {
+
+   ...
+
+    // Now synchronize the receipts
+    iap.synchronizeReceipts(0, res->{
+        // Update the UI as necessary to reflect
+
+    });
+}
+
+And we also provide a button to allow the user to manually synchronize the receipts.
+
+Button syncReceipts = new Button("Synchronize Receipts");
+
+syncReceipts.addActionListener(e->{
+
+    iap.synchronizeReceipts(0, res->{
+        // Update the UI
+    });
+});
+
+Expiry Dates and Subscription Status
+
+Now that we have a receipt store registered, and we have synchronized our receipts, we can query
+the Purchase instance to see if a SKU or set of SKUs is currently subscribed. There are three useful
+methods in this realm:
+
+1. boolean isSubscribed(String… skus) - Checks to see if the user is currently subscribed to any of
+
+the provided SKUs.
+
+2. Date getExpiryDate(String… skus) - Gets the latest expiry date of a set of SKUs.
+
+3. Receipt  getFirstReceiptExpiringAfter(Date  dt,  String…  skus)  -  This  method  will  return  the
+earliest receipt with an expiry date after the given date. This is needed in cases where you need
+
+to decide if the user should have access to some content based on its publication date. E.g. If you
+
+published an issue of your e-zine on March 1, and the user purchased a subscription on March
+
+15th, then they should get access to the March 1st issue even though it doesn’t necessarily fall in
+
+the  subscription  period.  Being  able  to  easily  fetch  the  first  receipt  after  a  given  date  makes  it
+
+easier to determine if a particular issue should be covered by a subscription.
+
+346
+
+If you need to know more information about subscriptions, you can always just call getReceipts()
+to obtain a list of all of the current receipts and determine for yourself what the user should have
+
+access to.
+
+In the hello world app we’ll use this information in a few different places. On our main form we’ll
+
+include  a  label  to  show  the  current  expiry  date,  and  we  allow  the  user  to  press  a  button  to
+
+synchronize receipts manually if they think the value is out of date.
+
+// ...
+
+SpanLabel rentalStatus = new SpanLabel("Loading rental details...");
+Button syncReceipts = new Button("Synchronize Receipts");
+
+syncReceipts.addActionListener(e->{
+
+    iap.synchronizeReceipts(0, res->{
+        if (iap.isSubscribed(PRODUCTS)) {
+            rentalStatus.setText("World rental expires "+iap.getExpiryDate(PRODUCTS));
+        } else {
+            rentalStatus.setText("You don't currently have a subscription to the world");
+        }
+        hi.revalidate();
+    });
+});
+
+Allowing the User to Purchase the Subscription
+
+You  should  now  have  all  of  the  background  required  to  implement  the  Hello  World  Subscription
+
+app. So we’ll return to the code and see how the user purchases a subscription.
+
+In  the  main  form,  we  want  two  buttons  to  subscribe  to  the  "World",  for  one  month  and  one  year
+
+respectively. They look like:
+
+347
+
+Purchase iap = Purchase.getInAppPurchase();
+// ...
+Button rentWorld1M = new Button("Rent World 1 Month");
+rentWorld1M.addActionListener(e->{
+    String msg = null;
+    if (iap.isSubscribed(PRODUCTS)) {  ①
+        msg = "You are already renting the world until "
+             +iap.getExpiryDate(PRODUCTS)  ②
+             +".  Extend it for one more month?";
+    } else {
+        msg = "Rent the world for 1 month?";
+    }
+    if (Dialog.show("Confirm", msg, "Yes", "No")) {
+        Purchase.getInAppPurchase().purchase(SKU_WORLD_1_MONTH); ③
+        // Note: since this is a non-renewable subscription it is just a regular
+        // product in the play store - therefore we use the purchase() method.
+        // If it were a "subscription" product in the play store, then we
+        // would use subscribe() instead.
+    }
+});
+
+Button rentWorld1Y = new Button("Rent World 1 Year");
+rentWorld1Y.addActionListener(e->{
+    String msg = null;
+    if (iap.isSubscribed(PRODUCTS)) {
+        msg = "You are already renting the world until "+
+               iap.getExpiryDate(PRODUCTS)+
+              ".  Extend it for one more year?";
+    } else {
+        msg = "Rent the world for 1 year?";
+    }
+    if (Dialog.show("Confirm", msg, "Yes", "No")) {
+        Purchase.getInAppPurchase().purchase(SKU_WORLD_1_YEAR);
+        // Note: since this is a non-renewable subscription it is just a regular
+        // product in the play store - therefore we use the purchase() method.
+        // If it were a "subscription" product in the play store, then we
+        // would use subscribe() instead.
+    }
+});
+
+① In the event handler we check if the user is subscribed by calling isSubscribed(PRODUCTS). Notice
+
+that we check it against the array of both the one month and one year subscription SKUs.
+
+② We are able to tell the user when the current expiry date is so that they can gauge whether to
+
+proceed.
+
+③ Since  this  is  a  non-renewable  subscription,  we  use  the  Purchase.purchase()  method.  See
+
+following note about subscribe() vs purchase()
+
+348
+
+9.2.8. subscribe() vs purchase()
+
+The Purchase class includes two methods for initiating a purchase:
+
+1. purchase(sku)
+
+2. subscribe(sku)
+
+Which one you use depends on the type of product that is being purchased. If your product is set up
+as  a  subscription  in  the  Google  Play  store,  then  you  should  use  subscribe(sku).  Otherwise,  you
+should use purchase(sku).
+
+Handling Purchase Callbacks
+
+The  purchase  callbacks  are  very  similar  to  the  ones  that  we  implemented  in  the  regular  in-app
+
+purchase examples:
+
+@Override
+public void itemPurchased(String sku) {
+    Purchase iap = Purchase.getInAppPurchase();
+
+    // Force us to reload the receipts from the store.
+    iap.synchronizeReceiptsSync(0);
+    ToastBar.showMessage("Your subscription has been extended to "+iap.getExpiryDate(PRODUCTS),
+FontImage.MATERIAL_THUMB_UP);
+}
+
+@Override
+public void itemPurchaseError(String sku, String errorMessage) {
+    ToastBar.showErrorMessage("Failure occurred: "+errorMessage);
+}
+
+Notice that, in itemPurchased() we don’t need to explicitly create any receipts or submit anything to
+the  receipt  store.  This 
+to
+synchronizeReceiptsSync() but this is just to ensure that our toast message has the new expiry date
+loaded already.
+
+for  you  automatically.  We  do  make  a  call 
+
+is  handled 
+
+9.2.9. Screenshots
+
+349
+
+Figure 317. Main form
+
+Figure 318. Dialog shown when subscribing to a product
+
+350
+
+Figure 319. Simulator confirm dialog when purchasing a subscription
+
+Figure 320. Upon successful purchase, the toastbar message is shown
+
+9.2.10. Summary
+
+This  section  demonstrated  how  to  set  up  an  app  to  use  non-renewable  subscriptions  using  in-app
+
+purchase.  Non-renewable  subscriptions  are  the  same  as  regular  consumable  products  except  for
+
+the fact that they are shared by all of the user’s devices, and thus, require a server component. The
+
+app store has no knowledge of the duration of your non-renewable subscriptions. It’s up to you to
+
+specify  the  expiry  date  of  purchased  subscriptions  on  their  receipts  when  they  are  submitted.
+
+Google  play  doesn’t  formally  have  a  "non-renewable"  subscription  product  type.  To  implement
+
+them in Google play, you would just set up a regular product. It’s how you handle it internally that
+
+makes it a subscription, and not just a regular product.
+
+Codename One uses the Receipt class as the foundation for its subscriptions infrastructure. You, as
+the developer, are responsible for implementing the ReceiptStore interface to provide the receipts.
+The  Purchase  instance  will  load  receipts  from  your  ReceiptStore,  and  use  them  to  determine
+whether the user is currently subscribed to a subscription, and when the subscription expires.
+
+9.2.11. Auto-Renewable Subscriptions
+
+Auto-renewable  subscriptions  provide,  arguably,  an  easier  path  to  recurring  revenue  than  non-
+
+renewable subscriptions because all of the subscription stuff is handled by the app store. You defer
+
+almost entirely to the app store (iTunes for iOS, and Play for Android) for billing and management.
+
+If there is a down-side, it would be that you are also subject to the rules of each app store - and they
+
+351
+
+take their cut of the revenue.
+
+1. For  more  information  about  Apple’s  auto-renewable  subscription  features  and  rules  see  this
+
+document [https://developer.apple.com/app-store/subscriptions/].
+
+2. For  more 
+
+information  about 
+
+subscriptions 
+
+in  Google  play, 
+
+see 
+
+this  document
+
+[https://developer.android.com/google/play/billing/billing_subscriptions.html].
+
+9.2.12. Auto-Renewable vs Non-Renewable.  Best Choice?
+
+When  deciding  between  auto-renewable  and  non-renewable  subscriptions,  as  always,  the  answer
+
+will depend on your needs and preferences. Auto-renewables are nice because it takes the process
+
+completely out of your hands. You just get paid. On the other hand, there are valid reasons to want
+
+to use non-renewables. E.g. You can’t cancel an auto-renewable subscription for a user. They have
+
+to do that themselves. You may also want more control over the subscription and renewal process,
+
+in which case a non-renewable might make more sense.
+
+
+
+There  are  some  developers  that  are  opposed  to  auto-renewable  subscriptions
+
+[https://marco.org/2013/12/02/auto-renewable-subscriptions],  we  don’t  have  enough
+
+information to make a solid recommendation on this matter
+
+On  a  practical  level,  if  you  are  using  auto-renewable  subscriptions  (and  therefore  subscription
+products in the Google play store) you must use the Purchase.subscribe(sku) method for initiating
+the  purchase  workflow.  For  non-renewable  subscriptions  (and  therefore  regular  products  in  the
+Google play store), you must use the Purchase.purchase(sku) method.
+
+9.2.13. Learning By Example
+
+In this section we’ll describe the general workflow of subscription management on the server. We
+
+also demonstrate how use Apple’s and Google’s web services to validate receipts and stay informed
+
+of important events (such as when users cancel or renew their subscriptions).
+
+9.2.14. Building the IAP Demo Project
+
+To aid in this process, we’ve created a fully-functional in-app purchase demo project that includes
+
+both  a  client  app  [https://gist.github.com/shannah/b61b9b6b35ea0eac923a54163f5d4deb]  and  a  server  app
+
+[https://github.com/shannah/cn1-iap-demo-server].
+
+Setting up the Client Project
+
+1. Create  a  new  Codename  One  project  in  Netbeans,  and  choose  the  "Bare-bones  Hello  World
+
+Template".  You  should  make  your  package  name  something  unique  so  that  you  are  able  to
+
+create real corresponding apps in both Google Play and iTunes connect.
+
+2. Once 
+
+the  project 
+
+is 
+
+created, 
+
+copy 
+
+this 
+
+source 
+
+file 
+
+[https://gist.github.com/shannah/
+
+b61b9b6b35ea0eac923a54163f5d4deb]  contents  into  your  main  class  file.  Then  change  the  package
+name,  and  class  name  in  the  file  to  match  your  project  settings.  E.g.  change  package
+ca.weblite.iapdemo;  to  package  <your.package.name.here>;  and  class  IAPDemo  implements
+PurchaseCallback to class YourClassName implements PurchaseCallback.
+
+352
+
+3. Add  the  Generic  Web  Service  Client  [https://github.com/shannah/cn1-generic-webservice-client]  library
+
+to  your  project  by  going  to  "Codename  Settings"  >  "Extensions",  finding  that  library,  and  click
+
+"Download". Then "Refresh CN1 libs" as it suggests.
+
+4. Change  the  localHost  property  to  point  to  your  local  machine’s  network  address.  Using
+"http://localhost" is not going to cut it here because when the app is running on a phone, it needs
+
+to  be  able  to  connect  to  your  web  server  over  the  network.  This  address  will  be  your  local
+
+network address (e.g. 192.168.0.9, or something like that).
+
+private static final String localHost = "http://10.0.1.32";
+
+5. Add 
+
+the 
+
+ios.plistInject 
+
+build 
+
+hint 
+
+to 
+
+your 
+
+project  with 
+
+the 
+
+value
+
+"<key>NSAppTransportSecurity</key>  <dict>  <key>NSAllowsArbitraryLoads</key>  <true/>
+
+</dict>".  This  is  so  that  we  can  use  http  urls  in  iOS.  Since  we  don’t  intend  to  fully  publish  this
+
+app, we can cut corners like this. If you were creating a real app, you would use proper secure
+
+URLs.
+
+Setting up the Server Project
+
+Download  the  CN1-IAP-Server  demo  project  from  Github,  and  run  its  "install-deps"  ANT  task  in
+
+order to download and install its dependencies to your local Maven repo.
+
+ For the following commands to work, make sure you have "ant", "mvn", and "git"
+
+in your environment PATH.
+
+$ git clone https://github.com/shannah/cn1-iap-demo-server
+$ cd cn1-iap-demo-server
+$ ant install-deps
+
+Open the project in Netbeans
+
+Setting up the Database
+
+1. Create a new database in your preferred DBMS. Call it anything you like.
+
+2. Create a new table named "RECEIPTS" in this database with the following structure:
+
+353
+
+create TABLE RECEIPTS
+(
+    TRANSACTION_ID VARCHAR(128) not null,
+    USERNAME VARCHAR(64) not null,
+    SKU VARCHAR(128) not null,
+    ORDER_DATA VARCHAR(32000),
+    PURCHASE_DATE BIGINT,
+    EXPIRY_DATE BIGINT,
+    CANCELLATION_DATE BIGINT,
+    LAST_VALIDATED BIGINT,
+    STORE_CODE VARCHAR(20) default '' not null,
+    primary key (TRANSACTION_ID, STORE_CODE)
+)
+
+3. Open the "persistence.xml" file in the server netbeans project.
+
+4. Change the data source to the database you just created.
+
+If you’re not sure how to create a data source, see my previous tutorial on connecting to a MySQL
+
+database [https://www.codenameone.com/blog/connecting-to-a-mysql-database-part-2.html].
+
+Testing the Project
+
+At this point we should be able to test out the project in the Codename One simulator to make sure
+
+it’s working.
+
+1. Build and Run the server project in Netbeans. You may need to tell it which application server
+
+you wish to run it on. I am running it on the Glassfish 4.1 that comes bundled with Netbeans.
+
+2. Build and run the client project in Netbeans. This should open the Codename One simulator.
+
+When the app first opens you’ll see a screen as follows:
+
+354
+
+Figure 321. First screen of app
+
+This screen is for testing consumable products, so we won’t be making use of this right now.
+
+Open the hamburger menu and select "Subscriptions". You should see something like this:
+
+Figure 322. Subscriptions form
+
+Click on the "Subscribe 1 Month No Ads" button. You will be prompted to accept the purchase:
+
+355
+
+Figure 323. Approve purchase dialog
+
+Upon  completion,  the  app  will  submit  the  purchase  to  your  server,  and  if  all  went  well,  it  will
+
+retrieve the updated list of receipts from your server also, and update the label on this form to say
+
+"No Ads. Expires <some date>":
+
+Figure 324. After successful purchase
+
+
+
+This project is set up to use an expedited expiry date schedule for purchases from
+
+the simulator. 1 month = 5 minutes. 3 months = 15 minutes. This helps for testing.
+
+That is why your expiry date may be different than expected.
+
+Just  to  verify  that  the  receipt  was  inserted  correctly,  you  should  check  the  contents  of  your
+
+"RECEIPTS"  table  in  your  database.  In  Netbeans,  I  can  do  this  easily  from  the  "Services"  pane.
+
+Expand  the  database  connection  down  to  the  RECEIPTS  table,  right  click  "RECEIPTS"  and  select
+
+"View Data". This will open a data table similar the the following:
+
+356
+
+Figure 325. Receipts table after insertion
+
+Figure 326. Table view
+
+A few things to mention here:
+
+1. The "username" was provided by the client. It’s hard-coded to "admin", but the idea is that you
+
+would have the user log in and you would have access to their real username.
+
+2. All dates are stored as unix timestamps in milliseconds.
+
+If you delete the receipt from your database, then press the "Synchronize Receipts" button in your
+
+app, the app will again say "No subscriptions." Similarly if you wait 5 minutes and hit "Synchronize
+
+receipts" the app will say no subscriptions found, and the "ads" will be back.
+
+Troubleshooting
+
+Let’s not pretend that everything worked for you on the first try. There’s a lot that could go wrong
+
+here. If you make a purchase and nothing appears to happen, the first thing you should do is check
+
+the  Network  Monitor  in  the  simulator  ("Simulate"  >  "Network"  >  "Network  Monitor").  You  should
+
+see  a  list  of  network  requests.  Some  will  be  GET  requests  and  there  will  be  at  least  one  POST
+
+request. Check the response of these requests to see if they succeeded.
+
+Also check the Glassfish server log to see if there is an exception.
+
+Common problems would be that the URL you have set in the client app for endpointURL is incorrect,
+or that there is a database connection problem.
+
+9.2.15. Looking at the Source of the App
+
+Now that we’ve set up and built the app, let’s take a look at the source code so you can see how it all
+
+works.
+
+Client Side
+
+I  use  the  Generic  Webservice  Client  Library  [https://github.com/shannah/cn1-generic-webservice-client]
+
+357
+
+from inside my ReceiptStore implementation to load receipts from the web service, and insert new
+receipts to the database.
+
+The source for my ReceiptStore is as follows:
+
+private ReceiptStore createReceiptStore() {
+    return new ReceiptStore() {
+
+        RESTfulWebServiceClient client = createRESTClient(receiptsEndpoint);
+
+        @Override
+        public void fetchReceipts(SuccessCallback<Receipt[]> callback) {
+            RESTfulWebServiceClient.Query query = new RESTfulWebServiceClient.Query() {
+
+                @Override
+                protected void setupConnectionRequest(RESTfulWebServiceClient client, ConnectionRequest req) {
+                    super.setupConnectionRequest(client, req);
+                    req.setUrl(receiptsEndpoint);
+                }
+
+            };
+            client.find(query, rowset->{
+                List<Receipt> out = new ArrayList<Receipt>();
+                for (Map m : rowset) {
+                    Result res = Result.fromContent(m);
+                    Receipt r = new Receipt();
+                    r.setTransactionId(res.getAsString("transactionId"));
+                    r.setPurchaseDate(new Date(res.getAsLong("purchaseDate")));
+                    r.setQuantity(1);
+                    r.setStoreCode(m.getAsString("storeCode"));
+                    r.setSku(res.getAsString("sku"));
+
+                    if (m.containsKey("cancellationDate") && m.get("cancellationDate") != null) {
+                        r.setCancellationDate(new Date(res.getAsLong("cancellationDate")));
+                    }
+                    if (m.containsKey("expiryDate") && m.get("expiryDate") != null) {
+                        r.setExpiryDate(new Date(res.getAsLong("expiryDate")));
+                    }
+                    out.add(r);
+
+                }
+                callback.onSucess(out.toArray(new Receipt[out.size()]));
+            });
+        }
+
+        @Override
+        public void submitReceipt(Receipt r, SuccessCallback<Boolean> callback) {
+            Map m = new HashMap();
+            m.put("transactionId", r.getTransactionId());
+            m.put("sku", r.getSku());
+            m.put("purchaseDate", r.getPurchaseDate().getTime());
+            m.put("orderData", r.getOrderData());
+            m.put("storeCode", r.getStoreCode());
+            client.create(m, callback);
+        }
+
+    };
+}
+
+358
+
+Notice  that  we  are  not  doing  any  calculation  of  expiry  dates  in  our  client  app,  as  we  did  in  the
+
+previous post (on non-renewable receipts). Since we are using a server now, it makes sense to move
+
+all of that logic over to the server.
+
+The  createRESTClient()  method  shown  there  simply  creates  a  RESTfulWebServiceClient  and
+configuring it to use basic authentication with a username and password. The idea is that your user
+
+would have logged into your app at some point, and you would have a username and password on
+
+hand to pass back to the web service with the receipt data so that you can connect the subscription
+
+to a user account. The source of that method is listed here:
+
+/**
+ * Creates a REST client to connect to a particular endpoint.  The REST client
+ * generated here will automatically add the Authorization header
+ * which tells the service what platform we are on.
+ * @param url The url of the endpoint.
+ * @return
+ */
+private RESTfulWebServiceClient createRESTClient(String url) {
+    return new RESTfulWebServiceClient(url) {
+
+        @Override
+        protected void setupConnectionRequest(ConnectionRequest req) {
+            try {
+                req.addRequestHeader("Authorization", "Basic " +
+Base64.encode((getUsername()+":"+getPassword()).getBytes("UTF-8")));
+            } catch (Exception ex) {}
+        }
+
+    };
+}
+
+Server-Side
+
+On  the  server-side,  our  REST  controller  is  a  standard  JAX-RS  REST  interface.  I  used  Netbeans  web
+
+service  wizard  to  generate  it  and  then  modified  it  to  suit  my  purposes.  The  methods  of  the
+ReceiptsFacadeREST class pertaining to the REST API are shown here:
+
+359
+
+@Stateless
+@Path("com.codename1.demos.iapserver.receipts")
+public class ReceiptsFacadeREST extends AbstractFacade<Receipts> {
+
+    // ...
+
+    @POST
+    @Consumes({"application/xml", "application/json"})
+    public void create(Receipts entity) {
+
+        String username = credentialsWithBasicAuthentication(request).getName();
+        entity.setUsername(username);
+
+        // Save the receipt first in case something goes wrong in the validation stage
+        super.create(entity);
+
+        // Let's validate the receipt
+        validateAndSaveReceipt(entity);
+            // validates the receipt against appropriate web service
+            // and updates database if expiry date has changed.
+    }
+
+    // ...
+    @GET
+    @Override
+    @Produces({"application/xml", "application/json"})
+    public List<Receipts> findAll() {
+        String username = credentialsWithBasicAuthentication(request).getName();
+        return getEntityManager()
+                .createNamedQuery("Receipts.findByUsername")
+                .setParameter("username", username)
+                .getResultList();
+    }
+}
+
+The magic happens inside that validateAndSaveReceipt() method, which I’ll cover in detail soon.
+
+Notifications
+
+It’s  important  to  note  that  you  will  not  be  notified  by  apple  or  google  when  changes  are  made  to
+
+subscriptions. It’s up to you to periodically "poll" their web service to find if any changes have been
+
+made.  Changes  we  would  be  interested  in  are  primarily  renewals  and  cancellations.  In  order  to
+
+deal  with  this,  set  up  a  method  to  run  periodically  (once-per  day  might  be  enough).  For  testing,  I
+
+actually set it up to run once per minute as shown below:
+
+360
+
+private static final long ONE_DAY = 24 * 60 * 60 * 1000;
+private static final long ONE_DAY_SANDBOX = 10 * 1000;
+@Schedule(hour="*", minute="*")
+public void validateSubscriptionsCron() {
+    System.out.println("----------- DOING TIMED TASK ---------");
+    List<Receipts> res = null;
+    final Set<String> completedTransactionIds = new HashSet<String>();
+    for (String storeCode : new String[]{Receipt.STORE_CODE_ITUNES, Receipt.STORE_CODE_PLAY}) {
+        while (!(res = getEntityManager().createNamedQuery("Receipts.findNextToValidate")
+                .setParameter("threshold", System.currentTimeMillis() - ONE_DAY_SANDBOX)
+                .setParameter("storeCode", storeCode)
+                .setMaxResults(1)
+                .getResultList()).isEmpty() &&
+                !completedTransactionIds.contains(res.get(0).getTransactionId())) {
+
+            final Receipts curr = res.get(0);
+            completedTransactionIds.add(curr.getTransactionId());
+            Receipts[] validatedReceipts =  validateAndSaveReceipt(curr);
+            em.flush();
+            for (Receipts r : validatedReceipts) {
+                completedTransactionIds.add(r.getTransactionId());
+            }
+
+        }
+    }
+}
+
+That  method  simply  finds  all  of  the  receipts  in  the  database  that  haven’t  been  validated  in  some
+period  of  time,  and  validates  it.  Again,  the  magic  happens  inside  the  validateAndSaveReceipt()
+method which we cover later.
+
+ In this example we only validate receipts from the iTunes and Play stores because
+
+those are the only ones that we currently support auto-renewing subscriptions on.
+
+9.2.16. The CN1-IAP-Validator Library
+
+For the purpose of this tutorial, I created a library to handle receipt validation in a way that hides
+
+as much of the complexity as possible. It supports both Google Play receipts and iTunes receipts.
+
+The general usage is as follows:
+
+361
+
+IAPValidator validator = IAPValidator.getValidatorForPlatform(receipt.getStoreCode());
+if (validator == null) {
+   // no validators were found for this store
+   // Do custom validation
+} else {
+    validator.setAppleSecret(APPLE_SECRET);
+    validator.setGoogleClientId(GOOGLE_DEVELOPER_API_CLIENT_ID);
+    validator.setGooglePrivateKey(GOOGLE_DEVELOPER_PRIVATE_KEY);
+    Receipt[] result = validator.validate(receipt);
+    ...
+}
+
+As you can see from this snippet, the complexity of receipt validation has been reduced to entering
+
+three configuration strings:
+
+1. APPLE_SECRET  -  This  is  a  "secret"  string  that  you  will  get  from  iTunes  connect  when  you  set  up
+
+your in-app products.
+
+2. GOOGLE_DEVELOPER_API_CLIENT_ID  -  A  client  ID  that  you’ll  get  from  the  google  developer  API
+
+console when you set up your API service credentials.
+
+3. GOOGLE_DEVELOPER_PRIVATE_KEY  -  A  PKCS8  encoded  string  with  an  RSA  private  key  that  you’ll
+
+receive at the same time as the GOOGLE_DEVELOPER_API_CLIENT_ID.
+
+I will go through the steps to obtain these values soon.
+
+9.2.17. The validateAndSaveReceipt() Method
+
+You are now ready to see the full magic of the validateAndSaveReceipt() method in all its glory:
+
+/**
+ * Validates a given receipt, updating the expiry date,
+ * @param receipt The receipt to be validated
+ * @param forInsert If true, then an expiry date will be calculated even if there is no validator.
+ */
+private Receipts[] validateAndSaveReceipt(Receipts receipt) {
+    EntityManager em = getEntityManager();
+    Receipts managedReceipt = getManagedReceipt(receipt);
+        // managedReceipt == receipt if receipt is in database or null otherwise
+
+    if (Receipt.STORE_CODE_SIMULATOR.equals(receipt.getStoreCode())) { ①
+        if (receipt.getExpiryDate() == null && managedReceipt == null) {
+            //Not inserted yet and no expiry date set yet
+            Date dt = calculateExpiryDate(receipt.getSku(), true);
+            if (dt != null) {
+                receipt.setExpiryDate(dt.getTime());
+            }
+        }
+        if (managedReceipt == null) {
+            // Receipt is not in the database yet.  Add it
+            em.persist(receipt);
+            return new Receipts[]{receipt};
+
+362
+
+        } else {
+            // The receipt is already in the database.  Update it.
+            em.merge(managedReceipt);
+            return new Receipts[]{managedReceipt};
+        }
+    } else {
+        // It's not a simulator receipt
+        IAPValidator validator = IAPValidator.getValidatorForPlatform(receipt.getStoreCode());
+        if (validator == null) {
+            // Receipt must have come from a platform other than iTunes or Play
+            // Because there is no validator
+
+            if (receipt.getExpiryDate() == null && managedReceipt == null) {
+                // No expiry date.
+                // Generate one.
+                Date dt = calculateExpiryDate(receipt.getSku(), false);
+                if (dt != null) {
+                    receipt.setExpiryDate(dt.getTime());
+                }
+
+            }
+            if (managedReceipt == null) {
+                em.persist(receipt);
+                return new Receipts[]{receipt};
+            } else {
+                em.merge(managedReceipt);
+                return new Receipts[]{managedReceipt};
+            }
+
+        }
+
+        // Set credentials for the validator
+        validator.setAppleSecret(APPLE_SECRET);
+        validator.setGoogleClientId(GOOGLE_DEVELOPER_API_CLIENT_ID);
+        validator.setGooglePrivateKey(GOOGLE_DEVELOPER_PRIVATE_KEY);
+
+        // Create a dummy receipt with only transaction ID and order data to pass
+        // to the validator.  Really all it needs is order data to be able to validate
+        Receipt r2 = Receipt();
+        r2.setTransactionId(receipt.getTransactionId());
+        r2.setOrderData(receipt.getOrderData());
+        try {
+            Receipt[] result = validator.validate(r2);
+            // Depending on the platform, result may contain many receipts or a single receipt
+            // matching our receipt.  In the case of iTunes, none of the receipt transaction IDs
+            // might match the original receipt's transactionId because the validator
+            // will set the transaction ID to the *original* receipt's transaction ID.
+            // If none match, then we should remove our receipt, and update each of the returned
+            // receipts in the database.
+             Receipt matchingValidatedReceipt = null;
+            for (Receipt r3 : result) {
+                if (r3.getTransactionId().equals(receipt.getTransactionId())) {
+                    matchingValidatedReceipt = r3;
+                    break;
+                }
+            }
+
+363
+
+            if (matchingValidatedReceipt == null) {
+                // Since the validator didn't find our receipt,
+                // we should remove the receipt.  The equivalent
+                // is stored under the original receipt's transaction ID
+                if (managedReceipt != null) {
+                    em.remove(managedReceipt);
+                    managedReceipt = null;
+                }
+            }
+            List<Receipts> out = new ArrayList<Receipts>();
+            // Now go through and
+            for (Receipt r3 : result) {
+                if (r3.getOrderData() == null) {
+                    // No order data found in receipt.  Setting it to the original order data
+                    r3.setOrderData(receipt.getOrderData());
+                }
+                Receipts eReceipt = new Receipts();
+                eReceipt.setTransactionId(r3.getTransactionId());
+                eReceipt.setStoreCode(receipt.getStoreCode());
+                Receipts eManagedReceipt = getManagedReceipt(eReceipt);
+                if (eManagedReceipt == null) {
+                    copy(eReceipt, r3);
+                    eReceipt.setUsername(receipt.getUsername());
+                    eReceipt.setLastValidated(System.currentTimeMillis());
+                    em.persist(eReceipt);
+                    out.add(eReceipt);
+                } else {
+
+                    copy(eManagedReceipt, r3);
+                    eManagedReceipt.setUsername(receipt.getUsername());
+                    eManagedReceipt.setLastValidated(System.currentTimeMillis());
+                    em.merge(eManagedReceipt);
+                    out.add(eManagedReceipt);
+                }
+            }
+
+            return out.toArray(new Receipts[out.size()]);
+
+        } catch (Exception ex) {
+            // We should probably store some info about the failure in the
+            // database to make it easier to find receipts that aren't validating,
+            // but for now we'll just log it.
+            Log.p("Failed to validate receipt "+r2);
+            Log.p("Reason: "+ex.getMessage());
+            Log.e(ex);
+            return new Receipts[]{receipt};
+
+        }
+    }
+}
+
+① We need to handle the case where the app is being used in the CN1 simulator. We’ll treat this as
+a  non-renewable  receipt,  and  we’ll  calculate  the  expiry  date  using  an  "accelerated"  clock  to
+
+assist in testing.
+
+364
+
+
+
+In many of the code snippets for the Server-side code, you’ll see references to both
+a Receipts class and a Receipt class. I know this is slightly confusing. The Receipts
+class  is  a  JPA  entity  the  encapsulates  a  row  from  the  "receipts"  table  of  our  SQL
+database. The Receipt class is com.codename1.payment.Receipt. It’s used to interface
+with the IAP validation library.
+
+9.2.18. Google Play Setup
+
+Creating the App in Google Play
+
+In order to test out in-app purchase on an Android device, you’ll need to create an app the Google
+
+Play  Developer  Console  [https://play.google.com/apps/publish/].  I  won’t  describe  the  process  in  this
+
+section,  but  there  is  plenty  of  information  around  the  internet  on  how  to  do  this.  Some  useful
+
+references for this include:
+
+1. Getting  Started  With  Publishing  [https://developer.android.com/distribute/googleplay/start.html]  -  If  you
+
+don’t already have an account with Google to publish your apps.
+
+2. Launch Checklist [https://developer.android.com/distribute/tools/launch-checklist.html]
+
+Graphics, Icons, etc..
+
+You are required to upload some screenshots and feature graphics. Don’t waste time making these
+
+perfect.  For  the  screenshots,  you  can  just  use  the  "Screenshot"  option  in  the  simulator.  (Use  the
+
+Nexus  5  skin).  For  the  feature  graphics,  I  used  this  site  [https://www.norio.be/android-feature-graphic-
+
+generator/] that will generate the graphics in the correct dimensions for Google Play. You can also just
+
+leave the icon as the default Codename One icon.
+
+Creating Test Accounts
+
+ You cannot purchase in-app products from your app using your publisher account.
+
+You need to set up at least one test account for the purpose of testing the app.
+
+In order to test your app, you need to set up a test account. A test account must be associated with a
+
+real gmail email address. If you have a domain that is managed by Google apps, then you can also
+
+use an address from that domain.
+
+The 
+
+full  process 
+
+for 
+
+testing 
+
+in-app  billing  can  be 
+
+found 
+
+in 
+
+this  google  document
+
+[https://developer.android.com/google/play/billing/billing_testing.html].  However,  I  personally  found  this
+
+documentation difficult to follow.
+
+For your purposes, you’ll need to set up a tester list in Google Play. Choose "Settings" > "Tester Lists".
+
+Then create a list with all of the email address that you want to have treated as test accounts. Any
+
+purchases  made  by  these  email  addresses  will  be  treated  as  "Sandbox"  purchases,  and  won’t
+
+require real money to change hands.
+
+Alpha Channel Distribution
+
+In order to test in-app purchase on Android, you must first publish your app. You can’t just build
+
+and  install  your  app  manually.  The  app  needs  to  be  published  on  the  Play  store,  and  it  must  be
+
+365
+
+installed through the play store for in-app purchase to work. Luckily you can publish to an Alpha
+
+channel so that your app won’t be publicly available.
+
+For  more  information  about  setting  up  alpha  testing  on  Google  play  see  this  Google  support
+
+document on the subject [https://support.google.com/googleplay/android-developer/answer/3131213?hl=en].
+
+Once you have set your app up for alpha testing, you can send an invite link to your test accounts.
+
+You can find the link in the Google Play console under the APK section, under the "Alpha" tab (and
+
+assuming you’ve enabled alpha testing.
+
+Figure 327. Alpha testing tab in google play
+
+The format of the link is https://play.google.com/apps/testing/your-app-id in case you can’t find it.
+You  can  email  this  to  your  alpha  testers.  Make  sure  that  you  have  added  all  testers  to  your  tester
+
+lists so that their purchases will be made in the sandbox environment.
+
+Also,  before  proceeding  with  testing  in-app  purchases,  you  need  to  add  the  in-app  products  in
+
+Google Play.
+
+Adding In-App Products
+
+After  you  have  published  your  APK  to  the  alpha  channel,  you  can  create  the  products.  For  the
+
+purposes of this tutorial, we’ll just add two products:
+
+1. iapdemo.noads.month.auto - The 1 month subscription.
+
+2. iapdemo.noads.3month.auto - The 3 month subscription.
+
+
+
+Since  we  will  be  adding  products  as  "Subscriptions"  in  the  pay  store,  your  app
+must  use  the  Purchase.subscribe(sku)  method  for  initiating  a  purchase  on  these
+products,  and  not  the  Purchase.purchase(sku)  method.  If  you  accidentally  use
+purchase()  to  purchase  a  subscription  on  Android,  the  payment  will  go  through,
+but your purchase callback will receive an error.
+
+Adding 1 month Subscription
+
+1. Open Google Play Developer Console, and navigate to your app.
+
+2. Click on "In-app Products" in the menu. Then click the "Add New Product" button.
+
+3. Select  "Subscription",  and  enter  "iapdemo.noads.month.auto"  for  the  Product  ID.  Then  click
+
+"Continue"
+
+366
+
+Figure 328. Add new product dialog
+
+Now fill in the form. You can choose your own price and name for the product. The following is a
+
+screenshot of the options I chose.
+
+Figure 329. Add product to google
+
+Adding 3 month Subscription
+
+Follow the same process as for the 1 month subscription except use "iapdemo.noads.3month.auto"
+
+for the product ID, and select "3 months" for the billing period instead of "Monthly".
+
+Testing The App
+
+At this point we should be ready to test our app. Assuming you’ve installed the app using the invite
+
+link you sent yourself from Google play, as a test account that is listed on your testers list, you
+
+should be good to go.
+
+Open the app, click on "Subscriptions", and try to purchase a 1-month subscription. If all goes well,
+
+it should insert the subscription into your database. But with no expiry date, since we haven’t yet
+
+implemented receipt validation yet. We’ll do that next.
+
+Creating Google Play Receipt Validation Credentials
+
+Google  play  receipt  validation  is  accomplished  via  the  android-publisher  Purchases:  get  API
+
+[https://developers.google.com/android-publisher/api-ref/purchases/subscriptions/get].  The  CN1-IAP-Validation
+
+library  shields  you  from  most  of  the  complexities  of  using  this  API,  but  you  still  need  to  obtain  a
+
+367
+
+"private  key"  and  a  "client  id"  to  access  this  API.  Both  of  these  are  provided  when  you  set  up  an
+
+OAuth2  Service  Account  [https://developers.google.com/identity/protocols/OAuth2ServiceAccount]  for  your
+
+app.
+
+
+
+Steps:
+
+The following steps assume that you have already created your app in Google play
+
+and have published it to at least the alpha channel. See my previous post on this
+
+topic here (Link to be provided).
+
+1. Open  the  Google  API  Developer  Console  [https://console.developers.google.com/apis],  and  select  your
+
+App from the the menu.
+
+2. Click  on  the  "Library"  menu  item  in  the  left  menu,  and  then  click  the  "Google  Play  Developer
+
+API" link.
+
+Figure 330. Google Play Developer API Link
+
+3. Click on the button that says "Enable". (If you already have it enabled, then just proceed to the
+
+next step).
+
+Figure 331. Enable API button
+
+4. Click on the "Credentials" menu item in the left menu.
+
+5. In the "Credentials" drop-down menu, select the "Service Account Key" option.
+
+Figure 332. Credentials dropdown
+
+6. You will be presented with a new form. In the "Service Account" drop-down, select "New Service
+
+Account". This will give you some additional options.
+
+Figure 333. Create service account key
+
+7. Enter  anything  you  like  for  the  "Service  account  name".  For  the  role,  we’ll  select  "Project"  >
+
+368
+
+"Owner"  for  now  just  so  we  don’t  run  into  permissions  issues.  You’ll  probably  want  to
+
+investigate further to fine a more limited role that only allows receipt verification, but for now, I
+
+don’t  want  any  unnecessary  road  blocks  for  getting  this  to  work. We’re  probably  going  to  run
+
+into "permission denied" errors at first anyways, so the fewer reasons for this, the better.
+
+8. It will auto-generate an account ID for you.
+
+9. Finally, for the "Key type", select "JSON". Then click the "Create" button.
+
+This should prompt the download of a JSON file that will have contents similar to the following:
+
+{
+  "type": "service_account",
+  "project_id": "iapdemo-152500",
+  "private_key_id": "1b1d39f2bc083026b164b10a444ff7d839826b8a",
+  "private_key": "-----BEGIN PRIVATE KEY----- ... some private key string -----END PRIVATE KEY-----\n",
+  "client_email": "iapdemo@iapdemo-152500.iam.gserviceaccount.com",
+  "client_id": "117601572633333082772",
+  "auth_uri": "https://accounts.google.com/o/oauth2/auth",
+  "token_uri": "https://accounts.google.com/o/oauth2/token",
+  "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
+  "client_x509_cert_url": "https://www.googleapis.com/robot/v1/metadata/x509/iapdemo%40iapdemo-
+152500.iam.gserviceaccount.com"
+}
+
+This is where we get the information we’re looking for. The "client_email" is what we’ll use for your
+googleClientId, and the "private_key" is what we’ll use for the googlePrivateKey.
+
+ Use the "client_email" value as our client ID, not the "client_id" value as you might
+
+be tempted to do.
+
+We’ll set these in our constants:
+
+public static final String GOOGLE_DEVELOPER_API_CLIENT_ID="iapdemo@iapdemo-152500.iam.gserviceaccount.com";
+public static final String GOOGLE_DEVELOPER_PRIVATE_KEY="-----BEGIN PRIVATE KEY----- ... -----END PRIVATE KEY-----\n";
+
+...
+
+validator.setGoogleClientId(GOOGLE_DEVELOPER_API_CLIENT_ID);
+validator.setGooglePrivateKey(GOOGLE_DEVELOPER_PRIVATE_KEY);
+
+NOT DONE YET
+
+Before we can use these credentials to verify receipts for our app, we need to link our app to this
+
+new service account from within Google Play.
+
+Steps:
+
+1. Open  the  Google  Play  Developer  Console  [https://play.google.com/apps/publish/],  then  click  on
+
+"Settings" > "API Access".
+
+2. You should see your app listed on this page. Click the "Link" button next to your app.
+
+369
+
+Figure 334. Link to API
+
+3. This should reveal some more options on the page. You should see a "Service Accounts" section
+
+with a list of all of the service accounts that you have created. Find the one we just created, and
+
+click the "Grant Access" button in its row.
+
+Figure 335. Grant access
+
+4. This  will  open  a  dialog  titled  "Add  New  User".  Leave  everything  default,  except  change  the
+
+"Role" to "Administrator". This provides "ALL" permissions to this account, which probably isn’t
+
+a good idea for production. Later on, after everything is working, you can circle back and try to
+
+refine  permissions.  For  the  purpose  of  this  tutorial,  I  just  want  to  pull  out  all  of  the  potential
+
+road blocks.
+
+Figure 336. New User
+
+5. Press the "Add User" button.
+
+At this point, the service account should be active so we can try to validate receipts.
+
+Testing Receipt Validation
+
+The  ReceiptsFacadeREST  class  includes  a  flag  to  enable/disable  play  store  validation.  By  default  it’s
+disabled. Let’s enable it:
+
+public static final boolean DISABLE_PLAY_STORE_VALIDATION=true;
+
+Change this to false.
+
+Then build and run the server app. The validateSubscriptionsCron() method is set to run once per
+minute, so we just need to wait for the timer to come up and it should try to validate all of the play
+
+store receipts.
+
+ I’m  assuming  you’ve  already  added  a  receipt  in  the  previous  test  that  we  did.  If
+
+necessary, you should purchase the subscription again in your app.
+
+After a minute or so, you should see "----------- VALIDATING RECEIPTS ---------" written in the Glassfish
+
+370
+
+log, and it will validate your receipts. If it works, your receipt’s expiry date will get populated in the
+
+database, and you can press "Synchronize Receipts" in your app to see this reflected. If it fails, there
+
+will like be a big ugly stack trace and exception readout with some clues about what went wrong.
+
+Realistically,  your  first  attempt  will  fail  for  some  reason.  Use  the  error  codes  and  stack  traces  to
+
+help lead you to the problem. And feel free to post questions here.
+
+9.2.19. iTunes Connect Setup
+
+The process for setting up and testing your app on iOS is much simpler than on Android (IMHO). It
+
+took me a couple hours to get the iTunes version working, vs a couple days on the Google Play side
+
+of things. One notable difference that makes things simpler is that you don’t need to actually upload
+
+your app to the store to test in-app purchase. You can just use your debug build on your device. It’s
+
+also much easier to roll a bunch of test accounts than on Google Play. You don’t need to set up an
+
+alpha program, you just create a few "test accounts" (and this is easy to do) in your iTunes connect
+
+account, and then make sure to use one of these accounts when making a purchase. You can easily
+
+switch  accounts  on  your  device  from  the  "Settings"  app,  where  you  can  just  log  out  of  the  iTunes
+
+store - which will cause you to be prompted in your app the next time you make a purchase.
+
+Setting up In-App Products
+
+The  process  to  add  products  in  iTunes  connect  is  outlined  in  this  apple  developer  document
+
+[https://developer.apple.com/library/content/documentation/LanguagesUtilities/Conceptual/
+iTunesConnectInAppPurchase_Guide/Chapters/CreatingInAppPurchaseProducts.html#//apple_ref/doc/uid/
+
+TP40013727-CH3-SW1]. We’ll add our two SKUs:
+
+1. iapdemo.noads.month.auto - The 1 month subscription.
+
+2. iapdemo.noads.3month.auto - The 3 month subscription.
+
+Just make sure you add them as auto-renewable subscriptions, and that you specify the appropriate
+
+renewal periods. Use the SKU as the product ID. Both of these products will be added to the same
+
+subscription group. Call the group whatever you like.
+
+Creating Test Accounts
+
+In  order  to  test  purchases,  you  need  to  create  some  test  accounts.  See  this  apple  document
+
+[https://developer.apple.com/library/content/documentation/LanguagesUtilities/Conceptual/iTunesConnect_Guide/
+
+Chapters/SettingUpUserAccounts.html#//apple_ref/doc/uid/TP40011225-CH25-SW10] for details on how to create
+
+these test accounts. Don’t worry, the process is much simpler than for Android. It should take you
+
+under 5 minutes.
+
+Once you have the test accounts created, you should be set to test the app.
+
+1. Make sure your server is running.
+
+2. Log out from the app store. The process is described here [https://support.apple.com/en-ca/HT203983].
+
+3. Open your app.
+
+4. Try to purchase a 1-month subscription
+
+371
+
+If  all  went  well,  you  should  see  the  receipt  listed  in  the  RECEIPTS  table  of  your  database.  But  the
+
+expiry date will be null. We need to set up receipt verification in order for this to work.
+
+Setting up Receipt Verification
+
+In  order  for  receipt  verification  to  work  we  simply  need  to  generate  a  shared  secret  in  iTunes
+
+connect.  The  process 
+LanguagesUtilities/Conceptual/iTunesConnectInAppPurchase_Guide/Chapters/
+
+is  described  here 
+
+[https://developer.apple.com/library/content/documentation/
+
+CreatingInAppPurchaseProducts.html].
+
+Once you have a shared secret, update the ReceiptsFacadeREST class with the value:
+
+public static final String APPLE_SECRET = "your-shared-secret-here";
+
+And enable iTunes store validation:
+
+public static final boolean DISABLE_ITUNES_STORE_VALIDATION=true;
+
+Change this to false.
+
+If you rebuild and run the server project, and wait for the validateSubscriptionsCron() method to
+run,  it  should  validate  the  receipt.  After  about  a  minute  (or  less),  you’ll  see  the  text  "-----------
+
+VALIDATING  RECEIPTS  ---------"  written  to  the  Glassfish  log  file,  followed  by  some  output  from
+
+connecting to the iTunes validation service. If all went well, you should see your receipt expiration
+
+date  updated  in  the  database.  If  not,  you’ll  likely  see  some  exception  stack  traces  in  the  Glassfish
+
+Sandbox receipts in the iTunes store are set to run on an accelerated schedule. A 1
+
+month  subscription  is  actually  5  minutes,  3  months  is  15  minutes  etc…  Also
+
+sandbox  subscriptions  don’t  seem  to  persist  in  perpetuity  until  the  user  has
+
+cancelled it. I have found that they usually renew only 4 or 5 times before they are
+
+allowed to lapse by Apple.
+
+log.
+
+
+
+372
+
+10. Graphics, Drawing, Images & Fonts
+
+ Drawing  is  considered  a  low  level  API  that  might  introduce  some  platform
+
+fragmentation.
+
+10.1. Basics - Where & How Do I Draw Manually?
+
+The  Graphics  [https://www.codenameone.com/javadoc/com/codename1/ui/Graphics.html]  class  is  responsible
+
+for drawing basics, shapes, images and text, it is never instantiated by the developer and is always
+
+passed on by the Codename One API.
+
+You can gain access to a Graphics using one of the following methods:
+
+• Derive Component [https://www.codenameone.com/javadoc/com/codename1/ui/Component.html] or a
+subclass of Component - within Component there are several methods that allow developers to
+modify  the  drawing  behavior.  These  can  be  overridden  to  change  the  way  the  component  is
+
+drawn:
+
+◦ paint(Graphics)  -  invoked  to  draw  the  component,  this  can  be  overridden  to  draw  the
+
+component from scratch.
+
+◦ paintBackground(Graphics) / paintBackgrounds(Graphics) - these allow overriding the way the
+component background is painted although you would probably be better off implementing
+
+a painter (see below).
+
+◦ paintBorder(Graphics)  -  allows  overriding  the  process  of  drawing  a  border,  notice  that
+
+border drawing might differ based on the style of the component.
+
+◦ paintComponent(Graphics) - allows painting only the components contents while leaving the
+
+default paint behavior to the style.
+
+◦ paintScrollbars(Graphics),  paintScrollbarX(Graphics),  paintScrollbarY(Graphics)  allows
+
+overriding the behavior of scrollbar painting.
+
+• Implement  the  painter  interface,  this  interface  can  be  used  as  a  GlassPane  or  a  background
+
+painter.
+
+The painter interface is a simple interface that includes 1 paint method, this is a useful way to
+allow  developers  to  perform  custom  painting  without  subclassing  Component.  Painters  can  be
+the  PainterChain
+to  create  elaborate  paint  behavior  by  using 
+chained 
+
+together 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/painter/PainterChain.html] class.
+
+◦ Glass pane - a glass pane allows developers to paint on top of the form painting. This allows
+
+an overlay effect on top of a form.
+
+For a novice it might seem that a glass pane is similar to overriding the Form’s paint method
+and drawing after super.paint(g) completed. This isn’t the case. When a component repaints
+is  drawn  and  Form
+(by 
+[https://www.codenameone.com/javadoc/com/codename1/ui/Form.html]’s  paint()  method  wouldn’t  be
+invoked. However, the glass pane painter is invoked for such cases and would work exactly
+
+the  repaint()  method)  only 
+
+that  component 
+
+invoking 
+
+as expected.
+
+373
+
+Container [https://www.codenameone.com/javadoc/com/codename1/ui/Container.html] has a glass pane
+method called paintGlass(Graphics), which can be overridden to provide a similar effect on
+a  Container  level.  This  is  especially  useful  for  complex  containers  such  as  Table
+[https://www.codenameone.com/javadoc/com/codename1/ui/table/Table.html]  which  draws  its  lines
+
+using such a methodology.
+
+◦ Background  painter  -  the  background  painter  is  installed  via  the  style,  by  default
+
+Codename  installs  a  custom  background  painter  of  its  own.  Installing  a  custom  painter
+
+allows a developer to completely define how the background of the component is drawn.
+
+Notice that a lot of the background style behaviors can be achieved using styles alone.
+
+
+
+A  common  mistake  developers  make  is  overriding  the  paint(Graphics)  method  of
+Form.  The  problem  with  that  is  that  form  has  child  components  which  might
+request a repaint. To prevent that either place a paintable component in the center
+of the Form, override the glasspane or the background painter.
+
+A paint method can be implemented as such:
+
+// hide the title
+Form hi = new Form("", new BorderLayout());
+hi.add(BorderLayout.CENTER, new Component() {
+    @Override
+    public void paint(Graphics g) {
+        // red color
+        g.setColor(0xff0000);
+
+        // paint the screen in red
+        g.fillRect(getX(), getY(), getWidth(), getHeight());
+
+        // draw hi world in white text at the top left corner of the screen
+        g.setColor(0xffffff);
+        g.drawString("Hi World", getX(), getY());
+    }
+});
+hi.show();
+
+Figure 337. Hi world demo code, notice that the blue bar on top is the iOS7+ status bar
+
+374
+
+10.2. Glass Pane
+
+The  GlassPane  `in  Codename  One  is  inspired  by  the  Swing  `GlassPane  &  LayeredPane  with  quite  a
+few  twists.  We  tried  to  imagine  how  Swing  developers  would  have  implemented  the  glass  pane
+
+knowing  what  they  do  now  about  painters  and  Swings  learning  curve.  But  first:  what  is  the  glass
+
+pane?
+
+A  typical  Codename  One  application  is  essentially  composed  of  3  layers  (this  is  a  gross
+
+simplification though), the background painters are responsible for drawing the background of all
+
+components including the main form. The component draws its own content (which might overrule
+
+the painter) and the glass pane paints last…
+
+Figure 338. Form layout graphic
+
+Essentially the glass pane is a painter that allows us to draw an overlay on top of the Codename One
+
+application.
+
+Overriding the paint method of a form isn’t a substitute for glasspane as it would appear to work
+initially,  when  you  enter  a  Form.  However,  when  modifying  an  element  within  the  form  only  that
+element gets repainted not the entire Form!
+
+So  if  we  have  a  form  with  a  Button  [https://www.codenameone.com/javadoc/com/codename1/ui/Button.html]
+
+and text drawn on top using the Form’s paint method it would get erased whenever the button gets
+
+focus.
+
+The  glass  pane  is  called  whenever  a  component  gets  painted,  it  only  paints  within  the  clipping
+region of the component hence it won’t break the rest of the components on the Form which weren’t
+modified.
+
+You can set a painter on a form using code like this:
+
+hi.setGlassPane(new Painter() {
+    @Override
+    public void paint(Graphics g, Rectangle rect) {
+    }
+});
+
+Or you can use Java 8 lambdas to tighten the code a bit:
+
+hi.setGlassPane((g, rect) -> {
+});
+
+PainterChain  [https://www.codenameone.com/javadoc/com/codename1/ui/painter/PainterChain.html]  allows  us
+
+375
+
+to  chain  several  painters  together  to  perform  different  logical  tasks  such  as  a  validation  painter
+
+coupled with a fade out painter. The sample below shows a crude validation panel that allows us to
+
+draw error icons next to components while exceeding their physical bounds as is common in many
+
+user interfaces
+
+Form hi = new Form("Glass Pane", new BoxLayout(BoxLayout.Y_AXIS));
+Style s = UIManager.getInstance().getComponentStyle("Label");
+s.setFgColor(0xff0000);
+s.setBgTransparency(0);
+Image warningImage = FontImage.createMaterial(FontImage.MATERIAL_WARNING, s).toImage();
+TextField tf1 = new TextField("My Field");
+tf1.getAllStyles().setMarginUnit(Style.UNIT_TYPE_DIPS);
+tf1.getAllStyles().setMargin(5, 5, 5, 5);
+hi.add(tf1);
+hi.setGlassPane((g, rect) -> {
+    int x = tf1.getAbsoluteX() + tf1.getWidth();
+    int y = tf1.getAbsoluteY();
+    x -= warningImage.getWidth() / 2;
+    y += (tf1.getHeight() / 2 - warningImage.getHeight() / 2);
+    g.drawImage(warningImage, x, y);
+});
+hi.show();
+
+Figure 339. The glass pane draws the warning sign on the border of the component partially peeking out
+
+10.3. Shapes & Transforms
+
+The graphics API provides a high performance shape API that allows drawing arbitrary shapes by
+
+defining paths and curves and caching the shape drawn in the GPU.
+
+10.4. Device Support
+
+Shapes  and  transforms  are  available  on  most  smartphone  platforms  with  some  caveats  for  the
+
+current Windows Phone port.
+
+Notice that perspective transform is missing from the desktop/simulator port. Unfortunately there
+
+is no real equivalent to perspective transform in JavaSE that we could use.
+
+10.5. A 2D Drawing App
+
+We can demonstrate shape drawing with a simple example of a drawing app, that allows the user to
+
+tap the screen to draw a contour picture.
+
+The  app  works  by  simply  keeping  a  GeneralPath  [https://www.codenameone.com/javadoc/com/codename1/
+
+376
+
+ui/geom/GeneralPath.html]  in  memory,  and  continually  adding  points  as  bezier  curves.  Whenever  a
+
+point is added, the path is redrawn to the screen.
+
+The 
+
+center  of 
+
+the  app 
+
+is 
+
+the 
+
+DrawingCanvas 
+
+class,  which 
+
+extends  Component
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/Component.html].
+
+public class DrawingCanvas extends Component {
+    GeneralPath p = new GeneralPath();
+    int strokeColor = 0x0000ff;
+    int strokeWidth = 10;
+
+    public void addPoint(float x, float y){
+        // To be written
+    }
+
+    @Override
+    protected void paintBackground(Graphics g) {
+        super.paintBackground(g);
+            Stroke stroke = new Stroke(
+                strokeWidth,
+                Stroke.CAP_BUTT,
+                Stroke.JOIN_ROUND, 1f
+            );
+            g.setColor(strokeColor);
+
+            // Draw the shape
+            g.drawShape(p, stroke);
+
+    }
+
+    @Override
+    public void pointerPressed(int x, int y) {
+        addPoint(x-getParent().getAbsoluteX(), y-getParent().getAbsoluteY());
+    }
+}
+
+Conceptually  this  is  very  basic  component.  We  will  be  overriding  the  paintBackground()
+[https://www.codenameone.com/javadoc/com/codename1/ui/Component.html#
+
+paintBackground(com.codename1.ui.Graphics)]  method  to  draw  the  path.  We  keep  a  reference  to  a
+
+GeneralPath [https://www.codenameone.com/javadoc/com/codename1/ui/geom/GeneralPath.html] object (which
+
+is  the  concrete  implementation  of  the  Shape  [https://www.codenameone.com/javadoc/com/codename1/ui/
+
+geom/Shape.html] interface in Codename One) to store each successive point in the drawing. We also
+
+parametrize the stroke width and color.
+
+The  implementation  of  the  paintBackground()  method  (shown  above)  should  be  fairly  straight
+forward.  It  creates  a  stroke  of  the  appropriate  width,  and  sets  the  color  on  the  graphics  context.
+Then it calls drawShape() to render the path of points.
+
+377
+
+10.5.1. Implementing addPoint()
+
+The addPoint method is designed to allow us to add points to the drawing. A simple implementation
+
+that uses straight lines rather than curves might look like this:
+
+private float lastX = -1;
+private float lastY = -1;
+
+public void addPoint(float x, float y) {
+    if (lastX == -1) {
+        // this is the first point... don't draw a line yet
+        p.moveTo(x, y);
+    } else {
+        p.lineTo(x, y);
+    }
+    lastX = x;
+    lastY = y;
+
+    repaint();
+}
+
+We  introduced  a  couple  house-keeping  member  vars  (lastX  and  lastY)  to  store  the  last  point  that
+was added so that we know whether this is the first tap or a subsequent tap. The first tap triggers a
+moveTo() call, whereas subsequent taps trigger lineTo() calls, which draw lines from the last point
+to the current point.
+
+A drawing might look like this:
+
+Figure 340. lineTo example
+
+10.5.2. Using Bezier Curves
+
+Our previous implementation of addPoint() used lines for each segment of the drawing. Let’s make
+
+an adjustment to allow for smoother edges by using quadratic curves instead of lines.
+
+Codename One’s GeneralPath class includes two methods for drawing curves:
+
+378
+
+1. quadTo() 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/geom/GeneralPath.html#
+
+quadTo(float,%20float,%20float,%20float)]  :  Appends  a  quadratic  bezier  curve.  It  takes  2  points:  a
+
+control point, and an end point.
+
+2. curveTo() 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/geom/GeneralPath.html#
+
+curveTo(float,%20float,%20float,%20float,%20float,%20float)]  :  Appends  a  cubic  bezier  curve,  taking  3
+
+points: 2 control points, and an end point.
+
+See 
+
+the  General  Path 
+
+javadocs 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/geom/
+
+GeneralPath.html] for the full API.
+
+We  will  make  use  of  the  quadTo()  [https://www.codenameone.com/javadoc/com/codename1/ui/geom/
+GeneralPath.html#quadTo(float,%20float,%20float,%20float)]  method  to  append  curves  to  the  drawing  as
+
+follows:
+
+private boolean odd=true;
+public void addPoint(float x, float y){
+    if ( lastX == -1 ){
+        p.moveTo(x, y);
+
+    } else {
+        float controlX = odd ? lastX : x;
+        float controlY = odd ? y : lastY;
+        p.quadTo(controlX, controlY, x, y);
+    }
+    odd = !odd;
+    lastX = x;
+    lastY = y;
+    repaint();
+}
+
+This  change  should  be  fairly  straight  forward  except,  perhaps,  the  business  with  the  odd  variable.
+Since  quadratic  curves  require  two  points  (in  addition  to  the  implied  starting  point),  we  can’t
+
+simply take the last tap point and the current tap point. We need a point between them to act as a
+
+control  point.  This  is  where  we  get  the  curve  from.  The  control  point  works  by  exerting  a  sort  of
+
+"gravity" on the line segment, to pull the line towards it. This results in the line being curved. I use
+the odd marker to alternate the control point between positions above the line and below the line.
+
+A drawing from the resulting app looks like:
+
+379
+
+Figure 341. Result of quadTo example
+
+10.5.3. Detecting Platform Support
+
+The DrawingCanvas example is a bit naive in that it assumes that the device supports the shape API. If
+I  were  to  run  this  code  on  a  device  that  doesn’t  support  the  Shape  [https://www.codenameone.com/
+
+javadoc/com/codename1/ui/geom/Shape.html] API, it would just draw a blank canvas where I expected my
+shape to be drawn. You can fall back gracefully if you make use of the Graphics.isShapeSupported()
+[https://www.codenameone.com/javadoc/com/codename1/ui/Graphics.html#isShapeSupported()] method. E.g.
+
+@Override
+protected void paintBackground(Graphics g) {
+    super.paintBackground(g);
+    if ( g.isShapeSupported() ){
+       // do my shape drawing code here
+    } else {
+        // draw an alternate representation for device
+        // that doesn't support shapes.
+        // E.g. you could defer to the Pisces
+        // library in this case
+    }
+
+}
+
+10.6. Transforms
+
+The  Graphics  [https://www.codenameone.com/javadoc/com/codename1/ui/Graphics.html]  class  has  included
+
+limited  support  for  2D  transformations  for  some  time  now  including  scaling,  rotation,  and
+
+translation:
+
+• scale(x,y) : Scales drawing operations by a factor in each direction.
+
+• translate(x,y) : Translates drawing operations by an offset in each direction.
+
+• rotate(angle) : Rotates about the origin.
+
+• rotate(angle, px, py) : Rotates about a pivot point.
+
+380
+
+ scale() and rotate() methods are only available on platforms that support Affine
+
+transforms. See table X for a compatibility list.
+
+10.6.1. Device Support
+
+As of this writing, not all devices support transforms (i.e. scale() and rotate()). The following is a
+list of platforms and their respective levels of support.
+
+Table 7. Transforms Device Support
+
+Platform
+
+Simulator
+
+iOS
+
+Android
+
+JavaScript
+
+J2ME
+
+BlackBerry (4.2 & 5)
+
+Windows Phone
+
+Affine Supported
+
+Yes
+
+Yes
+
+Yes
+
+Yes
+
+No
+
+No
+
+No (pending)
+
+You  can  check 
+Graphics.html] context supports rotation and scaling using the isAffineSupported() method.
+
+if  a  particular  Graphics  [https://www.codenameone.com/javadoc/com/codename1/ui/
+
+e.g.
+
+public void paint(Graphics g){
+    if ( g.isAffineSupported() ){
+        // Do something that requires rotation and scaling
+
+    } else {
+        // Fallback behavior here
+    }
+}
+
+10.7. Example: Drawing an Analog Clock
+
+In the following sections, I will implement an analog clock component. This will demonstrate three
+
+key concepts in Codename One’s graphics:
+
+1. Using the GeneralPath class for drawing arbitrary shapes.
+
+2. Using Graphics.translate() to translate our drawing position by an offset.
+
+3. Using Graphics.rotate() to rotate our drawing position.
+
+There are three separate things that need to be drawn in a clock:
+
+1. The  tick  marks.  E.g.  most  clocks  will  have  a  tick  mark  for  each  second,  larger  tick  marks  for
+
+381
+
+each hour, and sometimes even larger tick marks for each quarter hour.
+
+2. The numbers. We will draw the clock numbers (1 through 12) in the appropriate positions.
+
+3. The  hands.  We  will  draw  the  clock  hands  to  point  at  the  appropriate  points  to  display  the
+
+current time.
+
+10.7.1. The AnalogClock Component
+
+Our  clock  will  extend 
+Component.html] class, and override the paintBackground() method to draw the clock as follows:
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/
+
+the  Component 
+
+public class AnalogClock extends Component {
+    Date currentTime = new Date();
+
+    @Override
+    public void paintBackground(Graphics g) {
+        // Draw the clock in this method
+    }
+}
+
+10.7.2. Setting up the Parameters
+
+Before we actually draw anything, let’s take a moment to figure out what values we need to know
+
+in order to draw an effective clock. Minimally, we need two values:
+
+1. The center point of the clock.
+
+2. The radius of the clock.
+
+In addition, I am adding the following parameters to to help customize how the clock is rendered:
+
+1. The padding (i.e. the space between the edge of the component and the edge of the clock circle.
+
+2. The tick lengths. I will be using 3 different lengths of tick marks on this clock. The longest ticks
+
+will be displayed at quarter points (i.e. 12, 3, 6, and 9). Slightly shorter ticks will be displayed at
+
+the  five-minute  marks  (i.e.  where  the  numbers  appear),  and  the  remaining  marks
+
+(corresponding with seconds) will be quite short.
+
+382
+
+// Hard code the padding at 10 pixels for now
+double padding = 10;
+
+// Clock radius
+double r = Math.min(getWidth(), getHeight())/2-padding;
+
+// Center point.
+double cX = getX()+getWidth()/2;
+double cY = getY()+getHeight()/2;
+
+//Tick Styles
+int tickLen = 10;  // short tick
+int medTickLen = 30;  // at 5-minute intervals
+int longTickLen = 50; // at the quarters
+int tickColor = 0xCCCCCC;
+Stroke tickStroke = new Stroke(2f, Stroke.CAP_BUTT, Stroke.JOIN_ROUND, 1f);
+
+10.7.3. Drawing the Tick Marks
+
+For  the  tick  marks,  we  will  use  a  single  GeneralPath  [https://www.codenameone.com/javadoc/com/
+codename1/ui/geom/GeneralPath.html] object, making use of the moveTo() and lineTo() methods to draw
+each individual tick.
+
+383
+
+// Draw a tick for each "second" (1 through 60)
+for ( int i=1; i<= 60; i++){
+    // default tick length is short
+    int len = tickLen;
+    if ( i % 15 == 0 ){
+        // Longest tick on quarters (every 15 ticks)
+        len = longTickLen;
+    } else if ( i % 5 == 0 ){
+        // Medium ticks on the '5's (every 5 ticks)
+        len = medTickLen;
+    }
+
+    double di = (double)i; // tick num as double for easier math
+
+    // Get the angle from 12 O'Clock to this tick (radians)
+    double angleFrom12 = di/60.0*2.0*Math.PI;
+
+    // Get the angle from 3 O'Clock to this tick
+        // Note: 3 O'Clock corresponds with zero angle in unit circle
+        // Makes it easier to do the math.
+    double angleFrom3 = Math.PI/2.0-angleFrom12;
+
+    // Move to the outer edge of the circle at correct position
+    // for this tick.
+    ticksPath.moveTo(
+            (float)(cX+Math.cos(angleFrom3)*r),
+            (float)(cY-Math.sin(angleFrom3)*r)
+    );
+
+    // Draw line inward along radius for length of tick mark
+    ticksPath.lineTo(
+            (float)(cX+Math.cos(angleFrom3)*(r-len)),
+            (float)(cY-Math.sin(angleFrom3)*(r-len))
+    );
+}
+
+// Draw the full shape onto the graphics context.
+g.setColor(tickColor);
+g.drawShape(ticksPath, tickStroke);
+
+
+
+This example uses a little bit of trigonometry to calculate the (x,y) coordinates of
+the  tick  marks  based  on  the  angle  and  the  radius.  If  math  isn’t  your  thing,  don’t
+worry. This example just makes use of the identities: x=r*cosθ and y=r*sinθ.
+
+At this point our clock should include a series of tick marks orbiting a blank center as shown below:
+
+384
+
+Figure 342. Drawing tick marks on the watch face
+
+10.7.4. Drawing the Numbers
+
+The Graphics.drawString(str, x, y) method allows you to draw text at any point of a component.
+The  tricky  part  here  is  calculating  the  correct  x  and  y  values  for  each  string  so  that  the  number
+appears in the correct location.
+
+For the purposes of this tutorial, we will use the following strategy. For each number (1 through 12):
+
+1. Use the Graphics.translate(x,y) method to apply a translation from the clock’s center point to
+
+the point where the number should appear.
+
+2. Draw  number  (using  drawString())  at  the  clock’s  center.  It  should  be  rendered  at  the  correct
+
+point due to our translation.
+
+3. Invert the translation performed in step 1.
+
+385
+
+for ( int i=1; i<=12; i++){
+    // Calculate the string width and height so we can center it properly
+    String numStr = ""+i;
+    int charWidth = g.getFont().stringWidth(numStr);
+    int charHeight = g.getFont().getHeight();
+
+    double di = (double)i;  // number as double for easier math
+
+    // Calculate the position along the edge of the clock where the number should
+    // be drawn
+     // Get the angle from 12 O'Clock to this tick (radians)
+    double angleFrom12 = di/12.0*2.0*Math.PI;
+
+    // Get the angle from 3 O'Clock to this tick
+        // Note: 3 O'Clock corresponds with zero angle in unit circle
+        // Makes it easier to do the math.
+    double angleFrom3 = Math.PI/2.0-angleFrom12;
+
+    // Get diff between number position and clock center
+    int tx = (int)(Math.cos(angleFrom3)*(r-longTickLen));
+    int ty = (int)(-Math.sin(angleFrom3)*(r-longTickLen));
+
+    // For 6 and 12 we will shift number slightly so they are more even
+    if ( i == 6 ){
+        ty -= charHeight/2;
+    } else if ( i == 12 ){
+        ty += charHeight/2;
+    }
+
+    // Translate the graphics context by delta between clock center and
+    // number position
+    g.translate(
+            tx,
+            ty
+    );
+
+    // Draw number at clock center.
+    g.drawString(numStr, (int)cX-charWidth/2, (int)cY-charHeight/2);
+
+    // Undo translation
+    g.translate(-tx, -ty);
+
+}
+
+
+
+386
+
+This  example  is,  admittedly,  a  little  contrived  to  allow  for  a  demonstration  of  the
+Graphics.translate()  method.  We  could  have  just  as  easily  passed  the  exact
+location  of  the  number  to  drawString()  rather  than  draw  at  the  clock  center  and
+translate to the correct location.
+
+Now, we should have a clock with tick marks and numbers as shown below:
+
+Figure 343. Drawing the numbers on the watch face
+
+10.7.5. Drawing the Hands
+
+The clock will include three hands: Hour, Minute, and Second. We will use a separate GeneralPath
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/geom/GeneralPath.html]  object  for  each  hand.  For
+
+the positioning/angle of each, I will employ the following strategy:
+
+1. Draw the hand at the clock center pointing toward 12 (straight up).
+
+2. Translate the hand slightly down so that it overlaps the center.
+
+3. Rotate the hand at the appropriate angle for the current time, using the clock center as a pivot
+
+point.
+
+Drawing the Second Hand:
+
+For the "second" hand, we will just use a simple line from the clock center to the inside edge of the
+
+medium tick mark at the 12 o’clock position.
+
+GeneralPath secondHand = new GeneralPath();
+secondHand.moveTo((float)cX, (float)cY);
+secondHand.lineTo((float)cX, (float)(cY-(r-medTickLen)));
+
+And  we  will  translate  it  down  slightly  so  that  it  overlaps  the  center.  This  translation  will  be
+performed on the GeneralPath object directly rather than through the Graphics context:
+
+Shape translatedSecondHand = secondHand.createTransformedShape(
+    Transform.makeTranslation(0f, 5)
+);
+
+Rotating the Second Hand::
+
+The rotation of the second hand will be performed in the Graphics context via the rotate(angle, px,
+py)  method.  This  requires  us  to  calculate  the  angle.  The  px  and  py  arguments  constitute  the  pivot
+
+387
+
+point of the rotation, which, in our case will be the clock center.
+
+
+
+The  rotation  pivot  point  is  expected  to  be  in  absolute  screen  coordinates  rather
+
+than relative coordinates of the component. Therefore we need to get the absolute
+
+clock center position in order to perform the rotation.
+
+// Calculate the angle of the second hand
+Calendar calendar = Calendar.getInstance(TimeZone.getDefault());
+double second = (double)(calendar.get(Calendar.SECOND));
+double secondAngle = second/60.0*2.0*Math.PI;
+
+// Get absolute center position of the clock
+double absCX = getAbsoluteX()+cX-getX();
+double absCY = getAbsoluteY()+cY-getY();
+
+g.rotate((float)secondAngle, (int)absCX, (int)absCY);
+g.setColor(0xff0000);
+g.drawShape(
+        translatedSecondHand,
+        new Stroke(2f, Stroke.CAP_BUTT, Stroke.JOIN_BEVEL, 1f)
+);
+g.resetAffine();
+
+ Remember to call resetAffine() after you’re done with the rotation, or you will see
+
+some unexpected results on your form.
+
+Drawing the Minute And Hour Hands:
+
+The mechanism for drawing the hour and minute hands is largely the same as for the minute hand.
+
+There are a couple of added complexities though:
+
+1. We’ll make these hands trapezoidal, and almost triangular rather than just using a simple line.
+
+Therefore the GeneralPath construction will be slightly more complex.
+
+2. Calculation of the angles will be slightly more complex because they need to take into account
+
+multiple parameters. E.g. The hour hand angle is informed by both the hour of the day and the
+
+minute of the hour.
+
+The remaining drawing code is as follows:
+
+388
+
+// Draw the minute hand
+GeneralPath minuteHand = new GeneralPath();
+minuteHand.moveTo((float)cX, (float)cY);
+minuteHand.lineTo((float)cX+6, (float)cY);
+minuteHand.lineTo((float)cX+2, (float)(cY-(r-tickLen)));
+minuteHand.lineTo((float)cX-2, (float)(cY-(r-tickLen)));
+minuteHand.lineTo((float)cX-6, (float)cY);
+minuteHand.closePath();
+
+// Translate the minute hand slightly down so it overlaps the center
+Shape translatedMinuteHand = minuteHand.createTransformedShape(
+    Transform.makeTranslation(0f, 5)
+);
+
+double minute = (double)(calendar.get(Calendar.MINUTE)) +
+        (double)(calendar.get(Calendar.SECOND))/60.0;
+
+double minuteAngle = minute/60.0*2.0*Math.PI;
+
+// Rotate and draw the minute hand
+g.rotate((float)minuteAngle, (int)absCX, (int)absCY);
+g.setColor(0x000000);
+g.fillShape(translatedMinuteHand);
+g.resetAffine();
+
+// Draw the hour hand
+GeneralPath hourHand = new GeneralPath();
+hourHand.moveTo((float)cX, (float)cY);
+hourHand.lineTo((float)cX+4, (float)cY);
+hourHand.lineTo((float)cX+1, (float)(cY-(r-longTickLen)*0.75));
+hourHand.lineTo((float)cX-1, (float)(cY-(r-longTickLen)*0.75));
+hourHand.lineTo((float)cX-4, (float)cY);
+hourHand.closePath();
+
+Shape translatedHourHand = hourHand.createTransformedShape(
+    Transform.makeTranslation(0f, 5)
+);
+
+//Calendar cal = Calendar.getInstance().get
+double hour = (double)(calendar.get(Calendar.HOUR_OF_DAY)%12) +
+        (double)(calendar.get(Calendar.MINUTE))/60.0;
+
+double angle = hour/12.0*2.0*Math.PI;
+g.rotate((float)angle, (int)absCX, (int)absCY);
+g.setColor(0x000000);
+g.fillShape(translatedHourHand);
+g.resetAffine();
+
+389
+
+10.7.6. The Final Result
+
+At this point, we have a complete clock as shown below:
+
+Figure 344. The final result - fully rendered watch face
+
+10.7.7. Animating the Clock
+
+The current clock component is cool, but it is static. It just displays the time at the point the clock
+
+was created. We discussed low level animations in the animation section of the guide, here we will
+
+show a somewhat more elaborate example.
+
+In order to animate our clock so that it updates once per second, we only need to do two things:
+
+1. Implement the animate() method to indicate when the clock needs to be updated/re-drawn.
+
+2. Register the component with the form so that it will receive animation "pulses".
+
+The animate() method in the AnalogClock class:
+
+Date currentTime = new Date();
+long lastRenderedTime = 0;
+
+@Override
+public boolean animate() {
+    if ( System.currentTimeMillis()/1000 != lastRenderedTime/1000){
+        currentTime.setTime(System.currentTimeMillis());
+        return true;
+    }
+    return false;
+}
+
+This  method  will  be  invoked  on  each  "pulse"  of  the  EDT.  It  checks  the  last  time  the  clock  was
+rendered  and  returns  true  only  if  the  clock  hasn’t  been  rendered  in  the  current  "time  second"
+interval. Otherwise it returns false. This ensures that the clock will only be redrawn when the time
+
+changes.
+
+390
+
+10.8. Starting and Stopping the Animation
+
+the  Form.registerAnimated(component)  and
+Animations  can  be  started  and  stopped  via 
+Form.deregisterAnimated(component)  methods.  We  chose  to  encapsulate  these  calls  in  start()  and
+stop() methods in the component as follows:
+
+public void start(){
+    getComponentForm().registerAnimated(this);
+}
+
+public void stop(){
+    getComponentForm().deregisterAnimated(this);
+}
+
+So the code to instantiate the clock, and start the animation would be something like:
+
+AnalogClock clock = new AnalogClock();
+parent.addComponent(clock);
+clock.start();
+
+10.9. Shape Clipping
+
+Clipping is one of the core tenants of graphics programming, you define the boundaries for drawing
+
+and when you exceed said boundaries things aren’t drawn. Shape clipping allows us to clip based
+on  any  arbitrary  Shape  and  not  just  a  rectangle,  this  allows  some  unique  effects  generated  in
+runtime.
+
+E.g. this code allows us to draw a rather complex image of duke:
+
+391
+
+Image duke = null;
+try {
+    // duke.png is just the default Codename One icon copied into place
+    duke = Image.createImage("/duke.png");
+} catch(IOException err) {
+    Log.e(err);
+}
+final Image finalDuke = duke;
+
+Form hi = new Form("Shape Clip");
+
+// We create a 50 x 100 shape, this is arbitrary since we can scale it easily
+GeneralPath path = new GeneralPath();
+path.moveTo(20,0);
+path.lineTo(30, 0);
+path.lineTo(30, 100);
+path.lineTo(20, 100);
+path.lineTo(20, 15);
+path.lineTo(5, 40);
+path.lineTo(5, 25);
+path.lineTo(20,0);
+
+Stroke stroke = new Stroke(0.5f, Stroke.CAP_ROUND, Stroke.JOIN_ROUND, 4);
+hi.getContentPane().getUnselectedStyle().setBgPainter((Graphics g, Rectangle rect) -> {
+    g.setColor(0xff);
+    float widthRatio = ((float)rect.getWidth()) / 50f;
+    float heightRatio = ((float)rect.getHeight()) / 100f;
+    g.scale(widthRatio, heightRatio);
+    g.translate((int)(((float)rect.getX()) / widthRatio), (int)(((float)rect.getY()) / heightRatio));
+    g.setClip(path);
+    g.setAntiAliased(true);
+    g.drawImage(finalDuke, 0, 0, 50, 100);
+    g.setClip(path.getBounds());
+    g.drawShape(path, stroke);
+    g.translate(-(int)(((float)rect.getX()) / widthRatio), -(int)(((float)rect.getY()) / heightRatio));
+    g.resetAffine();
+});
+
+hi.show();
+
+Figure 345. Shape Clipping used to clip the image of duke within the given shape
+
+
+
+Notice that this functionality isn’t available on all platforms so you normally need
+
+to 
+
+test 
+
+if 
+
+shaped  clipping 
+
+is 
+
+supported  using 
+
+isShapeClipSupported()
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/Graphics.html#
+
+isShapeClipSupported--].
+
+392
+
+10.10. The Coordinate System
+
+The Codename One coordinate system follows the example of Swing (and many other - but not all-
+
+graphics libraries) and places the origin in the upper left corner of the screen. X-values grow to the
+
+right, and Y-values grow downward as illustrated below:
+
+Figure 346. The Codename One graphics coordinate space
+
+Therefore the screen origin is at the top left corner of the screen. Given this information, consider
+
+the  method  call  on  the  Graphics  [https://www.codenameone.com/javadoc/com/codename1/ui/Graphics.html]
+context g:
+
+g.drawRect(10,10, 100, 100);
+
+Where would this rectangle be drawn on the screen?
+
+If you answered something something like "10 pixels from the top, and 10 pixels from the left of the
+
+screen",  you  might  be  right.  It  depends  on  whether  the  graphics  has  a  translation  or  transform
+applied  to  it.  If  there  is  currently  a  translation  of  (20,20)  (i.e.  20  pixels  to  the  right,  and  20  pixels
+down), then the rectangle would be rendered at (30, 30).
+
+You  can  always  find  out 
+Graphics.getTranslateX() and Graphics.getTranslateY() methods:
+
+translation  of 
+
+the  current 
+
+the  graphics  context  using 
+
+// Find out the current translation
+int currX = g.getTranslateX();
+int currY = g.getTranslateY();
+
+// Reset the translation to zeroes
+g.translate(-currX, -currY);
+
+// Now we are working in absolute screen coordinates
+g.drawRect(10, 10, 100, 100);
+
+// This rectangle should now be drawn at the exact screen
+// coordinates (10,10).
+
+//Restore the translation
+g.translate(currX, currY);
+
+the
+
+393
+
+
+
+This example glosses over issues such as clipping and transforms which may cause
+it  to  not  work  as  you  expect.  E.g.  When  painting  a  component  inside  its  paint()
+method,  there  is  a  clip  applied  to  the  context  so  that  only  the  content  you  draw
+
+within the bounds of the component will be seen.
+
+If, in addition, there is a transform applied that rotates the context 45 degrees clockwise, then the
+
+rectangle will be drawn at a 45 degree angle with its top left corner somewhere on the left edge of
+
+the screen.
+
+Luckily you usually don’t have to worry about the exact screen coordinates for the things you paint.
+
+Most of the time, you will only be concerned with relative coordinates.
+
+10.10.1. Relative Coordinates
+
+Usually,  when  you  are  drawing  onto  a  Graphics  context,  you  are  doing  so  within  the  context  of  a
+Component’s paint() method (or one of its variants). In this case, you generally don’t care what the
+exact screen coordinates are of your drawing. You are only concerned with their relative location
+
+within  the  coordinate.  You  can  leave  the  positioning  (and  even  sizing)  of  the  coordinate  up  to
+
+Codename One. Thank you for reading.
+
+To  demonstrate  this,  let’s  create  a  simple  component  called  Rectangle  [https://www.codenameone.com/
+
+javadoc/com/codename1/ui/geom/Rectangle.html] component, that simply draws a rectangle on the screen.
+
+We will use the component’s position and size to dictate the size of the rectangle to be drawn. And
+
+we will keep a 5 pixel padding between the edge of the component and the edge of our rectangle.
+
+class RectangleComponent extends Component {
+    public void paint(Graphics g){
+        g.setColor(0x0000ff);
+        g.drawRect(getX()+5, getY()+5, getWidth()-10, getHeight()-10);
+    }
+}
+
+The result is as follows:
+
+Figure 347. The rectangle component
+
+
+
+The  x  and  y  coordinates  that  are  passed  to  the  drawRect(x,y,w,h)  method  are
+relative  to  the  component’s  parent’s  origin — not  the  component  itself  ..  its
+parent. This is why we the x position is getX()+5 and not just 5.
+
+394
+
+10.10.2. Transforms and Rotations
+
+Unlike  the  Graphics  drawXXX  primitives,  methods  for  setting  transformations,  including  scale(x,y)
+and rotate(angle), are always applied in terms of screen coordinates. This can be confusing at first,
+because you may be unsure whether to provide a relative coordinate or an absolute coordinate for
+
+a given method.
+
+The general rule is:
+
+1. All  coordinates  passed  to  the  drawXXX()  and  fillXXX()  methods  will  be  subject  to  the
+
+graphics context’s transform and translation settings.
+
+2. All  coordinates  passed  to  the  context’s  transformation  settings  are  considered  to  be
+
+screen coordinates, and are not subject to current transform and translation settings.
+
+Let’s  take  our  RectangleComponent  as  an  example.  Suppose  we  want  to  rotate  the  rectangle  by  45
+degrees, our first attempt might look something like:
+
+    class RectangleComponent extends Component {
+
+        @Override
+        protected Dimension calcPreferredSize() {
+            return new Dimension(250,250);
+        }
+
+        public void paint(Graphics g) {
+            g.setColor(0x0000ff);
+            g.rotate((float) (Math.PI / 4.0));
+            g.drawRect(getX() + 5, getY() + 5, getWidth() - 10, getHeight() - 10);
+            g.rotate(-(float) (Math.PI / 4.0));
+        }
+    }
+
+
+
+When performing rotations and transformations inside a paint() method, always
+remember  to  revert  your  transformations  at  the  end  of  the  method  so  that  it
+
+doesn’t pollute the rendering pipeline for subsequent components.
+
+The behavior of this rotation will vary based on where the component is rendered on the screen. To
+
+demonstrate  this,  let’s  try  to  place  five  of  these  components  on  a  form  inside  a  BorderLayout
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/layouts/BorderLayout.html] and see how it looks:
+
+395
+
+    class MyForm extends Form {
+
+        public MyForm() {
+            super("Rectangle Rotations");
+            for ( int i=0; i< 10; i++ ){
+                this.addComponent(new RectangleComponent());
+            }
+        }
+    }
+
+The result is as follows:
+
+Figure 348. Rotating the rectangle
+
+This  may  not  be  an  intuitive  outcome  since  we  drew  10  rectangle  components,  be  we  only  see  a
+portion of one rectangle. The reason is that the rotate(angle) method uses the screen origin as the
+pivot point for the rotation. Components nearer to this pivot point will experience a less dramatic
+
+effect than components farther from it. In our case, the rotation has caused all rectangles except the
+
+first one to be rotated outside the bounds of their containing component - so they are being clipped.
+
+A more sensible solution for our component would be to place the rotation pivot point somewhere
+
+inside  the  component.  That  way  all  of  the  components  would  look  the  same.  Some  possibilities
+
+would be:
+
+Top Left Corner:
+
+        public void paint(Graphics g) {
+            g.setColor(0x0000ff);
+            g.rotate((float)(Math.PI/4.0), getAbsoluteX(), getAbsoluteY());
+            g.drawRect(getX() + 5, getY() + 5, getWidth() - 10, getHeight() - 10);
+            g.rotate(-(float) (Math.PI / 4.0), getAbsoluteX(), getAbsoluteY());
+        }
+
+396
+
+Figure 349. Rotating the rectangle with wrong pivot point
+
+Center:
+
+public void paint(Graphics g) {
+    g.setColor(0x0000ff);
+    g.rotate(
+        (float)(Math.PI/4.0),
+        getAbsoluteX()+getWidth()/2,
+        getAbsoluteY()+getHeight()/2
+    );
+    g.drawRect(getX() + 5, getY() + 5, getWidth() - 10, getHeight() - 10);
+    g.rotate(
+        -(float)(Math.PI/4.0),
+        getAbsoluteX()+getWidth()/2,
+        getAbsoluteY()+getHeight()/2
+    );
+}
+
+Figure 350. Rotating the rectangle with the center pivot point
+
+You  could  also  use  the  Graphics.setTransform()  class  to  apply  rotations  and  other  complex
+transformations (including 3D perspective transforms), but I’ll leave that for its own topic as it is a
+
+397
+
+little bit more complex.
+
+10.10.3. Event Coordinates
+
+The  coordinate  system  and  event  handling  are  closely  tied.  You  can  listen  for  touch  events  on  a
+component by overriding the pointerPressed(x,y) method. The coordinates received in this method
+will  be  absolute  screen  coordinates,  so  you  may  need  to  do  some  conversions  on  these
+coordinates before using them in your drawXXX() methods.
+
+E.g. a pointerPressed() callback method can look like this:
+
+public void pointerPressed(int x, int y) {
+    addPoint(x-getParent().getAbsoluteX(), y-getParent().getAbsoluteY());
+}
+
+In  this  case  we  translated  these  points  so  that  they  would  be  relative  to  the  origin  of  the  parent
+component. This is because the drawXXX() methods for this component take coordinates relative to
+the parent component.
+
+10.11. Images
+
+Codename One has quite a few image types: loaded, RGB (builtin), RGB (Codename One), Mutable,
+
+EncodedImage,  SVG,  MultiImage,  FontImage  &  Timeline.  There  are  also  URLImage,
+FileEncodedImage, FileEncodedImageAsync, StorageEncodedImage/Async that will be covered in the
+IO section.
+
+All  image  types  are  mostly  seamless  to  use  and  will  just  work  with  drawImage  and  various  image
+related image API’s for the most part with caveats on performance etc.
+
+
+
+For  animation  images  the  code  must  invoke  the  animate()  method  on  the  image
+(this  is  done  automatically  by  Codename  One  when  placing  the  image  as  a
+
+background or as an icon!
+You  only  need  to  do  it  if  you  invoke  drawImage  in  code  rather  than  use  a  builtin
+component).
+
+Performance  and  memory  wise  you  should  read  the  section  below  carefully  and  be  aware  of  the
+
+image  types  you  use.  The  Codename  One  designer  tries  to  conserve  memory  and  be  "clever"  by
+using  only  EncodedImage.  While  these  are  great  for  low  memory  you  need  to  understand  the
+complexities of image locking and be aware that you might pay a penalty if you don’t.
+
+Here are the pros/cons and logic behind every image type. This covers the logic of how it’s created:
+
+10.11.1. Loaded Image
+
+This  is  the  basic  image  you  get  when  loading  an  image  from  the  jar  or  network  using
+
+Image.createImage(String) 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/Image.html#
+
+createImage-java.lang.String-], Image.createImage(InputStream) [https://www.codenameone.com/javadoc/com/
+
+codename1/ui/Image.html#createImage-java.io.InputStream-]  & 
+
+Image.createImage(byte 
+
+array,int,int)
+
+398
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/Image.html#createImage-byte:A-int-int-], …
+
+
+
+Some other API’s might return this image type but those API’s do so explicitly!
+
+In  some  platforms  calling  getGraphics()  on  an  image  like  this  will  throw  an  exception  as  it’s
+immutable). This is true for almost all other images as well.
+
+This restriction might not apply for all platforms.
+
+The  image  is  stored  in  RAM  based  on  device  logic  and  should  be  reasonably  efficient  in  terms  of
+
+drawing speed. However, it usually takes up a lot of RAM.
+
+To calculate the amount of RAM taken by a loaded image we use the following formula:
+
+Image Width * Image Height * 4 = Size In RAM in Bytes
+
+E.g. a 50x100 image will take up 20,000 bytes of RAM.
+
+The  logic  behind  this  is  simple,  every  pixel  contains  3  color  channels  and  an  alpha  component
+
+hence 3 bytes for color and one for alpha.
+
+
+
+This  isn’t  the  case  for  all  images  but  it’s  very  common  and  we  prefer  calculating
+
+for the worst case scenario. Even with JPEG’s that don’t include an alpha channel
+
+some OS’s might reuire that additional byte.
+
+10.11.2. The RGB Image’s
+
+There are two types of RGB constructed images that are very different from one another but since
+
+they are both technically "RGB image’s" we are bundling them under the same subsection.
+
+Internal
+
+This  is  a  close  cousin  of  the  loaded  image.  This  image  is  created  using  the  method
+
+Image.createImage(int array, int, int) [https://www.codenameone.com/javadoc/com/codename1/ui/Image.html#
+
+createImage-int:A-int-int-] and receives the AARRGGBB data to form the image. It’s more efficient than
+
+the Codename One RGB image but can’t be modified, at least not on the pixel level.
+
+The  goal  of  this  image  type  is  to  provide  an  easy  way  to  render  RGB  data  that  isn’t  modified
+
+efficiently at platform native speeds. It’s technically a standard "Loaded Image" internally.
+
+RGBImage class
+
+RGBImage 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/RGBImage.html] 
+
+is  effectively  an
+
+AARRGGBB array that can be drawn by Codename One.
+
+On  most  platforms  this  is  quite  inefficient  but  for  some  pixel  level  manipulations  there  is  just  no
+
+other way.
+
+An  RGBImage  is  constructed  with  an  int  array  (int[])  that  includes  width*height  elements.  You  can
+
+399
+
+then  modify  the  colors  and  alpha  channel  directly  within  the  array  and  draw  the  image  to  any
+
+source using standard image drawing API’s.
+
+
+
+This  is  very  inefficient  in  terms  of  rendering  speed  and  memory  overhead.  Only
+
+use this technique if there is absolutely no other way!
+
+10.11.3. EncodedImage
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/EncodedImage.html] 
+
+the
+EncodedImage 
+workhorse of Codename One. Images returned from resource files are EncodedImage and many API’s
+expect it.
+
+is 
+
+The EncodedImage is effectively a loaded image that is "hidden" and extracted as needed to remove
+the memory overhead associated with loaded image. When creating an EncodedImage only the PNG
+(or JPEG etc.) is loaded to an array in RAM. Normally such images are very small (relatively) so they
+
+can be kept in memory without much overhead.
+
+When image information is needed (pixels) the image is decoded into RAM and kept in a weak/sort
+
+reference. This allows the image to be cached for performance and allows the garbage collector to
+
+reclaim it when the memory becomes scarce.
+
+Since  the  fully  decoded  image  can  be  pretty  big  (width  X  height  X  4)  the  ability  to  store  just  the
+encoded  image  can  be  pretty  stark.  E.g.  taking  our  example  above  a  50x100  image  will  take  up
+20,000 bytes of RAM for a loaded image but an EncodedImage can reduce that to 1kb-2kb of RAM.
+
+
+
+An  EncodedImage  might  be  more  expensive  than  a  loaded  image  as  it  will  take  up
+both  the  encoded  size  and  the  loaded  size.  So  the  cost  might  be  slightly  bigger  in
+
+some cases. It’s main value is its ability to shrink.
+
+When drawing an EncodedImage it checks the weak reference cache and if the image is cached then
+it is shown otherwise the image is loaded the encoded image cache it then drawn.
+
+EncodedImage is not final and can be derived to produce complex image fetching strategies e.g. the
+can
+URLImage 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/URLImage.html] 
+
+class 
+
+that 
+
+dynamically download its content from the web.
+
+EncodedImage can be instantiated via the create methods in the EncodedImage class. Pretty much any
+image  can  be  converted  into  an  EncodedImage  via  the  createFromImage(Image,  boolean)
+[https://www.codenameone.com/javadoc/com/codename1/ui/EncodedImage.html#createFromImage-
+
+com.codename1.ui.Image-boolean-] method.
+
+400
+
+EncodedImage Locking
+
+Naturally loading the image is more expensive so we want the images that are on the current
+form to remain in cache (otherwise GC will thrash a lot). That’s where lock() kicks in, when
+lock() is active we keep a hard reference to the actual native image so it won’t get GC’d. This
+significantly improves performance!
+
+Internally this is invoked automatically for background images, icons etc. which results in a
+
+huge  performance  boost.  This  makes  sense  since  these  images  are  currently  showing  and
+
+they will be in RAM anyway. However, if you use a complex renderer or custom drawing UI
+you should lock() your images where possible!
+
+To  verify  that  locking  might  be  a  problem  you  can  launch  the  performance  monitor  tool
+
+(accessible from the simulator menu), if you get log messages that indicate that an unlocked
+
+image was drawn you might have a problem.
+
+10.11.4. MultiImage
+
+Multi images don’t physically exist as a concept within the Codename One API so there is no way to
+actually create them and they are in no way distinguishable from EnclodedImage.
+
+The only builtin support for multi images is in the resource file loading logic where a MultiImage is
+
+decoded and only the version that matches the current DPI is physically loaded. From that point on
+user code can treat it like any other EnclodedImage.
+
+9-image borders use multi images by default to keep their appearance more refined on the different
+
+DPI’s.
+
+10.11.5. FontImage & Material Design Icons
+
+FontImage  [https://www.codenameone.com/javadoc/com/codename1/ui/FontImage.html]  allows  using  an  icon
+font as if it was an image. You can specify the character, color and size and then treat the FontImage
+as  if  its  a  regular  image.  The  huge  benefits  are  that  the  font  image  can  adapt  to  platform
+
+conventions in terms of color and easily scale to adapt to DPI.
+
+You  can  generate  icon  fonts  using  free  tools  on  the  internet  such  as  this  [http://fontello.com/].  Icon
+
+fonts are a remarkably simple and powerful technique to create a small, modern applications.
+
+Icon fonts can be created in 2 basic ways the first is explicitly by defining all of the elements within
+
+the font.
+
+Form hi = new Form("Icon Font");
+Font materialFont = FontImage.getMaterialDesignFont();
+int w = Display.getInstance().getDisplayWidth();
+FontImage fntImage = FontImage.createFixed("\uE161", materialFont, 0xff0000, w, w);
+hi.add(fntImage);
+hi.show();
+
+401
+
+Figure 351. Icon font from material design icons created with the fixed size of display width
+
+
+
+The  samples  use  the  builtin  material  design  icon  font.  This  is  for  convenience  so
+
+the sample will work out of the box, for everyone. However you should be able to
+
+do this with any arbitrary icon font off the internet as long as its a valid TTF file.
+
+A  more  common  and  arguably  "correct"  way  to  construct  such  an  icon  would  be  thru  the  Style
+[https://www.codenameone.com/javadoc/com/codename1/ui/plaf/Style.html]  object.  The  Style  object  can
+provide the color, size and background information needed by FontImage.
+
+There are two versions of this method, the first one expects the Style object to have the correct icon
+font set to its font attribute. The second accepts a Font object as an argument. The latter is useful for
+a case where you want to reuse the same Style object that you defined for a general UI element e.g.
+we can set an icon for a Button like this and it will take up the style of the Button:
+
+Form hi = new Form("Icon Font");
+Font materialFont = FontImage.getMaterialDesignFont();
+int size = Display.getInstance().convertToPixels(6, true);
+materialFont = materialFont.derive(size, Font.STYLE_PLAIN);
+Button myButton = new Button("Save");
+myButton.setIcon(FontImage.create("\uE161", myButton.getUnselectedStyle(), materialFont));
+hi.add(myButton);
+hi.show();
+
+Figure 352. An image created from the Style object
+
+
+
+Notice  that  for  this  specific  version  of  the  method  the  size  of  the  font  is  used  to
+determine the icon size. In the other methods for FontImage creation the size of the
+font is ignored!
+
+Material Design Icons
+
+There are many icon fonts in the web, the field is rather volatile and constantly changing. However,
+
+we  wanted  to  have  builtin  icons  that  would  allow  us  to  create  better  looking  demos  and  builtin
+
+components.
+
+402
+
+That’s why we picked the material design icon font for inclusion in the Codename One distribution.
+
+It features a relatively stable core set of icons, that aren’t IP encumbered.
+
+You can use the builtin font directly as demonstrated above but there are far better ways to create a
+
+material design icon. To find the icon you want you can check out the material design icon gallery
+
+[https://design.google.com/icons/]. E.g. we used the save icon in the samples above.
+
+To recreate the save icon from above we can do something like:
+
+Form hi = new Form("Icon Font");
+Button myButton = new Button("Save");
+myButton.setIcon(FontImage.createMaterial(FontImage.MATERIAL_SAVE, myButton.getUnselectedStyle()));
+hi.add(myButton);
+
+Figure 353. Material save icon
+
+ Notice that the icon is smaller now as it’s calculated based on the font size of the
+
+Button UIID.
+
+We can even write the code in a more terse style using:
+
+Form hi = new Form("Icon Font");
+Button myButton = new Button("Save");
+FontImage.setMaterialIcon(myButton, FontImage.MATERIAL_SAVE);
+hi.add(myButton);
+
+This will produce the same result for slightly shorter syntax.
+
+
+
+FontImage  can  conflict  with  some  complex  API’s  that  expect  a  "real"  image
+underneath.  Some  odd  issues  can  often  be  resolved  by  using  the  toImage()  or
+toEncodedImage() methods to convert the scaled FontImage to a loaded image.
+
+10.11.6. Timeline
+
+Timeline’s  allow  rudimentary  animation  and  enable  GIF  importing  using  the  Codename  One
+
+Designer.  Effectively  a  timeline  is  a  set  of  images  that  can  be  moved  rotated,  scaled  &  blended  to
+
+provide 
+
+interesting  animation  effects.  It  can  be  created  manually  using  the  Timeline
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/animations/Timeline.html] class.
+
+10.11.7. Image Masking
+
+Image masking allows us to manipulate images by changing the opacity of an image according to a
+
+mask image. The mask image can be hardcoded or generated dynamically, it is then converted to a
+
+Mask object that can be applied to any image. Notice that the masking process is computationally
+
+intensive, it should be done once and cached/saved.
+
+403
+
+The code below can convert an image to a rounded image:
+
+Toolbar.setGlobalToolbar(true);
+Form hi = new Form("Rounder", new BorderLayout());
+Label picture = new Label("", "Container");
+hi.add(BorderLayout.CENTER, picture);
+hi.getUnselectedStyle().setBgColor(0xff0000);
+hi.getUnselectedStyle().setBgTransparency(255);
+Style s = UIManager.getInstance().getComponentStyle("TitleCommand");
+Image camera = FontImage.createMaterial(FontImage.MATERIAL_CAMERA, s);
+hi.getToolbar().addCommandToRightBar("", camera, (ev) -> {
+    try {
+        int width = Display.getInstance().getDisplayWidth();
+        Image capturedImage = Image.createImage(Capture.capturePhoto(width, -1));
+        Image roundMask = Image.createImage(width, capturedImage.getHeight(), 0xff000000);
+        Graphics gr = roundMask.getGraphics();
+        gr.setColor(0xffffff);
+        gr.fillArc(0, 0, width, width, 0, 360);
+        Object mask = roundMask.createMask();
+        capturedImage = capturedImage.applyMask(mask);
+        picture.setIcon(capturedImage);
+        hi.revalidate();
+    } catch(IOException err) {
+        Log.e(err);
+    }
+});
+
+Figure 354. Picture after the capture was complete and the resulted image was rounded. The background
+
+was set to red so the rounding effect will be more noticeable
+
+Notice  that  this  example  is  simplistic  in  order  to  be  self  contained.  We  often  recommend  that
+
+developers  ship  "ready  made"  mask  images  with  their  application  which  can  allow  very  complex
+
+effects on the images.
+
+10.11.8. URLImage
+
+URLImage  [https://www.codenameone.com/javadoc/com/codename1/ui/URLImage.html]  is  an  image  created
+
+with a URL, it implicitly downloads and adapts the image in the given URL while caching it locally.
+
+The  typical  adapt  process  scales  the  image  or  crops  it  to  fit  into  the  same  size  which  is  a  hard
+restriction because of the way URLImage is implemented.
+
+404
+
+How Does URLImage Work?
+
+The  reason  for  the  size  restriction  lies  in  the  implementation  of  URLImage.  URLImage  is
+physically  an  animated  image  and  so  the  UI  thread  tries  to  invoke  its  animate()  method  to
+refresh.  The  URLImage  uses  that  call  to  check  if  the  image  was  fetched  and  if  not  fetches  it
+asynchronously.
+
+Once the image was fetched the animate() method returns true to refresh the UI. During the
+loading process the placeholder is shown, the reason for the restriction in size is that image
+
+animations  can’t  "grow"  the  image.  They  are  assumed  to  be  fixed  so  the  placeholder  must
+
+match the dimensions of the resulting image.
+
+The simple use case is pretty trivial:
+
+Image i = URLImage.createToStorage(placeholder, "fileNameInStorage", "http://xxx/myurl.jpg", URLImage.RESIZE_SCALE);
+
+Alternatively  you  can  use  the  similar  URLImage.createToFileSystem  method  instead  of  the  Storage
+[https://www.codenameone.com/javadoc/com/codename1/io/Storage.html] version.
+
+This  image  can  now  be  used  anywhere  a  regular  image  will  appear,  it  will  initially  show  the
+
+placeholder image and then seamlessly replace it with the file after it was downloaded and stored.
+Notice that if you make changes to the image itself (e.g. the scaled method) it will generate a new
+image which won’t be able to fetch the actual image.
+
+
+
+Since  ImageIO  [https://www.codenameone.com/javadoc/com/codename1/ui/util/ImageIO.html]
+is used to perform the operations of the adapter interface its required that ImageIO
+will  work.  It  is  currently  working  in  JavaSE,  Android,  iOS  &  Windows  Phone.  It
+
+doesn’t  work  on  J2ME/Blackberry  devices  so  if  you  pass  an  adapter  instance  on
+
+those platforms it will probably fail to perform its task.
+
+If  the  file  in  the  URL  contains  an  image  that  is  too  big  it  will  scale  it  to  match  the  size  of  the
+
+placeholder precisely!
+
+There is also an option to fail if the sizes don’t match. Notice that the image that will be saved is the
+
+scaled  image,  this  means  you  will  have  very  little  overhead  in  downloading  images  that  are  the
+
+wrong size although you will get some artifacts.
+
+The  last  argument  is  really  quite  powerful,  its  an  interface  called  URLImage.ImageAdapter
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/URLImage.ImageAdapter.html] 
+
+and 
+
+you 
+
+can
+
+implement it to adapt the downloaded image in any way you like. E.g. you can use an image mask
+
+to automatically create a rounded version of the downloaded image.
+
+To do this you can just override:
+
+public EncodedImage adaptImage(EncodedImage downloadedImage, Image placeholderImage)
+
+In the adapter interface and just return the processed encoded image. If you do heavy processing
+
+405
+
+(e.g.  rounded  edge  images)  you  would  need  to  convert  the  processed  image  back  to  an  encoded
+
+image  so  it  can  be  saved.  You  would  then  also  want  to  indicate  that  this  operation  should  run
+
+asynchronously via the appropriate method in the class.
+
+If  you  need  to  download  the  file  instantly  and  not  wait  for  the  image  to  appear  before  download
+initiates  you  can  explicitly  invoke  the  fetch()  method  which  will  asynchronously  fetch  the  image
+from  the  network.  Notice  that  the  downloading  will  still  take  time  so  the  placeholder  is  still
+
+required.
+
+Mask Adapter
+
+A  URLImage  can  be  created  with  a  mask  adapter  to  apply  an  effect  to  an  image.  This  allows  us  to
+round  downloaded  images  or  apply  any  sort  of  masking  e.g.  we  can  adapt  the  round  mask  code
+
+above as such:
+
+Image roundMask = Image.createImage(placeholder.getWidth(), placeholder.getHeight(), 0xff000000);
+Graphics gr = roundMask.getGraphics();
+gr.setColor(0xffffff);
+gr.fillArc(0, 0, placeholder.getWidth(), placeholder.getHeight(), 0, 360);
+
+URLImage.ImageAdapter ada = URLImage.createMaskAdapter(roundMask);
+Image i = URLImage.createToStorage(placeholder, "fileNameInStorage", "http://xxx/myurl.jpg", ada);
+
+URLImage In Lists
+
+The  biggest  problem  with  image  download  service  is  with  lists.  We  decided  to  attack  this  issue  at
+
+the core by integrating URLImage [https://www.codenameone.com/javadoc/com/codename1/ui/URLImage.html]
+
+support  directly  into  GenericListCellRenderer  [https://www.codenameone.com/javadoc/com/codename1/ui/
+
+list/GenericListCellRenderer.html] which means it will work with MultiList [https://www.codenameone.com/
+
+javadoc/com/codename1/ui/list/MultiList.html],  List  [https://www.codenameone.com/javadoc/java/util/List.html]  &
+
+ContainerList  [https://www.codenameone.com/javadoc/com/codename1/ui/list/ContainerList.html].  To  use  this
+support just define the name of the component (name not UIID) to end with _URLImage and give it an
+icon  to  use  as  the  placeholder.  This  is  easy  to  do  in  the  multilist  by  changing  the  name  of  icon  to
+icon_URLImage then using this in the data:
+
+map.put("icon_URLImage", urlToActualImage);
+
+Make sure you also set a "real" icon to the entry in the GUI builder or in handcoded applications.
+
+This  is  important  since  the  icon  will  be  implicitly  extracted  and  used  as  the  placeholder  value.
+Everything  else  should  be  handled  automatically.  You  can  use  setDefaultAdapter  &  setAdapter  on
+the  generic  list  cell  renderer  to  install  adapters  for  the  images.  The  default  is  a  scale  adapter
+
+although we might change that to scale fill in the future.
+
+406
+
+Style s = UIManager.getInstance().getComponentStyle("Button");
+FontImage p = FontImage.createMaterial(FontImage.MATERIAL_PORTRAIT, s);
+EncodedImage placeholder = EncodedImage.createFromImage(p.scaled(p.getWidth() * 3, p.getHeight() * 4), false);
+
+Form hi = new Form("MultiList", new BorderLayout());
+
+ArrayList<Map<String, Object>> data = new ArrayList<>();
+
+data.add(createListEntry("A Game of Thrones", "1996", "http://www.georgerrmartin.com/wp-
+content/uploads/2013/03/GOTMTI2.jpg"));
+data.add(createListEntry("A Clash Of Kings", "1998", "http://www.georgerrmartin.com/wp-
+content/uploads/2012/08/clashofkings.jpg"));
+data.add(createListEntry("A Storm Of Swords", "2000", "http://www.georgerrmartin.com/wp-
+content/uploads/2013/03/stormswordsMTI.jpg"));
+data.add(createListEntry("A Feast For Crows", "2005", "http://www.georgerrmartin.com/wp-
+content/uploads/2012/08/feastforcrows.jpg"));
+data.add(createListEntry("A Dance With Dragons", "2011", "http://georgerrmartin.com/gallery/art/dragons05.jpg"));
+data.add(createListEntry("The Winds of Winter", "2016 (please, please, please)", "http://www.georgerrmartin.com/wp-
+content/uploads/2013/03/GOTMTI2.jpg"));
+data.add(createListEntry("A Dream of Spring", "Ugh", "http://www.georgerrmartin.com/wp-
+content/uploads/2013/03/GOTMTI2.jpg"));
+
+DefaultListModel<Map<String, Object>> model = new DefaultListModel<>(data);
+MultiList ml = new MultiList(model);
+ml.getUnselectedButton().setIconName("icon_URLImage");
+ml.getSelectedButton().setIconName("icon_URLImage");
+ml.getUnselectedButton().setIcon(placeholder);
+ml.getSelectedButton().setIcon(placeholder);
+hi.add(BorderLayout.CENTER, ml);
+
+The createListEntry method then looks like this:
+
+private Map<String, Object> createListEntry(String name, String date, String coverURL) {
+    Map<String, Object> entry = new HashMap<>();
+    entry.put("Line1", name);
+    entry.put("Line2", date);
+    entry.put("icon_URLImage", coverURL);
+    entry.put("icon_URLImageName", name);
+    return entry;
+}
+
+Figure 355. A URL image fetched dynamically into the list model
+
+407
+
+408
+
+11. Events
+
+Most  events  in  Codename  One  are  routed  via  the  high  level  events  (e.g.  action  listener)  but
+
+sometimes we need access to low level events (e.g. when drawing via Graphics) that provide more
+
+fine  grained  access.  Typically  working  with  the  higher  level  events  is  far  more  potable  since  it
+
+might map to different functionality on different devices.
+
+11.1. High Level Events
+
+High level events are broadcast using an addListener/setListener - publish/subscribe system. Most
+of them are channeled via the EventDispatcher [https://www.codenameone.com/javadoc/com/codename1/ui/
+
+util/EventDispatcher.html]  class  which  further  simplifies  that  and  makes  sending  events  correctly  far
+
+easier.
+
+
+
+All events are fired on the Event Dispatch Thread, the EventDispatcher makes sure
+of that.
+
+11.1.1. Chain Of Events
+
+Since all events fire on the EDT some complexities occur. E.g.:
+
+We have two listeners monitoring the same event (or related events e.g. pointer event and button
+
+click event both of which will fire when the button is touched).
+
+When the event occurs we can run into a scenario like this:
+
+1. First event fires
+
+2. It shows a blocking dialog or invokes an "AndWait" API
+
+3. Second event fires only after the dialog was dismissed!
+
+This  happens  because  events  are  processed  in-order  per  cycle.  Since  the  old  EDT  cycle  is  stuck
+(because of the Dialog) the rest of the events within the cycle can’t complete. New events are in a
+new EDT cycle so they can finish just fine!
+
+A workaround to this issue is to wrap the code in a callSerially, you shouldn’t do this universally
+as this can create a case of shifting the problem to the next EDT cycle. However, using callSerially
+
+will allow the current cycle to flush which should help.
+
+Another workaround for the issue is avoiding blocking calls within an event chain.
+
+11.1.2. Action Events
+
+The  most  common  high  level  event  is  the  ActionListener  [https://www.codenameone.com/javadoc/com/
+
+codename1/ui/events/ActionListener.html]  which  allows  binding  a  generic  action  event  to  pretty  much
+
+anything.  This  is  so  ubiquitous  in  Codename  One  that  it  is  even  used  for  networking  (as  a  base
+
+class) and for some of the low level event options.
+
+E.g. we can bind an event callback for a Button [https://www.codenameone.com/javadoc/com/codename1/ui/
+
+409
+
+Button.html] by using:
+
+Button b = new Button("Click Me");
+b.addActionListener(new ActionListener() {
+    public void actionPerformed(ActionEvent ev) {
+        // button was clicked, you can do anything you want here...
+    }
+});
+
+Or thanks to the Java 8 lambdas we can write it as:
+
+Button b = new Button("Click Me");
+b.addActionListener((ev) ->
+    // button was clicked, you can do anything you want here...
+});
+
+Notice  that  the  click  will  work  whether  the  button  was  touched  using  a  mouse,  finger  or  keypad
+
+shortcut seamlessly with an action listener. Many components work with action events e.g. buttons,
+
+text components, slider etc.
+
+There are quite a few types of high level event types that are more specific to requirements.
+
+Types Of Action Events
+
+When  an  action  event  is  fired  it  is  given  a  type,  however  this  type  might  change  as  the  event
+
+evolves  e.g.  a  command  triggered  by  a  pointer  event  won’t  include  details  of  the  original  pointer
+
+event.
+
+You can get the event type from getEventType() [https://www.codenameone.com/javadoc/com/codename1/ui/
+
+events/ActionEvent.html#getEventType--], this also gives you a rather exhaustive list of the possible event
+
+types for the action event.
+
+Source Of Event
+
+ActionEvent  has  a  source  object,  what  that  source  is  depends  heavily  on  the  event  type.  For  most
+component based events this is the component but there are some nuances.
+
+The getComponent() method might not get the actual component. In case of a lead component such
+the
+as  MultiButton 
+
+[https://www.codenameone.com/javadoc/com/codename1/components/MultiButton.html] 
+
+underlying  Button  [https://www.codenameone.com/javadoc/com/codename1/ui/Button.html]  will  be  returned
+and not the MultiButton itself.
+
+To  get  the  component  that  you  would  logically  think  of  as  the  source  component  use  the
+getActualComponent() method.
+
+Event Consumption
+
+An ActionEvent can be consumed, once consumed it will no longer proceed down the chain of event
+
+410
+
+processing. This is useful for some cases where we would like to block behavior from proceeding
+
+down the path.
+
+E.g. the event dispatch thread allows us to listen to errors on the EDT using:
+
+Display.getInstance().addEdtErrorHandler((e) -> {
+    Exception err = (Exception)e.getSource();
+    // ...
+});
+
+This  will  work  great  but  you  will  still  get  the  default  error  message  from  the  EDT  over  that
+
+exception. To prevent the event from proceeding to the default error handling you can just do this:
+
+Display.getInstance().addEdtErrorHandler((e) -> {
+    e.consume();
+    Exception err = (Exception)e.getSource();
+    // ...
+});
+
+Notice that you can check if an event was already consumed using the isConsumed() method but it’s
+pretty unlikely that you will receive a consumed event as the system will usually stop sending it.
+
+NetworkEvent
+
+NetworkEvent [https://www.codenameone.com/javadoc/com/codename1/io/NetworkEvent.html] is a subclass of
+ActionEvent  that  is  passed  to  actionPerformed  callbacks  made  in  relation  to  generic  network  code.
+E.g.
+
+NetworkManager.getInstance().addErrorListener(new ActionListener<NetworkEvent>() {
+    public void actionPerformed(NetworkEvent ev) {
+        // now we have access to the methods on NetworkEvent that provide more information about the network specific
+flags
+    }
+});
+
+Or with Java 8 lambdas:
+
+NetworkManager.getInstance().addErrorListener((ev) -> {
+    // now we have access to the methods on NetworkEvent that provide more information about the network specific flags
+});
+
+The  NetworkEvent  allows  the  networking  code  to  reuse  the  EventDispatcher  infrastructure  and  to
+simplify  event  firing  thru  the  EDT.  But  you  should  notice  that  some  code  might  not  be  equivalent
+
+e.g. we could do this to read the input stream:
+
+411
+
+ConnectionRequest r = new ConnectionRequest() {
+    @Override
+    protected void readResponse(InputStream input) throws IOException {
+        // read the input stream
+    }
+};
+
+or we can do something similar using this code:
+
+ConnectionRequest r = new ConnectionRequest();
+r.addResponseListener((e) -> {
+    byte[] data = (byte[])e.getMetaData();
+    // work with the byte data
+});
+
+These seem very similar but they have one important distinction. The latter code is invoked on the
+EDT, so if data is big it might slow down processing significantly. The ConnectionRequest is invoked
+on  the  network  thread  and  so  can  process  any  amount  of  data  without  slowing  down  the  UI
+
+significantly.
+
+11.1.3. DataChangeListener
+
+The 
+
+DataChangedListener 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/events/
+
+DataChangedListener.html]  is  used  in  several  places  to  indicate  that  the  underlying  model  data  has
+
+changed:
+
+• TextField  [https://www.codenameone.com/javadoc/com/codename1/ui/TextField.html] 
+
+-  the  text  field
+
+provides  an  action  listener  but  that  only  "fires"  when  the  data  input  is  complete.
+DataChangeListener  fires  with  every  key  entered  and  thus  allows  functionality  such  as  "auto
+complete" and is indeed used internally in the Codename One AutoCompleteTextField.
+
+• TableModel 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/table/TableModel.html] 
+
+&
+
+ListModel  [https://www.codenameone.com/javadoc/com/codename1/ui/list/ListModel.html]  -  the  model  for
+
+the  Table  [https://www.codenameone.com/javadoc/com/codename1/ui/table/Table.html]  class  notifies  the
+
+view that its content has changed via this event, thus allowing the UI to refresh properly.
+
+There is a very exhaustive example of search that is implemented using the DataChangedListener in
+the Toolbar section [https://www.codenameone.com/manual/components.html#Advanced-search-code].
+
+11.1.4. FocusListener
+
+The  focus  listener  allows  us  to  track  the  currently  "selected"  or  focused  component.  It’s  not  as
+
+useful as it used to be in feature phones.
+
+You can bind a focus listener to the Component itself and receive an event when it gained focus, or
+you  can  bind  the  listener  to  the  Form  and  receive  events  for  every  focus  change  event  within  the
+hierarchy.
+
+412
+
+11.1.5. ScrollListener
+
+ScrollListener 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/events/ScrollListener.html]  allows
+
+tracking scroll events so UI elements can be adapted if necessary.
+
+Normally  scrolling  is  seamless  and  this  event  isn’t  necessary,  however  if  developers  wish  to
+
+"shrink" or "fade" an element on scrolling this interface can be used to achieve that. Notice that you
+
+should  bind  the  scroll  listener  to  the  actual  scrollable  component  and  not  to  an  arbitrary
+
+component.
+
+E.g. in this code from the Flickr demo the Toolbar [https://www.codenameone.com/javadoc/com/codename1/
+ui/Toolbar.html] is faded based on scroll position:
+
+public class CustomToolbar extends Toolbar implements ScrollListener {
+    private int alpha;
+
+    public CustomToolbar() {
+    }
+
+    public void paintComponentBackground(Graphics g) {
+        int a = g.getAlpha();
+        g.setAlpha(alpha);
+        super.paintComponentBackground(g);
+        g.setAlpha(a);
+    }
+
+    public void scrollChanged(int scrollX, int scrollY, int oldscrollX, int oldscrollY) {
+        alpha = scrollY;
+        alpha = Math.max(alpha, 0);
+        alpha = Math.min(alpha, 255);
+    }
+}
+
+
+
+There  is  a  better  way  of  implementing  this  exact  effect  using  title  animations
+
+illustrated  here  [https://www.codenameone.com/manual/components.html#title-animations-
+
+section].
+
+11.1.6. SelectionListener
+
+The SelectionListener [https://www.codenameone.com/javadoc/com/codename1/ui/events/SelectionListener.html]
+
+event is mostly used to broadcast list model selection changes to the list view. Since list supports the
+ActionListener event callback its usually the better option since it’s more coarse grained.
+
+SelectionListener  gets  fired  too  often  for  events  and  that  might  result  in  a  performance  penalty.
+When  running  on  non-touch  devices  list  selection  could  be  changed  with  the  keypad  and  only  a
+specific fire button click would fire the action event, for those cases SelectionListener made a lot of
+sense. However, in touch devices this API isn’t as useful.
+
+413
+
+11.1.7. StyleListener
+
+StyleListener 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/events/StyleListener.html] 
+
+allows
+
+components to track changes to the style objects. E.g. if the developer does something like:
+
+cmp.getUnselectedStyle().setFgColor(0xffffff);
+
+This  will  trigger  a  style  event  that  will  eventually  lead  to  the  component  being  repainted.  This  is
+
+quite important for the component class but not a very important event for general user code. It is
+
+recommended that developers don’t bind a style listener.
+
+11.1.8. Event Dispatcher
+
+When  creating  your  own  components  and  objects  you  sometimes  want  to  broadcast  your  own
+
+events,  for  that  purpose  Codename  One  has  the  EventDispatcher  [https://www.codenameone.com/
+
+javadoc/com/codename1/ui/util/EventDispatcher.html] class which saves a lot of coding effort in this regard.
+
+E.g.  if  you  wish  to  provide  an  ActionListener  [https://www.codenameone.com/javadoc/com/codename1/ui/
+
+events/ActionListener.html] event for components you can just add this to your class:
+
+private final EventDispatcher listeners = new EventDispatcher();
+
+public void addActionListener(ActionListener a) {
+    listeners.addListener(a);
+}
+public void removeActionListener(ActionListener a) {
+    listeners.removeListener(a);
+}
+
+Then when you need to broadcast the event just use:
+
+private void fireEvent(ActionEvent ev) {
+    listeners.fireActionEvent(ev);
+}
+
+11.2. Low Level Events
+
+Low level events map to "system" events directly. Touch events are considered low level since they
+
+might expose platform specific nuances to your code.
+
+E.g. one platform might send a very large number of events during drag while another might send
+
+only  a  few.  Normally  the  high  level  event  handling  hides  those  complexities  but  some  of  them
+
+trickle down into the low level event handling.
+
+
+
+Codename One tries to hide some of the complexities from the low level events as
+
+well. However, due to the nature of the event types it’s a more challenging task.
+
+414
+
+Low level events can be bound in one of 3 ways:
+
+• Use  one  of  the  add  listener  methods  in  Form  [https://www.codenameone.com/javadoc/com/codename1/
+
+ui/Form.html] e.g. addPointerPressedListener.
+
+• Override one of the event callbacks on Form
+
+• Override  one  of  the  event  callbacks  on  a  Component  [https://www.codenameone.com/javadoc/com/
+
+codename1/ui/Component.html].
+
+
+
+When you override event callbacks on a Component the Component in question must
+be focusable and have focus at that point. This can be an advantage for some use
+
+cases as it will save you the need of handling unrelated events.
+
+Each of those has advantages and disadvantages, specifically:
+
+• 'Form' based events and callbacks deliver pointer events in the 'Form' coordinate space.
+
+• 'Component' based events require focus
+
+• 'Form' based events can block existing functionality from proceeding thru the event chain e.g.
+
+you can avoid calling super in a form event and thus block other events from happening (e.g.
+
+block a listener or component event from triggering).
+
+Table 8. Event type map
+
+Listener
+
+Override Form
+
+Override Component
+
+Coordinate System
+
+Form
+
+Form
+
+Component
+
+Block current
+
+functionality
+
+Yes, just avoid super
+
+Partially (event
+
+No
+
+consume)
+
+11.2.1. Low Level Event Types
+
+There are two basic types of low level events: Key and Pointer.
+
+
+
+Key  events  are  only  relevant  to  physical  keys  and  will  not  trigger  on  virtual
+
+keyboard  keys,  to  track  those  use  a  TextField  [https://www.codenameone.com/javadoc/
+com/codename1/ui/TextField.html] with a DataChangeListener as mentioned above.
+
+The pointer events (touch events) can be intercepted by overriding one or more of these methods in
+Component  or  Form.  Notice  that  unless  you  want  to  block  functionality  you  should  probably  invoke
+super when overriding:
+
+415
+
+public void pointerDragged(int[] x, int[] y)
+public void pointerDragged(final int x, final int y)
+public void pointerPressed(int[] x, int[] y)
+public void pointerPressed(int x, int y)
+public void pointerReleased(int[] x, int[] y)
+public void pointerReleased(int x, int y)
+public void longPointerPress(int x, int y)
+public void keyPressed(int keyCode)
+public void keyReleased(int keyCode)
+public void keyRepeated(int keyCode)
+
+Notice that most pointer events have a version that accepts an array as an argument, this allows for
+
+multi-touch event handling by sending all the currently touched coordinates.
+
+11.2.2. Drag Event Sanitation
+
+Drag  events  are  quite  difficult  to  handle  properly  across  devices.  Some  devices  send  a  ridiculous
+
+number  of  events  for  even  the  lightest  touch  while  others  send  too  little.  It  seems  like  too  many
+
+drag  events  wouldn’t  be  a  problem,  however  if  we  drag  over  a  button  then  it  might  disable  the
+
+buttons action event (since this might be the user trying to scroll).
+
+Drag  sensitivity  is  really  about  the  component  being  dragged  which  is  why  we  have  the  method
+getDragRegionStatus  that  allows  us  to  "hint"  to  the  drag  API  whether  we  are  interested  in  drag
+events or not and if so in which directional bias.
+
+E.g. if our component is a painting app where we are trying to draw using drag gestures we would
+
+use code such as:
+
+public class MyComponent extends Component {
+    protected int getDragRegionStatus(int x, int y) {
+        return DRAG_REGION_LIKELY_DRAG_XY;
+    }
+}
+
+This indicates that we want all drag events on both AXIS to be sent as soon as possible. Notice that
+
+this doesn’t completely disable event sanitation.
+
+11.3. BrowserNavigationCallback
+
+The 
+
+BrowserNavigationCallback 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/events/
+
+BrowserNavigationCallback.html] isn’t quite an "event" but there is no real "proper" classification for it.
+
+
+
+The  callback  method  of  this  interface  is  invoked  off  the  EDT!  You  must  NEVER
+
+block this method and must not access UI or Codename One sensitive elements in
+
+this method!
+
+The browser navigation callback is invoked directly from the native web component as it navigates
+
+416
+
+to  a  new  page.  Because  of  that  it  is  invoked  on  the  native  OS  thread  and  gives  us  a  unique
+
+opportunity to handle the navigation ourselves as we see fit. That is why it MUST be invoked on the
+
+native  thread,  since  the  native  browser  is  pending  on  our  response  to  that  method,  spanning  an
+
+invokeAndBlock/callSerially would be to slow and would bog down the browser.
+
+You  can  use  the  browser  navigation  callback  to  change  the  UI  or  even  to  invoke  Java  code  from
+
+JavaScript code e.g.:
+
+bc.setBrowserNavigationCallback((url) -> {
+    if(url.startsWith("http://click")) {
+        Display.getInstance().callSerially(() -> bc.execute("fnc('<p>You clicked!</p>')"));
+        return false;
+    }
+    return true;
+});
+
+417
+
+418
+
+12. File System, Storage, Network & Parsing
+
+12.1. Jar Resources
+
+Resources  that  are  packaged  within  the  "JAR"  don’t  really  belong  in  this  section  of  the  developer
+guide but since they are often confused with Storage/FileSystemStorage this might be the best place
+to clarify what they are.
+
+You can place arbitrary files within the src directory of a Codename One project. This file will get
+packaged into the final distribution. In standard Java SE you can usually do something like:
+
+InputStream i = getClass().getResourceAsStream("/myFile");
+
+This isn’t guaranteed to work on all platforms and will probably fail on some. Instead you should
+
+use something such as:
+
+InputStream i = Display.getInstance().getResourceAsStream(getClass(), "/myFile");
+
+This isn’t the only limitation though, you can use hierarchies so something like this would fail:
+
+InputStream i = Display.getInstance().getResourceAsStream(getClass(), "/res/myFile");
+
+You can’t use relative paths either so this will fail as well (notice the lack of the first slash):
+
+InputStream i = Display.getInstance().getResourceAsStream(getClass(), "myFile");
+
+The  reason  for  those  limitations  is  portability,  on  iOS  and  Android  resources  behave  quite
+
+differently so supporting the full Java SE semantics is unrealistic.
+
+
+
+This is even worse in some regards. Because of the way iOS works with resources
+some unique file names might fail e.g. if you use the @ character or have a . more
+than once (e.g. file.ext.act)
+
+Notice that just like in Java SE, the entries within the "JAR" are read only and can’t be modified. You
+
+can’t gain access to the actual file, only to the stream!
+
+12.2. Storage
+
+Storage  [https://www.codenameone.com/javadoc/com/codename1/io/Storage.html]  is  accessed  via  the  Storage
+class. It is a flat filesystem like interface and contains the ability to list/delete and write to named
+
+storage entries.
+
+The Storage API also provides convenient methods to write objects to Storage and read them from
+
+419
+
+Storage specifically readObject & writeObject.
+
+The  objects  in  Storage  are  usually  deleted  when  an  app  is  uninstalled  but  are
+
+
+
+retained  between  application  updates.  A  notable  exception  is  Android  which,  on
+
+some  devices,  keeps  by  default  objects  in  Storage  after  app  uninstalling.  To  force
+
+Android 
+android.allowBackup=false
+
+to  remove 
+
+them  on  app  uninstalling,  use 
+
+the  build  hint
+
+The sample code below demonstrates listing the content of the storage, adding/viewing and deleting
+
+entries within the storage:
+
+420
+
+Toolbar.setGlobalToolbar(true);
+Form hi = new Form("Storage", new BoxLayout(BoxLayout.Y_AXIS));
+hi.getToolbar().addCommandToRightBar("+", null, e -> {
+    TextField tf = new TextField("", "File Name", 20, TextField.ANY);
+    TextArea body = new TextArea(5, 20);
+    body.setHint("File Body");
+    Command ok = new Command("OK");
+    Command cancel = new Command("Cancel");
+    Command result = Dialog.show("File Name", BorderLayout.north(tf).add(BorderLayout.CENTER, body), ok, cancel);
+    if(ok == result) {
+        try(OutputStream os = Storage.getInstance().createOutputStream(tf.getText());) {
+            os.write(body.getText().getBytes("UTF-8"));
+            createFileEntry(hi, tf.getText());
+            hi.getContentPane().animateLayout(250);
+        } catch(IOException err) {
+            Log.e(err);
+        }
+    }
+});
+for(String file : Storage.getInstance().listEntries()) {
+    createFileEntry(hi, file);
+}
+hi.show();
+
+private void createFileEntry(Form hi, String file) {
+   Label fileField = new Label(file);
+   Button delete = new Button();
+   Button view = new Button();
+   FontImage.setMaterialIcon(delete, FontImage.MATERIAL_DELETE);
+   FontImage.setMaterialIcon(view, FontImage.MATERIAL_OPEN_IN_NEW);
+   Container content = BorderLayout.center(fileField);
+   int size = Storage.getInstance().entrySize(file);
+   content.add(BorderLayout.EAST, BoxLayout.encloseX(new Label(size + "bytes"), delete, view));
+   delete.addActionListener(e -> {
+       Storage.getInstance().deleteStorageFile(file);
+       content.setY(hi.getWidth());
+       hi.getContentPane().animateUnlayoutAndWait(150, 255);
+       hi.removeComponent(content);
+       hi.getContentPane().animateLayout(150);
+   });
+   view.addActionListener(e -> {
+       try(InputStream is = Storage.getInstance().createInputStream(file);) {
+           String s = Util.readToString(is, "UTF-8");
+           Dialog.show(file, s, "OK", null);
+       } catch(IOException err) {
+           Log.e(err);
+       }
+   });
+   hi.add(content);
+}
+
+421
+
+Figure 356. List of files within the storage
+
+Figure 357. Content of a file added to the storage
+
+12.2.1. The Preferences API
+
+Storage  also  offers  a  very  simple  API  in  the  form  of  the  Preferences  [https://www.codenameone.com/
+javadoc/com/codename1/io/Preferences.html]  class.  The  Preferences  class  allows  developers  to  store
+simple variables, strings, numbers, booleans etc. in storage without writing any storage code. This is
+
+a common use case within applications e.g. you have a server token that you need to store you can
+
+store it like this:
+
+Preferences.set("token", myToken);
+
+You can then read the token like this:
+
+String token = Preferences.get("token", null);
+
+This  gets  somewhat  confusing  with  primitive  numbers  e.g. 
+Preferences.set("primitiveLongValue", 
+then 
+Preferences.get("primitiveLongValue", 0) you might get an exception!
+This would happen because the value is physically a Long object but you are trying
+to  get  an  Integer.  The  workaround  is  to  remain  consistent  and  use  code  like  this
+Preferences.get("primitiveLongValue", (long)0).
+
+myLongNumber) 
+
+if  you  use
+
+invoke
+
+
+
+422
+
+12.3. File System
+
+FileSystemStorage 
+
+[https://www.codenameone.com/javadoc/com/codename1/io/FileSystemStorage.html]
+
+provides  file  system  access.  It  maps  to  the  underlying  OS’s  file  system  API  providing  most  of  the
+common  operations  expected  from  a  file  API  somewhat  in  the  vain  of  java.io.File  &
+java.io.FileInputStream e.g. opening, renaming, deleting etc.
+
+Notice that the file system API is somewhat platform specific in its behavior. All paths used the API
+
+should be absolute otherwise they are not guaranteed to work.
+
+The main reason java.io.File & java.io.FileInputStream weren’t supported directly has a lot to do
+with the richness of those two API’s. They effectively allow saving a file anywhere, however mobile
+
+devices  are  far  more  restrictive  and  don’t  allow  apps  to  see/modify  files  that  are  owned  by  other
+
+apps.
+
+12.3.1. File Paths & App Home
+
+All paths in FileSystemStorage are absolute, this simplifies the issue of portability significantly since
+the concept of relativity and current working directory aren’t very portable.
+
+All URL’s use the / as their path separator we try to enforce this behavior even in Windows.
+
+Directories end with the / character and thus can be easily distinguished by their name.
+
+The  FileSystemStorage  API  provides  a  getRoots()  call  to  list  the  root  directories  of  the  file  system
+(you  can  then  "dig  in"  via  the  listFiles  API).  However,  this  is  confusing  and  unintuitive  for
+developers.
+
+To  simplify  the  process  of  creating/reading  files  we  added  the  getAppHomePath()  method.  This
+method allows us to obtain the path to a directory where files can be stored/read.
+
+We  can  use  this  directory  to  place  an  image  to  share  as  we  did  in  the  share  sample
+
+[https://www.codenameone.com/manual/components.html#sharebutton-section].
+
+
+
+A  common  Android  hack  is  to  write  files  to  the  SDCard  storage  to  share  them
+
+among  apps.  Android  4.x  disabled  the  ability  to  write  to  arbitrary  directories  on
+
+the SDCard even when the appropriate permission was requested.
+
+A more advanced usage of the FileSystemStorage API can be a FileSystemStorage Tree:
+
+423
+
+Form hi = new Form("FileSystemTree", new BorderLayout());
+TreeModel tm = new TreeModel() {
+    @Override
+    public Vector getChildren(Object parent) {
+        String[] files;
+        if(parent == null) {
+            files = FileSystemStorage.getInstance().getRoots();
+            return new Vector<Object>(Arrays.asList(files));
+        } else {
+            try {
+                files = FileSystemStorage.getInstance().listFiles((String)parent);
+            } catch(IOException err) {
+                Log.e(err);
+                files = new String[0];
+            }
+        }
+        String p = (String)parent;
+        Vector result = new Vector();
+        for(String s : files) {
+            result.add(p + s);
+        }
+        return result;
+    }
+
+    @Override
+    public boolean isLeaf(Object node) {
+        return !FileSystemStorage.getInstance().isDirectory((String)node);
+    }
+};
+Tree t = new Tree(tm) {
+    @Override
+    protected String childToDisplayLabel(Object child) {
+        String n = (String)child;
+        int pos = n.lastIndexOf("/");
+        if(pos < 0) {
+            return n;
+        }
+        return n.substring(pos);
+    }
+};
+hi.add(BorderLayout.CENTER, t);
+hi.show();
+
+424
+
+Figure 358. Simple sample of a tree for the FileSystemStorage API
+
+12.3.2. Storage vs. File System
+
+The question of storage vs. file system is often confusing for novice mobile developers. This embeds
+
+two separate questions:
+
+• Why are there 2 API’s where one would have worked?
+
+• Which one should I pick?
+
+The main reasons for the 2 API’s are technical. Many OS’s provide 2 ways of accessing data specific
+to the app and this is reflected within the API. E.g. on Android the FileSystemStorage maps to API’s
+such as java.io.FileInputStream whereas the Storage maps to Context.openFileInput().
+
+The secondary reason for the two API’s is conceptual. FileSystemStorage is more powerful and in a
+sense provides more ways to fail, this is compounded by the complex on-device behavior of the API.
+Storage is designed to be friendlier to the uninitiated and more portable.
+
+You should pick Storage unless you have a specific requirement that prevents it. Some API’s such as
+Capture expect a FileSystemStorage URI so in those cases this would also be a requirement.
+
+Another case where FileSystemStorage is beneficial is the case of hierarchy or native API usage. If
+you need a a directory structure or need to communicate with a native API the FileSystemStorage
+approach is usually easier.
+
+
+
+In some OS’s the FileSystemStorage API can find the content of the Storage API. As
+one  is  implemented  on  top  of  the  other.  This  is  undocumented  behavior  that  can
+
+change at any moment!
+
+To summarize the differences between the 3 file storage options:
+
+Table 9. Compare Storage, FileSystem & Jar Resources
+
+Option
+
+Storage
+
+File System
+
+JAR Resource
+
+Main Use Case
+
+General application
+
+Low level access
+
+Ship data within the
+
+Initial State
+
+Data
+
+Blank
+
+Blank
+
+app
+
+As defined by
+
+developer
+
+425
+
+Option
+
+Storage
+
+File System
+
+JAR Resource
+
+Modifiable
+
+Yes
+
+Supports Hierarchies No
+
+Yes
+
+Yes
+
+No
+
+No
+
+12.4. SQL
+
+Most new devices contain one version of sqlite or another; sqlite is a very lightweight SQL database
+
+designed for embedding into devices. For portability we recommend avoiding SQL altogether since
+
+it is both fragmented between devices (different sqlite versions) and isn’t supported on all devices.
+
+In general SQL seems overly complex for most embedded device programming tasks.
+
+Portability Of SQLite
+
+SQLite  is  supported  on  iOS,  Android,  RIM,  Desktop  &  JavaScript  builds.  However,  the
+
+JavaScript version of SQL has been deprecated and isn’t supported on all platforms.
+
+You will notice that at this time support is still missing from the Windows builds.
+
+The  biggest  issue  with  SQLite  portability  is  in  iOS.  The  SQLite  version  for  most  platforms  is
+
+threadsafe and as a result very stable. However, the iOS version is not!
+
+This might not seem like a big deal normally, however if you forget to close a connection the
+
+GC  might  close  it  for  you  thus  producing  a  crash.  This  is  such  a  common  occurrence  that
+
+Codename One logs a warning when the GC collects a database resource on the simulator.
+
+SQL is pretty powerful and very well suited for common tabular data. The Codename One SQL API
+
+is similar in spirit to JDBC but considerably simpler since many of the abstractions of JDBC designed
+
+for pluggable database architecture make no sense for a local database.
+
+The  Database  [https://www.codenameone.com/javadoc/com/codename1/db/Database.html]  API  is  a  high  level
+
+abstraction that allows you to open an arbitrary database file using syntax such as:
+
+Database db = Display.getInstance().openOrCreate(“databaseName”);
+
+Some SQLite apps ship with a "ready made" database. We allow you to replace the DB file by using
+
+the code:
+
+String path = Display.getInstance().getDatabasePath(“databaseName”);
+
+You  can  then  use  the  FileSystemStorage  class  to  write  the  content  of  your  DB  file  into  the  path.
+Notice that it must be a valid SQLite file!
+
+ getDatabasePath() is not supported in the Javascript port. It will always return null.
+
+426
+
+This  is  very  useful  for  applications  that  need  to  synchronize  with  a  central  server  or  applications
+
+that ship with a large database as part of their core product.
+
+Working with a database is pretty trivial, the application logic below can send arbitrary queries to
+the database and present the results in a Table. You can probably integrate this code into your app
+as a debugging tool:
+
+Toolbar.setGlobalToolbar(true);
+Style s = UIManager.getInstance().getComponentStyle("TitleCommand");
+FontImage icon = FontImage.createMaterial(FontImage.MATERIAL_QUERY_BUILDER, s);
+Form hi = new Form("SQL Explorer", new BorderLayout());
+hi.getToolbar().addCommandToRightBar("", icon, (e) -> {
+    TextArea query = new TextArea(3, 80);
+    Command ok = new Command("Execute");
+    Command cancel = new Command("Cancel");
+    if(Dialog.show("Query", query, ok, cancel) == ok) {
+        Database db = null;
+        Cursor cur = null;
+        try {
+            db = Display.getInstance().openOrCreate("MyDB.db");
+            if(query.getText().startsWith("select")) {
+                cur = db.executeQuery(query.getText());
+                int columns = cur.getColumnCount();
+                hi.removeAll();
+                if(columns > 0) {
+                    boolean next = cur.next();
+                    if(next) {
+                        ArrayList<String[]> data = new ArrayList<>();
+                        String[] columnNames = new String[columns];
+                        for(int iter = 0 ; iter < columns ; iter++) {
+                            columnNames[iter] = cur.getColumnName(iter);
+                        }
+                        while(next) {
+                            Row currentRow = cur.getRow();
+                            String[] currentRowArray = new String[columns];
+                            for(int iter = 0 ; iter < columns ; iter++) {
+                                currentRowArray[iter] = currentRow.getString(iter);
+                            }
+                            data.add(currentRowArray);
+                            next = cur.next();
+                        }
+                        Object[][] arr = new Object[data.size()][];
+                        data.toArray(arr);
+                        hi.add(BorderLayout.CENTER, new Table(new DefaultTableModel(columnNames, arr)));
+                    } else {
+                        hi.add(BorderLayout.CENTER, "Query returned no results");
+                    }
+                } else {
+                    hi.add(BorderLayout.CENTER, "Query returned no results");
+                }
+            } else {
+                db.execute(query.getText());
+                hi.add(BorderLayout.CENTER, "Query completed successfully");
+            }
+            hi.revalidate();
+        } catch(IOException err) {
+            Log.e(err);
+
+427
+
+            hi.removeAll();
+            hi.add(BorderLayout.CENTER, "Error: " + err);
+            hi.revalidate();
+        } finally {
+            Util.cleanup(db);
+            Util.cleanup(cur);
+        }
+    }
+});
+hi.show();
+
+Figure 359. Querying the temp demo generated by the SQLDemo application
+
+Figure 360. Issuing a query
+
+12.5. Network Manager & Connection Request
+
+One of the more common problems in Network programming is spawning a new thread to handle
+
+the network operations. In Codename One this is done seamlessly and becomes unessential thanks
+
+to the NetworkManager [http://www.codenameone.com/javadoc/com/codename1/io/NetworkManager.html].
+
+NetworkManager  effectively  alleviates  the  need  for  managing  network  threads  by  managing  the
+complexity of network threading. The connection request class can be used to facilitate web service
+
+requests when coupled with the JSON/XML parsing capabilities.
+
+To open a connection one needs to use a ConnectionRequest [http://www.codenameone.com/javadoc/com/
+
+codename1/io/ConnectionRequest.html]  object,  which  has  some  similarities 
+
+to 
+
+the  networking
+
+mechanism in JavaScript but is obviously somewhat more elaborate.
+
+You can send a get request to a URL using something like:
+
+428
+
+ConnectionRequest request = new ConnectionRequest(url, false);
+request.addResponseListener((e) -> {
+    // process the response
+});
+
+// request will be handled asynchronously
+NetworkManager.getInstance().addToQueue(request);
+
+Notice  that  you  can  also  implement  the  same  thing  and  much  more  by  avoiding  the  response
+listener  code  and  instead  overriding  the  methods  of  the  ConnectionRequest  class  which  offers
+multiple points to override e.g.
+
+ConnectionRequest request = new ConnectionRequest(url, false) {
+   protected void readResponse(InputStream input) {
+        // just read from the response input stream
+   }
+
+   protected void postResponse() {
+        // invoked on the EDT after processing is complete to allow the networking code
+        // to update the UI
+   }
+
+   protected void buildRequestBody(OutputStream os) {
+        // writes post data, by default this “just works” but if you want to write this
+       // manually then override this
+   }
+};
+NetworkManager.getInstance().addToQueue(request);
+
+
+
+Notice  that  overriding  buildRequestBody(OutputStream)  will  only  work  for  POST
+requests and will replace writing the arguments
+
+ You  don’t  need  to  close  the  output/input  streams  passed  to  the  request  methods.
+
+They are implicitly cleaned up.
+
+NetworkManager  also  supports  synchronous  requests  which  work  in  a  similar  way  to  Dialog  via  the
+invokeAndBlock call and thus don’t block the EDT [9] illegally. E.g. you can do something like this:
+
+ConnectionRequest request = new ConnectionRequest(url, false);
+// request will be handled synchronously
+NetworkManager.getInstance().addToQueueAndWait(request);
+byte[] resultOfRequest = request.getData();
+
+Notice that in this case the addToQueueAndWait method returned after the connection completed. Also
+notice that this was totally legal to do on the EDT!
+
+429
+
+12.5.1. Threading
+
+By  default  the  NetworkManager  launches  with  a  single  network  thread.  This  is  sufficient  for  very
+simple  applications  that  don’t  do  too  much  networking  but  if  you  need  to  fetch  many  images
+
+concurrently and perform web services in parallel this might be an issue.
+
+
+
+Once  you  increase  the  thread  count  there  is  no  guarantee  of  order  for  your
+
+requests. Requests might not execute in the order with which you added them to
+
+the queue!
+
+To update the number of threads use:
+
+NetworkManager.getInstance().updateThreadCount(4);
+
+All the callbacks in the ConnectionRequest occur on the network thread and not on the EDT!
+
+There  is  one  exception  to  this  rule  which  is  the  postResponse()  method  designed  to  update  the  UI
+after the networking code completes.
+
+
+
+Never  change  the  UI  from  a  ConnectionRequest  callback.  You  can  either  use  a
+listener on the ConnectionRequest, use postResponse() (which is the only exception
+to this rule) or wrap your UI code with callSerially.
+
+12.5.2. Arguments, Headers & Methods
+
+HTTP/S  is  a  complex  protocol  that  expects  complex  encoded  data  for  its  requests.  Codename  One
+
+tries  to  simplify  and  abstract  most  of  these  complexities  behind  common  sense  API’s  while  still
+
+providing the full low level access you would expect from such an API.
+
+Arguments
+
+HTTP supports several "request methods", most commonly GET & POST but also a few others such as
+HEAD, PUT, DELETE etc.
+
+Arguments in HTTP are passed differently between GET and POST methods. That is what the setPost
+method in Codename One determines, whether arguments added to the request should be placed
+using the GET semantics or the POST semantics.
+
+So if we continue our example from above we can do something like this:
+
+ConnectionRequest request = new ConnectionRequest(url, false);
+request.addArgument("MyArgName", value);
+
+This  will  implicitly  add  a  get  argument  with  the  content  of  value.  Notice  that  we  don’t  really  care
+what value is. It’s implicitly HTTP encoded based on the get/post semantics. In this case it will use
+the get encoding since we passed false to the constructor.
+
+430
+
+A simpler implementation could do something like this:
+
+ConnectionRequest request = new ConnectionRequest(url +
+    "MyArgName=" + Util.encodeUrl(value), false);
+
+This  would  be  almost  identical  but  doesn’t  provide  the  convenience  for  switching  back  and  forth
+between GET/POST and it isn’t as fluent.
+
+We can skip the encoding in complex cases where server code expects illegal HTTP characters (this
+happens)  using  the  addArgumentNoEncoding  method.  We  can  also  add  multiple  arguments  with  the
+same key using addArgumentArray.
+
+Methods
+
+As  we  explained  above,  the  setPost()  method  allows  us  to  manipulate  the  get/post  semantics  of  a
+request. This implicitly changes the POST or GET method submitted to the server.
+
+However, if you wish to have finer grained control over the submission process e.g. for making a
+HEAD request you can do this with code like:
+
+ConnectionRequest request = new ConnectionRequest(url, false);
+request.setHttpMethod("HEAD");
+
+Headers
+
+When  communicating  with  HTTP  servers  we  often  pass  data  within  headers  mostly  for
+
+authentication/authorization but also to convey various properties.
+
+Some headers are builtin as direct API’s e.g. content type is directly exposed within the API since it’s
+
+a pretty common use case. We can set the content type of a post request using:
+
+ConnectionRequest request = new ConnectionRequest(url, true);
+request.setContentType("text/xml");
+
+We  can  also  add  any  arbitrary  header  type  we  want,  e.g.  a  very  common  use  case  is  basic
+
+authorization  where  the  authorization  header  includes  the  Base64  encoded  user/password
+
+combination as such:
+
+String authCode = user + ":" + password;
+String authHeader = "Basic " + Base64.encode(authCode.getBytes());
+request.addRequestHeader("Authorization", authHeader);
+
+This can be quite tedious to do if you want all requests from your app to use this header. For this
+
+use case you can just use:
+
+431
+
+String authCode = user + ":" + password;
+String authHeader = "Basic " + Base64.encode(authCode.getBytes());
+NetworkManager.getInstance().addDefaultHeader("Authorization", authHeader);
+
+Server Headers
+
+Server returned headers are a bit trickier to read. We need to subclass the connection request and
+override the readHeaders method e.g.:
+
+ConnectionRequest request = new ConnectionRequest(url, false) {
+    protected void readHeaders(Object connection) throws IOException {
+        String[] headerNames = getHeaderFieldNames(connection);
+        for(String headerName : headerNames) {
+            String headerValue = getHeader(headerName);
+            //....
+        }
+    }
+    protected void readResponse(InputStream input) {
+        // just read from the response input stream
+    }
+};
+NetworkManager.getInstance().addToQueue(request);
+
+Here  we  can  extract  the  headers  one  by  one  to  handle  complex  headers  such  as  cookies,
+
+authentication etc.
+
+Error Handling
+
+As you noticed above practically all of the methods in the ConectionRequest throw IOException. This
+allows you to avoid the try/catch semantics and just let the error propagate up the chain so it can be
+handled uniformly by the application.
+
+There are two distinct placed where you can handle a networking error:
+
+• The ConnectionRequest - by overriding callback methods
+
+• The NetworkManager error handler
+
+Notice that the NetworkManager error handler takes precedence thus allowing you to define a global
+policy for network error handling by consuming errors.
+
+E.g.  if  I  would  like  to  block  all  network  errors  from  showing  anything  to  the  user  I  could  do
+
+something like this:
+
+NetworkManager.getInstance().addToQueue(request);
+NetworkManager.getInstance().addErrorListener((e) -> e.consume());
+
+The  error  listener  is  invoked  first  with  the  NetworkEvent  [https://www.codenameone.com/javadoc/com/
+
+432
+
+codename1/io/NetworkEvent.html]  matching  the  error.  Consuming  the  event  prevents  it  from
+propagating further down the chain into the ConnectionRequest callbacks.
+
+We  can  also  override  the  error  callbacks  of  the  various  types  in  the  request  e.g.  in  the  case  of  a
+
+server error code we can do:
+
+ConnectionRequest request = new ConnectionRequest(url, false) {
+    protected void handleErrorResponseCode(int code, String message) {
+        if(code == 444) {
+            // do something
+        }
+    }
+    protected void readResponse(InputStream input) {
+        // just read from the response input stream
+    }
+};
+NetworkManager.getInstance().addToQueue(request);
+
+ The error callback callback is triggered in the network thread!
+
+As a result it can’t access the UI to show a Dialog or anything like that.
+
+Another  approach  is  to  use  the  setFailSilently(true)  method  on  the  ConnectionRequest.  This  will
+prevent the ConnectionRequest from displaying any errors to the user. It’s a very powerful strategy if
+you use the synchronous version of the API’s e.g.:
+
+ConnectionRequest request = new ConnectionRequest(url, false);
+request.setFailSilently(true);
+NetworkManager.getInstance().addToQueueAndWait(request);
+if(request.getResponseCode() != 200) {
+    // probably an error...
+}
+
+
+
+This  code  will  only  work  with  the  synchronous  "AndWait"  version  of  the  method
+
+since the response code will take a while to return for the non-wait version.
+
+Error Stream
+
+When we get an error code that isn’t 200/300 we ignore the result. This is problematic as the result
+
+might contain information we need. E.g. many webservices provide further XML/JSON based details
+
+describing the reason for the error code.
+
+Calling  setReadResponseForErrors(true)  will  trigger  a  mode  where  even  errors  will  receive  the
+readResponse callback with the error stream. This also means that API’s like getData and the listener
+API’s will also work correctly in case of error.
+
+433
+
+12.5.3. GZIP
+
+Gzip  is  a  very  common  compression  format  based  on  the  lz  algorithm,  it’s  used  by  web  servers
+
+around the world to compress data.
+
+Codename  One  supports  GZipInputStream  [https://www.codenameone.com/javadoc/com/codename1/io/gzip/
+
+GZIPInputStream.html]  and  GZipOutputStream  [https://www.codenameone.com/javadoc/com/codename1/io/
+
+gzip/GZIPOutputStream.html], which allow you to compress data seamlessly into a stream and extract
+
+compressed data from a stream. This is very useful and can be applied to every arbitrary stream.
+
+Codename  One  also  features  a  GZConnectionRequest  [https://www.codenameone.com/javadoc/com/
+
+codename1/io/gzip/GZConnectionRequest.html],  which  will  automatically  unzip  an  HTTP  response  if  it  is
+
+indeed gzipped. Notice that some devices (iOS) always request gzip’ed data and always decompress
+it for us, however in the case of iOS it doesn’t remove the gziped header. The GZConnectionRequest is
+aware of such behaviors so it’s better to use that when connecting to the network (if applicable).
+
+By default GZConnectionRequest doesn’t request gzipped data (only unzips it when its received) but
+its pretty easy to do so just add the HTTP header Accept-Encoding: gzip e.g.:
+
+GZConnectionRequest con = new GZConnectionRequest();
+con.addRequestHeader("Accept-Encoding", "gzip");
+
+Do the rest as usual and you should have smaller responses from the servers.
+
+12.5.4. File Upload
+
+MultipartRequest  [https://www.codenameone.com/javadoc/com/codename1/io/MultipartRequest.html]  tries  to
+
+simplify the process of uploading a file from the local device to a remote server.
+
+You  can  always  submit  data  in  the  buildRequestBody  but  this  is  flaky  and  has  some  limitations  in
+terms of devices/size allowed. HTTP standardized file upload capabilities thru the multipart request
+
+protocol, this is implemented by countless servers and is well documented. Codename One supports
+
+this out of the box:
+
+MultipartRequest request = new MultipartRequest();
+request.setUrl(url);
+request.addData("myFileName", fullPathToFile, "text/plain")
+NetworkManager.getInstance().addToQueue(request);
+
+
+
+MultipartRequest  is  a  ConnectionRequest  most  stuff  you  expect  from  there  should
+work. Even addArgument etc.
+
+Since  we  assume  most  developers  reading  this  will  be  familiar  with  Java  here  is  the  way  to
+
+implement the multipart upload in the servlet API:
+
+434
+
+@WebServlet(name = "UploadServlet", urlPatterns = {"/upload"})
+@MultipartConfig(fileSizeThreshold = 1024 * 1024 * 100, // 10 MB
+        maxFileSize = 1024 * 1024 * 150, // 50 MB
+        maxRequestSize = 1024 * 1024 * 200)      // 100 MB
+public class UploadServlet extends HttpServlet {
+
+    @Override
+    public void doPost(HttpServletRequest req, HttpServletResponse res)
+            throws ServletException, IOException {
+        Collection<Part> parts = req.getParts();
+        Part data = parts.iterator().next();
+        try(InputStream is = data.getInputStream();) {}
+            // store or do something with the input stream
+        }
+    }
+}
+
+12.5.5. Parsing
+
+Codename One has several built in parsers for JSON, XML, CSV & Properties formats. You can use
+
+those parsers to read data from the Internet or data that is shipping with your product. E.g. use the
+
+CSV data to setup default values for your application.
+
+All our parsers are designed with simplicity and small distribution size; they don’t validate and will
+
+fail in odd ways when faced with broken data. The main logic behind this is that validation takes up
+
+CPU time on the device where CPU is a precious resource.
+
+Parsing CSV
+
+CSV  is  probably  the  easiest  to  use,  the  "Comma  Separated  Values"  format  is  just  a  list  of  values
+
+separated by commas (or some other character) with new lines to indicate another row in the table.
+
+These usually map well to an Excel spreadsheet or database table and are supported by default in
+
+all spreadsheets.
+
+To  parse  a  CSV 
+
+just  use  the  CSVParser  [https://www.codenameone.com/javadoc/com/codename1/io/
+
+CSVParser.html] class as such:
+
+435
+
+Form hi = new Form("CSV Parsing", new BorderLayout());
+CSVParser parser = new CSVParser();
+try(Reader r = new CharArrayReader("1997,Ford,E350,\"Super, \"\"luxurious\"\" truck\"".toCharArray());) {
+    String[][] data = parser.parse(r);
+    String[] columnNames = new String[data[0].length];
+    for(int iter=  0 ; iter < columnNames.length ; iter++) {
+        columnNames[iter] = "Col " + (iter + 1);
+    }
+    TableModel tm = new DefaultTableModel(columnNames, data);
+    hi.add(BorderLayout.CENTER, new Table(tm));
+} catch(IOException err) {
+    Log.e(err);
+}
+hi.show();
+
+Figure 361. CSV parsing results, notice the properly escaped parentheses and comma
+
+The  data  contains  a  two  dimensional  array  of  the  CSV  content.  You  can  change  the  delimiter
+character by using the CSVParser constructor that accepts a character.
+
+
+
+Notice  that  we  used  CharArrayReader  from  the  com.codename1.io  package  for  this
+sample.  Normally  you  would  want  to  use  java.util.InputStreamReader  for  real
+world data.
+
+JSON
+
+The  JSON  ("Java  Script  Object  Notation")  format  is  popular  on  the  web  for  passing  values  to/from
+
+webservices since it works so well with JavaScript. Parsing JSON is just as easy but has two different
+
+variations.  You  can  use  the  JSONParser  [https://www.codenameone.com/javadoc/com/codename1/io/
+
+JSONParser.html] class to build a tree of the JSON data as such:
+
+JSONParser parser = new JSONParser();
+Hashtable response = parser.parse(reader);
+
+The  response  is  a  Map  containing  a  nested  hierarchy  of  Collection  (java.util.List),  Strings  and
+numbers  to  represent  the  content  of  the  submitted  JSON.  To  extract  the  data  from  a  specific  path
+just iterate the Map keys and recurs into it.
+
+The sample below uses results from an API of ice and fire [https://anapioficeandfire.com/] that queries
+
+structured data about the "Song Of Ice & Fire" book series. Here is a sample result returned from
+
+the API for the query http://www.anapioficeandfire.com/api/characters?page=5&pageSize=3 :
+
+[
+  {
+    "url": "http://www.anapioficeandfire.com/api/characters/13",
+
+436
+
+    "name": "Chayle",
+    "culture": "",
+    "born": "",
+    "died": "In 299 AC, at Winterfell",
+    "titles": [
+      "Septon"
+    ],
+    "aliases": [],
+    "father": "",
+    "mother": "",
+    "spouse": "",
+    "allegiances": [],
+    "books": [
+      "http://www.anapioficeandfire.com/api/books/1",
+      "http://www.anapioficeandfire.com/api/books/2",
+      "http://www.anapioficeandfire.com/api/books/3"
+    ],
+    "povBooks": [],
+    "tvSeries": [],
+    "playedBy": []
+  },
+  {
+    "url": "http://www.anapioficeandfire.com/api/characters/14",
+    "name": "Gillam",
+    "culture": "",
+    "born": "",
+    "died": "",
+    "titles": [
+      "Brother"
+    ],
+    "aliases": [],
+    "father": "",
+    "mother": "",
+    "spouse": "",
+    "allegiances": [],
+    "books": [
+      "http://www.anapioficeandfire.com/api/books/5"
+    ],
+    "povBooks": [],
+    "tvSeries": [],
+    "playedBy": []
+  },
+  {
+    "url": "http://www.anapioficeandfire.com/api/characters/15",
+    "name": "High Septon",
+    "culture": "",
+    "born": "",
+    "died": "",
+    "titles": [
+      "High Septon",
+      "His High Holiness",
+
+437
+
+      "Father of the Faithful",
+      "Voice of the Seven on Earth"
+    ],
+    "aliases": [
+      "The High Sparrow"
+    ],
+    "father": "",
+    "mother": "",
+    "spouse": "",
+    "allegiances": [],
+    "books": [
+      "http://www.anapioficeandfire.com/api/books/5",
+      "http://www.anapioficeandfire.com/api/books/8"
+    ],
+    "povBooks": [],
+    "tvSeries": [
+      "Season 5"
+    ],
+    "playedBy": [
+      "Jonathan Pryce"
+    ]
+  }
+]
+
+We will place that into a file named "anapioficeandfire.json" in the src directory to make the next
+
+sample simpler:
+
+Form hi = new Form("JSON Parsing", new BoxLayout(BoxLayout.Y_AXIS));
+JSONParser json = new JSONParser();
+try(Reader r = new InputStreamReader(Display.getInstance().getResourceAsStream(getClass(), "/anapioficeandfire.json"),
+"UTF-8");) {
+    Map<String, Object> data = json.parseJSON(r);
+    java.util.List<Map<String, Object>> content = (java.util.List<Map<String, Object>>)data.get("root"); ①
+    for(Map<String, Object> obj : content) { ②
+        String url = (String)obj.get("url");
+        String name = (String)obj.get("name");
+        java.util.List<String> titles =  (java.util.List<String>)obj.get("titles"); ③
+        if(name == null || name.length() == 0) {
+            java.util.List<String> aliases = (java.util.List<String>)obj.get("aliases");
+            if(aliases != null && aliases.size() > 0) {
+                name = aliases.get(0);
+            }
+        }
+        MultiButton mb = new MultiButton(name);
+        if(titles != null && titles.size() > 0) {
+            mb.setTextLine2(titles.get(0));
+        }
+        mb.addActionListener((e) -> Display.getInstance().execute(url));
+        hi.add(mb);
+    }
+} catch(IOException err) {
+    Log.e(err);
+}
+hi.show();
+
+① The JSONParser returns a Map which is great if the root object is a Map but in some cases its a list of
+
+438
+
+elements (as is the case above). In this case a special case "root" element is created to contain the
+
+actual list of elements.
+
+② We rely that the entries are all maps, this might not be the case for every API type.
+
+③ Notice that the "titles" and "aliases" entries are both lists of elements. We use java.util.List to
+
+avoid a clash with com.codename1.ui.List.
+
+Figure 362. Parsed JSON result, clicking the elements opens the URL from the JSON
+
+The  structure  of  the  returned  map  is  sometimes  unintuitive  when  looking  at  the
+
+
+
+raw  JSON.  The  easiest  thing  to  do  is  set  a  breakpoint  on  the  method  and  use  the
+
+inspect variables capability of your IDE to inspect the returned element hierarchy
+
+while writing the code to extract that data
+
+An  alternative  approach  is  to  use  the  static  data  parse()  method  of  the  JSONParser  class  and
+implement a callback parser e.g.:
+
+JSONParser.parse(reader, callback);
+
+Notice  that  a  static  version  of  the  method  is  used!  The  callback  object  is  an  instance  of  the
+JSONParseCallback  interface,  which  includes  multiple  methods.  These  methods  are  invoked  by  the
+parser  to  indicate  internal  parser  states,  this  is  similar  to  the  way  traditional  XML  SAX  event
+
+parsers work.
+
+XML Parsing
+
+The  XMLParser  [https://www.codenameone.com/javadoc/com/codename1/xml/XMLParser.html]  started  its  life
+
+as an HTML parser built for displaying mobile HTML. That usage has since been deprecated but the
+
+parser  can  still  parse  many  HTML  pages  and  is  very  "loose"  in  terms  of  verification.  This  is  both
+
+good and bad as the parser will work with invalid data without complaining.
+
+The simplest usage of XMLParser looks a bit like this:
+
+XMLParser parser = new XMLParser();
+Element elem = parser.parse(reader);
+
+The  Element  [https://www.codenameone.com/javadoc/com/codename1/xml/Element.html]  contains  children
+
+and attributes. It represents a tag within the XML document and even the root document itself. You
+
+can iterate over the XML tree to extract the data from within the XML file.
+
+439
+
+We’ve  had 
+
+a 
+
+great 
+
+sample  of  working  with 
+
+XMLParser 
+
+in 
+
+the  Tree 
+
+Section
+
+[https://www.codenameone.com/manual/components.html#tree-section] of this guide.
+
+XMLParser  has  the  complimentary  XMLWriter  [https://www.codenameone.com/javadoc/com/codename1/xml/
+XMLWriter.html] class which can generate XML from the Element hierarchy. This allows a developers
+to mutate (modify) the elements and save them to a writer stream.
+
+XPath Processing
+
+The  Result  [https://www.codenameone.com/javadoc/com/codename1/processing/Result.html]  class  provides  a
+
+subset  of  XPath  [https://www.w3schools.com/xml/xpath_intro.asp],  but  it  is  not  limited  to  just  XML
+documents, it can also work with JSON documents, and even with raw Map objects.
+
+Lets  start  by  demonstrating  how  to  process  a  response  from  the  Google  Reverse  Geocoder  API
+
+[https://developers.google.com/maps/documentation/geocoding/]. Lets start with this XML snippet:
+
+<?xml version="1.0" encoding="UTF-8"?>
+<GeocodeResponse>
+  <status>OK</status>
+  <result> <!-- (irrelevant content removed) -->
+      <address_component>
+          <long_name>London</long_name>
+          <short_name>London</short_name>
+          <type>locality</type>
+          <type>political</type>
+      </address_component>
+      <!-- (irrelevant content removed) -->
+     <address_component>
+          <long_name>Ontario</long_name>
+          <short_name>ON</short_name>
+          <type>administrative_area_level_1</type>
+          <type>political</type>
+      </address_component>
+      <address_component>
+         <long_name>Canada</long_name>
+         <short_name>CA</short_name>
+         <type>country</type>
+         <type>political</type>
+      </address_component>
+  </result>
+</GeocodeResponse>
+
+We want to extract some of the data above into simpler string results. We can do this using:
+
+Result result = Result.fromContent(input, Result.XML);
+String country = result.getAsString("/result/address_component[type='country']/long_name");
+String region = result.getAsString("/result/address_component[type='administrative_area_level_1']/long_name");
+String city = result.getAsString("/result/address_component[type='locality']/long_name");
+
+440
+
+If  you  are  at  all  familiar  with  processing  responses  from  webservices,  you  will  notice  that  what
+
+would normally require several lines of code of selecting and testing nodes in regular java can now
+
+be done in a single line using the new path expressions.
+
+In the code above, input can be any of:
+
+• InputStream directly from ConnectionRequest.readResponse(java.io.InputStream).
+
+• XML or JSON document in the form of a {@code String}</li>
+
+• XML  DOM  Element  [https://www.codenameone.com/javadoc/com/codename1/xml/Element.html]  returned
+
+from XMLParser [https://www.codenameone.com/javadoc/com/codename1/xml/XMLParser.html]
+
+• JSON  DOM  Map  returned  from  JSONParser  [https://www.codenameone.com/javadoc/com/codename1/io/
+
+JSONParser.html]
+
+To  use  the  expression  processor  when  calling  a  webservice,  you  could  use  something  like  the
+
+following to parse JSON (notice this is interchangeable between JSON and XML):
+
+Form hi = new Form("Location", new BoxLayout(BoxLayout.Y_AXIS));
+hi.add("Pinpointing Location");
+Display.getInstance().callSerially(() -> {
+    Location l = Display.getInstance().getLocationManager().getCurrentLocationSync();
+    ConnectionRequest request = new ConnectionRequest("http://maps.googleapis.com/maps/api/geocode/json", false) {
+        private String country;
+        private String region;
+        private String city;
+        private String json;
+
+        @Override
+        protected void readResponse(InputStream input) throws IOException {
+                Result result = Result.fromContent(input, Result.JSON);
+                country = result.getAsString("/results/address_components[types='country']/long_name");
+                region =
+result.getAsString("/results/address_components[types='administrative_area_level_1']/long_name");
+                city = result.getAsString("/results/address_components[types='locality']/long_name");
+                json = result.toString();
+        }
+
+        @Override
+        protected void postResponse() {
+            hi.removeAll();
+            hi.add(country);
+            hi.add(region);
+            hi.add(city);
+            hi.add(new SpanLabel(json));
+            hi.revalidate();
+        }
+    };
+    request.setContentType("application/json");
+    request.addRequestHeader("Accept", "application/json");
+    request.addArgument("sensor", "true");
+    request.addArgument("latlng", l.getLatitude() + "," + l.getLongitude());
+
+    NetworkManager.getInstance().addToQueue(request);
+});
+hi.show();
+[source,java]
+
+The returned JSON looks something like this (notice it’s snipped because the data is too long):
+
+441
+
+{
+  "status": "OK",
+  "results": [
+    {
+      "place_id": "ChIJJ5T9-iFawokRTPGaOginEO4",
+      "formatted_address": "280 Broadway, New York, NY 10007, USA",
+      "address_components": [
+        {
+          "short_name": "280",
+          "types": ["street_number"],
+          "long_name": "280"
+        },
+        {
+          "short_name": "Broadway",
+          "types": ["route"],
+          "long_name": "Broadway"
+        },
+        {
+          "short_name": "Lower Manhattan",
+          "types": [
+            "neighborhood",
+            "political"
+          ],
+          "long_name": "Lower Manhattan"
+        },
+        {
+          "short_name": "Manhattan",
+          "types": [
+            "sublocality_level_1",
+            "sublocality",
+            "political"
+          ],
+          "long_name": "Manhattan"
+        },
+        {
+          "short_name": "New York",
+          "types": [
+            "locality",
+            "political"
+          ],
+          "long_name": "New York"
+        },
+        {
+          "short_name": "New York County",
+          "types": [
+            "administrative_area_level_2",
+            "political"
+          ],
+          "long_name": "New York County"
+        },
+
+442
+
+        {
+          "short_name": "NY",
+          "types": [
+            "administrative_area_level_1",
+            "political"
+          ],
+          "long_name": "New York"
+        },
+        {
+          "short_name": "US",
+          "types": [
+            "country",
+            "political"
+          ],
+          "long_name": "United States"
+        },
+        {
+          "short_name": "10007",
+          "types": ["postal_code"],
+          "long_name": "10007"
+        },
+        {
+          "short_name": "1868",
+          "types": ["postal_code_suffix"],
+          "long_name": "1868"
+        }
+      ],
+      "types": ["street_address"],
+      "geometry": {
+        "viewport": {
+          "northeast": {
+            "lng": -74.0044642197085,
+            "lat": 40.7156470802915
+          },
+          "southwest": {
+            "lng": -74.0071621802915,
+            "lat": 40.7129491197085
+          }
+        },
+        "location_type": "ROOFTOP",
+        "location": {
+          "lng": -74.00581319999999,
+          "lat": 40.7142981
+        }
+      }
+    }
+    /* SNIPED the rest */
+  ]
+}
+
+443
+
+Figure 363. Running the geocode sample above in the simulator
+
+The XML processor currently handles global selections by using a double slash anywhere within the
+
+expression, for example:
+
+// get all address_component names anywhere in the document with a type "political"
+String array[] = result.getAsStringArray("//address_component[type='political']/long_name");
+
+// get all types anywhere under the second result (dimension is 0-based)
+String array[] = result.getAsStringArray("/result[1]//type");
+
+
+
+Notice that Google’s JSON webservice uses plural form for each of the node names
+
+in  that  API  (ie.  results,  address_components,  and  types)  where  they  don’t  in  the
+
+XML services (ie result, address_component etc.)
+
+Second Example
+
+It also possible to do some more complex expressions. We’ll use the following XML fragment for the
+
+next batch of examples:
+
+444
+
+<rankings type="aus" gender="male" date="2011-12-31">
+    <player id="1036" coretennisid="6752" rank="1"
+       delta="0" singlespoints="485000" doublespoints="675"
+       deductedpoints="0" totalpoints="485675">
+        <firstname>Bernard</firstname>
+        <lastname>Tomic</lastname>
+        <town>SOUTHPORT</town>
+        <state>QLD</state>
+        <dob>1992-10-21</dob>
+    </player>
+    <player id="2585" coretennisid="1500" rank="2"
+       delta="0" singlespoints="313500" doublespoints="12630"
+       deductedpoints="0" totalpoints="326130">
+        <firstname>Mathew</firstname>
+        <lastname>Ebden</lastname>
+        <town>CHURCHLANDS</town>
+        <state>WA</state>
+        <dob>1987-11-26</dob>
+    </player>
+    <player id="6457" coretennisid="287" rank="3"
+        delta="0" singlespoints="132500" doublespoints="1500"
+        deductedpoints="0" totalpoints="134000">
+       <firstname>Lleyton</firstname>
+       <lastname>Hewitt</lastname>
+       <town>EXETER</town>
+       <state>SA</state>
+       <dob>1981-02-24</dob>
+    </player>
+    <!-- ... etc ... -->
+</rankings>
+
+Above,  if  you  want  to  select  the  IDs  of  all  players  that  are  ranked  in  the  top  2,  you  can  use  an
+
+expression like:
+
+int top2[] = result.getAsIntegerArray("//player[@rank < 3]/@id");
+
+
+
+Notice above that the expression is using an attribute for selecting both rank and
+
+id. In JSON documents, if you attempt to select an attribute, it will look for a child
+
+node under the attribute name you ask for)
+
+If a document is ordered, you might want to select nodes by their position, for example:
+
+String first2[] = result.getAsStringArray("//player[position() < 3]/firstname");
+
+String secondLast = result.getAsString("//player[last() - 1]/firstName");
+
+It is also possible to select parent nodes, by using the ‘..’ expression. For example:
+
+445
+
+int id = result.getAsInteger("//lastname[text()='Hewitt']/../@id");
+
+Above, we globally find a lastname element with a value of ‘Hewitt’, then grab the parent node of
+
+lastname  which  happens  to  be  the  player  node,  then  grab  the  id  attribute  from  the  player  node.
+
+Alternatively, you could get the same result from the following simpler statement:
+
+int id = result.getAsInteger("//player[lastname='Hewitt']/@id");
+
+It is also possible to nest expressions, for example:
+
+String id=result.getAsInteger("//player[//address[country/isocode='CA']]/@id");
+
+In the above example, if the player node had an address object, we’d be selecting all players from
+
+Canada.  This  is  a  simple  example  of  a  nested  expression,  but  they  can  get  much  more  complex,
+
+which will be required as the documents themselves get more complex.
+
+Moving on, to select a node based on the existence of an attribute:
+
+int id[] = result.getAsIntegerArray("//player[@rank]/@id");
+
+Above, we selected the IDs of all ranked players. Conversely, we can select the non-ranked players
+
+like this:
+
+int id[] = result.getAsIntegerArray("//player[@rank=null]/@id");
+
+ Logical not (!) operators currently are not implemented)
+
+You can also select by the existence of a child node
+
+int id[] = result.getAsIntegerArray("//player[middlename]/@id");
+
+Above, we selected all players that have a middle name.<br/> Keep in mind that the Codename One
+
+path expression language is not a full implementation of XPath 1.0, but does already handle many
+
+of the most useful features of the specification.
+
+Properties Files
+
+Properties  [https://www.codenameone.com/javadoc/com/codename1/io/Properties.html]  files  are  standard
+
+key/value pairs encoded into a text file. This file format is very familiar to Java developers and the
+
+Codename One specific version tries to be as close as possible to the original Java implementation.
+
+Notice  that  properties  file  both  in  Java  proper  and  in  Codename  One  don’t  support  non-ascii
+
+characters.  In  order  to  encode  unicode  values  into  the  properties  file  format  you  should  use  the
+native2ascii tool that ships with the JDK.
+
+446
+
+One  major  difference  between  standard  Java  properties  and  the  ones  in  Codename  One  is  that
+
+Codename One sorts properties alphabetically when saving. Java uses random order based on the
+Hashtable natural ordering.
+
+This was done to provide consistency for saved files.
+
+12.6. Debugging Network Connections
+
+Figure 364. Debugging Network Connections
+
+Codename  One  includes  a  Network  Monitor  tool  which  you  can  access  via  the  simulator  menu
+
+option. This tool reflects all the requests made through the connection requests and displays them
+
+in the left pane. This allows you to track issues in your code/web service and see everything the is
+
+"going through the wire".
+
+This is a remarkably useful tool for optimizing and for figuring out what exactly is happening with
+
+your server connection logic.
+
+12.6.1. Simpler Downloads
+
+A very common task is file download to storage or filesystem.
+
+The  Util  [https://www.codenameone.com/javadoc/com/codename1/io/Util.html]  class  has  simple  utility
+
+methods:
+
+downloadUrlToFileSystemInBackground, 
+downloadUrlToStorage.
+
+downloadUrlToStorageInBackground, 
+
+downloadUrlToFile  &
+
+These  all  delegate  to  a  feature  in  ConnectionRequest  [https://www.codenameone.com/javadoc/com/
+
+codename1/io/ConnectionRequest.html]:
+
+ConnectionRequest.setDestinationStorage(fileName) 
+ConnectionRequest.setDestinationFile(fileName);
+
+Both of which simplify the whole process of downloading a file.
+
+Downloading Images
+
+&
+
+Codename  One  has  multiple  ways  to  download  an  image  and  the  general  recommendation  is  the
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/URLImage.html].  However, 
+
+URLImage 
+the
+URLImage assumes that you know the size of the image in advance or that you are willing to resize it.
+In that regard it works great for some use cases but not so much for others.
+
+The  download  methods  mentioned  above  are  great  alternatives  but  they  are  a  bit  verbose  when
+working with images and don’t provide fine grained control over the ConnectionRequest e.g. making
+
+447
+
+a POST request to get an image.
+
+
+
+Adding  global  headers  is  another  use  case  but  you  can  use  addDefaultHeader
+
+[https://www.codenameone.com/javadoc/com/codename1/io/NetworkManager.html#
+
+addDefaultHeader-java.lang.String-java.lang.String-] to add those.
+
+To make this process simpler there is a set of helper methods in ConnectionRequest that downloads
+
+images 
+
+directly 
+
+[https://www.codenameone.com/javadoc/com/codename1/io/ConnectionRequest.html#
+
+downloadImageToStorage-java.lang.String-com.codename1.util.SuccessCallback-].
+
+These methods complement the Util methods but go a bit further and feature very terse syntax e.g.
+you can just download a ConnectionRequest to Storage using code like this:
+
+request.downloadImageToStorage(url, (img) -> theImageIsHereDoSomethingWithIt(img));
+
+This 
+
+effectively  maps 
+
+ConnectionRequest 
+[https://www.codenameone.com/javadoc/com/codename1/util/SuccessCallback.html] for further processing.
+
+directly 
+
+the 
+
+SuccessCallback
+
+to 
+
+a 
+
+URLImage Caching
+
+URLImage is great. It changed the way we do some things in Codename One.
+
+However,  when  we  introduced  it  we  didn’t  have  support  for  the  cache  filesystem  or  for  the
+JavaScript port. The cache filesystem is probably the best place for images of URLImage so supporting
+that as a target is a "no brainer" but JavaScript seems to work so why would it need a special case?
+
+JavaScript already knows how to download and cache images from the web. URLImage is actually a
+step back from the things a good browser can do so why not use the native abilities of the browser
+
+when we are running there and fallback to using the cache filesystem if it’s available and as a last
+
+resort go to storage…
+
+That’s exactly what the new method of URLImage does:
+
+public static Image createCachedImage(String imageName, String url, Image placeholder, int resizeRule);
+
+There are a few important things you need to notice about this method:
+
+• It returns Image and not URLImage. This is crucial. Down casting to `URLImage* will work on
+
+the simulator but might fail in some platforms (e.g. JavaScript) so don’t do that!
+
+Since  this  is  implemented  natively  in  JavaScript  we  need  a  different  abstraction  for  that
+
+platform.
+
+• It  doesn’t  support  image  adapters  and  instead  uses  a  simplified  resize  rule.  Image  adapters
+work  on  URLImage  since  we  have  a  lot  of  control  in  that  class.  However,  in  the  browser  our
+control is limited and so an adapter won’t work.
+
+If you do use this approach it would be far more efficient when running in the JavaScript port and
+
+will make better use of caching in most OS’s.
+
+448
+
+12.7. Rest API
+
+The  Rest  API  makes  it  easy  to  invoke  a  restfull  webservice  without  many  of  the  nuances  of
+ConnectionRequest. You can use it to define the HTTP method and start building based on that. So if I
+want to get a parsed JSON result from a URL you could do:
+
+Map<String, Object> jsonData = Rest.get(myUrl).getAsJsonMap();
+
+For a lot of REST requests this will fail because we need to add an HTTP header indicating that we
+
+accept JSON results. We have a special case support for that:
+
+Map<String, Object> jsonData = Rest.get(myUrl).acceptJson().getAsJsonMap();
+
+We can also do POST requests just as easily:
+
+Map<String, Object> jsonData = Rest.post(myUrl).body(bodyValueAsString).getAsJsonMap();
+
+Notice the usage of post and the body builder method. There are MANY methods in the builder class
+
+that cover pretty much everything you would expect and then some when it comes to the needs of
+
+rest services.
+
+I  changed  the  code  in  the  kitchen  sink  webservice  sample  to  use  this  API.  I  was  able  to  make  it
+
+shorter and more readable without sacrificing anything.
+
+12.7.1. Rest in Practice - Twilio
+
+The best way to explain the usage of this API is via a concrete "real world" example. Twilio provides
+
+many  great  telephony  oriented  webservices  to  developers.  One  of  those  is  an  SMS  sending
+
+webservice which can be useful for things such as "device activation".
+
+To get started you would need to signup to Twilio [http://twillo.com/] and have the following 3 variable
+
+values:
+
+String accountSID = "----------------";
+String authToken = "---------------";
+String fromPhone = "your Twilio phone number here";
+
+
+
+You  can  open  a  trial  Twilio  account  and  it  just  tags  all  of  your  SMS’s.  Notice  you
+
+would need to use a US based number if you don’t want to pay
+
+We can now send hello world as an SMS to the end user. Once this is in place sending an SMS via
+REST is just a matter of using the Rest API:
+
+449
+
+Response<Map> result = Rest.post("https://api.twilio.com/2010-04-01/Accounts/" + accountSID + "/Messages.json").
+        queryParam("To", destinationPhone).
+        queryParam("From", fromPhone).
+        queryParam("Body", "Hello World").
+        basicAuth(accountSID, authToken)).
+        getAsJsonMap();
+
+Notice that this is equivalent of this "curl" command:
+
+curl 'https://api.twilio.com/2010-04-01/Accounts/[accountSID]/Messages.json' -X POST \
+--data-urlencode 'To=[destinationPhone]' \
+--data-urlencode 'From=[fromPhone]' \
+--data-urlencode 'Body=Hello World' \
+-u [accountSID]:[AuthToken]
+
+That’s pretty cool as the curl command maps almost directly to the Rest API call!
+
+What we do here is actually pretty trivial, we open a connection the the api messages URL. We add
+
+arguments to the body of the post request and define the basic authentication data.
+
+The result is in JSON form we mostly ignore it since it isn’t that important but it might be useful for
+
+error handling. This is a sample response (redacted keys):
+
+{
+    "sid": "[sid value]",
+    "date_created": "Sat, 09 Sep 2017 19:47:30 +0000",
+    "date_updated": "Sat, 09 Sep 2017 19:47:30 +0000",
+    "date_sent": null,
+    "account_sid": "[sid value]",
+    "to": "[to phone number]",
+    "from": "[from phone number]",
+    "messaging_service_sid": null,
+    "body": "Sent from your Twilio trial account - Hello World",
+    "status": "queued",
+    "num_segments": "1",
+    "num_media": "0",
+    "direction": "outbound-api",
+    "api_version": "2010-04-01",
+    "price": null,
+    "price_unit": "USD",
+    "error_code": null,
+    "error_message": null,
+    "uri": "/2010-04-01/Accounts/[sid value]/Messages/SMe802d86b9f2246989c7c66e74b2d84ef.json",
+    "subresource_uris": {
+        "media": "/2010-04-01/Accounts/[sid value]/Messages/[message value]/Media.json"
+    }
+}
+
+Notice  the  error  message  entry  which  is  null  meaning  there  was  no  error,  if  there  was  an  error
+
+we’d have a message there or an error code that isn’t in the 200-210 range.
+
+450
+
+This should display an error message to the user if there was a problem sending the SMS:
+
+if(result.getResponseData() != null) {
+    String error = (String)result.getResponseData().get("error_message");
+    if(error != null) {
+        ToastBar.showErrorMessage(error);
+    }
+} else {
+    ToastBar.showErrorMessage("Error sending SMS: " + result.getResponseCode());
+}
+
+12.8. Webservice Wizard
+
+The  Webservice  Wizard  can  be  invoked  directly  from  the  plugin.  It  generates  stubs  for  the  client
+
+side that allow performing simple method invocations on the server. It also generates a servlet that
+
+can be installed on any servlet container to intercept client side calls.
+
+There are limits to the types of values that can be passed via the webservice wizard protocol but it
+
+is  highly  efficient  since  it  is  a  binary  protocol  and  very  extensible  thru  object  externalization.  All
+
+methods  are  provided  both  as  asynchronous  and  synchronous  calls  for  the  convenience  of  the
+
+developer.
+
+Figure 365. The first step in creating a client/server connection using the webservice wizard is to create a
+
+web application
+
+Figure 366. Any name will do
+
+Normally  you  should  have  a  server  setup  locally.  I  use  Tomcat  since  it’s  really  trivial  and  I  don’t
+
+really need much but there are many great Java webservers out there and this should work with all
+
+of them!
+
+451
+
+Figure 367. Setup your webserver in the IDE
+
+Figure 368. Configure the application server to the newly created app, notice the application context value
+
+which we will use later
+
+Figure 369. In the main Codename One project right click and select the WebService Wizard option
+
+Figure 370. Set the package and class name for the webservice abstraction (notice this isn’t your main class
+
+name) and then add the methods you want in the webservice
+
+Figure 371. Add the methods and their arguments/return types. Once you finished adding all of those press
+
+the "Generate" button
+
+452
+
+
+
+The  types  of  arguments  are  pretty  limited  however  you  can  pass  an  arbitrary
+Externalizable object which can be "anything"
+
+Figure 372. Pick the directory in the server project to which the source files will be generated by default this
+
+is the src/java directory under the project we created in the first step
+
+Figure 373. If you saved to the right location the server project directory should look like this
+
+We can now open the GameOfThronesServiceServer.java file in the server and it looks like this:
+
+public class GameOfThronesServiceServer {
+    public static String[] getBookNames() {
+        // your code goes here...
+        return null;
+    }
+
+    public static String[] getBookPovCharacters(String bookName) {
+        // your code goes here...
+        return null;
+    }
+}
+
+All  we  need  to  do  is  fill  in  the  code,  for  this  example  we’ll  only  implement  the  first  method  for
+
+simplicity:
+
+453
+
+public class GameOfThronesServiceServer {
+    public static String[] getBookNames() {
+        return new String[] {
+            "A Game of Thrones", "A Clash Of Kings", "A Storm Of Swords", "A Feast For Crows",
+            "A Dance With Dragons", "The Winds of Winter", "A Dream of Spring"
+        };
+    }
+
+    public static String[] getBookPovCharacters(String bookName) {
+        // your code goes here...
+        return null;
+    }
+}
+
+Now lets open the client side code, in the GameOfThronesService.java file we see this
+
+public class GameOfThronesService {
+    private static final String DESTINATION_URL = "http://localhost:8080/cn1proxy";
+
+//...
+}
+
+The destination URL needs to point at the actual server which you will recall from the new project
+
+creation should include "HelloWebServiceWizard". So we can fix the URL to:
+
+private static final String DESTINATION_URL = "http://localhost:8080/HelloWebServiceWizard/cn1proxy";
+
+You would naturally need to update the host name of the server for running on a device otherwise
+
+the device would need to reside within your internal network and point to your IP address.
+
+It is now time to write the actual client code that calls this. Every method we defined above is now
+defined  as  a  static  method  within  the  GameOfThronesService  class  with  two  permutations.  One  is  a
+synchronous  permutation  that  behaves  exactly  as  expected.  It  blocks  the  calling  thread  while
+calling the server and might throw an IOException if something failed.
+
+This type of method (synchronous method) is very easy to work with since it’s completely legal to
+
+call it from the event dispatch thread and it’s very easy to map it to application logic flow.
+
+The  second  type  of  method  uses  the  async  JavaScript  style  callbacks  and  accepts  the  callback
+
+interface.  It  returns  immediately  and  doesn’t  throw  any  exception.  It  will  call  onSuccess/onError
+
+based on the server result.
+
+You  can  pick  either  one  of  these  approaches  based  on  your  personal  preferences.  Here  we
+
+demonstrate both uses with the server API:
+
+454
+
+Form hi = new Form("WebService Wizard", new BoxLayout(BoxLayout.Y_AXIS));
+Button getNamesSync = new Button("Get Names - Sync");
+Button getNamesASync = new Button("Get Names - ASync");
+hi.add(getNamesSync).add(getNamesASync);
+
+getNamesSync.addActionListener((e) -> {
+    try {
+        String[] books = GameOfThronesService.getBookNames();
+        hi.add("--- SYNC");
+        for(String b : books) {
+            hi.add(b);
+        }
+        hi.revalidate();
+    } catch(IOException err) {
+        Log.e(err);
+    }
+});
+
+getNamesASync.addActionListener((e) -> {
+    GameOfThronesService.getBookNamesAsync(new Callback<String[]>() {
+        @Override
+        public void onSucess(String[] value) {
+            hi.add("--- ASYNC");
+            for(String b : value) {
+                hi.add(b);
+            }
+            hi.revalidate();
+        }
+
+        @Override
+        public void onError(Object sender, Throwable err, int errorCode, String errorMessage) {
+            Log.e(err);
+        }
+    });
+});
+
+Figure 374. The final result of the WebService Wizard code
+
+12.9. Connection Request Caching
+
+Caching  server  data  locally  is  a  huge  part  of  the  advantage  a  native  app  has  over  a  web  app.
+
+455
+
+Normally this is non-trivial as it requires a delicate balance especially if you want to test the server
+
+resource for changes.
+
+HTTP provides two ways to do that the ETag [https://en.wikipedia.org/wiki/HTTP_ETag] and Last-Modified
+
+[https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Last-Modified].  While  both  are  great  they  are
+
+non-trivial to use and by no definition seamless.
+
+We  just  added  an  experimental  feature  to  connection  request  that  allows  you  to  set  the  caching
+
+mode to one of 4 states either globally or per connection request:
+
+• OFF is the default meaning no caching.
+
+• SMART means all get requests are cached intelligently and caching is "mostly" seamless
+
+• MANUAL means that the developer is responsible for the actual caching but the system will not
+
+do a request on a resource that’s already "fresh"
+
+• OFFLINE will fetch data from the cache and wont try to go to the server. It will generate a 404
+
+error if data isn’t available
+
+You  can  toggle  these  in  the  specific  request  by  using  setCacheMode(CachingMode)  and  set  the  global
+default using setDefaultCacheMode(CachingMode).
+
+ Caching only applies to GET operations, it will not work for POST or other methods
+
+There are several methods of interest to keep an eye for:
+
+protected InputStream getCachedData() throws IOException;
+protected void cacheUnmodified() throws IOException;
+public void purgeCache();
+public static void purgeCacheDirectory() throws IOException;
+
+12.9.1. getCachedData()
+
+This  returns  the  cached  data.  This  is  invoked  to  implement  readResponse(InputStream)  when
+running offline or when we detect that the local cache isn’t stale.
+
+The smart mode implements this properly and will fetch the right data. However, the manual mode
+
+doesn’t store the data and relies on you to do so. In that case you need to return the data you stored
+
+at this point and must implement this method for manual mode.
+
+12.9.2. cacheUnmodified()
+
+This is a callback that’s invoked to indicate a cache hit, meaning that we already have the data.
+
+The  default  implementation  still  tries  to  call  all  the  pieces  for  compatibility  (e.g.  readResponse).
+However,  if  this  is  unnecessary  you  can  override  that  method  with  a  custom  implementation  or
+
+even a blank implementation to block such a case.
+
+456
+
+12.9.3. purgeCache & purgeCacheDirectory
+
+These methods are pretty self explanatory. Notice one caveat though…
+
+When  you  download  a  file  or  a  storage  element  we  don’t  cache  them  and  rely  on  the  file/storage
+
+element to be present and serve as "cache". When purging we won’t delete a file or storage element
+
+you downloaded and thus these might remain.
+
+However,  we  do  remove  the  ETag  and  Last-Modified  data  so  the  files  might  get  refreshed  the  next
+time around.
+
+12.10. Cached Data Service
+
+The 
+
+CachedDataService 
+
+[https://www.codenameone.com/javadoc/com/codename1/io/services/
+
+CachedDataService.html]  allows  caching  data  and  only  updating  it  if  the  data  changed  on  the  server.
+
+Normally  the  download  API’s  won’t  check  for  update  if  there  is  a  local  cache  of  the  data  (e.g.
+URLImage always uses the local copy). This isn’t a bad thing, it’s pretty efficient.
+
+However, it might be important to update the image if it changed but we still want caching.
+
+The  CachedDataService  will  fetch  data  if  it  isn’t  cached  locally  and  cache  it.  When  you  "refresh"  it
+will send a special HTTP request that will only send back the data if it has been updated since the
+
+last refresh:
+
+CachedDataService.register();
+CachedData d = (CachedData)Storage.getInstance().readObject("LocallyCachedData");
+
+if(d == null) {
+  d = new CachedData();
+  d.setUrl("http://....");
+}
+// check if there is a new version of this on the server
+CachedDataService.updateData(d, new ActionListener() {
+    public void actionPerformed(ActionEvent ev) {
+        // invoked when/if the data arrives, we now have a fresh cache
+        Storage.getInstance().writeObject("LocallyCachedData", d);
+    }
+});
+
+12.11. Externalizable Objects
+
+Codename  One  provides  the  Externalizable  [https://www.codenameone.com/javadoc/com/codename1/io/
+Externalizable.html] interface, which is similar to the Java SE Externalizable interface. This interface
+allows an object to declare itself as Externalizable for serialization (so an object can be stored in a
+file/storage or sent over the network). However, due to the lack of reflection and use of obfuscation
+
+these  objects  must  be  registered  with  the  Util  [https://www.codenameone.com/javadoc/com/codename1/io/
+
+Util.html] class.
+
+457
+
+Codename One doesn’t support the Java SE Serialization API due to the size issues and complexities
+
+related to obfuscation.
+
+The  major  objects  that  are  supported  by  default  in  the  Codename  One  Externalizable  are:  String,
+Collection,  Map,  ArrayList,  HashMap,  Vector,  Hashtable,  Integer,  Double,  Float,  Byte,  Short,  Long,
+Character, Boolean, Object[], byte[], int[], float[], long[], double[].
+
+Externalizing an object such as h below should work just fine:
+
+Map<String, Object> h = new HashMap<>();
+h.put("Hi","World");
+h.put("data", new byte[] {(byte)1});
+Storage.getInstance().writeObject("Test", h);
+
+However, notice that some things aren’t polymorphic e.g. if we will externalize a String[] we will
+get back an Object[] since String arrays aren’t detected by the implementation.
+
+ The externalization process caches objects so the app will seem to work and only
+
+fail on restart!
+
+Implementing the Externalizable interface is only important when we want to store a proprietary
+object.  In  this  case  we  must  register  the  object  with  the  com.codename1.io.Util  class  so  the
+externalization algorithm will be able to recognize it by name by invoking:
+
+Util.register("MyClass", MyClass.class);
+
+ You should do this early on in the app e.g. in the init(Object) but you shouldn’t do
+
+it in a static initializer within the object as that might never be invoked!
+
+An  Externalizable  object  must  have  a  default  public  constructor  and  must  implement  the
+following 4 methods:
+
+public int getVersion();
+public void externalize(DataOutputStream out) throws IOException;
+public void internalize(int version, DataInputStream in) throws IOException;
+public String getObjectId();
+
+The  getVersion()  method  returns  the  current  version  of  the  object  allowing  the  stored  data  to
+change  its  structure  in  the  future  (the  version  is  then  passed  when  internalizing  the  object).  The
+object id is a String uniquely representing the object; it usually corresponds to the class name (in
+the example above the Unique Name should be MyClass).
+
+458
+
+
+
+It’s a common mistake to use getClass().getName() to implement getObjectId() and
+it would seem to work in the simulator. This isn’t the case though!
+
+Since devices obfuscate the class names this becomes a problem as data is stored
+
+in a random name that changes with every release.
+
+Developers need to write the data of the object in the externalize method using the methods in the
+
+data output stream and read the data of the object in the internalize method e.g.:
+
+public void externalize(DataOutputStream out) throws IOException {
+    out.writeUTF(name);
+    if(value != null) {
+        out.writeBoolean(true);
+        out.writeUTF(value);
+    } else {
+        out.writeBoolean(false);
+    }
+    if(domain != null) {
+        out.writeBoolean(true);
+        out.writeUTF(domain);
+    } else {
+        out.writeBoolean(false);
+    }
+    out.writeLong(expires);
+}
+
+public void internalize(int version, DataInputStream in) throws IOException {
+    name = in.readUTF();
+    if(in.readBoolean()) {
+        value = in.readUTF();
+    }
+    if(in.readBoolean()) {
+        domain = in.readUTF();
+    }
+    expires = in.readLong();
+}
+
+Since  strings  might  be  null  sometimes  we  also  included  convenience  methods  to  implement  such
+
+externalization.  This  effectively  writes  a  boolean  before  writing  the  UTF  to  indicate  whether  the
+
+string is null:
+
+459
+
+public void externalize(DataOutputStream out) throws IOException {
+    Util.writeUTF(name, out);
+    Util.writeUTF(value, out);
+    Util.writeUTF(domain, out);
+    out.writeLong(expires);
+}
+
+public void internalize(int version, DataInputStream in) throws IOException {
+    name = Util.readUTF(in);
+    value = Util.readUTF(in);
+    domain = Util.readUTF(in);
+    expires = in.readLong();
+}
+
+Assuming  we  added  a  new  date  field  to  the  object  we  can  do  the  following.  Notice  that  a  Date  is
+really a long value in Java that can be null. For completeness the full class is presented below:
+
+460
+
+public class MyClass implements Externalizable {
+    private static final int VERSION = 2;
+    private String name;
+    private String value;
+    private String domain;
+    private Date date;
+    private long expires;
+
+    public MyClass() {}
+
+    public int getVersion() {
+        return VERSION;
+    }
+
+    public String getObjectId() {
+        return "MyClass";
+    }
+
+    public void externalize(DataOutputStream out) throws IOException {
+        Util.writeUTF(name, out);
+        Util.writeUTF(value, out);
+        Util.writeUTF(domain, out);
+        if(date != null) {
+            out.writeBoolean(true);
+            out.writeLong(date.getTime());
+        } else {
+            out.writeBoolean(false);
+        }
+        out.writeLong(expires);
+    }
+
+    public void internalize(int version, DataInputStream in) throws IOException {
+        name = Util.readUTF(in);
+        value = Util.readUTF(in);
+        domain = Util.readUTF(in);
+        if(version > 1) {
+            boolean hasDate = in.readBoolean();
+            if(hasDate) {
+                date = new Date(in.readLong());
+            }
+        }
+        expires = in.readLong();
+    }
+}
+
+Notice  that  we  only  need  to  check  for  compatibility  during  the  reading  process  as  the  writing
+
+process always writes the latest version of the data.
+
+461
+
+12.12. UI Bindings & Utilities
+
+Codename  One  provides  several  tools  to  simplify  the  path  between  networking/IO  &  GUI.  A
+
+common task of showing a wait dialog or progress indication while fetching network data can be
+
+simplified  by  using 
+
+the 
+
+InfiniteProgress 
+
+[https://www.codenameone.com/javadoc/com/codename1/
+
+components/InfiniteProgress.html] class e.g.:
+
+InfiniteProgress ip = new InfiniteProgress();
+Dialog dlg = ip.showInifiniteBlocking();
+request.setDisposeOnCompletion(dlg);
+
+The process of showing a progress bar for a long IO operation such as downloading is automatically
+
+mapped  to  the  IO  stream  in  Codename  One  using  the  SliderBridge  [https://www.codenameone.com/
+
+javadoc/com/codename1/components/SliderBridge.html] class.
+
+
+
+You  can  simulate  network  delays  and  disconnected  network  in  the  Simulator
+
+menu
+
+The SliderBridge class can bind a ConnectionRequest to a Slider and effectively indicate the progress
+of the download. E.g.:
+
+Form hi = new Form("Download Progress", new BorderLayout());
+Slider progress = new Slider();
+Button download = new Button("Download");
+download.addActionListener((e) -> {
+    ConnectionRequest cr = new ConnectionRequest("https://www.codenameone.com/img/blog/new_icon.png", false);
+    SliderBridge.bindProgress(cr, progress);
+    NetworkManager.getInstance().addToQueueAndWait(cr);
+    if(cr.getResponseCode() == 200) {
+        hi.add(BorderLayout.CENTER, new ScaleImageLabel(EncodedImage.create(cr.getResponseData())));
+        hi.revalidate();
+    }
+});
+hi.add(BorderLayout.SOUTH, progress).add(BorderLayout.NORTH, download);
+hi.show();
+
+Figure 375. SliderBridge progress for downloading the image in the slow network mode
+
+462
+
+12.13. Logging & Crash Protection
+
+Codename One includes a Log [https://www.codenameone.com/javadoc/com/codename1/io/Log.html] API that
+allows developers to just invoke Log.p(String) or Log.e(Throwable) to log information to storage.
+
+As part of the premium cloud features it is possible to invoke Log.sendLog() in order to email a log
+
+directly to the developer account. Codename One can do that seamlessly based on changes printed
+
+into the log or based on exceptions that are uncaught or logged e.g.:
+
+Log.setReportingLevel(Log.REPORTING_DEBUG);
+DefaultCrashReporter.init(true, 2);
+
+This code will send a log every 2 minutes to your email if anything was changed. You can place it
+
+within the init(Object) method of your application.
+
+For a production application you can use Log.REPORTING_PRODUCTION which will only email the log on
+exception.
+
+12.14. Sockets
+
+At  this  moment  Codename  One  only  supports  TCP  sockets.  Server  socket  (listen/accept)  is  only
+
+available on Android and the simulator but not on iOS.
+
+You  can  check  if  Sockets  are  supported  using  the  Socket.isSupported().  You  can  test  for  server
+socket support using Socket.isServerSocketSupported().
+
+To  use  sockets  you  can  use  the  Socket.connect(String  host,  int  port,  SocketConnection
+eventCallback) method.
+
+To  listen  on  sockets  you  can  use  the  Socket.listen(int  port,  Class  scClass)  method  which  will
+instantiate a SocketConnection instance (scClass is expected to be a subclass of SocketConnection) for
+every incoming connection.
+
+This simple example allows you to create a server and a client assuming the device supports both:
+
+public class MyApplication {
+    private Form current;
+
+    public void init(Object context) {
+        try {
+            Resources theme = Resources.openLayered("/theme");
+            UIManager.getInstance().setThemeProps(theme.getTheme(theme.getThemeResourceNames()[0]));
+        } catch(IOException e){
+            e.printStackTrace();
+        }
+    }
+
+    public void start() {
+        if(current != null){
+            current.show();
+
+463
+
+            return;
+        }
+        final Form soc = new Form("Socket Test");
+        Button btn = new Button("Create Server");
+        Button connect = new Button("Connect");
+        final TextField host = new TextField("127.0.0.1");
+        btn.addActionListener((evt) -> {
+            soc.addComponent(new Label("Listening: " + Socket.getIP()));
+            soc.revalidate();
+            Socket.listen(5557, SocketListenerCallback.class);
+        });
+        connect.addActionListener((evt) -> {
+            Socket.connect(host.getText(), 5557, new SocketConnection() {
+                @Override
+                public void connectionError(int errorCode, String message) {
+                    System.out.println("Error");
+                }
+
+                @Override
+                public void connectionEstablished(InputStream is, OutputStream os) {
+                    try {
+                        int counter = 1;
+                        while(isConnected()) {
+                            os.write(("Hi: " + counter).getBytes());
+                            counter++;
+                            Thread.sleep(2000);
+                        }
+                    } catch(Exception err) {
+                        err.printStackTrace();
+                    }
+                }
+            });
+        });
+        soc.setLayout(new BoxLayout(BoxLayout.Y_AXIS));
+        soc.addComponent(btn);
+        soc.addComponent(connect);
+        soc.addComponent(host);
+        soc.show();
+    }
+
+    public static class SocketListenerCallback extends SocketConnection {
+        private Label connectionLabel;
+
+        @Override
+        public void connectionError(int errorCode, String message) {
+            System.out.println("Error");
+        }
+
+        private void updateLabel(final String t) {
+            Display.getInstance().callSerially(new Runnable() {
+                public void run() {
+                    if(connectionLabel == null) {
+                        connectionLabel = new Label(t);
+                        Display.getInstance().getCurrent().addComponent(connectionLabel);
+                    } else {
+                        connectionLabel.setText(t);
+                    }
+
+464
+
+                    Display.getInstance().getCurrent().revalidate();
+                }
+            });
+        }
+
+        @Override
+        public void connectionEstablished(InputStream is, OutputStream os) {
+            try {
+                byte[] buffer = new byte[8192];
+                while(isConnected()) {
+                    int pending = is.available();
+                    if(pending > 0) {
+                        int size = is.read(buffer, 0, 8192);
+                        if(size == -1) {
+                            return;
+                        }
+                        if(size > 0) {
+                            updateLabel(new String(buffer, 0, size));
+                        }
+                    } else {
+                        Thread.sleep(50);
+                    }
+                }
+            } catch(Exception err) {
+                err.printStackTrace();
+            }
+        }
+    }
+
+    public void stop() {
+        current = Display.getInstance().getCurrent();
+    }
+
+    public void destroy() {
+    }
+}
+
+12.15. Properties
+
+In  standard  Java  we  usually  have  a  POJO  (Plain  Old  Java  Object)  which  has  getters/setters  e.g.  we
+can have a simple Meeting class like this:
+
+465
+
+public class Meeting {
+     private Date when;
+     private String subject;
+     private int attendance;
+
+     public Date getWhen() {
+        return when;
+    }
+
+     public String getSubject() {
+        return subject;
+     }
+
+     public int getAttendance() {
+        return attendance;
+     }
+
+     public void setWhen(Date when) {
+        this.when = when;
+    }
+
+     public void setSubject(String subject) {
+        this.subject  = subject;
+     }
+
+     public void setAttendance(int attendance) {
+        this.attendance = attendance;
+     }
+}
+
+That’s a classic POJO and it is the force that underlies JavaBeans and quite a few tools in Java.
+
+The  properties  are  effectively  the  getters/setters  e.g.  subject,  when  etc.  but  properties  have  several
+features that are crucial:
+
+• They can be manipulated in runtime by a tool that had no knowledge of them during compile
+
+time
+
+• They are observable - a tool can monitor changes to a value of a property
+
+• They can have meta-data associated with them
+
+These  features  are  crucial  since  properties  allow  us  all  kinds  of  magic  e.g.  hibernate/ORM  uses
+
+properties to bind Java objects to a database representation, jaxb does it to parse XML directly into
+
+Java objects and GUI builders use them to let us customize UI’s visually.
+
+POJO’s  don’t  support  most  of  that  so  pretty  much  all  Java  based  tools  use  a  lot  of  reflection  &
+
+bytecode manipulation. This works but has a lot of downsides e.g. say I want to map an object both
+
+to the Database and to XML/JSON.
+
+Would the bytecode manipulation collide?
+
+466
+
+Would it result in duplicate efforts?
+
+And how do I write custom generic code that uses such abilities? Do I need to manipulate the VM?
+
+12.15.1. Properties in Java
+
+These are all very abstract ideas, lets look at how we think properties should look in Java and how
+
+we can benefit from this moving forward.
+
+This is the same class as the one above written with properties:
+
+public class Meeting implements PropertyBusinessObject {
+     public final Property<Date,Meeting> when = new Property<>("when");
+     public final Property<String,Meeting> subject = new Property<>("subject");
+     public final Property<Integer,Meeting>  attendance = new Property<>("attendance");
+     private final PropertyIndex idx = new PropertyIndex(this, "Meeting", when, subject, attendance);
+
+    @Override
+    public PropertyIndex getPropertyIndex() {
+        return idx;
+    }
+}
+
+This looks a bit like a handful so let’s start with usage which might clarify a few things then dig into
+
+the class itself.
+
+When we used a POJO we did this:
+
+Meeting meet = new Meeting();
+meet.setSubject("My Subject");
+Log.p(meet.getSubject());
+
+With properties we do this:
+
+Meeting meet = new Meeting();
+meet.subject.set("My Subject");
+Log.p(meet.subject.get());
+
+Encapsulation
+
+At first glance it looks like we just created public fields (which we did) but if you will look closely at
+the declaration you will notice the final keyword:
+
+public final Property<String,Meeting> subject = new Property<>("subject");
+
+This means that this code will not compile:
+
+467
+
+meet.subject = otherValue;
+
+So  all  setting/getting  must  happen  thru  the  set/get  methods  and  they  can  be  replaced.  E.g.  this  is
+
+valid syntax that prevents setting the property to null and defaults it to an empty string:
+
+public final Property<String,Meeting> subject = new Property<>("subject", "") {
+     public Meeting set(String value) {
+         if(value == null) {
+            return Meeting.this;
+         }
+         return super.set(value);
+     }
+};
+
+ We’ll discuss the reason for returning the Meeting instance below
+
+Introspection & Observability
+
+Since  Property  is  a  common  class  it’s  pretty  easy  for  introspective  code  to  manipulate  properties.
+However, it can’t detect properties in an object without reflection.
+
+That’s  why  we  have  the  index  object  and  the  PropertyBusinessObject  interface  (which  defines
+getPropertyIndex).
+
+The  PropertyIndex  class  provides  meta  data  for  the  surrounding  class  including  the  list  of  the
+properties  within.  It  allows  enumerating  the  properties  and  iterating  over  them  making  them
+
+accessible to all tools.
+
+Furthermore all properties are observable with the property change listener. I can just write this to
+
+instantly print out any change made to the property:
+
+meet.subject.addChangeListener((p) -> Log.p("New property value is: " + p.get()));
+
+12.15.2. The Cool Stuff
+
+That’s the simple stuff that can be done with properties, but they can do much more!
+
+For starters all the common methods of Object can be implemented with almost no code:
+
+468
+
+public class Meeting implements PropertyBusinessObject {
+     public final Property<Date,Meeting> when = new Property<>("when");
+     public final Property<String,Meeting> subject = new Property<>("subject");
+     public final Property<Integer,Meeting>  attendance = new Property<>("attendance");
+     private final PropertyIndex idx = new PropertyIndex(this, "Meeting", when, subject, attendance);
+
+    @Override
+    public PropertyIndex getPropertyIndex() {
+        return idx;
+    }
+
+    public String toString() {
+        return idx.toString();
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        return obj.getClass() == getClass() && idx.equals(((TodoTask)obj).getPropertyIndex());
+    }
+
+    @Override
+    public int hashCode() {
+        return idx.hashCode();
+    }
+}
+
+This is easy thanks to introspection…
+
+We already have some simple code that can convert an object to/from JSON Maps e.g. this can fill
+
+the property values from parsed JSON:
+
+meet.getPropertyIndex().populateFromMap(jsonParsedData);
+
+And visa versa:
+
+String jsonString = meet.toJSON();
+
+We also have a very simple ORM solution that maps values to table columns and can create tables.
+
+It’s no hibernate but sqlite isn’t exactly big iron so it might be good enough.
+
+Constructors
+
+One of the problematic issues with constructors is that any change starts propagating everywhere.
+
+If I have fields in the constructor and I add a new field later I need to keep the old constructor for
+
+compatibility.
+
+So we added a new syntax:
+
+469
+
+Meeting meet = new Meeting().
+        subject.set("My Subject").
+        when.set(new Date());
+
+That is why every property in the definition needed the Meeting generic and the set method returns
+the Meeting instance…
+
+We are pretty conflicted on this feature and are thinking about removing it.
+
+Without this feature the code would look like this:
+
+Meeting meet = new Meeting();
+meet.subject.set("My Subject");
+meet.when.set(new Date());
+
+Seamless Serialization
+
+Lets assume I have an object called Contacts which includes contact information of contact e.g.:
+
+public class Contact implements PropertyBusinessObject {
+    public final IntProperty<Contact> id  = new IntProperty<>("id");
+    public final Property<String, Contact> name = new Property<>("name");
+    public final Property<String, Contact> email = new Property<>("email");
+    public final Property<String, Contact> phone = new Property<>("phone");
+    public final Property<Date, Contact> dateOfBirth = new Property<>("dateOfBirth", Date.class);
+    public final Property<String, Contact> gender  = new Property<>("gender");
+    public final IntProperty<Contact> rank  = new IntProperty<>("rank");
+    public final PropertyIndex idx = new PropertyIndex(this, "Contact", id, name, email, phone, dateOfBirth, gender,
+rank);
+
+    @Override
+    public PropertyIndex getPropertyIndex() {
+        return idx;
+    }
+
+    public Contact() {
+        name.setLabel("Name");
+        email.setLabel("E-Mail");
+        phone.setLabel("Phone");
+        dateOfBirth.setLabel("Date Of Birth");
+        gender.setLabel("Gender");
+        rank.setLabel("Rank");
+    }
+}
+
+Standard  Java  Objects  can  be  serialized  in  Codename  One  by  implementing  the  Codename  One
+Externalizable interface. You also need to register the Externalizable object so the implementation
+will be aware of it. Codename One business objects are seamlessly Externalizable and you just need
+to register them.
+
+E.g. you can do something like this in your init(Object) method:
+
+470
+
+new Contact().getPropertyIndex().registerExternalizable();
+
+After you do that once you can write/read contacts from storage if you so desire:
+
+Storage.getInstance().writeObject("MyContact", contact);
+
+Contact readContact = (Contact)Storage.getInstance().readObject("MyContact");
+
+This will obviously also work for things like List<Contact> etc…
+
+Seamless SQL Storage
+
+Writing  SQL  code  can  be  tedious.  Which  is  why  SQLMap  is  such  an  important  API  for  some  of  us.
+SQLMap allows CRUD (Create, Read, Update, Delete) operations on the builtin SQLite database using
+property objects.
+
+If  we  continue  the  example  from  above  to  show  persistence  to  the  SQL  database  we  can  just  do
+
+something like this:
+
+private Database db;
+private SQLMap sm;
+public void init(Object context) {
+    theme = UIManager.initFirstTheme("/theme");
+    Toolbar.setGlobalToolbar(true);
+    Log.bindCrashProtection(true);
+
+    try {
+        Contact c = new Contact();
+        db = Display.getInstance().openOrCreate("propertiesdemo.db"); ①
+        sm = SQLMap.create(db); ②
+        sm.setPrimaryKeyAutoIncrement(c, c.id); ③
+        sm.createTable(c); ④
+    } catch(IOException err) {
+        Log.e(err);
+    }
+}
+
+In the above code we do the following:
+
+① Create or open an SQLite database using the standard syntax
+
+② Create a properties binding instance
+
+③ Define the primary key for contact as id and set it to auto increment which will give it a unique
+
+value from the database
+
+④ Call SQL’s createTable if the table doesn’t exist yet!
+
+471
+
+
+
+Notice  that  at  this  time  altering  a  created  table  isn’t  possible  so  if  you  add  a  new
+property you might need to detect that and do an alter call manually
+
+We can then add entries to the contact table using:
+
+sm.insert(myContact);
+
+We can update an entry using:
+
+sm.update(myContact);
+
+And delete an entry using:
+
+sm.delete(myContact);
+
+Listing the entries is more interesting:
+
+List<PropertyBusinessObject> contacts = sm.select(c, c.name, true, 1000, 0);
+
+for(PropertyBusinessObject cc : contacts) {
+    Contact currentContact = (Contact)cc;
+
+   // ...
+}
+
+The arguments for the select method are:
+
+• The object type
+
+• The attribute by which we want to sort the result (can be null)
+
+• Whether sort is ascending
+
+• Number of elements to fetch
+
+• Page to start with - in this case if we have more than 1000 elements we can fetch the next page
+
+using sm.select(c, c.name, true, 1000, 1)
+
+There are many additional configurations where we can fine tune how a specific property maps to
+
+a column etc.
+
+What’s Still Missing
+
+The  SQLMap  API  is  very  simplistic  and  doesn’t  try  to  be  Hibernate/JPA  for  mobile.  So  basic  things
+aren’t  available  at  this  time  and  just  won’t  work.  This  isn’t  necessarily  a  problem  as  mobile
+
+databases don’t need to be as powerful as server databases.
+
+472
+
+Relational Mappings/JOIN
+
+Right now we can’t map an object to another object in the database with the typical one-many, one-
+one  etc.  relationships  that  would  could  do  with  JPA.  The  SQLMap  API  is  really  simplistic  and  isn’t
+suited for that level of mapping at this time.
+
+If  there  is  demand  for  this  it’s  something  we  might  add  moving  forward  but  our  goal  isn’t  to  re-
+
+invent hibernate.
+
+Threading
+
+SQLite is sensitive to threading issues especially on iOS. We mostly ignored the issue of threading
+
+and issue all calls in process. This can be a problem for larger data sets as the calls would usually go
+
+on the EDT.
+
+This  is  something  we  might  want  to  fix  for  the  generic  SQLite  API  so  low  level  SQL  queries  will
+
+work with our mapping in a sensible way.
+
+Alter
+
+Right now we don’t support table altering to support updated schemas. This is doable and shouldn’t
+
+be too hard to implement correctly so if there is demand for doing it we’ll probably add support for
+
+this.
+
+Complex SQL/Transactions
+
+We ignored functions, joins, transactions and a lot of other SQL capabilities.
+
+You  can  use  SQL  directly  to  use  all  of  these  capabilities  e.g.  if  you  begin  a  transaction  before
+
+inserting/updating  or  deleting  this  will  work  as  advertised  however  if  a  rollback  occurs  our
+
+mapping will be unaware of that so you will need to re-fetch the data.
+
+You will notice we mapped auto-increment so we will generally try to map things that make sense
+
+for various use cases, if you have such a use case we’d appreciate pull requests and feedback on the
+
+implementation.
+
+Caching/Collision
+
+As mentioned above, we don’t cache anything and there might be a collision if you select the same
+
+object  twice  you  will  get  two  separate  instances  that  might  collide  if  you  update  both  (one  will
+
+"win").
+
+That  means  you  need  to  pay  attention  to  the  way  you  cache  objects  to  avoid  a  case  of  a  modified
+
+version of an object kept with an older version.
+
+Preferences Binding
+
+Some  objects  make  sense  as  global  objects,  we  can  just  use  the  Preferences  API  to  store  that  data
+directly but then we don’t have the type safety that property objects bring to the table. That’s where
+the  binding  of  property  objects  to  preferences  makes  sense.  E.g.  say  we  have  a  global  Settings
+property object we can just bind it to preferences using:
+
+473
+
+PreferencesObject.create(settingsInstance).bind();
+
+So  if  settings  has  a  property  called  companyName  it  would  bind  into  Preferences  under  the
+Settings.companyName entry.
+
+We can do some more elaborate bindings such as:
+
+PreferencesObject.create(settingsInstance).
+    setPrefix("MySettings-").
+    setName(settingsInstance.companyName, "company").
+    bind();
+
+This would customize all entry keys to start with MySettings- instead of Settings.. This would also
+set  the  company  name  entry  to  company  so  in  this  case  instead  of  Settings.companyName  we’d  have
+MySettings-company.
+
+UI Binding
+
+One of the bigger features of properties are their ability to bind UI to a property. E.g. if we continue
+the sample above with the Contact class let’s say we have a text field on the form and we want the
+property  (which  we  mapped  to  the  database)  to  have  the  value  of  the  text  field.  We  could  do
+
+something like this:
+
+myNameTextField.setText(myNameTextField.getText());
+myNameTextField.addActionListener(e -> myContact.name.set(myNameTextField.getText()));
+
+That would work nicely but what if we changed the property value, that wouldn’t be reflected back
+
+into the text field?
+
+Also that works nicely for text field but what about other types e.g. numbers, check boxes, pickers
+
+etc. this becomes a bit more tedious with those.
+
+Binding makes this all seamless. E.g. the code above can be written as:
+
+UiBinding uib = new UiBinding();
+uib.bind(myNameTextField, myContact.name);
+
+The  cool  thing  is  that  this  works  with  multiple  component  types  and  property  types  almost
+
+magically. Binding works by using an adapter class to convert the data to/from the component. The
+
+adapter itself works with a generic converter e.g. this code:
+
+uib.bind(myRankTextField, myContact.rank);
+
+Seems similar to the one above but it takes a String that is returned by the text field and seamlessly
+
+474
+
+converts it to the integer needed by rank. This also works in the other direction…
+
+We can easily build a UI that would allow us to edit the Contact property in memory:
+
+Container resp = new Container(BoxLayout.y());
+UiBinding uib = new UiBinding();
+
+TextField nameTf = new TextField();
+uib.bind(c.name, nameTf);
+resp.add(c.name.getLabel()). ①
+        add(nameTf);
+
+TextField emailTf = new TextField();
+emailTf.setConstraint(TextField.EMAILADDR);
+uib.bind(c.email, emailTf);
+resp.add(c.email.getLabel()).
+        add(emailTf);
+
+TextField phoneTf = new TextField();
+phoneTf.setConstraint(TextField.PHONENUMBER);
+uib.bind(c.phone, phoneTf);
+resp.add(c.phone.getLabel()).
+        add(phoneTf);
+
+Picker dateOfBirth = new Picker();
+dateOfBirth.setType(Display.PICKER_TYPE_DATE); ②
+uib.bind(c.dateOfBirth, dateOfBirth);
+resp.add(c.dateOfBirth.getLabel()).
+        add(dateOfBirth);
+
+ButtonGroup genderGroup = new ButtonGroup();
+RadioButton male = RadioButton.createToggle("Male", genderGroup);
+RadioButton female = RadioButton.createToggle("Female", genderGroup);
+RadioButton undefined = RadioButton.createToggle("Undefined", genderGroup);
+uib.bindGroup(c.gender, new String[] {"M", "F", "U"}, male, female, undefined); ③
+resp.add(c.gender.getLabel()).
+        add(GridLayout.encloseIn(3, male, female, undefined));
+
+TextField rankTf = new TextField();
+rankTf.setConstraint(TextField.NUMERIC);
+uib.bind(c.rank, rankTf); ④
+resp.add(c.rank.getLabel()).
+        add(rankTf);
+
+① Notice I use the label of the property which allows better encapsulation
+
+② We can bind picker seamlessly
+
+③ We can bind multiple radio buttons to a single property to allow the user to select the gender,
+notice  that  labels  and  values  can  be  different  e.g.  "Male"  selection  will  translate  to  "M"  as  the
+
+value
+
+475
+
+④ Numeric bindings "just work"
+
+Figure 376. Properties form for the contact
+
+Binding Object & Auto Commit
+
+We  skipped  a  couple  of  fact  about  the  bind()  method.  It  has  an  additional  version  that  accepts  a
+ComponentAdapter which allows you to adapt the binding to any custom 3rd party component. That’s
+a bit advanced for now but I might discuss this later.
+
+However,  the  big  thing  I  "skipped"  was  the  return  value…  bind  returns  a  UiBinding.Binding  object
+when performing the bind. This object allows us to manipulate aspects of the binding specifically
+
+unbind a component and also manipulate auto commit for a specific binding.
+
+Auto  commit  determines  if  a  property  is  changed  instantly  or  on  commit.  This  is  useful  for  a  case
+where we have an "OK" button and want the changes to the UI to update the properties only when
+
+"OK"  is  pressed  (this  might  not  matter  if  you  keep  different  instances  of  the  object).  When  auto-
+commit is on (the default which you can change via setAutoCommit in the UiBinding) changes reflect
+instantly, when it’s off you need to explicitly call commit() or rollback() on the Binding class.
+
+commit()  applies  the  changes  in  the  UI  to  the  properties,  rollback()  restores  the  UI  to  the  values
+from the properties object (useful for a "reset changes" button).
+
+Binding  also  includes  the  ability  to  "unbind"  this  is  important  if  you  have  a  global  object  that’s
+
+bound  to  a  UI  that’s  discarded.  Binding  might  hold  a  hard  reference  to  the  UI  and  the  property
+
+object might create a memory leak.
+
+By using the disconnect() method in Binding we can separate the UI from the object and allow the
+GC to cleanup.
+
+UI Generation
+
+Up until now this was pretty cool but if you looked at the UI construction code above you would see
+
+that  it’s  pretty  full  of  boilerplate  code.  The  thing  about  boilerplate  is  that  it  shows  where
+
+automation  can  be  applied,  that’s  the  exact  idea  behind  the  magical  "InstantUI"  class.  This  means
+
+that the UI above can be generated using this code:
+
+476
+
+InstantUI iui = new InstantUI();
+iui.excludeProperty(myContact.id); ①
+iui.setMultiChoiceLabels(myContact.gender, "Male", "Female", "Undefined"); ②
+iui.setMultiChoiceValues(myContact.gender, "M", "F", "U");
+Container cnt = iui.createEditUI(myContact, true); ③
+
+① The id property is useful for database storage but we want to exclude it from the UI
+
+② This  implements  the  gender  toggle  button  selection,  we  provide  a  hint  to  the  UI  so  labels  and
+
+values differ
+
+③ We  create  the  UI  from  the  screenshot  above  with  one  line  and  it’s  seamlessly  bound  to  the
+
+properties of myContact. The second argument indicates the "auto commit" status.
+
+This  still  carries  most  of  the  flexibilities  of  the  regular  binding  e.g.  I  can  still  get  a  binding  object
+
+using:
+
+UiBinding.Binding b = iui.getBindings(cnt);
+
+You might not have noticed this but in the previous vebose code we had lines like:
+
+emailTf.setConstraint(TextField.EMAILADDR);
+
+You  might  be  surprised  to  know  that  this  will  still  work  seamlessly  without  doing  anything,  as
+
+would the picker component used to pick a date…
+
+The picker component implicitly works for date type properties, numeric constraints and numbers
+
+are implicitly used for number properties and check boxes are used for booleans.
+
+But how do we know to use an email constraint for the email property?
+
+We  have  some  special  case  defaults  for  some  common  property  names,  so  if  your  property  is
+
+named email it will use an email constraint by default. If it’s named url or password etc. it will do
+
+the  "right  thing"  unless  you  explicitly  state  otherwise.  You  can  customize  the  constraint  for  a
+
+specific property using something like:
+
+iui.setTextFieldConstraint(contact.email, TextArea.ANY);
+
+This will override the defaults we have in place. The goal of this tool is to have sensible "magical"
+
+defaults that "just work".
+
+[9] Event Dispatch Thread
+
+477
+
+478
+
+13. Push Notifications
+
+This chapter discusses push support in Codename One applications. It covers how to set up push on
+
+the  various  platforms,  how  to  respond  to  push  notifications  in  your  app,  and  how  to  send  push
+
+notifications to your app.
+
+ Push  notifications  require  a  Codename  One  Pro  account  or  higher.  You  must
+
+notification 
+
+receive 
+
+push 
+
+using
+
+register 
+Display.getInstance().registerPush();
+
+your 
+
+app 
+
+to 
+
+
+
+For  a  quick  reference  on  setting  up  Push  notifications,  check  out  the  Push
+
+Cheatsheet [https://www.codenameone.com/files/push-cheatsheet.pdf].
+
+13.1. Understanding Push Notifications
+
+Push  notifications  provide  a  way  to  inform  users  that  something  of  interest  has  taken  place.  It  is
+
+one of the few mechanisms available to interact with the user even when the app isn’t running. If
+
+your app is registered to receive push notifications, then you can send messages to the user’s device
+
+via REST API either from another device, or, as is usually the case, from a web server.
+
+Messages may contain a short title and text body that will be displayed to the user in their device’s
+
+messages stream. They may also specify a badge to display on the app’s icon (e.g. that red circle on
+
+your mail app icon that indicates how many unread messages you have), a sound to play then the
+
+message arrives, an image attachment, and a set of "actions" that the user can perform directly in
+
+the push notification.
+
+In addition to messages that the user sees, a push notification can contain non-visual information
+
+that is silently sent to your app.
+
+13.2. Implementing Push Support
+
+Enabling  push  support  in  your  application  is  just  a  matter  of  implementing  the  PushCallback
+interface  in  your  application’s  main  class  (i.e.  the  class  that  includes  your  start(),  init(),  etc…
+methods.
+
+479
+
+public class MyApplication implements PushCallback {
+
+    // ....
+
+    /**
+     * Invoked when the push notification occurs
+     *
+     * @param value the value of the push notification
+     */
+    public void push(String value) {
+        System.out.println("Received push message: "+value);
+    }
+
+    /**
+     * Invoked when push registration is complete to pass the device ID to the application.
+     *
+     * @param deviceId OS native push id you should not use this value and instead use <code>Push.getPushKey()</code>
+     * @see Push#getPushKey()
+     */
+    public void registeredForPush(String deviceId) {
+        System.out.println("The Push ID for this device is "+Push.getPushKey());
+    }
+
+    /**
+     * Invoked to indicate an error occurred during registration for push notification
+     * @param error descriptive error string
+     * @param errorCode an error code
+     */
+    public void pushRegistrationError(String error, int errorCode) {
+        System.out.println("An error occurred during push registration.");
+    }
+}
+
+There will be additional steps required to deploy to each platform (e.g. iOS requires you to generate
+
+push certificates, Android needs you to register your app ID with their cloud messaging platform,
+
+etc…), but, fundamentally, this is all that is required to enable push support in your app.
+
+13.3. The Push Lifecycle
+
+Let’s take minute to go over the three callbacks in our application.
+
+13.3.1. Registration
+
+When your application first opens, it needs to register with the platform’s central cloud messaging
+
+infrastructure. On Android this involves a call to their GCM/FCM server; on iOS, the call will be to
+
+the APNS server, on Windows (UWP) the call will be to the WNS server. And so on. That server will
+
+return a unique device ID that can be used to send push notifications to the device. This device ID
+will then be passed to your registeredForPush() method as the deviceId parameter so that you can
+save  it  somewhere.  Typically  you  would  send  this  value  to  your  own  web  service  so  that  you  can
+
+use it to send notifications to the device later on. The device ID will generally not change unless you
+
+uninstall and reinstall the app, but you will receive the callback every time the app starts.
+
+480
+
+
+
+The deviceId parameter cannot be used directly when sending push messages via
+the Codename One push service. It needs to be prefixed with a platform identifier
+
+so  the  that  push  server  knows  which  messaging  service  to  route  the  message
+
+through. You can obtain the complete device ID, including the platform prefix, by
+calling Push.getPushKey()
+
+If  the  registration  failed  for  some  reason,  the  the  pushRegistrationError()  callback  will  be  fired
+instead.
+
+Notice that all of this happens seamlessly behind the scenes when your app loads. You don’t need to
+
+initiate any of this workflow.
+
+13.3.2. Sending a Push Notification
+
+Codename  One  provides  a  secure  REST  API  for  sending  push  notifications.  As  an  HTTP  API,  it  is
+
+language  agnostic.  You  can  send  push  notifications  to  your  app  using  Java,  PHP,  Python,  Ruby,  or
+
+even by hand using something like curl. Each HTTP request can contain a push message and a list
+
+of device IDs to which the message should be sent. You don’t need to worry about whether your app
+
+is  running  on  Android,  iOS,  Windows,  or  the  web.  A  single  HTTP  request  can  send  a  message  to
+
+many devices at once.
+
+13.3.3. Receiving a Push Notification
+
+There are two different scenarios to be aware of when it comes to receiving push notifications. If
+
+your app is running in the foreground when the message arrives, then it will be passed directly to
+your push() callback. If your app is either in the background, or not running, then the notification
+will  be  displayed  in  your  device’s  notifications.  If  the  user  then  taps  the  notification,  it  will  open
+your app, and the push() callback will be run with the contents of the message.
+
+Some  push  message  types  include  hidden  content  that  will  not  be  displayed  in  your  device’s
+notifications.  These  hidden  messages  (or  portions  of  messages)  are  passed  directly  to  the  push()
+callback of your app for processing.
+
+ On iOS, hidden push messages (push type 2) will not be delivered when the app is
+
+in the background.
+
+
+
+You  can  set  the  android.background_push_handling  build  hint  to  "true"  to  deliver
+push  messages  on  Android  when  the  app  is  minimized  (running  in  the
+
+background). There is no equivalent setting on other platforms currently.
+
+13.4. Testing Push Support
+
+The easiest way to test push notifications in your app is to use the push simulation feature of the
+
+Codename One Simulator.
+
+481
+
+Figure 377. The "Push Simulation" menu item in the simulator opens the push simulator tool.
+
+The  "Registered  Successfully"  button  will  trigger  your  app’s  registeredForPush()  method,  and  the
+"Registration Error" button will trigger your app’s pushRegistrationError() method.
+
+The "Send" button will trigger the push() callback with the message body that you place in the "Send
+Message" field.
+
+The "Push Type" drop-down allows you to select the "type" of the push message. This dictates how
+
+the  message  body  (i.e.  the  contents  of  the  "Send  Message"  field)  is  interpreted.  Some  push  types
+
+simply  pass  the  message  to  the  device  verbatim,  while  others  assume  that  the  message  contains
+
+structure that is meant to be parsed by the client to extract such things as badges, sounds, images,
+
+and  actions  that  are  associated  with  the  message.  We’ll  go  over  the  available  push  types  in  a
+
+moment,  but  for  now,  we’ll  keep  it  simple  by  just  using  a  push  type  of  "1"  -  which  just  sends  the
+
+message verbatim.
+
+Figure 378. Sending a basic hello world push from the push simulator
+
+Let’s  try  a  simple  "hello  world"  push  message.  Select  "1"  from  the  "Push  Type"  drop-down  menu,
+
+and enter "Hello World" into the "Send Message" field as shown above. Then press "send".
+
+482
+
+Assuming your push() method looks like:
+
+public void push(String value) {
+    System.out.println("Received push message: "+value);
+}
+
+You should see the following output in your console:
+
+Received push message: Hello World
+
+This experiment simulated a push notification while the app is running in the foreground. Now let’s
+
+simulate the case where the app is not running, or running in the background. We can simulate this
+
+by pausing the app. Return to the Codename One simulator window, and select "Pause App" from
+
+the "Simulate" menu as shown below.
+
+Figure 379. Pausing the app in the simulator so we can simulate push notifications while app is in the
+
+background.
+
+When the app is paused it will simply display a white screen in the simulator with the text "Paused"
+
+in the middle.
+
+Now return to the push simulator again, and press "Send" again with same values in the other fields
+(Push type 1, and Message "Hello World"). Rather than running the push() callback this time, it will
+display a popup dialog outside the app, as shown below.
+
+483
+
+Figure 380. Push message causes a popup dialog in the simulator when the app is paused.
+
+While  this  popup  dialog  doesn’t  replicate  what  a  push  notification  will  look  like  in  a  device’s
+
+notifications stream when the app is closed, it does simulate the conceptual workflow. The process
+
+whereby  the  user  is  notified  of  the  message  outside  of  the  app,  and  the  app  is  not  notified
+
+until/unless the user taps on the notification.
+
+If  you  monitor  the  console  for  your  app,  you  should  notice  that  the  push()  callback  hasn’t  been
+called yet for this notification, but if you click "OK" in the dialog, your push() callback will be run.
+Clicking OK is analogous to the user tapping on the notification. If you simply close the dialog box
+
+(by clicking the "x" in the corner), this would be analogous to the user dismissing the notification. In
+this case the push() callback would not be called at all.
+
+13.5. Push Types and Message Structure
+
+The  example  above  sends  a  simple  message  to  be  displayed  to  the  user.  Push  notifications  can
+
+include more data than just an alert message, though. When the selected "push type" is 0 or 1, the
+
+push  server  will  interpret  the  message  body  a  simple  alert  string.  Selecting  a  different  push  type
+
+will affect how the message body is interpreted. The following push types are supported:
+
+• 0, 1 - The default push types, they work everywhere and present the string as the push alert to
+
+the user
+
+• 2 - hidden, non-visual push. This won’t show any visual indicator on any OS!
+
+In  Android  this  will  trigger  the  push(String)  call  with  the  message  body.  In  iOS  this  will  only
+
+happen if the application is in the foreground otherwise the push will be lost
+
+• 3 - 1 + 2 = 3 allows combining a visual push with a non-visual portion. Expects a message in the
+form:  This  is  what  the  user  won’t  see;This  is  something  he  will  see.  E.g.  you  can  bundle  a
+special  ID  or  even  a  JSON  string  in  the  hidden  part  while  including  a  friendly  message  in  the
+
+visual part.
+
+When active this will trigger the push(String) method twice, once with the visual and once with
+
+the hidden data.
+
+• 4 - Allows splitting a visual push request based on the format title;body to provide better visual
+
+representation in some OS’s.
+
+• 5 - Sends a regular push message but doesn’t play a sound when the push arrives
+
+• 99 - The message body is expected to be XML, where the root element contains at least type and
+body  attributes  which  correspond  to  one  of  the  other  push  push  types  and  message  body
+respectively.  This  push  type  supports  additional  information  such  as  image  attachments  and
+push actions. E.g. <push type="1" body="Hello World"/>
+
+• 100 - Applicable only to iOS and Windows. Allows setting the numeric badge on the icon to the
+
+484
+
+given number. The body of the message must be a number e.g. unread count.
+
+• 101 - identical to 100 with an added message payload separated with a space. E.g. 30 You have 30
+unread messages will set the badge to "30" and present the push notification text of "You have 30
+unread messages". Supported on Android, iOS, and Windows.
+
+The  following  sections  will  show  examples  of  the  various  kinds  of  pushes.  You  can  try  them  out
+
+yourself by opening the push simulator.
+
+13.5.1. Example Push Type 1
+
+Push Type 1; Message Body: "Hello World"
+
+Figure 381. Push type 1 "Hello World" message in simulator.
+
+Figure 382. Push type 1 "Hello World" message in Android when app is in background.
+
+Figure 383. Push type 1 "Hello World" message in iOS when app is in background.
+
+Figure 384. Push type 1 "Hello World" message in Chrome desktop.
+
+In all cases, if the user taps/clicks the notification, it will bring the app to the foreground and call
+the push() callback with "Hello World" as the argument.
+
+13.5.2. Example Push Type 2
+
+Push Type 2; Message Body: "Hello World"
+
+Push type 2 is a hidden push so it will behave differently on different platforms. On Android, the
+push() callback will be fired even if the app is in the background. On iOS, it will simply be ignored if
+the app is in the background.
+
+If  the  app  is  in  the  foreground,  this  will  trigger  the  push()  callback  with  "Hello  World"  as  the
+argument.
+
+485
+
+
+
+You  can  determine  the  the  type  of  push  that  has  been  received  in  your  push()
+callback by calling Display.getInstance().getProperty("pushType"). This will return
+case
+a 
+Display.getInstance().getProperty("pushType") will return "2".
+
+String 
+
+push 
+
+type. 
+
+this 
+
+E.g. 
+
+the 
+
+in 
+
+of 
+
+13.5.3. Example Push Type 3
+
+Push Type 3; Message Body Hello World;{"from":"Jim", "content":"Hello World"}
+
+Push  type  3  combines  an  alert  message  with  some  hidden  content  that  the  user  won’t  see.  In  the
+
+example above, the alert message is "Hello World" and the hidden content is a JSON string that will
+
+be passed to our app to be parsed.
+
+If the app is in the background, then the alert message will be posted to the user’s notifications. See
+
+"Example Push Type 1" above as this message will be identical.
+
+Figure 385. Push type 3 shows only the alert message (the portion before the first ";").
+
+the 
+
+This push will result in our push() callback being fired twice; once with the alert message, and once
+with 
+alert  message,
+it 
+Display.getInstance().getProperty("pushType")  will  report  a  type  of  "1".  When  it  is  fired  with  the
+JSON hidden content, it will report a push type of "2".
+
+content.  When 
+
+fired  with 
+
+hidden 
+
+the 
+
+is 
+
+13.5.4. Example Push Type 4
+
+Push Type 4; Message Body "Hello World;I’m just saying hello"
+
+Push type 4 specifies a title and a message body. In this example, alert title will be "Hello World",
+
+and the body will by "I’m just saying hello".
+
+Figure 386. Push type 4 "Hello World" message in simulator.
+
+Figure 387. Push type 4 "Hello World" message in Android when app is in background.
+
+Figure 388. Push type 4 "Hello World" message in iOS when app is in background.
+
+486
+
+Figure 389. Push type 4 "Hello World" message in Firefox desktop.
+
+With this push type, the push() callback will be fired only if the user taps/opens the notification, and
+the argument will contain the entire message ("Title;Body").
+
+
+
+On  some  platforms,  the  argument  of  the  push()  callback  will  only  include  the
+"body"  portion  of  the  payload,  and  in  other  platforms  it  will  include  the  full
+
+"Title;Body" payload.
+
+13.5.5. Example Push Type 5
+
+Push Type 5; Message Body "Hello World"
+
+Push  type  5  will  behave  identically  to  push  type  1,  except  that  the  notification  won’t  make  any
+sound on the device. On some platforms, Display.getInstance().getProperty("pushType") will report
+a push type of "1", when it receives a push of type 5.
+
+13.5.6. Example Push Type 100
+
+Push Type 100; Message Body "5"
+
+Push  type  100  just  expects  an  integer  in  the  message  body.  This  is  interpreted  as  the  badge  that
+
+should be set on the app. This is currently only supported on Windows and iOS.
+
+Figure 390. Push type 100 on iOS, setting the badge to "5"
+
+Push type 100 should not trigger the push() callback.
+
+13.5.7. Example Push Type 101
+
+Push Type 101; Message Body "5 Hello World"
+
+Push type 101 combines a badge with an alert message. The badge number should be the first thing
+
+in the payload, followed by a space, and the remainder is the alert message.
+
+On platforms that do not support badges, Push type 101 will behave exactly as push type 1, except
+
+that the badge prefix will be stripped from the message.
+
+487
+
+push() 
+
+The 
+Display.getInstance().getProperty("pushType") will return "1" for this type.
+
+callback  will  be 
+
+the  user 
+
+called 
+
+only 
+
+if 
+
+taps 
+
+the  notification.
+
+Badging on iOS
+
+The  badge  number  can  be  set  thru  code  as  well,  this  is  useful  if  you  want  the  badge  to
+
+represent the unread count within your application.
+
+To  do  this  we  have  two  methods  in  the  Display  [https://www.codenameone.com/javadoc/com/
+codename1/ui/Display.html] class: isBadgingSupported() and setBadgeNumber(int). Notice that even
+if isBadgingSupported will return true, it will not work unless you activate push support!
+
+To truly utilize this you might need to disable the clearing of the badges on startup which you
+can do with the build hint ios.enableBadgeClear=false.
+
+13.6. Rich Push Notifications
+
+Rich  push  notifications  refer  to  push  notifications  that  include  functionality  above  and  beyond
+
+simply  displaying  an  alert  message  to  the  user.  Codename  One’s  support  for  rich  notifications
+
+includes image attachments and push actions.
+
+13.6.1. Image Attachment Support
+
+When  you  attach  an  image  to  a  push  notification,  it  will  appear  as  a  large  image  in  the  push
+
+notification  on  the  user’s  device  if  that  device  supports  it.  iOS  supports  image  attachments  in  iOS
+
+10,  Android  supports  them  in  API  26.  The  Javascript  port,  and  Windows  (UWP)  port  do  not
+
+currently  support  image  attachments.  If  a  platform  that  doesn’t  support  image  attachments
+
+receives a push notification with an image attachment, it will just ignore it.
+
+Push  type  "99"  is  used  to  send  rich  push  notifications.  It  is  sort  of  a  "meta"  push  type,  or  a
+
+"container", as it can be used to send any of the other push types, but to attach additional content,
+
+such as image attachments.
+
+The  message  body  should  be  an  XML  string.  A  minimal  example  of  a  push  type  99  that  actually
+
+sends a push type 1, which message "Hello World", but with an attached image is:
+
+<push type="1" body="Hello World"><img src="https://exmaple.com/myimage.jpg"/></push>
+
+ The  image  URL  must  be  a  secure  URL  (i.e.  start  with  "https:"  and  not  "http:",
+
+otherwise, iOS will simply ignore it.
+
+488
+
+Figure 391. Push type 99 with attached image in simulator.
+
+Figure 392. Push type 99 with attached image in Android when app is in background.
+
+489
+
+Figure 393. Push type 99 with attached image in iOS when app is in background.
+
+
+
+The  image  will  only  be  shown  if  you  press  and  pull  down  on  the  notification.
+
+When the notification initially appears in the user’s notifications it will appear like
+
+a normal alert - but possibly with the image shown as a small thumbnail.
+
+push() 
+
+The 
+its 
+Display.getInstance().getProperty("pushType") will return "1" in this example.
+
+"Hello  World" 
+
+callback  will 
+
+receive 
+
+as 
+
+argument 
+
+and
+
+can 
+
+You 
+com.codename1.push.PushContent class, as follows:
+
+additional 
+
+information 
+
+access 
+
+about 
+
+the 
+
+push 
+
+content 
+
+using 
+
+the
+
+public void push(String message) {
+    PushContent content = PushContent.get();
+    if (content != null) {
+        String imageUrl = content.getImageUrl();
+            // The image attachment URL in the push notification
+            // or `null` if there was no image attachment.
+    }
+}
+
+
+
+Make  sure  to  only  call  PushContent.get()  once  inside  your  push()  callback,  and
+store the return value. PushContent.get() works like a queue of size=1, and it pops
+off the item from the front of the queue when it is called. If you call it twice, the
+second time will return null.
+
+13.6.2. Notification Actions
+
+When you include actions in a push notification, the user will be presented with buttons as part of
+
+the notification on supported platforms. E.g. if the notification is intended to invite the user to an
+
+490
+
+event, you might want to include buttons/actions like "Attending", "Not Attending", "Maybe", so that
+
+the user can respond quickly to the notification and not necessarily have to open your app.
+
+You can determine whether the user has pressed a particular button on the notification using the
+`PushContent.getActionId()` method inside your `push()` callback.
+
+How it works
+
+Your  app  defines  which  action  categories  it  supports,  and  associates  a  set  of  actions  with  each
+
+category.  If  a  push  notification  includes  a  "category"  attribute,  then  the  notification  will  be
+
+presented with the associated actions manifested as buttons.
+
+Defining the Categories and Actions
+
+You  can  specify  the  available  categories  and  actions  for  your  app  by  implementing  the
+com.codename1.push.PushActionsProvider interface in your app’s main class.
+
+E.g.
+
+import com.codename1.push.PushAction;
+import com.codename1.push.PushActionCategory;
+import com.codename1.push.PushActionsProvider;
+...
+
+public class MyApplication implements PushCallback, PushActionsProvider {
+
+    ...
+
+    @Override
+    public PushActionCategory[] getPushActionCategories() {
+        return new PushActionCategory[]{
+            new PushActionCategory("invite", new PushAction[]{
+                new PushAction("yes", "Yes"),
+                new PushAction("no", "No"),
+                new PushAction("maybe", "Maybe")
+            })
+
+        };
+    }
+}
+
+In  the  above  example,  we  create  only  a  single  category,  "invite"  that  has  actions  "yes",  "no",  and
+
+"maybe".
+
+Sending a Push Notification with "invite" Category
+
+Now we can test our new category. In the push simulator, you can select Push Type "99", with the
+
+message body:
+
+491
+
+<push type="1" body="Would you like to come to a party?" category="invite"/>
+
+Figure 394. Push notification with "invite" category on the simulator will show dialog with buttons to select
+
+between the actions defined in the "invite" category.
+
+Figure 395. Push notification with "invite" category on the android will show dialog with buttons to select
+
+between the actions defined in the "invite" category.
+
+Figure 396. Push notification with "invite" category on the android will show dialog with buttons to select
+
+between the actions defined in the "invite" category.
+
+Figure 397. Push notification with "invite" category on the Chrome desktop includes a "More" dropdown
+
+where user can select the action.
+
+The push() callback will be fired after the user taps on the notification, or one of its actions. If the
+
+492
+
+user taps the notification itself, and not one of the actions, then your PushContent.getActionId() will
+return  null.  If  they  selected  one  of  the  actions,  then  the  action  ID  of  that  action  can  be  obtained
+from getActionId().
+
+The  category  of  the  notification  will  be  made  available  via  the  getCategory()  method  of
+PushContent.
+
+E.g.
+
+public void push(String message) {
+    PushContent content = PushContent.get();
+    if (content != null) {
+        if ("invite".equals(content.getCategory())) {
+            if (content.getActionId() != null) {
+                System.out.println("The user selected the "+content.getActionid()+" action");
+            } else {
+                System.out.println("The user clicked on the invite notification, but didn't select an action.");
+            }
+        }
+    }
+}
+
+13.7. Deploying Push-Enabled Apps to Device
+
+So,  you’ve  implemented  the  Push  callback  in  your  app,  and  tested  it  in  the  push  simulator  and  it
+
+works. If you try to deploy your app to a device, you may be disappointed to discover that your app
+
+doesn’t seem to be receiving push notifications when installed on the device. This is because each
+
+platform has its own bureaucracy and hoops that you have to jump through before they will deliver
+
+notifications to your app. Read on to find out how to satisfy their requirements.
+
+13.7.1. The Push Bureaucracy - Android
+
+
+
+To  set  the  push  icon  place  a  24x24  icon  named  ic_stat_notify.png  under  the
+native/android folder of the app. The icon can be white with transparency areas
+
+Android Push goes thru Google servers and to do that we need to register with Google to get keys
+
+for server usage. Google uses Firebase for its cloud messaging, so we’ll begin by creating a Firebase
+
+project.
+
+Go to https://console.firebase.google.com/ and click Add project:
+
+493
+
+Figure 398. Click "Add project"
+
+This will open a form as shown here:
+
+Figure 399. Enter project name
+
+Enter the project name, select your country, read/accept their terms, and press "Create Project".
+
+Once  the  project  has  been  created  (should  take  only  a  few  seconds),  you’ll  be  sent  to  your  new
+
+project’s dashboard.
+
+Figure 400. Firebase Project Dashboard
+
+Expand the "Grow" section of the left menu bar, then click on the "Cloud Messaging" link.
+
+494
+
+Figure 401. Expand "Grow" Section and select "Cloud Messaging"
+
+On the next screen, click on the Android icon where is says "Add an app to get started".
+
+Figure 402. Click on the "Android" icon to add an Android App to the project
+
+This  will  bring  us  to  the  "Add  Application  Form",  which  visually  shows  us  the  remainder  of  the
+
+steps.
+
+Fill  in  the  Android  package  name  with  the  package  name  of  your  project,  and  the  app  nickname
+
+with your app’s name.
+
+The  Debug  signing  certificate  SHA-1  is  optional,  but  you  can  paste  the  SHA-1  from  your  app’s
+
+certificate here if you like.
+
+Figure 403. Fill in the package name
+
+Press "Register app" once you have filled in the required fields.
+
+This will expand "Step 2" of this form: "Download config file".
+
+495
+
+Figure 404. Download the google-services.json file
+
+All we need to do here is press the "Download google-services.json" file, then copy the file into your
+
+project’s native/android directory.
+
+Firebase  console  directs  you  to  copy  the  google-services.json  file  into  the  "app"
+
+
+
+directory of your project. Ignore this direction as it only applies for Android studio
+
+projects. For Codename One, this file goes into the native/android directory of your
+
+project.
+
+There is one last piece of information that we need so that we can send push notifications to our
+app: The FCM_SERVER_API_KEY value.
+
+Go to your project dashboard in Firebase console. Then click the "Settings" menu (the "Gear" icon
+
+next to "Project Overview" in the upper left):
+
+Figure 405. Select "Project settings"
+
+Then select the "Cloud Messaging" tab.
+
+The  "Server  Key"  displayed  here  is  the  FCM_SERVER_API_KEY  that  we  refer  to  throughout  this
+document.  It  will  be  used  to  send  push  notifications  to  your  app  from  a  server,  or  from  another
+
+device.  You  can  copy  and  paste  this  value  now,  or  you  can  retrieve  it  later  by  logging  into  the
+
+Firebase console.
+
+Figure 406. Save the Server key for later use.
+
+
+
+The Sender ID shown in the above is not required for our Android app, however it
+
+it is helpful/required to support Push notifications in Javascript builds (in Chrome).
+This value is referred to elsewhere in this document as GCM_SENDER_ID.
+
+13.7.2. The Push Bureaucracy - iOS
+
+Push  on  iOS  is  much  harder  to  handle  than  the  Android  version,  however  we  simplified  this
+
+496
+
+significantly with the certificate wizard.
+
+iOS push needs two additional P12 certificates.
+
+
+
+Please notice that these are NOT the signing certificates!
+
+They are completely different certificates that have nothing to do with the build
+
+process!
+
+The  certificate  wizard  can  generate  these  additional  push  certificates  and  do  quite  a  few  other
+
+things if you just check this flag in the end of the wizard:
+
+Figure 407. Enable Push in the certificate wizard
+
+ If  you  already  have  signing  certificated  defined  for  your  app  just  skip  the
+
+certificate generation phase (answer no) the rest will work as usual.
+
+You can then install the push certificates locally and use them later on but there is an easier way.
+
+You  need  to  host  the  push  certificates  in  the  cloud  so  they  will  be  reachable  by  the  push  servers,
+
+Codename One that for you seamlessly.
+
+Once  you  go  thru  the  wizard  you  should  get  an  automated  email  containing  information  about
+
+push and the location of the push certificates, it should start like this:
+
+iOS Push certificates have been created for your app with bundle ID com.mycompany.myapp.mypushdemo.  Please file this
+email away for safe keeping as you will need the details about the certificate locations and passwords to use Push
+successfully in your apps.
+
+Development Push Certificate URL:
+https://codename-one-push-
+certificates.s3.amazonaws.com/com.mycompany.myapp.mypushdemo_DevelopmentPush_LONG_UNIQUE_KEY.p12
+
+Development Push Certificate Password: ssDfdsfer324
+
+Production Push Certificate URL:
+https://codename-one-push-certificates.s3.amazonaws.com/com.mycompany.myapp.mypushdemo_ProductionPush_LONG_UNIQUE_KEY.p12
+
+Production Push Certificate Password: ssDfdsfer324
+
+The  URL’s  and  passwords  are  everything  that  you  will  need  later  on  to  get  push  working  on  iOS.
+
+497
+
+Notice that the wizard also performs a couple of other tasks specifically it sets the ios.includePush
+build hint to true & adds push to the provisioning profile etc.
+
+You  can  read  more  about  the  certificate  wizard  in  the  signing  section  [https://www.codenameone.com/
+
+manual/signing.html].
+
+13.7.3. The Push Bureaucracy - UWP (Windows 10)
+
+Push on UWP requires only that you register your app in the Windows Store Dashboard. You will
+
+then be provided with credentials (Package Security Identifier (SID) and a secret key) that you can
+
+use  to  send  push  notifications  to  your  app.  To  begin  this  process,  go  to  the  Windows  Dev  Center
+
+[https://developer.microsoft.com/en-us/windows] and select "Dashboard".
+
+You  can  read  more  about 
+
+the  registering  your  app 
+
+in 
+
+the  Windows  store  here
+
+[https://www.codenameone.com/manual/appendix-uwp.html#building-for-the-windows-store].
+
+Once you have registered your app in the Windows Store, and completed the corresponding setup
+
+in Codename One settings (e.g. generated a certificate), you should proceed to configure your app
+
+for push notifications.
+
+Navigate  to  the  App  overview  page  for  your  app  inside  the  Windows  store  dashboard.  Under  the
+
+"Services" menu (left side), select "Push notifications".
+
+Figure 408. Push notifications menu item in Windows Store dashboard
+
+Then, select the "WNS/MPNS" option that appears in the left menu under "Push notifications"
+
+Figure 409. WNS menu item in Windows Store dashboard
+
+This will bring you to a page with information about WNS push notifications. You’ll be interested in
+
+the paragraph shown here:
+
+Figure 410. Live services link
+
+Click on the "Live Services Site" link.
+
+You’ll be prompted to log in using your Windows Store account. Then you’ll be taken to a page that
+
+contains  the  push  credentials  that  you  can  use  for  sending  push  messages  to  your  app.  You’ll  be
+
+interested in two values:
+
+Package SID. (It will be of the form "ms-app://XXXXXXXXXXX…")
+
+498
+
+Figure 411. WNS Package SID
+
+Client Secret. This will be listed in a section called "Application Secrets"
+
+Figure 412. WNS Client secret
+
+You will use these two values for sending push notifications to your app.
+
+Microsoft  provides  full  instructions  on  setting  up  WNS  notifications  here  [https://msdn.microsoft.com/
+
+library/windows/apps/hh465407]  but  much  of  this  is  not  relevant  for  Codename  One  apps.  For
+
+Codename One apps, one need only obtain Package Security ID and client secret values for the app.
+
+13.7.4. The Push Bureaucracy - Javascript
+
+Codename  One  apps  support  push  in  browsers  that  implement  the  Web  Push  API.  At  time  of
+
+writing, this list includes:
+
+• Firefox (Version 50)
+
+• Chrome (Version 49)
+
+• Opera (Version 42)
+
+• Chrome for Android (Version 56)
+
+• MS Edge
+
+Firefox doesn’t require any special setup for Push. If your main class implements the PushCallback
+interface, it should just work.
+
+Chrome uses FCM for its push notifications - the same system that Android uses. The directions for
+setting up a FCM account are the same as provided here, and you can reuse the same GCM_SENDER_ID
+and FCM_API_SERVER_KEY values. For Chrome push support you will need to add the GCM_SENDER_ID in
+the gcm.sender_id build hint so that the GCM_SENDER_ID will be added to the app’s manifest file:
+
+gcm.sender_id=GCM_SENDER_ID
+
+Where GCM_SENDER_ID is your GCM_SENDER_ID.
+
+
+
+Push  support  requires  that  your  app  be  served  over  https  with  a  valid  SSL
+
+certificate. It will not work with the "preview" version of your app. You’ll need to
+
+download the .zip or .war file and host the file on your own site - with a valid SSL
+
+certificate.
+
+499
+
+13.8. Sending Push Messages
+
+You can send a push message in many ways e.g. from another device or any type of server but there
+
+are some values that you will need regardless of the way in which you send the push message.
+
+private static final String PUSH_TOKEN = "********-****-****-****-*************";
+
+The push token is a unique "key" that you can use to send push thru your Codename One account. It
+
+allows  you  to  send  push  messages  without  placing  your  Codename  One  email  or  password  into
+
+your source files.
+
+You 
+
+can  get 
+
+it  by  going 
+
+to 
+
+the  Codename  One  build 
+
+server  dashboard  at
+
+https://www.codenameone.com/build-server.html and selecting the Account tab.
+
+The token should appear at the bottom as such:
+
+Figure 413. Push Token from the build server
+
+The instructions for extracting the API key for Google are listed above.
+
+private static final String FCM_SERVER_API_KEY = "******************-********************";
+
+The instructions for extracting the SID and Client Secret for Windows are listed above.
+
+private static final String WNS_SID = "ms-app://**************************************";
+private static final String WNS_CLIENT_SECRET = "*************************";
+
+When sending push to iOS devices we have two modes: - Production - Distribution
+
+This allows you to debug the push related functionality without risking the possibility of sending a
+
+push  into  a  production  app.  Its  important  to  send  the  values  to  the  right  server  during
+
+development/production.
+
+private static final boolean ITUNES_PRODUCTION_PUSH = false;
+
+iOS needs a certificate in order to send a push, this allows you to prove to Apples push servers that
+
+you are who you claim to be (the author of the app).
+
+500
+
+ These are not the signing certificates and are completely separate from them!
+
+You  can  obtain  these  two  certificates  (for  development/appstore)  via  the  certificate  wizard  as
+
+explained above.
+
+private static final String ITUNES_PRODUCTION_PUSH_CERT = "https://domain.com/linkToP12Prod.p12";
+private static final String ITUNES_PRODUCTION_PUSH_CERT_PASSWORD = "ProdPassword";
+private static final String ITUNES_DEVELOPMENT_PUSH_CERT = "https://domain.com/linkToP12Dev.p12";
+private static final String ITUNES_DEVELOPMENT_PUSH_CERT_PASSWORD = "DevPassword";
+
+13.8.1. Sending a Push Message From Codename One
+
+While  normally  sending  a  push  message  to  a  device  should  involve  a  server  code  there  might  be
+
+cases (e.g. instant messaging/social) where initiating a push from one client to another makes sense.
+
+To  simplify  these  use  cases  we  added  the  Push  [https://www.codenameone.com/javadoc/com/codename1/
+push/Push.html] API. To use the Push API you need the device key of the destination device to which
+you  want  to  send  the  message.  You  can  get  that  value  from  the  Push.getPushKey()  method.  Notice
+that you need that value from the destination device and not the local device!
+
+To send a message to another device just use:
+
+String cert = ITUNES_DEVELOPMENT_PUSH_CERT;
+String pass = ITUNES_DEVELOPMENT_PUSH_CERT_PASSWORD;
+if(ITUNES_PRODUCTION_PUSH) {
+    cert = ITUNES_PRODUCTION_PUSH_CERT;
+    pass = ITUNES_PRODUCTION_PUSH_CERT_PASSWORD;
+}
+new Push(PUSH_TOKEN, "Hello World", deviceKey)
+    .apnsAuth(cert, pass, ITUNES_PRODUCTION_PUSH)
+    .gcmAuth(FCM_SERVER_API_KEY)
+    .wnsAuth(WNS_SID, WNS_CLIENT_SECRET)
+    .send();
+
+The "builder" style API used in the above sample was added post Codename One 3.6 to facilitate the
+
+addition of new Push services. If you are building against Codename one 3.6 or earlier, you should
+use the static Push.sendPushMessage() instead as shown below:
+
+Push.sendPushMessage(PUSH_TOKEN, "Hello World",
+         ITUNES_PRODUCTION_PUSH, FCM_SERVER_API_KEY, cert, pass, 1, deviceKey));
+
+This will send the push message "Hello World" to the device with the key deviceKey. The 1 argument
+represents the standard push message type, which we discussed previously.
+
+501
+
+13.8.2. Sending Push Message From A Java or Generic Server
+
+Sending a push message from the server is a more elaborate affair and might require sending push
+
+messages to many devices in a single batch.
+
+We can send a push message as an HTTP POST request to https://push.codenameone.com/push/push
+[https://push.codenameone.com/push/push]. That URL accepts the following arguments:
+
+• token - your developer token to identify the account sending the push - PUSH_TOKEN
+
+• device - one or more device keys to send the push to. You can send push to up to 500 devices
+
+with a single request -
+
+• type - the message type identical to the old set of supported types in the old push servers
+
+• body - the body of the message
+
+• auth  -  the  Google  push  auth  key  -  FCM_SERVER_API_KEY  (also  used  for  sending  to  Chrome
+
+Javascript Apps)
+
+• production  -  true/false  whether  to  push  to  production  or  sandbox  environment  in  iOS  -
+
+ITUNES_PRODUCTION_PUSH
+
+• certPassword 
+
+- 
+
+password 
+
+for 
+
+the 
+
+push 
+
+certificate 
+
+in 
+
+iOS 
+
+push 
+
+ITUNES_DEVELOPMENT_PUSH_CERT_PASSWORD or ITUNES_PRODUCTION_PUSH_CERT_PASSWORD
+
+• cert 
+
+-  http  or  https  URL  containing 
+
+the  push  certificate 
+
+for  an 
+
+iOS  push 
+
+ITUNES_DEVELOPMENT_PUSH_CERT or ITUNES_PRODUCTION_PUSH_CERT
+
+-
+
+-
+
+• sid - The package security ID (SID) for UWP apps.
+
+• client_secret - The client secret for UWP apps.
+
+We can thus send a push from Java EE using code like this:
+
+502
+
+HttpURLConnection connection = (HttpURLConnection)new URL("https://push.codenameone.com/push/push").openConnection();
+connection.setDoOutput(true);
+connection.setRequestMethod("POST");
+connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8");
+String cert = ITUNES_DEVELOPMENT_PUSH_CERT;
+String pass = ITUNES_DEVELOPMENT_PUSH_CERT_PASSWORD;
+if(ITUNES_PRODUCTION_PUSH) {
+    cert = ITUNES_PRODUCTION_PUSH_CERT;
+    pass = ITUNES_PRODUCTION_PUSH_CERT_PASSWORD;
+}
+String query = "token="  + PUSH_TOKEN +
+    "&device=" + URLEncoder.encode(deviceId1, "UTF-8") +
+    "&device=" + URLEncoder.encode(deviceId2, "UTF-8") +
+    "&device=" + URLEncoder.encode(deviceId3, "UTF-8") +
+    "&type=1" +
+    "&auth=" + URLEncoder.encode(FCM_SERVER_API_KEY, "UTF-8") +
+    "&certPassword=" + URLEncoder.encode(pass, "UTF-8") +
+    "&cert=" + URLEncoder.encode(cert, "UTF-8") +
+    "&body=" + URLEncoder.encode(MESSAGE_BODY, "UTF-8") +
+    "&production=" + ITUNES_PRODUCTION_PUSH +
+    "&sid=" + URLEncoder.encode(WNS_SID, "UTF-8") +
+    "&client_secret=" + URLEncoder.encode(WNS_CLIENT_SECRET, "UTF-8");
+try (OutputStream output = connection.getOutputStream()) {
+    output.write(query.getBytes("UTF-8"));
+}
+int c = connection.getResponseCode();
+// read response JSON
+
+Notice that you can send a push to 500 devices. To send in larger batches you need to split the push
+
+requests into 500 device batches.
+
+Server JSON Responses
+
+The push servers send responses in JSON form. It’s crucial to parse and manage those as they might
+
+contain important information.
+
+If  there  is  an  error  that  isn’t  fatal  such  as  quota  exceeded  etc.  you  will  get  an  error  message  like
+
+this:
+
+{"error":"Error message"}
+
+A normal response, will be an array with results:
+
+[
+   {"id"="deviceId","status"="error","message"="Invalid Device ID"},
+   {"id"="cn1-gcm-nativegcmkey","status"="updateId", "newId"="cn1-gcm-newgcmkey"},
+   {"id"="cn1-gcm-okgcmkey","status"="OK"},
+   {"id"="cn1-gcm-errorkey","status"="error","message"="Server error message"},
+   {"id"="cn1-ios-iphonekey","status"="inactive"},
+]
+
+There are several things to notice in the responses above:
+
+503
+
+• If the response contains status=updateId it means that the GCM server wants you to update the
+device id to a new device id. You should do that in the database and avoid sending pushes to the
+
+old key
+
+• iOS  doesn’t  acknowledge  device  receipt  but  it  does  send  a  status=inactive  result  which  you
+
+should use to remove the device from the list of devices
+
+ APNS  (Apple’s  push  service)  returns  uppercase  key  results.  This  means  that  code
+
+for managing the keys in your database must be case insensitive
+
+
+
+Apple doesn’t always send back a result for a device being inactive and might fail
+
+silently
+
+504
+
+14. Miscellaneous Features
+
+14.1. Phone Functions
+
+Most  of  the  low  level  phone  functionality  is  accessible  in  the  Display  [https://www.codenameone.com/
+
+javadoc/com/codename1/ui/Display.html] class. Think of it as a global central class covering your access to
+
+the "system".
+
+14.1.1. SMS
+
+Codename  One  supports  sending  SMS  messages  but  not  receiving  them  as  this  functionality  isn’t
+
+portable. You can send an SMS using:
+
+Display.getInstance().setSMS("+999999999", "My SMS Message");
+
+Android/Blackberry support sending SMS’s in the background without showing the user anything.
+
+iOS & Windows Phone just don’t have that ability, the best they can offer is to launch the native SMS
+
+app with your message already in that app. Android supports that capability as well (launching the
+
+OS native SMS app).
+
+The  default  sendSMS  API  ignores  that  difference  and  simply  works  interactively  on  iOS/Windows
+Phone while sending in the background for the other platforms.
+
+The getSMSSupport API returns one of the following options:
+
+• SMS_NOT_SUPPORTED - for desktop, tablet etc.
+
+• SMS_SEAMLESS - sendSMS will not show a UI and will just send in the background
+
+• SMS_INTERACTIVE - sendSMS will show an SMS sending UI
+
+• SMS_BOTH - sendSMS can support both seamless and interactive mode, this currently only works
+
+on Android
+
+The  sendSMS  can  accept  an  interactive  argument:  sendSMS(String  phoneNumber,  String  message,
+boolean interactive)
+
+The  last  argument  will  be  ignored  unless  SMS_BOTH  is  returned  from  getSMSSupport  at  which  point
+you would be able to choose one way or the other. The default behavior (when not using that flag)
+
+is the background sending which is the current behavior on Android.
+
+A typical use of this API would be something like this:
+
+505
+
+switch(Display.getInstance().getSMSSupport()) {
+    case Display.SMS_NOT_SUPPORTED:
+        return;
+    case Display.SMS_SEAMLESS:
+        showUIDialogToEditMessageData();
+        Display.getInstance().sendSMS(phone, data);
+        return;
+    default:
+        Display.getInstance().sendSMS(phone, data);
+        return;
+}
+
+14.1.2. Dialing
+
+Dialog  the  phone  is  pretty  trivial,  this  should  open  the  dialer  UI  without  physically  dialing  the
+
+phone as that is discouraged by device vendors.
+
+You can dial the phone by using:
+
+Display.getInstance().dial("+999999999");
+
+14.1.3. E-Mail
+
+You can send an email via the platforms native email client with code such as this:
+
+Message m = new Message("Body of message");
+Display.getInstance().sendMessage(new String[] {"someone@gmail.com"}, "Subject of message", m);
+
+You can add one attachment by using setAttachment and setAttachmentMimeType.
+
+ You need to use files from FileSystemStorage and NOT Storage files!
+
+You can add more than one attachment by putting them directly into the attachment map e.g.:
+
+Message m = new Message("Body of message");
+m.getAttachments().put(textAttachmentUri, "text/plain");
+m.getAttachments().put(imageAttachmentUri, "image/png");
+Display.getInstance().sendMessage(new String[] {"someone@gmail.com"}, "Subject of message", m);
+
+ Some  features  such  as  attachments  etc.  don’t  work  correctly  in  the  simulator  but
+
+should work on iOS/Android
+
+The email messaging API has an additional ability within the Message [https://www.codenameone.com/
+javadoc/com/codename1/messaging/Message.html] class. The sendMessageViaCloud method allows you to use
+the Codename One cloud to send an email without end user interaction. This feature is available to
+
+506
+
+pro users only since it makes use of the Codename One cloud:
+
+Message m = new Message("<html><body>Check out <a href=\"https://www.codenameone.com/\">Codename One</a></body></html>");
+m.setMimeType(Message.MIME_HTML);
+
+// notice that we provide a plain text alternative as well in the send method
+boolean success = m.sendMessageViaCloudSync("Codename One", "destination@domain.com", "Name Of User", "Message Subject",
+                            "Check out Codename One at https://www.codenameone.com/");
+
+14.2. Contacts API
+
+The  contacts  API  provides  us  with  the  means  to  query  the  phone’s  address  book,  delete  elements
+
+from  it  and  create  new  entries  into  it.  To  get  the  platform  specific  list  of  contacts  you  can  use
+String[] contacts = ContactsManager.getAllContacts();
+
+Notice that on some platforms this will prompt the user for permissions and the user might choose
+
+to  grant 
+
+that  permission.  To  detect  whether 
+
+invoke
+not 
+isContactsPermissionGranted() after invoking getAllContacts(). This can help you adapt your error
+message to the user.
+
+the  case  you  can 
+
+this 
+
+is 
+
+Once  you  have  a  Contact  [https://www.codenameone.com/javadoc/com/codename1/contacts/Contact.html]  you
+can use the getContactById method, however the default method is a bit slow if you want to pull a
+large batch of contacts. The solution for this is to only extract the data that you need via
+
+getContactById(String id, boolean includesFullName,
+            boolean includesPicture, boolean includesNumbers, boolean includesEmail,
+            boolean includeAddress)
+
+Here you can specify true only for the attributes that actually matter to you.
+
+Another capability of the contacts API is the ability to extract all of the contacts very quickly. This
+
+isn’t supported on all platforms but platforms such as Android can really get a boost from this API
+
+as extracting the contacts one by one is remarkably slow on Android.
+
+You  can  check  if  a  platform  supports  the  extraction  of  all  the  contacts  quickly  thru
+ContactsManager.isGetAllContactsFast().
+
+ When  retrieving  all  the  contacts,  notice  that  you  should  probably  not  retrieve  all
+
+the data and should set some fields to false to perform a more efficient query
+
+You can then extract all the contacts using code that looks a bit like this, notice that we use a thread
+
+so the UI won’t be blocked!
+
+507
+
+Form hi = new Form("Contacts", new BoxLayout(BoxLayout.Y_AXIS));
+hi.add(new InfiniteProgress());
+Display.getInstance().scheduleBackgroundTask(() -> {
+    Contact[] contacts = ContactsManager.getAllContacts(true, true, false, true, false, false);
+    Display.getInstance().callSerially(() -> {
+        hi.removeAll();
+        for(Contact c : contacts) {
+            MultiButton mb = new MultiButton(c.getDisplayName());
+            mb.setTextLine2(c.getPrimaryPhoneNumber());
+            hi.add(mb);
+            mb.putClientProperty("id", c.getId());
+        }
+        hi.getContentPane().animateLayout(150);
+    });
+});
+hi.show();
+
+Figure 414. List of contacts
+
+Notice  that  we  didn’t  fetch  the  image  of  the  contact  as  the  performance  of  loading  these  images
+
+might  be  prohibitive.  We  can  enhance  the  code  above  to  include  images  by  using  slightly  more
+
+complex code such as this:
+
+
+
+The  scheduleBackgroundTask  method  is  similar  to  new  Thread()  in  some  regards.  It
+places elements in a queue instead of opening too many threads so it can be good
+
+for non-urgent tasks
+
+508
+
+Form hi = new Form("Contacts", new BoxLayout(BoxLayout.Y_AXIS));
+hi.add(new InfiniteProgress());
+int size = Display.getInstance().convertToPixels(5, true);
+FontImage fi = FontImage.createFixed("" + FontImage.MATERIAL_PERSON, FontImage.getMaterialDesignFont(), 0xff, size,
+size);
+
+Display.getInstance().scheduleBackgroundTask(() -> {
+    Contact[] contacts = ContactsManager.getContacts(true, true, false, true, false, false);
+    Display.getInstance().callSerially(() -> {
+        hi.removeAll();
+        for(Contact c : contacts) {
+            MultiButton mb = new MultiButton(c.getDisplayName());
+            mb.setIcon(fi);
+            mb.setTextLine2(c.getPrimaryPhoneNumber());
+            hi.add(mb);
+            mb.putClientProperty("id", c.getId());
+            Display.getInstance().scheduleBackgroundTask(() -> {
+                Contact cc = ContactsManager.getContactById(c.getId(), false, true, false, false, false);
+                Display.getInstance().callSerially(() -> {
+                    Image photo = cc.getPhoto();
+                    if(photo != null) {
+                        mb.setIcon(photo.fill(size, size));
+                        mb.revalidate();
+                    }
+                });
+            });
+        }
+        hi.getContentPane().animateLayout(150);
+    });
+});
+
+Figure 415. Contacts with the default photos on the simulator, on device these will use actual user photos
+
+when available
+
+
+
+Notice that the code above uses callSerially & scheduleBackgroundTask in a liberal
+nested way. This is important to avoid an EDT violation
+
+You  can  use  createContact(String  firstName,  String  familyName,  String  officePhone,  String
+homePhone,  String  cellPhone,  String  email)  to  add  a  new  contact  and  deleteContact(String  id)  to
+delete a contact.
+
+509
+
+14.3. Localization & Internationalization (L10N & I18N)
+
+Localization  (l10n)  means  adapting  to  a  locale  which  is  more  than  just  translating  to  a  specific
+language  within  environment  e.g.  en_US  !=  en_UK.
+Internationalization (i18n) is the process of creating one application that adapts to all locales and
+
+language  but  also 
+
+to  a  specific 
+
+regional requirements.
+
+Codename One supports automatic localization and seamless internationalization of an application
+
+using the Codename One design tool.
+
+
+
+Although localization is performed in the design tool most features apply to hand
+
+coded  applications  as  well.  The  only  exception  is  the  tool  that  automatically
+
+extracts localizable strings from the GUI.
+
+Figure 416. Localization tool in the Designer
+
+To translate an application you need to use the localization section of the Codename One Designer.
+
+This section features a handy tool to extract localization called Sync With UI, it’s a great tool to get
+
+you started assuming you used the old GUI builder.
+
+Some fields on some components (e.g. Commands) are not added when using "Sync With UI" button.
+But you can add them manually on the localization bundle and they will be automatically localized.
+
+You  can  just  use  the  Property Key  used  in  the  localization  bundle  in  the  Command  name  of  the
+
+form.
+
+You can add additional languages by pressing the Add Locale button.
+
+This generates “bundles” in the resource file which are really just key/value pairs mapping a string
+
+in one language to another language. You can install the bundle using code like this:
+
+UIManager.getInstance().setBundle(res.getL10N("l10n", local));
+
+The device language (as an ISO 639 two letter code) could be retrieved with this:
+
+String local = L10NManager.getInstance().getLanguage();
+
+Once  installed  a  resource  bundle  takes  over  the  UI  and  every  string  set  to  a  label  (and  label  like
+
+510
+
+components)  will  be  automatically  localized  based  on  the  bundle.  You  can  also  use  the  localize
+
+method  of  UIManager  [https://www.codenameone.com/javadoc/com/codename1/ui/plaf/UIManager.html]  to
+
+perform localization on your own:
+
+UIManager.getInstance().localize( "KeyInBundle", "DefaultValue");
+
+The list of available languages in the resource bundle could be retrieved like this. Notice that this a
+
+list that was set by you and doesn’t need to confirm to the ISO language code standards:
+
+Resources res = fetchResourceFile();
+Enumeration locales = res.listL10NLocales( "l10n" );
+
+An exception for localization is the TextField/TextArea components both of which contain user data,
+in those cases the text will not be localized to avoid accidental localization of user input.
+
+You  can  preview  localization  in  the  theme  mode  within  the  Codename  One  designer  by  selecting
+
+Advanced, picking your locale then clicking the theme again.
+
+You can export and import resource bundles as standard Java properties files, CSV
+
+
+
+and  XML.  The  formats  are  pretty  standard  for  most  localization  shops,  the  XML
+
+format Codename One supports is the one used by Android’s string bundles which
+
+means most localization specialists should easily localize it
+
+The resource bundle is just a map between keys and values e.g. the code below displays "This Label
+is  localized"  on  the  Label  with  the  hardcoded  resource  bundle.  It  would  work  the  same  with  a
+resource bundle loaded from a resource file:
+
+Form hi = new Form("L10N", new BoxLayout(BoxLayout.Y_AXIS));
+HashMap<String, String> resourceBudle = new HashMap<String, String>();
+resourceBudle.put("Localize", "This Label is localized");
+UIManager.getInstance().setBundle(resourceBudle);
+hi.add(new Label("Localize"));
+hi.show();
+
+Figure 417. Localized label
+
+14.3.1. Localization Manager
+
+The  L10NManager 
+
+[https://www.codenameone.com/javadoc/com/codename1/l10n/L10NManager.html]  class
+
+includes a multitude of features useful for common localization tasks.
+
+It allows formatting numbers/dates & time based on platform locale. It also provides a great deal of
+
+the  information  you  need  such  as  the  language/locale  information  you  need  to  pick  the  proper
+
+511
+
+resource bundle.
+
+Form hi = new Form("L10N", new TableLayout(16, 2));
+L10NManager l10n = L10NManager.getInstance();
+hi.add("format(double)").add(l10n.format(11.11)).
+    add("format(int)").add(l10n.format(33)).
+    add("formatCurrency").add(l10n.formatCurrency(53.267)).
+    add("formatDateLongStyle").add(l10n.formatDateLongStyle(new Date())).
+    add("formatDateShortStyle").add(l10n.formatDateShortStyle(new Date())).
+    add("formatDateTime").add(l10n.formatDateTime(new Date())).
+    add("formatDateTimeMedium").add(l10n.formatDateTimeMedium(new Date())).
+    add("formatDateTimeShort").add(l10n.formatDateTimeShort(new Date())).
+    add("getCurrencySymbol").add(l10n.getCurrencySymbol()).
+    add("getLanguage").add(l10n.getLanguage()).
+    add("getLocale").add(l10n.getLocale()).
+    add("isRTLLocale").add("" + l10n.isRTLLocale()).
+    add("parseCurrency").add(l10n.formatCurrency(l10n.parseCurrency("33.77$"))).
+    add("parseDouble").add(l10n.format(l10n.parseDouble("34.35"))).
+    add("parseInt").add(l10n.format(l10n.parseInt("56"))).
+    add("parseLong").add("" + l10n.parseLong("4444444"));
+hi.show();
+
+Figure 418. Localization formatting/parsing and information
+
+14.3.2. RTL/Bidi
+
+RTL  stands  for  right  to  left,  in  the  world  of  internationalization  it  refers  to  languages  that  are
+
+written from right to left (Arabic, Hebrew, Syriac, Thaana).
+
+Most western languages are written from left to right (LTR), however some languages are written
+
+from right to left (RTL) speakers of these languages expect the UI to flow in the opposite direction
+
+otherwise it seems weird just like reading this word would be to most English speakers: "drieW".
+
+The  problem  posed  by  RTL  languages  is  known  as  BiDi  (Bi-directional)  and  not  as  RTL  since  the
+
+"true" problem isn’t the reversal of the writing/UI but rather the mixing of RTL and LTR together.
+
+E.g. numbers are always written from left to right (just like in English) so in an RTL language the
+
+direction is from right to left and once we reach a number or English text embedded in the middle
+
+of the sentence (such as a name) the direction switches for a duration and is later restored.
+
+512
+
+The  main  issue  in  the  Codename  One  world  is  in  the  layouts,  which  need  to  reverse  on  the  fly.
+Codename One supports this via an RTL flag on all components that is derived from the global RTL
+flag in UIManager [https://www.codenameone.com/javadoc/com/codename1/ui/plaf/UIManager.html].
+
+Resource  bundles  can  also  include  special  case  constant  @rtl,  which  indicates  if  a  language  is
+
+written from right to left. This allows everything to automatically reverse.
+
+When in RTL mode the UI will be the exact mirror so WEST will become EAST, RIGHT will become LEFT
+and this would be true for paddings/margins as well.
+
+If you have a special case where you don’t want this behavior you will need to wrap it with an isRTL
+check.  You  can  also  use  setRTL  on  a  per  Component  basis  to  disable  RTL  behavior  for  a  specific
+Component.
+
+
+
+Most  UI  API’s  have  special  cases  for  BiDi  instead  of  applying  it  globally  e.g.  AWT
+introduced  constants  such  as  LEADING  instead  of  making  WEST  mean  the  opposite
+direction.  We  think  that  was  a  mistake  since  the  cases  where  you  wouldn’t  want
+
+the behavior of automatic reversal are quite rare.
+
+Codename One’s support for bidi includes the following components:
+
+• Bidi algorithm - allows converting between logical to visual representation for rendering
+
+• Global RTL flag - default flag for the entire application indicating the UI should flow from right
+
+to left
+
+• Individual RTL flag - flag indicating that the specific component/container should be presented
+
+as an RTL/LTR component (e.g. for displaying English elements within a RTL UI).
+
+• RTL text field input
+
+Most  of  Codename  One’s  RTL 
+
+support 
+
+is  under 
+
+the  hood, 
+
+the  LookAndFeel
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/plaf/LookAndFeel.html]  global  RTL  flag  can  be
+
+enabled using:
+
+UIManager.getInstance().getLookAndFeel().setRTL(true);
+
+Once RTL is activated all positions in Codename One become reversed and the UI becomes a mirror
+of  itself.  E.g.  Adding  a  Toolbar  command  to  the  left  will  actually  make  it  appear  on  the  right.
+Padding on the left becomes padding on the right. The scroll moves to the left etc.
+
+This applies to the layout managers (except for group layout) and most components. Bidi is mostly
+
+seamless in Codename One but a developer still needs to be aware that his UI might be mirrored for
+
+these cases.
+
+14.4. Location - GPS
+
+The Location [https://www.codenameone.com/javadoc/com/codename1/location/Location.html] API allows us to
+
+track changes in device location or the current user position.
+
+513
+
+
+
+The  Simulator  includes  a  Location Simulation  tool  that  you  can  launch  to
+
+determine the current position of the simulator and debug location events
+
+The  most  basic  usage  for  the  API  allows  us  to  just  fetch  a  device  Location,  notice  that  this  API  is
+
+blocking and can take a while to return:
+
+Location position = LocationManager.getLocationManager().getCurrentLocationSync();
+
+
+
+In  order  for  location  to  work  on  iOS  you  MUST  define  the  build  hint
+ios.locationUsageDescription  and  describe  why  your  application  needs  access  to
+location. Otherwise you won’t get location updates!
+
+The getCurrentLocationSync() method is very good for cases where you only need to fetch a current
+location  once  and  not  repeatedly  query  location.  It  activates  the  GPS  then  turns  it  off  to  avoid
+
+excessive battery usage. However, if an application needs to track motion or position over time it
+
+should use the location listener API to track location as such:
+
+
+
+Notice  that  there  is  a  method  called  getCurrentLocation()  which  will  return  the
+current state immediately and might not be accurate for some cases.
+
+public MyListener implements LocationListener {
+    public void locationUpdated(Location location) {
+        // update UI etc.
+    }
+
+    public void providerStateChanged(int newState) {
+        // handle status changes/errors appropriately
+    }
+}
+LocationManager.getLocationManager().setLocationListener(new MyListener());
+
+
+
+On Android location maps to low level API’s if you disable the usage of Google Play
+
+Services.  By  default  location  should  perform  well  if  you  leave  the  Google  Play
+
+Services on
+
+14.4.1. Location In The Background - Geofencing
+
+Polling  location  is  generally  expensive  and  requires  a  special  permission  on  iOS.  Its  also
+
+implemented  rather  differently  both  in  iOS  and  Android.  Both  platforms  place  restrictions  on  the
+
+location API usage in the background.
+
+Because  of  the  nature  of  background  location  the  API  is  non-trivial.  It  starts  with  the  venerable
+LocationManager 
+setBackgroundLocationListener.
+
+standard  API 
+
+instead 
+
+using 
+
+need 
+
+you 
+
+but 
+
+the 
+
+use
+
+of 
+
+to 
+
+Instead  of  passing  a  LocationListener  instance  you  need  to  pass  a  Class  object  instance.  This  is
+
+514
+
+important because background location might be invoked when the app isn’t running and an object
+
+would need to be allocated.
+
+Notice that you should NOT perform long operations in the background listener callback. IOS wake-
+
+up time is limited to approximately 10 seconds and the app could get killed if it exceeds that time
+
+slice.
+
+Notice  that  the  listener  can  also  send  events  when  the  app  is  in  the  foreground,  therefore  it  is
+
+recommended  to  check  the  app  state  before  deciding  how  to  process  this  event.  You  can  use
+Display.isMinimized() to determine if the app is currently running or in the background.
+
+When implementing this make sure that:
+
+• The class passed to the API is a public class in the global scope. Not an inner class or anything
+
+like that!
+
+• The class has a public no-argument constructor
+
+• You  need 
+
+to  pass 
+
+it 
+
+as 
+
+a 
+
+class 
+
+literal 
+
+e.g. 
+
+MyClassName.class.  Don’t  use
+
+Class.forName("my.package.MyClassName")!
+Class  names  are  problematic  since  device  builds  are  obfuscated,  you  should  only  use  literals
+
+which the obfuscator detects and handles correctly.
+
+The following code demonstrates usage of the GeoFence API:
+
+Geofence gf = new Geofence("test", loc, 100, 100000);
+
+LocationManager.getLocationManager()
+        .addGeoFencing(GeofenceListenerImpl.class, gf);
+
+public class GeofenceListenerImpl implements GeofenceListener {
+    @Override
+    public void onExit(String id) {
+    }
+
+    @Override
+    public void onEntered(String id) {
+        if(Display.getInstance().isMinimized()) {
+            Display.getInstance().callSerially(() -> {
+                Dialog.show("Welcome", "Thanks for arriving", "OK", null);
+            });
+        } else {
+            LocalNotification ln = new LocalNotification();
+            ln.setAlertTitle("Welcome");
+            ln.setAlertBody("Thanks for arriving!");
+            Display.getInstance().scheduleLocalNotification(ln, 10, false);
+        }
+    }
+}
+
+515
+
+14.5. Background Music Playback
+
+Codename One supports playing music in the background (e.g. when the app is minimized) which is
+
+quite useful for developers building a music player style application.
+
+This  support  isn’t  totally  portable  since  the  Android  and  iOS  approaches  for  background  music
+
+playback  differ  a  great  deal.  To  get  this  to  work  on  Android  you  need  to  use  the  API:
+MediaManager.createBackgroundMedia().
+
+You should use that API when you want to create a media stream that will work even when your
+
+app is minimized.
+
+For iOS you will need to use a special build hint: ios.background_modes=music.
+
+Which  should  allow  background  playback  of  music  on  iOS  and  would  work  with  the
+createBackgroundMedia() method.
+
+14.6. Capture - Photos, Video, Audio
+
+The capture API allows us to use the camera to capture photographs or the microphone to capture
+
+audio. It even includes an API for video capture.
+
+The API itself couldn’t be simpler:
+
+String filePath = Capture.capturePhoto();
+
+Just  captures  and  returns  a  path  to  a  photo  you  can  either  open  it  using  the  Image
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/Image.html] class or save it somewhere.
+
+ The  returned  file  is  a  temporary  file,  you  shouldn’t  store  a  reference  to  it  and
+
+instead copy it locally or work with the Image object
+
+E.g. you can copy the Image to Storage using:
+
+String filePath = Capture.capturePhoto();
+if(filePath != null) {
+    Util.copy(FileSystemStorage.getInstance().openInputStream(filePath),
+Storage.getInstance().createOutputStream(myImageFileName));
+}
+
+
+
+When running on the simulator the Capture API opens a file chooser API instead of
+physically  capturing  the  data.  This  makes  debugging  device  or  situation  specific
+
+issues simpler
+
+We can capture an image from the camera using an API like this:
+
+516
+
+Form hi = new Form("Capture", new BorderLayout());
+hi.setToolbar(new Toolbar());
+Style s = UIManager.getInstance().getComponentStyle("Title");
+FontImage icon = FontImage.createMaterial(FontImage.MATERIAL_CAMERA, s);
+
+ImageViewer iv = new ImageViewer(icon);
+
+hi.getToolbar().addCommandToRightBar("", icon, (ev) -> {
+    String filePath = Capture.capturePhoto();
+    if(filePath != null) {
+        try {
+            DefaultListModel<Image> m = (DefaultListModel<Image>)iv.getImageList();
+            Image img = Image.createImage(filePath);
+            if(m == null) {
+                m = new DefaultListModel<>(img);
+                iv.setImageList(m);
+                iv.setImage(img);
+            } else {
+                m.addItem(img);
+            }
+            m.setSelectedIndex(m.getSize() - 1);
+        } catch(IOException err) {
+            Log.e(err);
+        }
+    }
+});
+
+hi.add(BorderLayout.CENTER, iv);
+hi.show();
+
+Figure 419. Captured photos previewed in the ImageViewer
+
+We  demonstrate  video  capture  in  the  MediaManager  section  [https://www.codenameone.com/manual/
+
+components.html#mediamanager-section].
+
+The  sample  below  captures  audio  recordings  (using  the  'Capture'  API)  and  copies  them  locally
+
+under unique names. It also demonstrates the storage and organization of captured audio:
+
+517
+
+Form hi = new Form("Capture", BoxLayout.y());
+hi.setToolbar(new Toolbar());
+Style s = UIManager.getInstance().getComponentStyle("Title");
+FontImage icon = FontImage.createMaterial(FontImage.MATERIAL_MIC, s);
+
+FileSystemStorage fs = FileSystemStorage.getInstance();
+String recordingsDir = fs.getAppHomePath() + "recordings/";
+fs.mkdir(recordingsDir);
+try {
+    for(String file : fs.listFiles(recordingsDir)) {
+        MultiButton mb = new MultiButton(file.substring(file.lastIndexOf("/") + 1));
+        mb.addActionListener((e) -> {
+            try {
+                Media m = MediaManager.createMedia(recordingsDir + file, false);
+                m.play();
+            } catch(IOException err) {
+                Log.e(err);
+            }
+        });
+        hi.add(mb);
+    }
+
+    hi.getToolbar().addCommandToRightBar("", icon, (ev) -> {
+        try {
+            String file = Capture.captureAudio();
+            if(file != null) {
+                SimpleDateFormat sd = new SimpleDateFormat("yyyy-MMM-dd-kk-mm");
+                String fileName =sd.format(new Date());
+                String filePath = recordingsDir + fileName;
+                Util.copy(fs.openInputStream(file), fs.openOutputStream(filePath));
+                MultiButton mb = new MultiButton(fileName);
+                mb.addActionListener((e) -> {
+                    try {
+                        Media m = MediaManager.createMedia(filePath, false);
+                        m.play();
+                    } catch(IOException err) {
+                        Log.e(err);
+                    }
+                });
+                hi.add(mb);
+                hi.revalidate();
+            }
+        } catch(IOException err) {
+            Log.e(err);
+        }
+    });
+} catch(IOException err) {
+    Log.e(err);
+}
+hi.show();
+
+518
+
+Figure 420. Captured recordings in the demo
+
+Alternatively, you can use the Media, MediaManager and MediaRecorderBuilder APIs to capture audio,
+as a more customizable approach than using the Capture API:
+
+    private static final EasyThread countTime = EasyThread.start("countTime");
+
+    public void start() {
+        if (current != null) {
+            current.show();
+            return;
+        }
+        Form hi = new Form("Recording audio", BoxLayout.y());
+        hi.add(new SpanLabel("Example of recording and playback audio using the Media, MediaManager and
+MediaRecorderBuilder APIs"));
+        hi.add(recordAudio((String filePath) -> {
+            ToastBar.showInfoMessage("Do something with the recorded audio file: " + filePath);
+        }));
+        hi.show();
+    }
+
+    public static Component recordAudio(OnComplete<String> callback) {
+        try {
+            // mime types supported by Android: audio/amr, audio/aac, audio/mp4
+            // mime types supported by iOS: audio/mp4, audio/aac, audio/m4a
+            // mime type supported by Simulator: audio/wav
+            // more info: https://www.iana.org/assignments/media-types/media-types.xhtml
+
+            List<String> availableMimetypes = Arrays.asList(MediaManager.getAvailableRecordingMimeTypes());
+            String mimetype;
+            if (availableMimetypes.contains("audio/aac")) {
+                // Android and iOS
+                mimetype = "audio/aac";
+            } else if (availableMimetypes.contains("audio/wav")) {
+                // Simulator
+                mimetype = "audio/wav";
+            } else {
+                // others
+                mimetype = availableMimetypes.get(0);
+            }
+            String fileName = "audioExample." + mimetype.substring(mimetype.indexOf("/") + 1);
+            String output = FileSystemStorage.getInstance().getAppHomePath() + "/" + fileName;
+            // https://tritondigitalcommunity.force.com/s/article/Choosing-Audio-Bitrate-Settings
+            MediaRecorderBuilder options = new MediaRecorderBuilder()
+                    .mimeType(mimetype)
+                    .path(output)
+                    .bitRate(64000)
+                    .samplingRate(44100);
+            Media[] microphone = {MediaManager.createMediaRecorder(options)};
+            Media[] speaker = {null};
+
+519
+
+            Container recordingUI = new Container(BoxLayout.y());
+            Label time = new Label("0:00");
+            Button recordBtn = new Button("", FontImage.MATERIAL_FIBER_MANUAL_RECORD, "Button");
+            Button playBtn = new Button("", FontImage.MATERIAL_PLAY_ARROW, "Button");
+            Button stopBtn = new Button("", FontImage.MATERIAL_STOP, "Button");
+            Button sendBtn = new Button("Send");
+            sendBtn.setEnabled(false);
+            Container buttons = GridLayout.encloseIn(3, recordBtn, stopBtn, sendBtn);
+            recordingUI.addAll(FlowLayout.encloseCenter(time), FlowLayout.encloseCenter(buttons));
+
+            recordBtn.addActionListener(l -> {
+                try {
+                    // every time we have to create a new instance of Media to make it working correctly (as reported in
+the Javadoc)
+                    microphone[0] = MediaManager.createMediaRecorder(options);
+                    if (speaker[0] != null && speaker[0].isPlaying()) {
+                        return; // do nothing if the audio is currently recorded or played
+                    }
+                    recordBtn.setEnabled(false);
+                    sendBtn.setEnabled(true);
+                    Log.p("Audio recording started", Log.DEBUG);
+                    if (buttons.contains(playBtn)) {
+                        buttons.replace(playBtn, stopBtn, CommonTransitions.createEmpty());
+                        buttons.revalidateWithAnimationSafety();
+                    }
+                    if (speaker[0] != null) {
+                        speaker[0].pause();
+                    }
+
+                    microphone[0].play();
+                    startWatch(time);
+                } catch (IOException ex) {
+                    Log.p("ERROR recording audio", Log.ERROR);
+                    Log.e(ex);
+                }
+            });
+
+            stopBtn.addActionListener(l -> {
+                if (!microphone[0].isPlaying() && (speaker[0] == null || !speaker[0].isPlaying())) {
+                    return; // do nothing if the audio is NOT currently recorded or played
+                }
+                recordBtn.setEnabled(true);
+                sendBtn.setEnabled(true);
+                Log.p("Audio recording stopped");
+                if (microphone[0].isPlaying()) {
+                    microphone[0].pause();
+                } else if (speaker[0] != null) {
+                    speaker[0].pause();
+                } else {
+                    return;
+                }
+                stopWatch(time);
+                if (buttons.contains(stopBtn)) {
+                    buttons.replace(stopBtn, playBtn, CommonTransitions.createEmpty());
+                    buttons.revalidateWithAnimationSafety();
+                }
+                if (FileSystemStorage.getInstance().exists(output)) {
+                    Log.p("Audio saved to: " + output);
+                } else {
+                    ToastBar.showErrorMessage("Error recording audio", 5000);
+                    Log.p("ERROR SAVING AUDIO");
+                }
+            });
+
+            playBtn.addActionListener(l -> {
+                // every time we have to create a new instance of Media to make it working correctly (as reported in the
+Javadoc)
+
+520
+
+                if (microphone[0].isPlaying() || (speaker[0] != null && speaker[0].isPlaying())) {
+                    return; // do nothing if the audio is currently recorded or played
+                }
+                recordBtn.setEnabled(false);
+                sendBtn.setEnabled(true);
+                if (buttons.contains(playBtn)) {
+                    buttons.replace(playBtn, stopBtn, CommonTransitions.createEmpty());
+                    buttons.revalidateWithAnimationSafety();
+                }
+                if (FileSystemStorage.getInstance().exists(output)) {
+                    try {
+                        speaker[0] = MediaManager.createMedia(output, false, () -> {
+                            // callback on completation
+                            recordBtn.setEnabled(true);
+                            if (speaker[0].isPlaying()) {
+                                speaker[0].pause();
+                            }
+                            stopWatch(time);
+                            if (buttons.contains(stopBtn)) {
+                                buttons.replace(stopBtn, playBtn, CommonTransitions.createEmpty());
+                                buttons.revalidateWithAnimationSafety();
+                            }
+                        });
+                        speaker[0].play();
+                        startWatch(time);
+                    } catch (IOException ex) {
+                        Log.p("ERROR playing audio", Log.ERROR);
+                        Log.e(ex);
+                    }
+                }
+            });
+
+            sendBtn.addActionListener(l -> {
+                if (microphone[0].isPlaying()) {
+                    microphone[0].pause();
+                }
+                if (speaker[0] != null && speaker[0].isPlaying()) {
+                    speaker[0].pause();
+                }
+                if (buttons.contains(stopBtn)) {
+                    buttons.replace(stopBtn, playBtn, CommonTransitions.createEmpty());
+                    buttons.revalidateWithAnimationSafety();
+                }
+                stopWatch(time);
+                recordBtn.setEnabled(true);
+
+                callback.completed(output);
+            });
+
+            return FlowLayout.encloseCenter(recordingUI);
+
+        } catch (IOException ex) {
+            Log.p("ERROR recording audio", Log.ERROR);
+            Log.e(ex);
+            return new Label("Error recording audio");
+        }
+
+    }
+
+    private static void startWatch(Label label) {
+        label.putClientProperty("stopTime", Boolean.FALSE);
+        countTime.run(() -> {
+            long startTime = System.currentTimeMillis();
+            while (label.getClientProperty("stopTime") == Boolean.FALSE) {
+                // the sleep is every 200ms instead of 1000ms to make the app more reactive when stop is tapped
+                Util.sleep(200);
+                int seconds = (int) ((System.currentTimeMillis() - startTime) / 1000);
+
+521
+
+                String min = (seconds / 60) + "";
+                String sec = (seconds % 60) + "";
+                if (sec.length() == 1) {
+                    sec = "0" + sec;
+                }
+                String newTime = min + ":" + sec;
+                if (!label.getText().equals(newTime)) {
+                    CN.callSerially(() -> {
+                        label.setText(newTime);
+                        if (label.getParent() != null) {
+                            label.getParent().revalidateWithAnimationSafety();
+                        }
+                    });
+                }
+            }
+        });
+    }
+
+    private static void stopWatch(Label label) {
+        label.putClientProperty("stopTime", Boolean.TRUE);
+    }
+
+[Example of recording and playback audio using Media API] | https://user-
+
+522
+
+images.githubusercontent.com/1997316/78480286-02131b00-7735-11ea-8a70-5ca5512e7d92.png
+
+14.6.1. Capture Asynchronous API
+
+The  Capture  API  also  includes  a  callback  based  API  that  uses  the  ActionListener  interface  to
+implement capture. E.g. we can adapt the previous sample to use this API as such:
+
+hi.getToolbar().addCommandToRightBar("", icon, (ev) -> {
+    Capture.capturePhoto((e) -> {
+        if(e != null && e.getSource() != null) {
+            try {
+                DefaultListModel<Image> m = (DefaultListModel<Image>)iv.getImageList();
+                Image img = Image.createImage((String)e.getSource());
+                if(m == null) {
+                    m = new DefaultListModel<>(img);
+                    iv.setImageList(m);
+                    iv.setImage(img);
+                } else {
+                    m.addItem(img);
+                }
+                m.setSelectedIndex(m.getSize() - 1);
+            } catch(IOException err) {
+                Log.e(err);
+            }
+        }
+    });
+});
+
+14.7. Gallery
+
+The gallery API allows picking an image and/or video from the cameras gallery (camera roll).
+
+
+
+Like  the  Capture  API  the  image  returned  is  a  temporary  image  that  should  be
+copied  locally,  this  is  due  to  device  restrictions  that  don’t  allow  direct
+
+modifications of the gallery
+
+We can adapt the Capture sample above to use the gallery as such:
+
+523
+
+Form hi = new Form("Capture", new BorderLayout());
+hi.setToolbar(new Toolbar());
+Style s = UIManager.getInstance().getComponentStyle("Title");
+FontImage icon = FontImage.createMaterial(FontImage.MATERIAL_CAMERA, s);
+
+ImageViewer iv = new ImageViewer(icon);
+
+hi.getToolbar().addCommandToRightBar("", icon, (ev) -> {
+    Display.getInstance().openGallery((e) -> {
+        if(e != null && e.getSource() != null) {
+            try {
+                DefaultListModel<Image> m = (DefaultListModel<Image>)iv.getImageList();
+                Image img = Image.createImage((String)e.getSource());
+                if(m == null) {
+                    m = new DefaultListModel<>(img);
+                    iv.setImageList(m);
+                    iv.setImage(img);
+                } else {
+                    m.addItem(img);
+                }
+                m.setSelectedIndex(m.getSize() - 1);
+            } catch(IOException err) {
+                Log.e(err);
+            }
+        }
+    }, Display.GALLERY_IMAGE);
+});
+
+hi.add(BorderLayout.CENTER, iv);
+
+
+
+There  is  no  need  for  a  screenshot  as  it  will  look  identical  to  the  capture  image
+
+screenshot above
+
+The  last  value  is  the  type  of  content  picked  which  can  be  one  of:  Display.GALLERY_ALL,
+Display.GALLERY_VIDEO or Display.GALLERY_IMAGE.
+
+14.8. Analytics Integration
+
+One  of  the  features  in  Codename  One  is  builtin  support  for  analytic  instrumentation.  Currently
+
+Codename  One  has  builtin  support  for  Google  Analytics  [https://www.google.com/analytics/],  which
+
+provides reasonable enough statistics of application usage.
+
+Analytics is pretty seamless for the old GUI builder since navigation occurs via the Codename One
+
+API  and  can  be  logged  without  developer  interaction.  However,  to  begin  the  instrumentation  one
+
+needs to add the line:
+
+524
+
+AnalyticsService.setAppsMode(true);
+AnalyticsService.init(agent, domain);
+
+To get the value for the agent value just create a Google Analytics account and add a domain, then
+
+copy  and  paste  the  string  that  looks  something  like  UA-99999999-8  from  the  console  to  the  agent
+
+string. Once this is in place you should start receiving statistic events for the application.
+
+If  your  application  is  not  a  GUI  builder  application  or  you  would  like  to  send  more  detailed  data
+you can use the Analytics.visit() method to indicate that you are entering a specific page.
+
+14.8.1. Application Level Analytics
+
+In 2013 Google introduced an improved application level analytics API that is specifically built for
+
+mobile apps. However, it requires a slightly different API usage. You can activate this specific mode
+by invoking setAppsMode(true).
+
+When using this mode you can also report errors and crashes to the Google analytics server using
+the sendCrashReport(Throwable, String message, boolean fatal) method.
+
+We generally recommend using this mode and setting up an apps analytics account as the results
+
+are more refined.
+
+14.8.2. Overriding The Analytics Implementation
+
+The Analytics API can also be enhanced to support any other form of analytics solution of your own
+choosing by deriving the AnalyticsService class.
+
+This  allows  you  to  integrate  with  any  3rd  party  via  native  or  otherwise  by  overriding  methods  in
+the AnalyticsService class then invoking:
+
+AnalyticsService.init(new MyAnalyticsServiceSubclass());
+
+Notice that this removes the need to invoke the other init method or setAppsMode(boolean).
+
+14.9. Native Facebook Support
+
+
+
+Check 
+
+out 
+
+the 
+
+ShareButton 
+
+section 
+
+[https://www.codenameone.com/manual/
+
+components.html#sharebutton-section] it might be enough for most of your needs.
+
+Codename  One  supports  Facebooks  Oauth2  [https://www.codenameone.com/javadoc/com/codename1/io/
+
+Oauth2.html] login and Facebooks single sign on for iOS and Android.
+
+14.9.1. Getting Started - Web Setup
+
+To  get  started  first  you  will  need  to  create  a  facebook  app  on  the  Facebook  developer  portal  at
+
+https://developers.facebook.com/apps/
+
+525
+
+Figure 421. Create New App
+
+You need to repeat the process for web, Android & iOS (web is used by the simulator):
+
+Figure 422. Pick Platform
+
+For the first platform you need to enter the app name:
+
+Figure 423. Pick app name
+
+And provide some basic details:
+
+Figure 424. Basic details for the app
+
+For  iOS  we  need  the  bundle  ID  which  is  the  exact  same  thing  we  used  in  the  Google+  login  to
+
+identify the iOS app its effectively your package name:
+
+Figure 425. iOS specific basic details
+
+You should end up with something that looks like this:
+
+526
+
+Figure 426. Finished Facebook app
+
+The Android process is pretty similar but in this case we need the activity name too.
+
+
+
+The  activity  name  should  match  the  main  class  name  followed  by  the  word  Stub
+(uppercase  s).  E.g.  for  the  main  class  SociallChat  we  would  use  SocialChatStub  as
+the activity name
+
+Figure 427. Android Activity definition
+
+To  build  the  native  Android  app  we  must  make  sure  that  we  setup  the  keystore  correctly  for  our
+
+application. If you don’t have an Android certificate you can use the visual wizard (in the Android
+
+section in the project preferences the button labeled Generate) or use the command line:
+
+keytool -genkey -keystore Keystore.ks -alias [alias_name] -keyalg RSA -keysize 2048 -validity 15000 -dname "CN=[full
+name], OU=[ou], O=[comp], L=[City], S=[State], C=[Country Code]" -storepass [password] -keypass [password]
+
+
+
+You  can  reuse  the  certificate  in  all  your  apps,  some  developers  like  having  a
+
+different certificate for every app. This is like having one master key for all your
+
+doors, or a huge keyring filled with keys.
+
+With  the  certificate  we  need  an  SHA1  key  to  further  authenticate  us  to  Facebook  and  we  do  this
+
+using the keytool command line on Linux/Mac:
+
+keytool -exportcert -alias (your_keystore_alias) -keystore (path_to_your_keystore) | openssl sha1 -binary | openssl
+base64
+
+And on Windows:
+
+keytool -exportcert -alias androiddebugkey -keystore %HOMEPATH%\.android\debug.keystore | openssl sha1 -binary | openssl
+base64
+
+You  can  read  more  about  it  on  the  Facebook  guide  here  [https://developers.facebook.com/docs/android/
+
+527
+
+getting-started].
+
+Figure 428. Hash generation process, notice the command lines are listed as part of the web wizard
+
+Lastly you need to publish the Facebook app by flipping the switch in the apps "Status & Review"
+
+page as such:
+
+Figure 429. Without flipping the switch the app won’t "appear"
+
+14.9.2. IDE Setup
+
+We now need to set some important build hints in the project so it will work correctly. To set the
+
+build  hints  just  right  click  the  project  select  project  properties  and  in  the  Codename  One  section
+
+pick the second tab. Add this entry into the table:
+
+facebook.appId=...
+
+The app ID will be visible in your Facebook app page in the top left position.
+
+14.9.3. The Code
+
+To bind your mobile app into the Facebook app you can use the following code:
+
+528
+
+Login fb = FacebookConnect.getInstance();
+
+fb.setClientId("9999999");
+fb.setRedirectURI("http://www.youruri.com/");
+fb.setClientSecret("-------");
+
+// Sets a LoginCallback listener
+fb.setCallback(new LoginCallback() {
+    public void loginSuccessful() {
+        // we can now start fetching stuff from Facebook!
+    }
+
+    public void loginFailed(String errorMessage) {}
+});
+
+// trigger the login if not already logged in
+if(!fb.isUserLoggedIn()){
+    fb.doLogin();
+} else {
+    // get the token and now you can query the Facebook API
+    String token = fb.getAccessToken().getToken();
+    // ...
+}
+
+
+
+All of these values are from the web version of the app!
+
+They are only used in the simulator and on "unsupported" platforms as a fallback.
+
+Android and iOS will use the native login
+
+14.9.4. Facebook Publish Permissions
+
+In  order  to  post  something  to  Facebook  you  need  to  request  a  write  permission,  you  can  only  do
+
+write operations within the callback which is invoked when the user approves the permission.
+
+You can prompt the user for publish permissions by using this code on a logged in FacebookConnect
+
+[https://www.codenameone.com/javadoc/com/codename1/social/FacebookConnect.html]:
+
+FacebookConnect.getInstance()askPublishPermissions(new LoginCallback() {
+    public void loginSuccessful() {
+         // do something...
+    }
+    public void loginFailed(String errorMessage) {
+        // show error or just ignore
+    }
+});
+
+
+
+Notice that this won’t always prompt the user, but its required to verify that your
+
+token is valid for writing.
+
+529
+
+14.10. Google Sign-In
+
+Google  Login  is  a  bit  of  a  moving  target,  as  they  are  regularly  creating  new  APIs  and  deprecating
+
+old ones. Codename One 3.7 and earlier used the Google+ API for sign-in, which is now deprecated.
+
+While this API still works, it is no longer useful on iOS as it redirects to Safari to perform login, and
+
+Apple no longer allows this practice.
+
+The new, approved API is called Google Sign-In. Rather than using Safari to handle login (on iOS), it
+
+uses an embedded web view, which is permitted by Apple.
+
+The process involves four parts:
+
+1. Section 14.10.1, “iOS Setup Instructions”
+
+2. Section 14.10.2, “Android Setup Instructions”
+
+3. Section 14.10.3, “OAuth Setup (Simulator and REST API Access)”
+
+4. Section 14.10.5, “The Code”
+
+OAuth Setup is required for using Google Sign-In in the simulator, and for accessing other Google
+
+APIs in Android.
+
+14.10.1. iOS Setup Instructions
+
+Short Version
+
+Go  to  the  Google  Developer  Portal  [https://developers.google.com/mobile/add],  follow  the  steps  to  create
+
+an App, and enable Google Sign-In, and download the GoogleService-Info.plist file. Then copy this
+
+file into your project’s native/ios directory.
+
+Long Version
+
+Point your browser to this page [https://developers.google.com/mobile/add].
+
+Figure 430. Set up mobile app form on Google
+
+Click on the "Getting Started" button.
+
+530
+
+Figure 431. Getting started button
+
+Then click "iOS App"
+
+Figure 432. Pick a platform
+
+Now enter an app name and the bundle ID for your app on the form below. The app name doesn’t
+
+necessary  need  to  match  your  app’s  name,  but  the  bundle  ID  should  match  the  package  name  of
+
+your app.
+
+Figure 433. Create or Choose App
+
+Select your country, and then click the "Choose and Configure Services" button.
+
+Figure 434. Choose and Configure Services
+
+You’ll be presented with the following screen
+
+531
+
+Figure 435. Choose and Configure Services form
+
+Click on "Google Sign-In".
+
+Then press the "Enable Google Sign-In" button that appears.
+
+Figure 436. Enable Google Sign-In
+
+You  should  then  be  presented  with  another  button  to  "Generate  Configuration  Files"  as  shown
+
+below
+
+Figure 437. Generate Configuration Files
+
+Finally you will be presented with a button to "Download GoogleServices-Info.plist".
+
+Figure 438. Download GoogleService-Info.plist file
+
+Press this button to download the GoogleService-Info.plist file. Then copy this into the "native/ios"
+
+directory of your Codename One project.
+
+Figure 439. Project file structure after placing the GoogleService-Info.plist into the native/ios directory
+
+At this point, your app should be able to use Google Sign-In. Notice that we don’t require any build
+
+hints. Only that the GoogleService-Info.plist file is added to the project’s native/ios directory.
+
+532
+
+14.10.2. Android Setup Instructions
+
+Short Version
+
+Go  to  the  Google  Developer  Portal  [https://developers.google.com/mobile/add],  follow  the  steps  to  create
+
+an App, and enable Google Sign-In, and download the google-services.json file. Then copy this file
+
+into your project’s native/android directory.
+
+Long Version
+
+Point your browser to this page [https://developers.google.com/mobile/add].
+
+Figure 440. Set up mobile app form on Google
+
+Click on the "Getting Started" button.
+
+Then click "Android App"
+
+Now enter an app name and the platform for your app on the form below. The app name doesn’t
+
+necessary need to match your app’s name, but the package name should match the package name
+
+of your app.
+
+Figure 441. Create or Choose App
+
+Select your country, and then click the "Choose and Configure Services" button.
+
+533
+
+Figure 442. Choose and Configure Services
+
+Click on "Google Sign-In"
+
+Then you’ll be presented with a field to enter the Android Signing Certificate SHA-1.
+
+Figure 443. Android Signing Certifiate SHA-1
+
+The  value  that  you  enter  here  should  be  obtained  from  the  certificate  that  you  are  using  to  build
+
+your app. You an use the keytool app that is distributed with the JDK to extract this value
+
+$ keytool -exportcert -alias myAlias -keystore /path/to/my-keystore.keystore -list -v
+
+The snippet above assumes that your keystore is located at /path/to/my-keystore.keystore, and the
+certificate alias is "myAlias". You’ll be prompted to enter the password for your keystore, then the
+
+output will look something like:
+
+534
+
+Alias name: myAlias
+Creation date: 22-Jan-2014
+Entry type: PrivateKeyEntry
+Certificate chain length: 1
+Certificate[1]:
+Owner: CN=My Own Company Corp., OU=, O=, L=Vancouver, ST=British Columbia, C=CA
+Issuer: CN=My Own Company Corp., OU=, O=, L=Vancouver, ST=British Columbia, C=CA
+Serial number: 56b2fd42
+Valid from: Wed Jan 22 12:23:50 PST 2014 until: Tue Feb 16 12:23:50 PST 2055
+Certificate fingerprints:
+     MD5:  98:F9:34:5B:B5:1A:14:2D:3C:5D:F4:92:D2:73:30:6B
+     SHA1: 76:BA:AA:11:A9:22:42:24:93:82:6D:33:7E:48:BC:AF:45:4D:79:B0
+     SHA256: 3D:04:33:67:6A:13:FF:4F:EE:E8:C9:7D:D2:CC:DF:70:33:E1:90:44:BF:22:B6:96:11:C7:00:67:8D:CD:53:BC
+     Signature algorithm name: SHA256withRSA
+     Version: 3
+
+Extensions:
+
+#1: ObjectId: 2.5.29.14 Criticality=false
+SubjectKeyIdentifier [
+KeyIdentifier [
+0000: C2 A0 48 AA 60 BA DD E3   0C 3F 00 B4 2C D5 92 A5  ..H.`.......D...
+0010: 31 16 EF A2                                        1...
+]
+]
+
+You will be interested in SHA1 fingerprint. In the snippet above, the SHA1 fingerprint is:
+
+76:BA:AA:11:A9:22:42:24:93:82:6D:33:7E:48:BC:AF:45:4D:79:B0
+
+You would paste this value into the "Android Signing Certificate SHA-1" field in the web form.
+
+After pasting that in, you’ll see a new button with label "Enable Google Sign-in"
+
+Figure 444. Enable Google Sign-In
+
+Press this button and you’ll be presented with another button to "Generate Configuration Files" as
+
+shown below
+
+Figure 445. Generate Configuration Files
+
+Finally you will be presented with a button to "Download google-services.json".
+
+Figure 446. Download google-services.json file
+
+535
+
+Press this button to download the google-services.json file. Then copy this into the "native/android"
+
+directory of your Codename One project.
+
+Figure 447. Project file structure after placing the GoogleService-Info.plist into the native/android directory
+
+At this point, your app should be able to use Google Sign-In. Notice that we don’t require any build
+
+hints. Only that the google-services.json file is added to the project’s native/android directory.
+
+If  you  want  to  access  additional  information  about  the  logged  in  user  using
+
+
+
+Google’s REST APIs, you will require an OAuth2.0 client ID of type Web Application
+
+for this project as well. See Section 14.10.3, “OAuth Setup (Simulator and REST API
+
+Access)” for details.
+
+14.10.3. OAuth Setup (Simulator and REST API Access)
+
+Getting  Google  Sign-In  to  work  in  the  Codename  One  simulator  requires  an  additional  step  after
+
+you’ve set up iOS and/or Android apps. The Simulator can’t use the native Google Sign-In APIs, so it
+
+uses  the  standard  Web  Application  OAuth2.0  API.  In  addition,  the  Android  App  requires  a  Web
+
+Application OAuth2.0 client ID to access additional Google REST APIs.
+
+If  you’ve  set  up  the  Google  Sign-In  API  for  either  Android  or  iOS,  then  Google  will  have  already
+
+automatically generated a Web Application OAuth2.0 client ID for you. You just need to provide the
+ClientID and ClientSecret to the GoogleConnect instance (in your java code).
+
+Client ID, Client Secret and Redirect URL
+
+1. Log into the Google Cloud Platform API console [https://console.cloud.google.com/apis].
+
+2. Select your app from the drop-down-menu in the top bar
+
+3. Click on "Credentials" in the left menu. You’ll see a screen like this
+
+4. Under the "OAuth2.0 Client IDs", find the row with "Web application" listed in the type column
+
+5. Click the "Edit icon for that row.
+
+6. Make note of the "Client ID" and "Client Secret" on this page, as you’ll need to add them to your
+
+Java source in the next step.
+
+7. In  the  "Authorized  redirect  URIs"  section,  you  will  need  to  enter  the  URL  to  the  page  that  the
+
+user  will  be  sent  to  after  a  successful  login.  This  page  will  only  appear  in  the  simulator  for  a
+
+split  second,  as  Codename  One’s  BrowserComponent  will  intercept  this  request  to  obtain  the
+
+access  token  upon  successful  login.  You  can  use  any  URL  you  like  here,  but  it  must  match  the
+value you give to GoogleConnect.setRedirectURL() in Section 14.10.5, “The Code”.
+
+536
+
+14.10.4. Javascript Setup Instructions
+
+The Javascript port can use the same OAuth2.0 credentials as the simulator does. It doesn’t require
+
+your Client Secret or redirect URL. It only requires your Client ID, which you can specify using the
+GoogleConnect.setClientID() method.
+
+14.10.5. The Code
+
+Login gc = GoogleConnect.getInstance();
+gc.setClientId("*****************.apps.googleusercontent.com");
+gc.setRedirectURI("https://yourURL.com/");
+gc.setClientSecret("-------------------");
+
+// Sets a LoginCallback listener
+gc.setCallback(new LoginCallback() {
+    public void loginSuccessful() {
+        // we can now start fetching stuff from Google+!
+    }
+
+    public void loginFailed(String errorMessage) {}
+});
+
+// trigger the login if not already logged in
+if(!gc.isUserLoggedIn()){
+    gc.doLogin();
+} else {
+    // get the token and now you can query the Google API
+    String token = gc.getAccessToken().getToken();
+      // NOTE: On Android, this token will be null unless you provide valid
+      // client ID and secrets.
+}
+
+ The client ID and client secret values here are the ones from your OAuth2.0 Web
+
+Application.
+
+
+
+The  Client  ID  and  Client  Secret  values  are  used  on  both  the  Simulator  and  on
+
+Android.  On  simulator  these  values  are  required  for  login  to  work  at  all.  On
+
+Android  these  values  are  required  to  obtain  an  access  token  to  query  the  Google
+
+API  further  using  its  various  REST  APIs.  If  you  do  not  include  these  values  on
+Android, login will still work, but gc.getAccessToken().getToken() will return null.
+
+537
+
+14.11. Lead Component
+
+Codename One has two basic ways to create new components:
+
+1. Subclass a Component override paint, implement event callbacks etc.
+
+2. Compose multiple components into a new component, usually by subclassing a Container.
+
+Components  such  as  Tabs  [https://www.codenameone.com/javadoc/com/codename1/ui/Tabs.html]  subclass
+Container which make a lot of sense for that component since it is physically a Container.
+
+However, 
+
+components 
+
+like  MultiButton 
+
+[https://www.codenameone.com/javadoc/com/codename1/
+
+components/MultiButton.html], 
+
+SpanButton 
+
+[https://www.codenameone.com/javadoc/com/codename1/
+
+components/SpanButton.html] 
+
+& 
+
+SpanLabel 
+
+[https://www.codenameone.com/javadoc/com/codename1/
+
+components/SpanLabel.html]  don’t  necessarily  seem  like  the  right  candidate  for  compositing  but  they
+are all Container subclasses.
+
+Using  a  Container  provides  us  a  lot  of  flexibility  in  terms  of  layout  &  functionality  for  a  specific
+component. MultiButton is a great example of that. It’s a Container internally that is composed of 5
+labels and a Button.
+
+Codename  One  makes 
+setLeadComponent(Component) which turns the button into the "leader" of the component.
+
+like  a  single  button 
+
+the  MultiButton  "feel" 
+
+thru 
+
+the  use  of
+
+When a Container hierarchy is placed under a leader all events within the hierarchy are sent to the
+leader,  so  if  a  label  within  the  lead  component  receives  a  pointer  pressed  event  this  event  will
+
+really be sent to the leader.
+
+E.g.  in  the  case  of  the  MultiButton  the  internal  button  will  receive  that  event  and  send  the  action
+performed event, change the state etc.
+
+This creates some potential issues for instance in MultiButton:
+
+myMultiButton.addActionListener((e) -> {
+    if(e.getComponent() == myMultiButton) {
+        // this won't occur since the source component is really a button!
+    }
+    if(e.getActualComponent() == myMultiButton) {
+        // this will happen...
+    }
+});
+
+The leader also determines the style state, so all the elements being lead are in the same state. E.g. if
+
+the  the  button  is  pressed  all  elements  will  display  their  pressed  states,  notice  that  they  will  do  so
+with their own styles but they will each pick the pressed version of that style so a Label UIID within
+a lead component in the pressed state would return the Pressed state for a Label not for the Button.
+
+This is very convenient when you need to construct more elaborate UI’s and the cool thing about it
+
+is that you can do this entirely in the designer which allows assembling containers and defining the
+
+lead component inside the hierarchy.
+
+538
+
+E.g. the SpanButton class is very similar to this code:
+
+public class SpanButton extends Container {
+    private Button actualButton;
+    private TextArea text;
+
+    public SpanButton(String txt) {
+        setUIID("Button");
+        setLayout(new BorderLayout());
+        text = new TextArea(getUIManager().localize(txt, txt));
+        text.setUIID("Button");
+        text.setEditable(false);
+        text.setFocusable(false);
+        actualButton = new Button();
+        addComponent(BorderLayout.WEST, actualButton);
+        addComponent(BorderLayout.CENTER, text);
+        setLeadComponent(actualButton);
+    }
+
+    public void setText(String t) {
+        text.setText(getUIManager().localize(t, t));
+    }
+
+    public void setIcon(Image i) {
+        actualButton.setIcon(i);
+    }
+
+    public String getText() {
+        return text.getText();
+    }
+
+    public Image getIcon() {
+        return actualButton.getIcon();
+    }
+
+    public void addActionListener(ActionListener l) {
+        actualButton.addActionListener(l);
+    }
+
+    public void removeActionListener(ActionListener l) {
+        actualButton.removeActionListener(l);
+    }
+
+}
+
+14.11.1. Blocking Lead Behavior
+
+The  Component  class  has  two  methods  that  allow  us  to  exclude  a  component  from  lead  behavior:
+
+539
+
+setBlockLead(boolean) & isBlockLead().
+
+Effectively  when  you  have  a  Component  within  the  lead  hierarchy  that  you  would  like  to  treat
+differently from the rest you can use this method to exclude it from the lead component behavior
+
+while keeping the rest in line…
+
+This should have no effect if the component isn’t a part of a lead component.
+
+The sample below is based on the Accordion component which uses a lead component internally.
+
+Form f = new Form("Accordion", new BorderLayout());
+Accordion accr = new Accordion();
+f.getToolbar().addMaterialCommandToRightBar("", FontImage.MATERIAL_ADD, e -> addEntry(accr));
+addEntry(accr);
+f.add(BorderLayout.CENTER, accr);
+f.show();
+
+void addEntry(Accordion accr) {
+    TextArea t = new TextArea("New Entry");
+    Button delete = new Button();
+    FontImage.setMaterialIcon(delete, FontImage.MATERIAL_DELETE);
+    Label title = new Label(t.getText());
+    t.addActionListener(ee -> title.setText(t.getText()));
+    delete.addActionListener(ee -> {
+        accr.removeContent(t);
+        accr.animateLayout(200);
+    });
+    delete.setBlockLead(true);
+    delete.setUIID("Label");
+    Container header = BorderLayout.center(title).
+            add(BorderLayout.EAST, delete);
+    accr.addContent(header, t);
+    accr.animateLayout(200);
+}
+
+This  allows  us  to  add/edit  entries  but  it  also  allows  the  delete  button  above  to  actually  work
+separately.  Without  a  call  to  setBlockLead(true)  the  delete  button  would  cat  as  the  rest  of  the
+accordion title.
+
+Figure 448. Accordion with delete button entries that work despite the surrounding lead
+
+540
+
+14.12. Pull To Refresh
+
+Pull to refresh is the common UI paradigm that Twitter popularized where the user can pull down
+
+the form/container to receive an update. Adding this to Codename One couldn’t be simpler!
+
+Just  invoke  addPullToRefresh(Runnable)  on  a  scrollable  container  (or  form)  and  the  runnable
+method will be invoked when the refresh operation occurs.
+
+
+
+Pull to refresh is implicitly implements in the InifiniteContainer
+
+Form hi = new Form("Pull To Refresh", BoxLayout.y());
+hi.getContentPane().addPullToRefresh(() -> {
+    hi.add("Pulled at " + L10NManager.getInstance().formatDateTimeShort(new Date()));
+});
+hi.show();
+
+Figure 449. Pull to refresh demo
+
+14.13. Running 3rd Party Apps Using Display’s execute
+
+The  Display  [https://www.codenameone.com/javadoc/com/codename1/ui/Display.html]  class’s  execute  method
+allows us to invoke a URL which is bound to a particular application.
+
+This  works  rather  well  assuming  the  application  is  installed.  E.g.  this  list  [http://wiki.akosma.com/
+
+IPhone_URL_Schemes]  contains  a  set  of  valid  URL’s  that  can  be  used  on  iOS  to  run  common
+
+applications and use builtin functionality.
+
+Some URL’s might not be supported if an app isn’t installed, on Android there isn’t much that can be
+done but iOS has a canOpenURL method for Objective-C.
+
+On iOS you can use the Display.canExecute() method which returns a Boolean instead of a boolean
+which allows us to support 3 result states:
+
+1. Boolean.TRUE - the URL can be executed
+
+2. Boolean.FALSE - the URL isn’t supported or the app is missing
+
+3. null - we have no idea whether the URL will work on this platform.
+
+541
+
+The sample below launches a "godfather" search on IMDB only when this is sure to work (only on
+
+iOS currently). We can actually try to search in the case of null as well but this sample plays it safe
+
+by using the http link which is sure to work:
+
+Boolean can = Display.getInstance().canExecute("imdb:///find?q=godfather");
+if(can != null && can) {
+    Display.getInstance().execute("imdb:///find?q=godfather");
+} else {
+    Display.getInstance().execute("http://www.imdb.com");
+}
+
+14.14. Automatic Build Hint Configuration
+
+We  try  to  make  Codename  One  "seamless",  this  expresses  itself  in  small  details  such  as  the
+
+automatic  detection  of  permissions  on  Android  etc.  The  build  servers  go  a  long  way  in  setting  up
+
+the environment as intuitive. But it’s not enough, build hints are often confusing and obscure. It’s
+
+hard to abstract the mess that is native mobile OS’s and the odd policies from Apple/Google…
+
+A good example for a common problem developers face is location code that doesn’t work in iOS.
+This is due to the ios.locationUsageDescription build hint that’s required. The reason that build hint
+was added is a requirement by Apple to provide a description for every app that uses the location
+
+service.
+
+To solve this sort of used case we have two API’s in Display:
+
+/**
+ * Returns the build hints for the simulator, this will only work in the debug environment and it's
+ * designed to allow extensions/API's to verify user settings/build hints exist
+ * @return map of the build hints that isn't modified without the codename1.arg. prefix
+ */
+public Map<String, String> getProjectBuildHints() {}
+
+/**
+ * Sets a build hint into the settings while overwriting any previous value. This will only work in the
+ * debug environment and it's designed to allow extensions/API's to verify user settings/build hints exist.
+ * Important: this will throw an exception outside of the simulator!
+ * @param key the build hint without the codename1.arg. prefix
+ * @param value the value for the hint
+ */
+public void setProjectBuildHint(String key, String value) {}
+
+Both  of  these  allow  you  to  detect  if  a  build  hint  is  set  and  if  not  (or  if  it’s  set  incorrectly)  set  its
+
+value…
+
+if  you  will  use 
+
+So 
+the  simulator  and  you  didn’t  define
+from 
+ios.locationUsageDescription Codename One will implicitly define a string there. The cool thing is
+that you will now see that string in your settings and you would be able to customize it easily.
+
+location  API 
+
+the 
+
+However, this gets way better than just that trivial example!
+
+542
+
+The real value is for 3rd party cn1lib authors. E.g. Google Maps or Parse. They can inspect the build
+
+hints in the simulator and show an error in case of a misconfiguration. They can even show a setup
+
+UI.  Demos  that  need  special  keys  in  place  can  force  the  developer  to  set  them  up  properly  before
+
+continuing.
+
+14.15. Easy Thread
+
+Working  with  threads  is  usually  ranked  as  one  of  the  least  intuitive  and  painful  tasks  in
+
+programming.  This  is  such  an  error  prone  task  that  some  platforms/languages  took  the  route  of
+
+avoiding  threads  entirely.  I  needed  to  convert  some  code  to  work  on  a  separate  thread  but  I  still
+
+wanted the ability to communicate and transfer data from that thread.
+
+This is possible in Java but non-trivial, the thing is that this is relatively easy to do in Codename One
+with tools such as callSerially I can let arbitrary code run on the EDT. Why not offer that to any
+random thread?
+
+That’s why I created EasyThread which takes some of the concepts of Codeame One’s threading and
+makes  them  more  accessible  to  an  arbitrary  thread.  This  way  you  can  move  things  like  resource
+
+loading into a separate thread and easily synchronize the data back into the EDT as needed…
+
+Easy thread can be created like this:
+
+EasyThread e = EasyThread.start("ThreadName");
+
+You can just send a task to the thread using:
+
+e.run(() -> doThisOnTheThread());
+
+But it gets better, say you want to return a value:
+
+e.run((success) -> success.onSuccess(doThisOnTheThread()), (myResult) -> onEDTGotResult(myRsult));
+
+Lets  break  that  down…  We  ran  the  thread  with  the  success  callback  on  the  new  thread  then  the
+→
+callback 
+success.onSuccess(doThisOnTheThread())  ran  off  the  EDT  in  the  thread  and  when  we  invoked  the
+onSuccess callback it sent it asynchronously to the EDT here: (myResult) → onEDTGotResult(myRsult).
+
+the  EDT 
+
+(success) 
+
+invoked 
+
+result. 
+
+code 
+
+this 
+
+got 
+
+on 
+
+So 
+
+as 
+
+a 
+
+These asynchronous calls make things a bit painful to wade thru so instead I chose to wrap them in
+
+a simplified synchronous version:
+
+EasyThread e = EasyThread.start("Hi");
+int result = e.run(() -> {
+    System.out.println("This is a thread");
+    return 3;
+});
+
+543
+
+There  are  a  few  other  variants  like  runAndWait  and  there  is  a  kill()  method  which  stops  a  thread
+and releases its resources.
+
+14.16. Mouse Cursor
+
+Codename  one  can  change  the  mouse  cursor  when  hovering  over  specific  areas  to  indicate
+
+resizability,  movability  etc.  For  obvious  reasons  this  feature  is  only  available  in  the  desktop  and
+
+JavaScript ports as the other ports rely mostly on touch interaction. The feature is off by default and
+needs  to  be  enabled  on  a  Form  by  using  Form.setEnableCursors(true);.  If  you  are  writing  a  custom
+component that can use cursors such as SplitPane you can use:
+
+@Override
+protected void initComponent() {
+    super.initComponent();
+    getComponentForm().setEnableCursors(true);
+}
+
+Once  this  is  enabled  you  can  set  the  cursor  over  a  specific  region  using  cmp.setCursor()  which
+accepts one of the cursor constants defined in Component.
+
+14.17. Working With GIT
+
+Working  with  GIT  for  storing  Codename  One  projects  isn’t  exactly  a  feature  but  since  it  is  so
+
+ubiquitous we think it’s important to have a common guideline.
+
+When we first started committing to git we used something like this for netbeans projects:
+
+*.jar
+nbproject/private/
+build/
+dist/
+lib/CodenameOne_SRC.zip
+
+Removing the jars, build, private folder etc. makes a lot of sense but there are a few nuances that
+
+are missing here…
+
+14.17.1. cn1lib’s
+
+You will notice we excluded the jars which are stored under lib and we exclude the Codename One
+
+source  zip.  But  I  didn’t  exclude  cn1libs…  That  was  an  omission  since  the  original  project  we
+
+committed didn’t have cn1libs. But should we commit a binary file to git?
+
+I don’t know. Generally git isn’t very good with binaries but cn1libs make sense. In another project
+
+that did have a cn1lib I did this:
+
+544
+
+*.jar
+nbproject/private/
+build/
+dist/
+lib/CodenameOne_SRC.zip
+lib/impl/
+native/internal_tmp/
+
+The important lines are lib/impl/ and native/internal_tmp/. Technically cn1libs are just zips. When
+you do a refresh libs they unzip into the right directories under lib/impl and native/internal_tmp.
+By excluding these directories we can remove duplicates that can result in conflicts.
+
+14.17.2. Resource Files
+
+Committing the res file is a matter of personal choice. It is committed in the git ignore files above
+
+but you can remove it. The res file is at risk of corruption and in that case having a history we can
+
+refer to, matters a lot.
+
+But the resource file is a bit of a problematic file. As a binary file if we have a team working with it
+
+the conflicts can be a major blocker. This was far worse with the old GUI builder, that was one of
+
+the big motivations of moving into the new GUI builder which works better for teams.
+
+Still, if you want to keep an eye of every change in the resource file you can switch on the  File →
+XML Team Mode which should be on by default. This mode creates a file hierarchy under the res
+directory to match the res file you opened. E.g. if you have a file named src/theme.res it will create
+a matching res/theme.xml and also nest all the images and resources you use in the res directory.
+
+That’s very useful as you can edit the files directly and keep track of every file in git. However, this
+
+has two big drawbacks:
+
+• It’s flaky - while this mode works it never reached the stability of the regular res file mode
+
+• It conflicts - the simulator/device are oblivious to this mode. So if you fetch an update you also
+
+need to update the res file and you might still have conflicts related to that file
+
+Ultimately both of these issues shouldn’t be a deal breaker. Even though this mode is a bit flaky it’s
+
+better than the alternative as you can literally "see" the content of the resource file. You can easily
+
+revert and reapply your changes to the res file when merging from git, it’s tedious but again not a
+
+deal breaker.
+
+14.17.3. Eclipse Version
+
+Building on the gitignore we have for NetBeans the eclipse version should look like this:
+
+545
+
+.DS_Store
+*.jar
+build/
+dist/
+lib/impl/
+native/internal_tmp/
+.metadata
+bin/
+tmp/
+*.tmp
+*.bak
+*.swp
+*.zip
+*~.nib
+local.properties
+.settings/
+.loadpath
+.recommenders
+.externalToolBuilders/
+*.launch
+*.pydevproject
+.cproject
+.factorypath
+.buildpath
+.project
+.classpath
+
+14.17.4. IntelliJ/IDEA
+
+546
+
+.DS_Store
+*.jar
+build/
+dist/
+lib/impl/
+native/internal_tmp/
+*.zip
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/dictionaries
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.xml
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+.idea/**/gradle.xml
+.idea/**/libraries
+*.iws
+/out/
+atlassian-ide-plugin.xml
+
+547
+
+548
+
+15. Performance, Size & Debugging
+
+15.1. Reducing Resource File Size
+
+It’s  easy  to  lose  track  of  size/performance  when  you  are  working  within  the  comforts  of  a  visual
+
+tool like the Codename One Designer. When optimizing resource files you need to keep in mind one
+
+thing: it’s all about image sizes.
+
+
+
+Images  will  take  up  95-99%  of  the  resource  file  size;  everything  else  pales  in
+
+comparison.
+
+Like every optimization the first rule is to reduce the size of the biggest images which will provide
+
+your  biggest  improvements,  for  this  purpose  we  introduced  the  ability  to  see  image  sizes  in
+
+kilobytes. To launch that feature use the menu item Images → Image Sizes (KB) in the designer.
+
+Figure 450. Image sizes window that allows us to find the biggest impact on our RAM/Storage
+
+This  produces  a  list  of  images  sorted  by  size  with  their  sizes.  Often  the  top  entries  will  be  multi-
+
+images,  which  include  HD  resolution  values  that  can  be  pretty  large.  These  very  high-resolution
+
+images take up a significant amount of space!
+
+Just  going  to  the  multi-images,  selecting  the  unnecessary  resolutions  &  deleting  these  images  can
+
+saves significant amounts of space:
+
+Figure 451. Removing unused DPI’s
+
+
+
+You can see the size in KB at the top right side in the designers image viewer
+
+Applications using the old GUI builder can use the  Images →  Delete Unused Images menu option
+
+(it’s  also  under  the  Images  menu).  This  tool  allows  detecting  and  deleting  images  that  aren’t  used
+
+549
+
+within the theme/GUI.
+
+If you have a very large image that is opaque you might want to consider converting it to JPEG and
+
+replacing  the  built  in  PNG’s.  Notice  that  JPEG’s  work  on  all  supported  devices  and  are  typically
+
+smaller.
+
+Figure 452. Convert a MultiImage to use JPEGs instead of PNGs
+
+You  can  use  the  excellent  OptiPng  [http://optipng.sourceforge.net/]  tool  to  optimize  image  files  right
+
+from the Codename One designer. To use this feature you need to install OptiPng then select Images
+
+→  Launch OptiPng from the menu. Once you do that the tool will automatically optimize all your
+
+PNG’s.
+
+When  faced  with  size  issues  make  sure  to  check  the  size  of  your  res  file,  if  your  JAR  file  is  large
+
+open it with a tool such as 7-zip and sort elements by size. Start reviewing which element justifies
+
+the size overhead.
+
+15.2. Improving Performance
+
+There are quite a few things you can do as a developer in order to improve the performance and
+
+memory  footprint  of  a  Codename  One  application.  This  sometimes  depends  on  specific  device
+
+behaviors but some of the tips here are true for all devices.
+
+The simulator contains some tools to measure performance overhead of a specific component and
+
+also detect EDT blocking logic. Other than that follow these guidelines to create more performance
+
+code:
+
+• Avoid  round  rect  borders  -  they  have  a  huge  overhead  on  all  platforms.  Use  image  borders
+
+instead (counter intuitively they are MUCH faster)
+
+• Avoid Gradients - they perform poorly on most OS’s. Use a background image instead
+
+• Use larger images when tiling or building image borders, using a 1 pixel (or event a few pixels)
+
+wide or high image and tiling it repeatedly can be very expensive
+
+• Shrink  resource  file  sizes  -  Otherwise  data  might  get  collected  by  the  garbage  collector  and
+
+reloading data might be expensive
+
+• Check  that  you  don’t  have  too  many  image  lock  misses  -  this  is  discussed  in  the  graphics
+
+section
+
+• On some platforms mutable images are slow - mutable images are images you can draw on
+(using  getGraphics()).  On  some  platforms  they  perform  quite  badly  (e.g.  iOS)  and  should
+
+550
+
+generally  be  avoided.  You  can  check  if  mutable  images  are  fast  in  a  platform  using
+Display.areMutableImagesFast()
+
+• *  Make  components  either  transparent  or  opaque  *  -  a  translucent  component  must  paint  it’s
+
+parent  every  time.  This  can  be  expensive.  An  opaque  component  might  have  margins  that
+
+would  require  that  we  paint  the  parent  so  there  is  often  overdraw  in  such  cases  (overdraw
+
+means the same pixel being painted twice).
+
+15.3. Performance Monitor
+
+The Performance Monitor tool can be accessible via the  Simulator →  Performance Monitor menu
+
+option  in  the  simulator.  This  launches  the  following  UI  that  can  help  you  improve  application
+
+performance:
+
+Figure 453. Main tab of the performance monitor: Logs and timings
+
+The  first  tab  of  the  performance  monitor  includes  a  table  of  the  drawn  components.  Each  entry
+
+includes the number of times it was drawn and the slowest/fastest and average drawing time.
+
+This is useful if a Form is slow. You might be able to pinpoint it to a specific component using this
+tool.
+
+The Log on the bottom includes debug related information. E.g. it warns about the usage of mutable
+
+images  which  might  be  slow  on  some  platforms.  This  also  displays  warnings  when  an  unlocked
+
+image is drawn etc.
+
+551
+
+Figure 454. Rendering tree
+
+The  rendering  tree  view  allows  us  to  inspect  the  hierarchy  painting.  You  can  press  the  refresh
+button which will trigger the painting of the current Form. Every graphics operation is logged and so
+is the stack to it.
+
+You can then inspect the hierarchy and see what was drawn by the various components. You can
+
+click the "stack" buttons to see the specific stack trace that lead to that specific drawing operation.
+
+This is a remarkably powerful debugging tool as you can literally see "overdraw" within this tool.
+E.g  if  you  see  fillRect  or  similar  API’s  invoked  in  the  parent  and  then  again  and  again  in  the
+children this could indicate a problem.
+
+
+
+Android devices have a very nice overdraw debugging tool
+
+15.4. Network Speed
+
+Figure 455. Network speed tool
+
+This  feature  is  actually  more  useful  for  general  debugging  however  it’s  sometimes  useful  to
+
+simulate a slow/disconnected network to see how this affects performance.
+
+For this purpose the Codename One simulator allows you to slow down networking or even fake a
+
+disconnected network to see how your application handles such cases.
+
+552
+
+15.5. Debugging Codename One Sources
+
+When you debug your app with our source code you can place breakpoints deep within Codename
+
+One and gain unique insight. You can also use the profilers and profile into Codename One to gain
+
+similar performance specific insight.
+
+When you run into a bug or a missing feature you can push that feature/fix back to Codename One
+
+[https://www.codenameone.com/] using a pull request. Github makes that process trivial and in this new
+
+video and slides below we show you how. The steps to use the code are:
+
+1. Signup for Github
+
+2. Fork  http://github.com/codenameone/CodenameOne  and  http://github.com/codenameone/
+
+codenameone-skins (also star and watch the projects for good measure).
+
+3. Clone the git URL’s from the projects into the IDE using the  Team →  Git →  Clone menu option.
+
+Notice that you must deselect projects in the IDE for the menu to appear.
+
+4. Download  the  cn1-binaries  project  from  github  here  [https://github.com/codenameone/cn1-binaries/
+
+archive/master.zip].
+
+5. Unzip  the  cn1-binaries  project  and  make  sure  the  directory  has  the  name  cn1-binaries.  Verify
+
+that cn1-binaries, CodenameOne and codenameone-skins are within the same parent directory.
+
+.In your own project remove the jars both in the build & run libraries section. Replace the build
+libraries  with  the  CodenameOne/CodenameOne  project.  Replace  the  runtime  libraries  with  the
+CodenameOne/Ports/JavaSEPort project.
+
+This allows you to run the existing Codename One project with the Codename One source code and
+
+debug  into  Codename  One.  You  can  now  also  commit,  push  and  send  a  pull  request  with  the
+
+changes.
+
+15.6. Device Testing Framework/Unit Testing
+
+Codename One includes a built in testing framework and test recorder tool as part of the simulator.
+
+This allows developers to build both functional and unit test execution on top of Codename One. It
+
+even enables sending tests for execution on the device (pro-only feature).
+
+To get started with the testing framework, launch the application and open the test recorder in the
+
+simulator menu.
+
+553
+
+Figure 456. The test recorder tool in the simulator
+
+Once you press record a test will be generate for you as you use the application.
+
+Figure 457. Test recording in progress, when done just press the save icon
+
+You can build tests using the Codename One testing package to manipulate the Codename One UI
+
+programmatically and perform various assertions.
+
+Unlike  frameworks  such  as  JUnit  which  assign  a  method  per  test,  the  Codename  One  test
+
+framework uses a class per test. This allows the framework to avoid reflection and thus allows it to
+
+work properly on the device.
+
+15.7. EDT Error Handler and sendLog
+
+Handling errors or exceptions in a deployed product is pretty difficult, most users would just throw
+
+away  your  app  and  some  would  give  it  a  negative  rating  without  providing  you  with  the
+
+opportunity to actually fix the bug that might have happened.
+
+Figure 458. Default error dialog
+
+554
+
+Google  improved  on  this  a  bit  by  allowing  users  to  submit  stack  traces  for  failures  on  Android
+
+devices but this requires the users approval for sending personal data which you might not need if
+
+you only want to receive the stack trace and maybe some basic application state (without violating
+
+user privacy).
+
+For quite some time Codename One had a very powerful feature that allows you to both catch and
+
+report such errors, the error reporting feature uses the Codename One cloud which is exclusive for
+
+pro/enterprise  users.  Normally  in  Codename  One  we  catch  all  exceptions  on  the  EDT  (which  is
+
+where  most  exceptions  occur)  and  just  display  an  error  to  the  user  as  you  can  see  in  the  picture.
+
+Unfortunately  this  isn’t  very  helpful  to  us  as  developers  who  really  want  to  see  the  stack;
+
+furthermore we might prefer the user doesn’t see an error message at all!
+
+Codename One allows us to grab all exceptions that occur on the EDT and handle them using the
+method  addEdtErrorHandler  in  the  Display  [https://www.codenameone.com/javadoc/com/codename1/ui/
+Display.html]  class.  Adding  this  to  the  Log’s  ability  to  report  errors  directly  to  us  and  we  can  get  a
+
+very powerful tool that will send us an email with information when a crash occurs!
+
+This can be accomplished with a single line of code:
+
+Log.bindCrashProtection(true);
+
+We  normally  place  this  in  the  init(Object)  method  so  all  future  on-device  errors  are  emailed  to
+you. Internally this method uses the Display.getInstance().addEdtErrorHandler() API to bind error
+listeners 
+(using
+ActionEvent.consume()). The Log data is then sent using Log.sendLog().
+
+the  EDT.  When  an  exception 
+
+is  swallowed 
+
+thrown 
+
+there 
+
+to 
+
+is 
+
+it 
+
+To truly benefit from this feature we need to use the Log class for all logging and exception handling
+instead of API’s such as System.out.
+
+To  log  standard  printouts  you  can  use  the  Log.p(String)  method  and  to  log  exceptions  with  their
+stack trace you can use Log.e(Throwable).
+
+15.8. Kitchen Sink Case Study
+
+Performance is one of those vague subjects that is often taught by example.
+
+During our debugging of the contacts demo that is a part of the new kitchen sink demo we noticed
+its performance was sub par. We assumed this was due to the implementation of getAllContacts &
+that  there  is  nothing  to  do.  While  debugging  another  issue  we  noticed  an  anomaly  during  the
+
+loading of the contacts.
+
+This led to the discovery that we are loading the same resource file over and over again for every
+
+single contact in the list!
+
+In  the  new  Contacts  demo  we  have  a  share  button  for  each  contact,  the  code  for  constructing  a
+ShareButton looks like this:
+
+555
+
+public ShareButton() {
+    setUIID("ShareButton");
+    FontImage.setMaterialIcon(this, FontImage.MATERIAL_SHARE);
+    addActionListener(this);
+    shareServices.addElement(new SMSShare());
+    shareServices.addElement(new EmailShare());
+    shareServices.addElement(new FacebookShare());
+}
+
+This  seems  reasonable  until  you  realize  that  the  constructors  for  SMSShare,  EmailShare  &
+FacebookShare load the icons for each of those…
+
+These  icons  are  in  a  shared  resource  file  that  we  load  and  don’t  properly  cache.  The  initial
+
+workaround was to cache this resource but a better solution was to convert this code:
+
+public SMSShare() {
+    super("SMS", Resources.getSystemResource().getImage("sms.png"));
+}
+
+Into this code:
+
+public SMSShare() {
+    super("SMS", null);
+}
+
+@Override
+public Image getIcon() {
+    Image i = super.getIcon();
+    if(i == null) {
+        i = Resources.getSystemResource().getImage("sms.png");
+        setIcon(i);
+    }
+    return i;
+}
+
+This way the resource uses lazy loading as needed.
+
+This small change boosted the loading performance and probably the general performance due to
+
+less memory fragmentation.
+
+The lesson that we should learn every day is to never assume about performance…
+
+15.8.1. Scroll Performance - Threads aren’t magic
+
+Another  performance  pitfall  in  this  same  demo  came  during  scrolling.  Scrolling  was  janky
+
+(uneven/unsmooth) right after loading finished would recover after a couple of minutes.
+
+556
+
+This relates to the images of the contacts.
+
+To  hasten  the  loading  of  contacts  we  load  them  all  without  images.  We  then  launch  a  thread  that
+
+iterates the contacts and loads an individual image for a contact. Then sets that image to the contact
+
+and replaces the placeholder image.
+
+This performed well in the simulator but didn’t do too well even on powerful mobile phones. We
+assumed  this  wouldn’t  be  a  problem  because  we  used  Util.sleep()  to  yield  CPU  time  but  that
+wasn’t enough.
+
+Often  when  we  see  performance  penalty  the  response  is:  "move  it  to  a  separate  thread".  The
+
+problem is that this separate thread needs to compete for the same system resources and merge its
+
+changes back into the EDT. When we perform something intensive we need to make sure that the
+
+CPU isn’t needed right now…
+
+In this and past cases we solved this using a class member indicating the last time a user interacted
+
+with the UI.
+
+Here we defined:
+
+private long lastScroll;
+
+Then we did this within the background loading thread:
+
+// don't do anything while we are scrolling or animating
+long idle = System.currentTimeMillis() - lastScroll;
+while(idle < 1500 || contactsDemo.getAnimationManager().isAnimating() || scrollY != contactsDemo.getScrollY()) {
+    scrollY = contactsDemo.getScrollY();
+    Util.sleep(Math.min(1500, Math.max(100, 2000 - ((int)idle))));
+    idle = System.currentTimeMillis() - lastScroll;
+}
+
+This  effectively  sleeps  when  the  user  interacts  with  the  UI  and  only  loads  the  images  if  the  user
+
+hasn’t touched the UI in a while.
+
+Notice that we also check if the scroll changes, this allows us to notice cases like the animation of
+
+scroll winding down.
+
+All we need to do now is update the lastScroll variable whenever user interaction is in place. This
+works for user touches:
+
+parentForm.addPointerDraggedListener(e -> lastScroll = System.currentTimeMillis());
+
+This works for general scrolling:
+
+557
+
+contactsDemo.addScrollListener(new ScrollListener() {
+    int initial = -1;
+    @Override
+    public void scrollChanged(int scrollX, int scrollY, int oldscrollX, int oldscrollY) {
+        // scrolling is sensitive on devices...
+        if(initial < 0) {
+            initial = scrollY;
+        }
+        lastScroll = System.currentTimeMillis();
+        ...
+    }
+});
+
+ Due to technical constraints we can’t use a lambda in this specific case…
+
+558
+
+16. Advanced Topics/Under the Hood
+
+16.1. Sending Arguments To The Build Server
+
+When sending a build to the server we can provide additional parameters to the build, which are
+
+incorporated into the build process on the server to "hint" on multiple different build time options.
+
+These  hints  are  often  referred  to  as  "build  hints"  or  "build  arguments",  they  are  effectively  very
+
+much  like  souped  up  compiler  flags  that  you  can  use  to  tune  the  build  server’s  behavior.  This  is
+
+useful  for  fast  iteration  on  new  functionality  without  building  plugin  UI  for  every  change.  This  is
+
+also useful for exposing very low level behavior such as customizing the Android manifest XML or
+
+the iOS plist.
+
+You  can  set  these  hints  by  right  clicking  the  project  in  the  IDE  and  selecting  Codename One  →
+Codename One Settings → Build Hints. The hints use the key=value style of data.
+
+Figure 459. The build hints UI in Codename One Settings
+
+You can set the build hints in the codenameone_settings.properties file directly notice that when you
+do  that  all  settings  need  to  start  with  the  codename1.arg.  prefix.  When  editing  the  properties  file
+directly  we  would 
+as
+need 
+codename1.arg.android.debug=true.
+
+android.debug=true 
+
+something 
+
+define 
+
+like 
+
+to 
+
+Here  is  the  current  list  of  supported  arguments,  notice  that  build  hints  are  added  all  the  time  so
+
+consult the discussion forum if you don’t find what you need here:
+
+Table 10. Build hints
+
+Name
+
+android.debug
+
+android.release
+
+android.installLocation
+
+Description
+
+true/false defaults to true - indicates whether to
+
+include the debug version in the build
+
+true/false defaults to true - indicates whether to
+
+include the release version in the build
+
+Maps to android:installLocation manifest entry
+
+defaults to auto. Can also be set to internalOnly
+
+or preferExternal.
+
+559
+
+Name
+
+android.gradle
+
+Description
+
+Deprecated, this mode is no longer supported.
+
+true/false defaults to false prior to 3.3 and true
+
+after. Uses Gradle instead of Ant to build the
+
+Android app
+
+android.xapplication
+
+defaults to an empty string. Allows developers of
+
+native Android code to add text within the
+
+application block to define things such as
+
+widgets, services etc.
+
+android.permission.PERMISSION_NAME
+
+true/false Whether to include a particular
+
+permission. Use of these build hints is preferred
+to android.xpermissions since they avoid possible
+conflicts with libraries. See Android’s
+
+Manifest.permission docs
+
+[https://developer.android.com/reference/android/
+
+Manifest.permission.html] for a full list of
+
+permissions.
+
+Will be translated to the maxSdkVersion attribute
+of the <uses-permission> tag for the
+corresponding
+android.permission.PERMISSION_NAME build hint.
+(Optional)
+
+true/false Will be translated to the required
+attribute of the <uses-permission> tag for the
+corresponding
+android.permission.PERMISSION_NAME build hint.
+(Optional)
+
+additional permissions for the Android manifest
+
+Allows adding an intent filter to the main
+
+android activity
+
+Allows explicitly setting the android:launchMode
+attribute of the main activity in android. Default
+
+is "singleTop", but for some applications you
+
+may need to change this behaviour. In
+
+particular, apps that are meant to open a file
+
+type will need to set this to "singleTask". See
+
+Android docs for the activity element
+
+[https://developer.android.com/guide/topics/manifest/
+
+activity-element.html] for more information about
+the android:launchMode attribute.
+
+The license key for the Android app, this is
+
+required if you use in-app-purchase on Android
+
+android.permission.PERMISSION_NAME.maxSd
+
+kVersion
+
+android.permission.PERMISSION_NAME.require
+
+d
+
+android.xpermissions
+
+android.xintent_filter
+
+android.activity.launchMode
+
+android.licenseKey
+
+android.stack_size
+
+Size in bytes for the Android stack thread
+
+560
+
+Name
+
+Description
+
+android.statusbar_hidden
+
+true/false defaults to false. When set to true
+
+hides the status bar on Android devices.
+
+android.facebook_permissions
+
+Permissions for Facebook used in the Android
+
+android.googleAdUnitId
+
+build target, applicable only if Facebook native
+
+integration is used.
+
+Allows integrating admob/google play ads, this is
+
+effectively identical to google.adUnitId but only
+
+applies to Android
+
+android.googleAdUnitTestDevice
+
+Device key used to mark a specific Android
+
+device as a test device for Google Play ads
+
+defaults to
+
+C6783E2486F0931D9D09FABC65094FDF
+
+android.includeGPlayServices
+
+Deprecated, please android.playService.*!
+
+android.playService.plus,
+
+android.playService.auth,
+
+android.playService.base,
+
+android.playService.identity,
+
+android.playService.indexing,
+
+android.playService.appInvite,
+
+android.playService.analytics,
+
+android.playService.cast,
+
+android.playService.gcm,
+
+android.playService.drive,
+
+android.playService.fitness,
+
+android.playService.location,
+
+android.playService.maps,
+
+android.playService.ads,
+
+android.playService.vision,
+
+android.playService.nearby,
+
+android.playService.panorama,
+
+android.playService.games,
+
+android.playService.safetynet,
+
+android.playService.wallet,
+
+android.playService.wearable
+
+Indicates whether Goolge Play Services should
+
+be included into the build, defaults to false but
+
+that might change based on the functionality of
+
+the application and other build hints. Adding
+
+Google Play Services support allows us to use a
+
+more refined location implementation and
+
+invoke some Google specific functionality from
+
+native code.
+
+Allows including only a specific play services
+
+library portion. Notice that this setting conflicts
+
+with the deprecated
+android.includeGPlayServices and only works
+with the gradle build (which is on by default but
+can be toggled using android.gradle).
+
+If none of the services are defined to true then
+
+plus, auth, base, analytics, gcm, location, maps &
+
+ads will be set to true. If one or more of the
+android.playService entries are defined to
+something then all entries will default to false.
+
+561
+
+Name
+
+Description
+
+android.playServicesVersion
+
+The version number of play services to build
+
+against. Experimental. Use with caution as
+
+building against versions other than the server
+
+default may introduce incompatibilities with
+
+some Codename One APIs.
+
+xxx.minPlayServicesVersion
+
+This is a special case build hint. You can use any
+
+prefix to the build hint and the convention is to
+
+use your cn1lib name. It’s identical to
+android.minPlayServicesVersion with the
+exception that the "highest version wins". That
+
+way if your cn1lib requires play services 9+ and
+uses: myLib.minPlayServicesVersion=9.0.0 and
+another library has
+otherLib.minPlayServicesVersion=10.0.0 then
+play services will be 10.0.0
+
+Boolean true/false defaults to false. Multidex
+
+allows Android binaries to reference more than
+
+65536 methods. This slows builds a bit so we
+
+have it off by default but if you get a build error
+
+mentioning this limit you should turn this on.
+
+android.multidex
+
+android.headphoneCallback
+
+Boolean true/false defaults to false. When set to
+
+true it assumes the main class has two methods:
+headphonesConnected & headphonesDisconnected
+which it invokes appropriately as needed
+
+Indicates whether the GPS permission should be
+
+requested, it is auto-detected by default if you
+
+use the location API. However, some code might
+
+want to explicitly define it
+
+Boolean true/false defaults to true. Toggles the
+
+Android pipeline between the legacy pipeline
+
+(false) and new pipeline (true)
+
+Allows injecting additional entries into the
+
+strings.xml file using a value that includes
+
+something like this`<string
+
+name="key1">value1</string><string
+
+name="key2">value2</string>`
+
+Boolean true/false defaults to false but that can
+
+change based on usage (e.g. push implicitly
+
+activates this). Indicates whether the android
+
+support v4 library should be included in the
+
+build
+
+android.gpsPermission
+
+android.asyncPaint
+
+android.stringsXml
+
+android.supportV4
+
+562
+
+Name
+
+android.style
+
+Description
+
+Allows injecting additional data into the
+styles.xml file right before the closing resources
+tag
+
+android.cusom_layout1
+
+Applies to any number of layouts as long as they
+
+are in sequence (e.g. android.cusom_layout2,
+
+android.cusom_layout3 etc.). Will write the
+
+content of the argument as a layout xml file and
+give it the name cusom_layout1.xml onwards.
+This can be used by native code to work with
+
+XML files
+
+android.keyboardOpen
+
+Boolean true/false defaults to true. Toggles the
+
+android.versionCode
+
+android.captureRecord
+
+new async keyboard mode that leaves the
+
+keyboard open while we move between text
+
+components
+
+Allows overriding the auto generated version
+
+number with a custom internal version number
+
+specifically used for the xml attribute
+android:versionCode
+
+Indicates whether the RECORD_AUDIO permission
+should be requested. Can be enabled or any other
+value to disable this option
+
+android.nonconsumable
+
+Comma delimited string of items that are non-
+
+android.removeBasePermissions
+
+consumable in the in-app-purchase API
+
+Boolean true/false defaults to false. Disables the
+builtin permissions specifically INTERNET
+permission (i.e. no networking…)
+
+android.blockExternalStoragePermission
+
+Boolean true/false defaults to false. Disables the
+
+external storage (SD card) permission
+
+android.min_sdk_version
+
+The minimum SDK required to run this app, the
+
+default value changes based on functionality but
+
+can be as low as 7. This corresponds to the XML
+attribute android:minSdkVersion.
+
+android.mockLocation
+
+Boolean true/false defaults to true. Toggles the
+
+android.smallScreens
+
+android.xapplication_attr
+
+mock location permission which is on by
+
+default, this allows easier debugging of Android
+
+device location based services
+
+Boolean true/false defaults to true. Corresponds
+to the android:smallScreens XML attribute and
+allows disabling the support for very small
+
+phones
+
+Allows injecting additional attributes into the
+application` tag in the Android XML
+
+563
+
+Name
+
+android.xactivity
+
+android.streamMode
+
+android.pushVibratePattern
+
+android.enableProguard
+
+android.proguardKeep
+
+Description
+
+Allows injecting additional attributes into the
+activity tag in the Android XML
+
+The mode in which the volume key should
+
+behave, defaults to OS default. Allows setting it
+to music for music playback apps
+
+Comma delimited long values to describe the
+push pattern of vibrate used for the setVibrate
+native method
+
+Boolean true/false defaults to true. Allows
+
+disabling the proguard obfuscation even on
+
+release builds, notice that this isn’t
+
+recommended
+
+Arguments for the keep option in proguard
+allowing us to keep a pattern of files e.g. -keep
+class com.mypackage.ProblemClass { *; }
+
+android.shrinkResources
+
+Boolean true/false defaults to false. Used only in
+
+conjunction with android.enableProguard.
+
+Strips out unused resources to reduce apk size.
+
+Since 7.0
+
+android.sharedUserId
+
+Allows adding a manifest attribute for the
+
+sharedUserId option
+
+android.sharedUserLabel
+
+Allows adding a manifest attribute for the
+
+sharedUserLabel option
+
+android.targetSDKVersion
+
+Indicates the Android SDK used to compile the
+
+android.useAndroidX
+
+android.theme
+
+Android build currently defaults to 21. Notice
+
+that not all targets will work since the source
+
+might have some limitations and not all SDK
+
+targets are installed on the build servers.
+
+Use Android X instead of support libraries. This
+
+will also run a find/replace on all source files to
+
+replace support libraries and artifacts with
+
+AndroidX equivalents.
+
+Light or Dark defaults to Light. On Android 4+
+
+the default Holo theme is used to render the
+
+native widgets in some cases and this indicates
+
+whether holo light or holo dark is used.
+
+Currently this doesn’t affect the Codename One
+
+theme but that might change in the future.
+
+android.web_loading_hidden
+
+true/false defaults to false - set to true to hide the
+
+progress indicator that appears when loading a
+
+web page on Android.
+
+564
+
+Name
+
+Description
+
+block_server_registration
+
+true/false flag defaults to false. By default
+
+facebook.appId
+
+Codename One applications register with our
+
+server, setting this to true blocks them from
+
+sending information to our cloud. We keep this
+
+data for statistical purposes and intend to
+
+provide additional installation stats in the
+
+future.
+
+The application ID for an app that requires
+
+native Facebook login integration, this defaults
+
+to null which means native Facebook support
+
+shouldn’t be in the app
+
+gcm.sender_id
+
+The Android/chrome push identifier, see the
+
+push section for more details
+
+android.background_push_handling
+
+Deliver push messages on Android when the app
+
+ios.associatedDomains
+
+is minimized by setting this to "true". Default
+
+behaviour is to deliver the message only if the
+
+app is in the foreground when received, or after
+
+the user taps on the notification to open the app,
+
+if the app was in the background when the
+
+message was received.
+
+Comma-delimited list of domains associated
+
+with this app. Since 6.0. Note that each domain
+
+should be prefixed by a supported prefix. E.g.
+
+"applinks:" or "webcredentials:". See Apple’s
+
+documentation on Associated domains
+
+[https://developer.apple.com/documentation/security/
+password_autofill/
+
+setting_up_an_app_s_associated_domains?
+
+language=objc] for more information.
+
+ios.bitcode
+
+true/false defaults to false. Enables bitcode
+
+ios.debug.archs
+
+support for the build.
+
+Can be set to "arm64" to force iOS debug builds
+
+to be 64 bit. By default, debug builds are 32 bit in
+
+order to shorten build-times and maintain
+
+compatibility with older devices.
+
+ios.distributionMethod
+
+Specifies distribution type for debug iOS builds.
+
+This is generally used for enterprise or ad-hoc
+
+builds (using values "enterprise" and "ad-hoc"
+
+respectively).
+
+ios.debug.distributionMethod
+
+Specifies distribution type for debug iOS builds
+
+only. This is generally used for enterprise or ad-
+
+hoc builds (using values "enterprise" and "ad-
+
+hoc" respectively).
+
+565
+
+Name
+
+Description
+
+ios.release.distributionMethod
+
+Specifies distribution type for release iOS builds
+
+ios.keyboardOpen
+
+ios.urlScheme
+
+ios.useAVKit
+
+ios.teamId
+
+ios.debug.teamId
+
+ios.release.teamId
+
+ios.project_type
+
+ios.rpmalloc
+
+only. This is generally used for enterprise or ad-
+
+hoc builds (using values "enterprise" and "ad-
+
+hoc" respectively).
+
+Flips between iOS keyboard open mode and
+
+auto-fold keyboard mode. Defaults to true which
+
+means the keyboard will remain open and not
+
+fold automatically when editing moves to
+
+another field.
+
+Allows intercepting a URL call using the syntax
+<string>urlPrefix<string>
+
+Use AVKit for video components on iOS rather
+than MPMoviePlayerController on iOS versions 8
+through 12. iOS 13 will always use AVKit, and
+
+iOS 7 and lower will always use
+MPMoviePlayerController. Default value false
+
+Specifies the team ID associated with the iOS
+
+provisioning profile and certificate. Use
+ios.debug.teamId and ios.release.teamId to
+specify different team IDs for debug and release
+
+builds respectively.
+
+Specifies the team ID associated with the iOS
+
+debug provisioning profile and certificate.
+
+Specifies the team ID associated with the iOS
+
+release provisioning profile and certificate.
+
+one of ios, ipad, iphone (defaults to ios).
+
+Indicates whether the resulting binary is
+
+targeted to the iphone only or ipad only. Notice
+
+that the IDE plugin has a "Project Type" combo
+
+box you should use under the iOS section.
+
+true/false Use rpmalloc [https://github.com/
+rampantpixels/rpmalloc] instead of malloc/free for
+
+memory allocation in ParparVM. This will cause
+
+the deployment target to be changed to a
+
+minimum of iOS 8.0.
+
+ios.statusbar_hidden
+
+true/false defaults to false. Hides the iOS status
+
+bar if set to true.
+
+566
+
+Name
+
+ios.newStorageLocation
+
+ios.prerendered_icon
+
+Description
+
+true/false defaults to false but defined on new
+
+projects as true by default. This changes the
+
+storage directory on iOS from using caches to
+
+using the documents directory which is more
+
+correct but might break compatibility. This is
+
+described in this issue [https://github.com/
+
+codenameone/CodenameOne/issues/1480]
+
+true/false defaults to false. The iOS build process
+
+adapts the submitted icon for iOS conventions
+
+(adding an overlay) that might not be
+
+appropriate on some icons. Setting this to true
+
+leaves the icon unchanged (only scaled).
+
+ios.app_groups
+
+Space-delimited list of app groups that this app
+
+belongs to as described in Apple’s
+
+documentation [https://developer.apple.com/library/
+content/documentation/Miscellaneous/Reference/
+
+EntitlementKeyReference/Chapters/
+
+EnablingAppSandbox.html#//apple_ref/doc/uid/
+
+TP40011195-CH4-SW19]. These are added to the
+
+entitlements file with key
+com.apple.security.application-groups.
+
+ios.keychainAccessGroup
+
+Space-delimited list of keychain access groups
+
+ios.application_exits
+
+that this app has access to as described in
+
+Apple’s documentation [https://developer.apple.com/
+library/content/documentation/Security/Conceptual/
+
+keychainServConcepts/02concepts/concepts.html#//
+
+apple_ref/doc/uid/TP30000897-CH204-SW11]. These are
+
+added to the entitlements file with the key
+keychain-access-groups.
+
+true/false (defaults to false). Indicates whether
+
+the application should exit immediately on
+
+home button press. The default is to exit, leaving
+
+the application running is only partially tested at
+
+the moment.
+
+ios.blockScreenshotsOnEnterBackground
+
+true/false (defaults to false). Indicates that app
+
+should prevent iOS from taking screenshots
+
+when app enters background. Described here
+
+[https://shannah.github.io/cn1-recipes/#
+
+_hiding_sensitive_data_when_entering_background].
+
+567
+
+Name
+
+Description
+
+ios.applicationQueriesSchemes
+
+ios.themeMode
+
+ios.interface_orientation
+
+Comma separated list of url schemes that
+canExecute will respect on iOS. If the url scheme
+isn’t mentioned here canExecute will return false
+starting with iOS 9. Notice that this collides with
+ios.plistInject when used with the
+<key>LSApplicationQueriesSchemes</key>… value
+so you should use one or the other. E.g. to enable
+canExecute for a url like myurl://xys you can use:
+myurl,myotherurl
+
+default/legacy/modern/auto (defaults to default).
+
+Default means you don’t define a theme mode.
+
+Currently this is equivalent to legacy. In the
+
+future we will switch this to be equivalent to
+
+auto. legacy - this will behave like iOS 6
+
+regardless of the device you are running on.
+
+modern - this will behave like iOS 7 regardless of
+
+the device you are running on. auto - this will
+
+behave like iOS 6 on older devices and iOS 7 on
+
+newer devices.
+
+UIInterfaceOrientationPortrait by default.
+
+Indicates the orientation, one or more of
+
+(separated by colon :):
+
+UIInterfaceOrientationPortrait,
+
+UIInterfaceOrientationPortraitUpsideDown,
+
+UIInterfaceOrientationLandscapeLeft,
+
+UIInterfaceOrientationLandscapeRight. Notice
+
+that the IDE plugin has an "Interface
+
+Orientation" combo box you should use under
+
+the iOS section.
+
+ios.xcode_version
+
+The version of xcode used on the server.
+
+Defaults to 4.5; currently accepts 5.0 as an option
+
+and nothing else.
+
+ios.multitasking
+
+Set to true to enable iOS multitasking and split-
+
+screen support. This only works if
+ios.xcode_verson=9.2.
+
+Valid values include 5 or 8. Indicates the JVM
+
+version that should be used for server
+
+compilation, this is defined by default for newly
+
+created apps based on the Java 8 mode selection
+
+java.version
+
+568
+
+Name
+
+javascript.inject_proxy
+
+javascript.inject.beforeHead
+
+javascript.inject.afterHead
+
+javascript.minifying
+
+Description
+
+true/false (defaults to true) By default, the build
+server will configure the .war version of your
+
+app to use the bundled proxy servlet for HTTP
+
+requests (to get around same-origin restrictions
+on network requests). Setting this to false
+prevents this, causing the application to make
+
+network requests without a proxy.
+
+Content to be injected into the index.html file at
+the beginning of the <head> tag.
+
+Content to be injected into the index.html file at
+the end of the <head> tag.
+
+true/false (defaults to true). By default the
+javascript code is minified to reduce file size.
+
+You may optionally disable minification by
+setting javascript.minifying to false.
+
+javascript.proxy.url
+
+The URL to the proxy servlet that should be used
+
+javascript.sourceFilesCopied
+
+javascript.stopOnErrors
+
+for making network requests. If this is omitted,
+
+the .war version of the app will be set to use the
+
+bundled proxy servlet, and the .zip version of
+
+the app will be set to use no proxy. If
+javascript.inject_proxy is false, this build-hint
+will be ignored.
+
+true/false (defaults to false). Setting this flag to
+true will cause available java source files to be
+included in the resulting .zip and .war files.
+
+These may be used by Chrome during
+
+debugging.
+
+true/false (defaults to true). Cause javascript
+build to fail if there are warnings during the
+
+build. In some cases build warnings won’t affect
+
+the running of the app. E.g. if the Javascript port
+
+is missing a method that the app depends on, but
+
+it isn’t used in most of the app. Or if there is
+
+multithreaded code detected in static initializers,
+
+but that code-path isn’t used by the app. Setting
+this to false may allow you to get past some
+build errors, but it might just result in runtime
+
+errors later on, which are much more difficult to
+
+debug. *This build hint is only available in
+
+Codename One 3.4 and later.
+
+javascript.teavm.version
+
+(Optional) The version of TeaVM to use for the
+
+build. Use caution, only use this property if you
+
+know what you are doing!
+
+569
+
+Name
+
+rim.askPermissions
+
+Description
+
+true/false defaults to true. Indicates whether the
+
+user is prompted for permissions on Blackberry
+
+devices.
+
+google.adUnitId
+
+Allows integrating Admob/Google Play ads into
+
+rim.ignor_legacy
+
+rim.obfuscation
+
+the application see this
+
+[https://www.codenameone.com/blog/adding-google-play-
+
+ads.html]
+
+true/false defaults to false. When set to true the
+
+Blackberry build targets only 5.0 devices and
+
+newer and doesn’t build the 4.x version.
+
+rim.nativeBrowser true/false defaults to false.
+
+Enables the native blackberry browser on OS 5
+
+or higher. It is disabled by default since it might
+
+casue crashes on some cases.
+
+true/false defaults to false. Obfuscate the JAR
+
+before invoking the rimc compiler.
+
+ios.plistInject
+
+entries to inject into the iOS plist file during
+
+ios.includePush
+
+ios.newPipeline
+
+ios.headphoneCallback
+
+build.
+
+true/false (defaults to false). Whether to include
+
+the push capabilities in the iOS build. Notice that
+
+the IDE plugin has an "Include Push" check box
+
+you should use under the iOS section.
+
+Boolean true/false defaults to true. Allows
+
+toggling the OpenGL ES 2.0 drawing pipeline off
+
+to the older OGL ES 1.0 pipeline.
+
+Boolean true/false defaults to false. When set to
+
+true it assumes the main class has two methods:
+headphonesConnected & headphonesDisconnected
+which it invokes appropriately as needed
+
+ios.facebook_permissions
+
+Permissions for Facebook used in the Android
+
+build target, applicable only if Facebook native
+
+integration is used.
+
+ios.applicationDidEnterBackground
+
+Objective-C code that can be injected into the iOS
+
+callback method (message)
+applicationDidEnterBackground.
+
+ios.enableAutoplayVideo
+
+Boolean true/false defaults to false. Makes videos
+
+"auto-play" when loaded on iOS
+
+Allows integrating admob/google play ads, this is
+
+effectively identical to google.adUnitId but only
+
+applies to iOS
+
+ios.googleAdUnitId
+
+570
+
+Name
+
+ios.viewDidLoad
+
+Description
+
+Objective-C code that can be injected into the iOS
+callback method (message) viewDidLoad
+
+ios.googleAdUnitIdPadding
+
+Indicates the amount of padding to pass to the
+
+ios.enableBadgeClear
+
+Google ads placed at the bottom of the screen
+with google.adUnitId
+
+Boolean true/false defaults to true. Clears the
+
+badge value with every load of the app, this is
+
+useful if the app doesn’t manually keep track of
+
+number values for the badge
+
+ios.glAppDelegateHeader
+
+Objective-C code that can be injected into the iOS
+
+ios.glAppDelegateBody
+
+app delegate at the top of the file. E.g. if you
+
+need to include headers or make special imports
+
+for other injected code
+
+Objective-C code that can be injected into the iOS
+
+app delegate within the body of the file before
+
+the end. This only makes sence for methods that
+
+aren’t already declared in the class
+
+ios.beforeFinishLaunching
+
+Objective-C code that can be injected into the iOS
+
+app delegate at the top of the body of the
+
+didFinishLaunchingWithOptions callback
+
+method
+
+ios.afterFinishLaunching
+
+Objective-C code that can be injected into the iOS
+
+app delegate at the bottom of the body of the
+
+didFinishLaunchingWithOptions callback
+
+method
+
+ios.locationUsageDescription
+
+This flag is required for iOS 8 and newer if you
+
+are using the location API. It needs to include a
+
+description of the reason for which you need
+
+access to the users location
+
+571
+
+Name
+
+Description
+
+ios.NSXXXUsageDescription
+
+iOS privacy flags for using certain APIs. Starting
+
+with Xcode 8, you are required to add usage
+
+description strings for certain APIs. Find a full
+
+list of the available keys in Apple’s docs
+
+[https://developer.apple.com/library/content/
+documentation/General/Reference/
+
+InfoPlistKeyReference/Articles/CocoaKeys.html]. Some
+
+relevant ones include
+ios.NSCameraUsageDescription,
+ios.NSContactsUsageDescription,
+ios.NSLocationAlwaysUsageDescription,
+NSLocationUsageDescription,
+ios.NSMicrophoneUsageDescription,
+ios.NSPhotoLibraryAddUsageDescription,
+ios.NSSpeechRecognitionUsageDescription,
+ios.NSSiriUsageDescription
+
+A semicolon separated list of libraries that
+
+should be linked to the app in order to build it
+
+A comma separated list of Cocoa Pods
+
+[https://cocoapods.org/] that should be linked to the
+app in order to build it. E.g. AFNetworking ~> 2.6,
+ORStackView ~> 3.0, SwiftyJSON ~> 2.3
+
+Sets the Cocoapods 'platform' for the Cocoapods.
+
+Some Cocoapods require a minimum platform
+level. E.g. ios.pods.platform=7.0.
+
+ios.add_libs
+
+ios.pods
+
+ios.pods.platform
+
+ios.deployment_target
+
+Sets the deployment target for iOS builds. This is
+
+the minimum version of iOS required by a
+
+device to install the app. E.g.
+ios.deployment_target=8.0. Default is '6.0'. Note:
+This build hint interacts with the ios.rpmalloc
+build hint. If ios.deployment_target is 8.0 or
+higher, ParparVM will use rpmalloc
+
+[https://github.com/rampantpixels/rpmalloc] by
+
+default. You can disable this default and revert
+
+back to using malloc/free by setting the
+ios.rpmalloc=false build hint.
+
+Indicates the version number of the bundle, this
+
+is useful if you want to create a minor version
+
+number change for the beta testing support
+
+Added the -ObjC compile flag to the project files
+which some native libraries require
+
+ios.bundleVersion
+
+ios.objC
+
+572
+
+Name
+
+ios.testFlight
+
+Description
+
+Boolean true/false defaults to false and works
+
+only for pro accounts. Enables the testflight
+
+support in the release binaries for easy beta
+
+testing. Notice that the IDE plugin has a "Test
+
+Flight" check box you should use under the iOS
+
+section.
+
+ios.generateSplashScreens
+
+Boolean true/false defaults to false as of 5.0.
+
+desktop.width
+
+desktop.height
+
+desktop.adaptToRetina
+
+desktop.resizable
+
+Enable legacy generation of splash screen
+
+images for use when launching the app. These
+
+have been replaced now by the new launch
+
+storyboards.
+
+Width in pixels for the form in desktop builds,
+
+will be doubled for retina grade displays.
+
+Defaults to 800.
+
+Height in pixels for the form in desktop builds,
+
+will be doubled for retina grade displays.
+
+Defaults to 600.
+
+Boolean true/false defaults to true. When set to
+
+true some values will ve implicitly doubled to
+
+deal with retina displays and icons etc. will use
+
+higher DPI’s
+
+Boolean true/false defaults to true. Indicates
+
+whether the UI in the desktop build is resizable
+
+desktop.fontSizes
+
+Indicates the sizes in pixels for the system fonts
+
+desktop.theme
+
+desktop.themeMac
+
+desktop.themeWin
+
+as a comma delimited string containing 3
+
+numbers for small,medium,large fonts.
+
+Name of the theme res file to use as the "native"
+
+theme. By default this is native indicating iOS
+
+theme on Mac and Windows Metro on Windows.
+
+If its something else then the app will try to load
+
+the file /themeName.res.
+
+Same as desktop.theme but specific to Mac OS
+
+Same as desktop.theme but specific to Windows
+
+desktop.windowsOutput
+
+Can be exe or msi depending on desired results
+
+windows.extensions
+
+Content to be embedded into the <Extensions>
+section of the Package.appxmanifest file for
+
+windows (UWP) builds.
+
+573
+
+Name
+
+win.vm32bit
+
+noExtraResources
+
+j2me.iconSize
+
+Description
+
+true/false (defaults to false). Forces windows
+
+desktop builds to use the Win32 JVM instead of
+
+the 64 bit VM making them compatible with
+
+older Windows Machines. This is off by default
+
+at the moment because of a bug in JDK 8 update
+
+112 that might cause this to fail for some cases
+
+true/false (defaults to false). Blocks codename
+
+one from injecting its own resources when set to
+
+true, the only effect this has is in slightly
+
+reducing archive size. This might have adverse
+
+effects on some features of Codename One so it
+
+isn’t recommended.
+
+Defaults to 48x48. The size of the icon in the
+
+format of width x height (without the spacing).
+
+16.2. Offline Build
+
+ Offline build is an enterprise feature
+
+At  this  time  Codename  One  supports  iOS  &  Android  targets  for  offline  builds.  We  require  an
+
+Enterprise grade subscription as explained in the sidebar.
+
+ If you signup for Enterprise and cancel you can still do the offline build. You won’t
+
+be able to update the builder though
+
+Why only Enterprise?
+
+There are several reasons, the technical one is that offline builds are no panacea. Things fail.
+
+The support effort for offline builds is huge, as evidence despite the fact that all of our code is
+
+open source very few people bothered trying to compile it because of the complexities.
+
+We don’t think building offline is convenient and we always recommended avoiding it. When
+
+we  build  our  own  apps  we  use  the  cloud  just  like  everyone  else  because  it’s  surprisingly
+
+faster and more convenient…
+
+However,  some  government  and  regulated  industries  have  issues  with  SaaS  delivered
+
+solutions and thus must use offline build. These organizations also require enterprise grade
+
+support for most cases and so it makes sense to bundle as an enterprise only solution.
+
+16.2.1. Prerequisites for iOS Builds
+
+You need the following installed tools/versions for Codename One’s offline build process:
+
+• Mac ideally with El Capitan, newer should work
+
+574
+
+• Xcode 7+ (but not 8+ at this time)
+
+• Oracle’s JDK 8
+
+• Cocoapods - in the terminal type sudo gem install cocoapods --pre.
+
+• xcodeproj - in the terminal type sudo gem install xcodeproj
+
+16.2.2. Prerequisites for Android Builds
+
+Android builds need the following:
+
+• Android Studio
+
+• Oracle’s JDK 8
+
+• Gradle version 2.11
+
+16.2.3. Installation
+
+To build offline you need to install the offline builder code which is a stripped down version of the
+
+build  servers.  When  you  install  a  version  of  the  offline  builder  it  maps  to  the  time  in  which  you
+
+downloaded it…
+
+That means that features like versioned builds won’t work. You can download/keep multiple offline
+
+builders and toggle between them which is similar in scope.
+
+E.g. if you installed an offline builder then installed a newer version and the newer version has a
+
+bug  you  can  revert  to  the  old  version.  Notice  that  the  older  version  might  not  have  features  that
+
+exist in a newer version.
+
+
+
+Since installation requires an enterprise account, you might need to re-login in the
+
+Codename One Settings UI
+
+To  install  an  offline  builder  open  the  Codename  One  Settings  UI  by  right  clicking  the  project  and
+
+selecting Codename One → Codname One Settings.
+
+Figure 460. Open Codename One settings
+
+
+
+Even though the settings are a part of a project, the offline build settings are global
+
+and apply to all the projects…
+
+Once the Codename One settings UI launches select the Offline Builds entry:
+
+575
+
+Figure 461. Offline build entry
+
+This should launch the settings UI which would be blank the first time around:
+
+Figure 462. Offline builds setting UI
+
+When  you  are  in  this  form  you  can  press  the  download  button  to  download  the  current  version
+
+from the build server. If there is no update nothing will happen. If there is the latest version will
+
+download and tag with a version number/date.
+
+You  can  see/change  the  selected  version  in  this  UI.  This  allows  building  against  an  older  version.
+
+You can also delete older builds to save space.
+
+16.2.4. Building
+
+Offline building is almost like building with the cloud. In the right click menu you can select one of
+
+the offline build targets as such:
+
+Figure 463. The offline build targets
+
+Once selected build generates a project under the build/and or build/iphone respectively.
+
+Open  these  directories  in  Android  Studio  or  xcode  to  run/build  in  the  native  IDE  to  the  device  or
+
+native emulator/simulator.
+
+ Build deletes previous offline builds, if you want to keep the sources of a build you
+
+need to move it to a different directory!
+
+To  get  this  to  work  with  Android  Studio  you  will  need  one  more  step.  You  will  need  to  configure
+
+Android studio to use your local version of gradle 2.11 by following these steps:
+
+• Open the Android Studio preferences
+
+576
+
+Figure 464. Android Studio Preferences
+
+• Select Build, Execution, Deployment → Build Tools → Gradle
+
+• Select the Use Local gradle distribution
+
+• Press the … and pick your local gradle 2.11 install
+
+Figure 465. Local gradle config
+
+16.2.5. FAQ
+
+Should I use the Offline Builder?
+
+Probably not.
+
+Cloud build is far more convenient, simple. Doesn’t require any installs (other than the plugin) and
+
+is much faster.
+
+We built this tool for developers who work in situations that prohibit cloud build. E.g. government,
+
+banking etc. where regulation is restrictive.
+
+Can I Move/Backup my Builders?
+
+No.
+
+We protect all the builders to avoid abuse. If you backup and restore on a new system the builders
+
+might stop working even if you are a paying enterprise customer.
+
+Can I install the builders for all our developers?
+
+Our  licensing  terms  require  a  parallel  developer  seat  for  the  Codename  One  developers  in  your
+
+company.  If  you  have  5  Codename  One  developers  they  must  all  have  an  enterprise  developer
+
+577
+
+account to comply.
+
+E.g. You can’t have one enterprise account and 4 basic accounts.
+
+The reason behind this is simple, in the past we saw a lot of funneling from developers who built
+
+such a licensing structure.
+
+What Happens if I Cancel?
+
+If you cancel your enterprise subscription all your existing installed offline builders should work as
+
+before but you won’t be able to update them or get support for this.
+
+When are Versions Released?
+
+We will try to keep this in the same release pace as library updates i.e. once a week typically on a
+
+Friday.
+
+Are Version Numbers Sequential?
+
+They  grow  but  we  sometimes  skip  versions.  Versions  map  to  our  cloud  deployment  versioning
+
+scheme and we might skip versions in some cases.
+
+Why is this Feature Limited to Enterprise Subscribers?
+
+This is a complex tool to support & maintain. SaaS has a well defined business model where we can
+
+reduce prices and maintenance costs.
+
+Offline builds are more like a shrinkwrap business model in which case our pricing needs to align
+
+itself to shrinkwrap pricing models for long term sustainability.
+
+The main use case this product tries to address is government and highly regulated industries who
+
+are in effect enterprise users.
+
+How Different is the Code From Cloud Builds?
+
+We use the same code as we do in the cloud build process with minor modifications in the process.
+
+Since the cloud servers are setup by us they work differently but should align reasonably well.
+
+16.3. Android Permissions
+
+One  of  the  annoying  tasks  when  programming  native  Android  applications  is  tuning  all  the
+
+required permissions to match your codes requirements, Codename One aims to simplify this. The
+
+build server automatically introspects the classes sent to it as part of the build and injects the right
+
+set of permissions required by the app.
+
+However, sometimes developers might find the permissions that come up a bit confusing and might
+
+not  understand  why  a  specific  permission  came  up.  This  maps  Android  permissions  to  the
+
+methods/classes in Codename One that would trigger them. Notice that this list isn’t exhaustive as
+
+the API is rather large:
+
+578
+
+android.permission.WRITE_EXTERNAL_STORAGE - this permission appears by default for Codename One
+applications,  since  the  FileSystemStorage  API  (which  is  used  extensively)  might  have  some
+hint
+dependencies 
+android.blockExternalStoragePermission=true,  notice  that  this  is  something  we  don’t  test  and  it
+might fail on devices.
+
+explicitly 
+
+disable 
+
+using 
+
+build 
+
+You 
+
+can 
+
+the 
+
+on 
+
+it. 
+
+it 
+
+android.permission.INTERNET  -  this  is  a  hardcoded  permission  in  Codename  One,  the  ability  to
+connect to the network is coded into all Codename One applications.
+
+android.hardware.camera 
+com.codename1.Capture
+
+& 
+
+android.permission.RECORD_AUDIO 
+
+- 
+
+are 
+
+triggered 
+
+by
+
+android.permission.RECORD_AUDIO  -  is  triggered  by  usage  of  MediaManager.createMediaRecorder()  &
+Display.createMediaRecorder()
+
+android.permission.READ_PHONE_STATE 
+package,
+com.codename1.media,
+com.codename1.components.Ads, 
+com.codename1.push, Display.getUdid() & Display.getMsisdn(). This permission is required for media
+in order to suspend audio playback when you get a phone call.
+
+triggered 
+com.codename1.components.ShareButton, 
+
+com.codename1.ads 
+
+by 
+
+is 
+
+- 
+
+android.hardware.location, 
+android.permission.ACCESS_FINE_LOCATION, 
+android.permission.ACCESS_COARSE_LOCATION - map to com.codename1.maps & com.codename1.location.
+
+android.hardware.location.gps,
+&
+
+android.permission.ACCESS_MOCK_LOCATION 
+
+package.permission.C2D_MESSAGE, 
+android.permission.RECEIVE_BOOT_COMPLETED - are requested by the com.codename1.push package
+
+com.google.android.c2dm.permission.RECEIVE,
+
+android.permission.READ_CONTACTS 
+Display.getAllContacts().
+
+- 
+
+triggers  by 
+
+the  package 
+
+com.codename1.contacts  &
+
+android.permission.VIBRATE - is triggered by Display.vibrate() and Display.notifyStatusBar()
+
+android.permission.SEND_SMS - is triggered by Display.sendSMS()
+
+android.permission.WAKE_LOCK 
+Display.setScreenSaverEnabled()
+
+- 
+
+is 
+
+triggered 
+
+by 
+
+Display.lockScreen() 
+
+&
+
+android.permission.WRITE_CONTACTS 
+is 
+Display.deleteContact(), ContactsManager.createContact() & ContactsManager.deleteContact()
+
+Display.createContact(),
+
+triggered 
+
+by 
+
+- 
+
+16.3.1. Permissions Under Marshmallow (Android 6+)
+
+Starting with Marshmallow (Android 6+ API level 23) Android shifted to a permissions system that
+
+prompts users for permission the first time an API is used e.g. when accessing contacts the user will
+
+receive a prompt whether to allow contacts access.
+
+ Permission  can  be  denied  and  a  user  can  later  on  revoke/grant  a  permission  via
+
+external settings UI
+
+This  is  really  great  as  it  allows  apps  to  be  installed  with  a  single  click  and  no  permission  prompt
+
+during install which can increase conversion rates!
+
+579
+
+Enabling Permissions
+
+Codenmae One compiles Android targets with SDK level 23 but not with target level 23!
+
+This means that by default the new permission mode is still off and you won’t see any of the effects
+
+mentioned below.
+
+ This will probably change to the default in the future but at the moment the target
+
+SDK defaults to 21
+
+To  activate  this  functionality  you  will  need  to  set  the  target  SDK  to  level  23  by  using  the
+android.targetSDKVersion=23 build hint.
+
+Permission Prompts
+
+To test this API see the following simple contacts app:
+
+Form f = new Form("Contacts", BoxLayout.y());
+f.add(new InfiniteProgress());
+Display.getInstance().invokeAndBlock(() -> {
+    Contact[] ct = Display.getInstance().getAllContacts(true, true, false, true, true, false);
+    Display.getInstance().callSerially(() -> {
+        f.removeAll();
+        for(Contact c : ct) {
+            MultiButton mb = new MultiButton(c.getDisplayName());
+            mb.setTextLine2(c.getPrimaryPhoneNumber());
+            f.add(mb);
+        }
+        f.revalidate();
+    });
+});
+
+f.show();
+
+When we try to install this app without changing anything on an Android 6 device we see this UI:
+
+Figure 466. Install UI when using the old permissions system
+
+When we set android.targetSDKVersion=23 in the build hints and try to install again the UI looks like
+
+580
+
+this:
+
+Figure 467. Install UI when using the new permissions system
+
+When we launch the UI under the old permissions system we see the contacts instantly. In the new
+
+system we are presented with this UI:
+
+Figure 468. Native permission prompt first time
+
+If  we  accept  and  allow  all  is  good  and  the  app  loads  as  usual  but  if  we  deny  then  Codename  One
+
+gives the user another chance to request the permission. Notice that in this case you can customize
+
+the prompt string as explained below.
+
+Figure 469. Codename One permission prompt
+
+581
+
+If we select don’t ask then you will get a blank screen since the contacts will return as a 0 length
+
+array. This makes sense as the user is aware he denied permission and the app will still function as
+
+expected on a device where no contacts are available. However, if the user realizes his mistake he
+
+can double back and ask to re-prompt for permission in which case he will see this native prompt:
+
+Figure 470. Native permission prompt second time
+
+Notice that denying this second request will not trigger another Codename One prompt.
+
+Code Changes
+
+There are no explicit code changes needed for this functionality to "just work". The respective API’s
+
+will work just like they always worked and will prompt the user seamlessly for permissions.
+
+
+
+Some  behaviors  that  never  occurred  on  Android  but  were  perfectly  legal  in  the
+
+past  might  start  occurring  with  the  switch  to  the  new  API.  E.g.  the  location
+
+manager  might  be  null  and  your  app  must  always  be  ready  to  deal  with  such  a
+
+situation
+
+When  permission  is  requested  a  user  will  be  seamlessly  prompted/warned,  Codename  One  has
+
+builtin text to control such prompts but you might want to customize the text. You can customize
+permission text via the Display properties e.g. to customize the text of the contacts permission we
+can do something such as:
+
+Display.getInstance().setProperty("android.permission.READ_CONTACTS", "MyCoolChatApp needs access to your contacts so we
+can show you which of your friends already have MyCoolChatApp installed");
+
+This  is  optional  as  there  is  a  default  value  defined.  You  can  define  this  once  in  the  init(Object)
+method but for some extreme cases permission might be needed for different things e.g. you might
+
+ask  for  this  permission  with  one  reason  at  one  point  in  the  app  and  with  a  different  reason  at
+
+another point in the app.
+
+following  permission  keys  are  supported: 
+
+The 
+"android.permission.READ_PHONE_STATE"
+android.permission.ACCESS_FINE_LOCATION,
+android.permission.WRITE_EXTERNAL_STORAGE, 
+android.permission.SEND_SMS,  android.permission.READ_CONTACTS,  android.permission.WRITE_CONTACTS,
+android.permission.RECORD_AUDIO.
+
+582
+
+Simulating Prompts
+
+You can simulate permission prompts by checking that option in the simulator menu.
+
+Figure 471. Simulate permission prompts menu item in the simulator
+
+This  will  produce  a  dialog  to  the  user  whenever  this  happens  in  Android  and  will  try  to  act  in  a
+
+similar way to the device. Notice that you can test it in the iOS simulator too.
+
+AndroidNativeUtil’s checkForPermission
+
+If  you  write  Android  native  code  using  native  interfaces  you  are  probably  familiar  with  the
+AndroidNativeUtil class from the com.codename1.impl.android package.
+
+This  class  provides  access  to  many  low  level  capabilities  you  would  need  as  a  developer  writing
+
+native  code.  Since  native  code  might  need  to  request  a  permission  we  introduced  the  same
+underlying logic we used namely: checkForPermission.
+
+To get a permission you can use this code as such:
+
+if(!AndroidNativeUtil.checkForPermission(
+    Manifest.permission.READ_PHONE_STATE, "
+    This should be the description shown to the user...")){
+    // you didn't get the permission, you might want to return here
+}
+// you have the permission, do what you need
+
+This  will  prompt  the  user  with  the  native  UI  and  later  on  with  the  fallback  option  as  described
+above.  Notice  that  the  checkForPermission  method  is  a  blocking  method  and  it  will  return  when
+there  is  a  final  conclusion  on  the  subject.  It  uses  invokeAndBlock  and  can  be  safely  invoked  on  the
+event dispatch thread without concern.
+
+16.4. On Device Debugging
+
+Codename One supports debugging applications on devices by using the natively generated project.
+
+All paid subscription levels include the ability to check an  Include Source flag in the settings that
+
+returns a native OS project. You can debug that project in the respective native IDE.
+
+In iOS this is usually strait forward, just open the project with xcode and run it optionally disabling
+bitcode.  Unzip  the  .bz2  file  and  open  the  .xcworkspace  file  if  it’s  available  otherwise  open  the
+.xcodeproj file inside the dist directory.
+
+583
+
+ Only the .xcworkspace if it is there, it is activated by the CocoaPods build pipeline
+
+so it won’t always be there
+
+With Android Studio this is sometimes as very easy task as it is possible to actually open the gradle
+
+project in Android Studio and just run it. However, due to the fragile nature of the gradle project
+
+this stopped working for some builds and has been "flaky".
+
+16.4.1. Android Studio Debugging (Easy Way)
+
+By  default  you  should  be  able  to  open  the  gradle  project  in  Android  Studio  and  just  run  it.  To  get
+
+this to work open the Android Studio Setting and select gradle 2.11.
+
+Figure 472. Gradle settings UI in Android Studio (notice you need gradle 2.11 and not 2.8 as pictured here)
+
+If this works for you then you can ignore the section below.
+
+16.4.2. Android Studio Debugging the Hard Way
+
+In some cases the gradle project might not work or this might fail with a change from Google.
+
+Here are steps that should work for everyone:
+
+1. Check the include source flag in the IDE and send a build
+
+2. Download the sources.zip result from the build server
+
+3. Launch Android Studio and create a new project
+
+4. Make  sure  to  use  the  same  package  and  app  name  as  you  did  in  the  Codename  One  project,
+
+select to not create an activity
+
+5. Unzip  the  sources.zip  file  and  copy  the  main  directory  from  its  src  directory  to  the  Android
+
+Studio projects src directory make sure to overwrite files/directories.
+
+6. Copy its libs directory on top of the existing libs
+
+7. Copy the source gradle dependencies content to the destination gradle file
+
+8. Connect your device and press the Debug button for the IDE
+
+ You might need to copy additional gradle file meta-data such as multi-dexing etc.
+
+You  might  not  need  to  repeat  the  whole  thing  with  every  build.  E.g.  it  might  be  practical  to  only
+
+584
+
+copy the userSources.jar from the libs directory to get the latest version of your code. You can copy
+the src/main directory to get the latest up to date Android port.
+
+16.5. Native Interfaces
+
+Sometimes you may wish to use an API that is unsupported by Codename One or integrate with a
+
+3rd party library/framework that isn’t supported. These are achievable tasks when writing native
+
+code and Codename One lets you encapsulate such native code using native interfaces.
+
+16.5.1. Introduction
+
+Notice  that  when  we  say  "native"  we  do  not  mean  C/C++  always  but  rather  the  platforms  "native"
+
+environment. So in the case of Android the Java code will be invoked with full access to the Android
+
+API, in case of iOS an Objective-C message would be sent and so forth.
+
+
+
+You  can  still  access  C  code  under  Android  either  by  using  JNI  from  the  Android
+
+native code or by using a library
+
+Native  interfaces  are  designed  to  only  allow  primitive  types,  Strings,  arrays  of  primitive  types
+
+(single  dimension  only)  &  PeerComponent  [https://www.codenameone.com/javadoc/com/codename1/ui/
+
+PeerComponent.html] values. Any other type of parameter/return type is prohibited. However, once in
+
+the native layer the native code can act freely and query the Java layer for additional information.
+
+
+
+The  reason  for  the  limits  is  the  disparity  between  the  platforms.  Mapping  a  Java
+Object  to  an  Objective-C  NSObject  is  possible  but  leads  to  odd  edge  cases  and
+complexity e.g. GC vs. ARC in a disparate object graph
+
+Furthermore,  native  methods  should  avoid  features  such  as  overloading,  varargs  (or  any  Java  5+
+
+feature for that matter) to allow portability for languages that do not support such features.
+
+ Do  not  rely  on  pass  by  reference/value  behavior  since  they  vary  between
+
+platforms
+
+Implementing a native layer effectively means:
+
+1. Creating  an  interface  that  extends  NativeInterface  [https://www.codenameone.com/javadoc/com/
+
+codename1/system/NativeInterface.html] and only defines methods with the arguments/return values
+
+declared in the previous paragraph.
+
+2. Creating  the  proper  native  implementation  hierarchy  based  on  the  call  conventions  for  every
+
+platform within the native directory
+
+E.g. to create a simple hello world interface do something like:
+
+585
+
+package com.mycompany.myapp;
+import com.codename1.system.NativeInterface;
+public interface MyNative extends NativeInterface {
+    String helloWorld(String hi);
+}
+
+We now need to right click the class in the IDE and select the Generate Native Access menu item:
+
+Figure 473. Generating the native code
+
+Figure 474. Once generated we are prompted that the native code is in the "native" directory
+
+We can now look int the  native directory in the project root (in NetBeans you can see that in the
+
+Files tab) and you can see something that looks like this:
+
+Figure 475. Native directory structure containing stubs for the various platforms
+
+These are effectively stubs you can edit to implement the methods in native code.
+
+586
+
+
+
+If you re-run the Generate Native Access tool you will get this dialog, if you answer
+
+yes  all  the  files  will  be  overwritten,  if  you  answer  no  only  files  you
+
+deleted/renamed will be recreated
+
+Figure 476. Running "Generate Native Access" when some/all of the native files exist already
+
+For now lets leave the stubs and come back to them soon. From the Codename One Java code we
+
+can call the implementation of this native interface using:
+
+MyNative my = NativeLookup.create(MyNative.class);
+if(my != null && my.isSupported()) {
+    Log.p(my.helloWorld("Hi"));
+}
+
+Notice that for this to work you must implement the native code on all supported platforms.
+
+We’ll start with Android which should be familiar and intuitive to many developers, this is how the
+generated file under the native/android directory looks:
+
+package com.mycompany.myapp;
+
+public class MyNativeImpl {
+    public String helloWorld(String param) {
+        return null;
+    }
+
+    public boolean isSupported() {
+        return false;
+    }
+
+}
+
+The stub implementation always returns false, null or 0 by default. The isSupported also defaults to
+false  thus  allowing  us  to  implement  a  NativeInterface  on  some  platforms  and  leave  the  rest  out
+without really knowing anything about these platforms.
+
+We can implement the Android version using code similar to this:
+
+587
+
+package com.mycompany.myapp;
+
+import android.util.Log; ①
+
+public class MyNativeImpl { ②
+    ③
+    public String helloWorld(String param) {
+        Log.d("MyApp", param);
+        return "Tada";
+    }
+
+    public boolean isSupported() { ④
+        return true;
+    }
+}
+
+① Notice  that  we  are  using  the  Android  native  android.util.Log  class  which  isn’t  accessible  from
+
+standard Codename One code
+
+② The impl class doesn’t physically implement the MyNative interface!
+
+This is intentional and due to the PeerComponent functionality mentioned below. You don’t need
+to add an implements clause.
+
+③ Notice that there is no constructor and the class is public. It is crucial that the system will be able
+to  allocate  the  class  without  obstruction.  You  can  use  a  constructor  but  it  can’t  have  any
+
+arguments and you shouldn’t rely on semantics of construction.
+
+④ We implemented the native method and that we set isSupported to true.
+
+The IDE won’t provide completion suggestions and will claim that there are errors
+
+in the code!
+
+Codename  One  doesn’t  include  the  native  platforms  in  its  bundle  e.g.  the  full
+
+Android SDK or the full xcode Objective-C runtime. However, since the native code
+
+is compiled on the servers (where these runteims are present) this shouldn’t be a
+
+problem
+
+When  implementing  a  non-trivial  native  interface,  send  a  server  build  with  the
+
+"Include Source" option checked. Implement the native interface in the native IDE
+
+then copy and paste the native code back into Codename One
+
+
+
+
+
+The implementation of this interface is nearly identical for Android, J2ME & Java SE.
+
+Use the Android Main Thread (Native EDT)
+
+iOS,  Android  &  pretty  much  any  modern  OS  has  an  EDT  like  thread  that  handles  events  etc.  The
+
+problem is that they differ in their nuanced behavior. E.g. Android will usually respect calls off of
+
+the EDT and iOS will often crash. Some OS’s enforce EDT access rigidly and will throw an exception
+
+when you violate that…
+
+Normally  you  don’t  need  to  know  about  these  things,  hidden  functionality  within  our
+
+588
+
+implementation bridges between our EDT and the native EDT to provide consistent cross platform
+
+behavior. But when you write native code you need awareness.
+
+Why not Implicitly call Native Interfaces on the Native EDT?
+
+Calling into the native EDT includes overhead and it might not be necessary for some features
+
+(e.g. IO, polling etc.). Furthermore, some calls might work well with asynchronous calls while
+
+others might need synchronous results and we can’t know in advance which ones you would
+
+need.
+
+How do we Access the Native EDT?
+
+Within your native code in Android do something like:
+
+com.codename1.impl.android.AndroidNativeUtil.getActivity().runOnUiThread(new Runnable() {
+    public void run() {
+       // your native code here...
+    }
+});
+
+This  will  execute  the  block  within  run()  asynchronously  on  the  native  Android  UI  thread.  If  you
+need synchronous execution we have a special method for Codename One:
+
+com.codename1.impl.android.AndroidImplementation.runOnUiThreadAndBlock(new Runnable() {
+    public void run() {
+       // your native code here...
+    }
+});
+
+This blocks in a way that’s OK with the Codename One EDT which is unique to our Android port.
+
+Gradle Dependencies
+
+Integrating a native OS library isn’t hard but it sometimes requires some juggling. Most instructions
+
+target  developers  working  with  xcode  or  Android  Studio  &  you  need  to  twist  your  head  around
+
+them. In Android the steps for integration in most modern libraries include a gradle dependency.
+
+E.g.  we  published  a  library  that  added  support  for  Intercom  [https://www.codenameone.com/blog/
+
+intercom-support.html]. The native Android integration instructions for the library looked like this:
+
+Add the following dependency to your app’s build.gradle file:
+
+dependencies {
+    compile 'io.intercom.android:intercom-sdk:3.+'
+}
+
+589
+
+Which instantly raises the question: "How in the world do I do that in Codename One"?
+
+Well, it’s actually pretty simple. You can add the build hint:
+
+android.gradleDep=compile 'io.intercom.android:intercom-sdk:3.+'
+
+This would "work" but there is a catch…
+
+You  might  need  to  define  the  specific  version  of  the  Android  SDK  used  and  specific  version  of
+
+Google play services version used. Intercom is pretty sensitive about those and demanded that we
+
+also add:
+
+android.playServices=9.8.0
+android.sdkVersion=25
+
+Once  those  were  defined  the  native  code  for  the  Android  implementation  became  trivial  to  write
+
+and the library was easy as there were no jars to include.
+
+16.5.2. Objective-C (iOS)
+
+When  generating  the  Objective-C  code  the  "Generate  Native  Sources"  tool  produces  two  files:
+com_mycompany_myapp_MyNativeImpl.h & com_mycompany_myapp_MyNativeImpl.m.
+
+The  .m  files  are  the  Objective-C  equivalent  of  .c  files  and  .h  files  contain  the  header/include
+information. In this case the com_mycompany_myapp_MyNativeImpl.h contains:
+
+#import <Foundation/Foundation.h>
+
+@interface com_mycompany_myapp_MyNativeImpl : NSObject {
+}
+
+-(NSString*)helloWorld:(NSString*)param;
+-(BOOL)isSupported;
+@end
+
+And com_mycompany_myapp_MyNativeImpl.m contains:
+
+590
+
+#import "com_mycompany_myapp_MyNativeImpl.h"
+
+@implementation com_mycompany_myapp_MyNativeImpl
+
+-(NSString*)helloWorld:(NSString*)param{
+    return nil;
+}
+
+-(BOOL)isSupported{
+    return NO;
+}
+
+@end
+
+
+
+Objective-C relies on argument names as part of the message (method) signature.
+
+-(NSString*)helloWorld:(NSString*)param 
+
+So 
+-(NSString*)helloWorld:(NSString*)iChangedThisName!
+Don’t change argument names in the Objective-C native interface!
+
+isn’t 
+
+the 
+
+same 
+
+as
+
+Here is a simple implementation similar to above:
+
+#import "com_mycompany_myapp_MyNativeImpl.h"
+
+@implementation com_mycompany_myapp_MyNativeImpl
+
+-(NSString*)helloWorld:(NSString*)param{
+    NSLog(@"MyApp: %@", param);
+    return @"Tada";
+}
+
+-(BOOL)isSupported{
+    return YES;
+}
+
+@end
+
+Using the iOS Main Thread (Native EDT)
+
+iOS has a native thread you should use for all calls just like Android. Check out the Native EDT on
+
+Android section above for reference.
+
+On iOS this is pretty similar to Android (if you consider objective-c to be similar). This is used for
+
+asynchronous invocation:
+
+591
+
+dispatch_async(dispatch_get_main_queue(), ^{
+    // your native code here...
+});
+
+You can use this for synchronous invocation, notice the lack of the a in the dispatch call:
+
+dispatch_sync(dispatch_get_main_queue(), ^{
+    // your native code here...
+});
+
+The problem with the synchronous call is that it will block the caller thread, if the caller thread is
+
+the EDT this can cause performance issues and even a deadlock. It’s important to be very cautious
+
+with this call!
+
+Use Cocoapods For Dependencies
+
+Cocoapods are the iOS equivalent of gradle dependencies.
+
+CocoaPods  allow  us  to  add  a  native  library  dependency  to  iOS  far  more  easily  than  Gradle.  By
+
+default  we  target  iOS  7.0  or  newer  which  is  supported  by  Intercom  only  for  older  versions  of  the
+
+library. Annoyingly CocoaPods might seem to work but some specific API’s won’t work since it fell
+
+back  to  an  older  version…  To  solve  this  you  have  to  explicitly  define  the  build  hint
+ios.pods.platform=8.0 to force iOS 8 or newer. You might need to force it to even newer versions as
+some libraries force an iOS 9 minimum etc.
+
+Including  intercom  itself  required  a  single  build  hint:  ios.pods=Intercom  which  you  can  obviously
+extend  by  using  commas  to  include  multiple  libraries.  You  can  search  the  cocoapods  website
+
+[https://cocoapods.org/] for supported 3rd party libraries which includes everything you would expect.
+
+One  important  advantage  when  working  with  CocoaPods  is  the  faster  build  time  as  the  upload  to
+
+the Codename One website is smaller and the bandwidth we have to CocoaPods is faster. Another
+
+advantage is the ability to keep up with the latest developments from the library providers.
+
+16.5.3. Javascript
+
+Native  interfaces  in  Javascript  look  a  little  different  than  the  other  platforms  since  Javascript
+
+doesn’t  natively  support  threads  or  classes.  The  native  implementation  should  be  placed  in  a  file
+
+with name matching the name of the package and the class name combined where the "." elements
+
+are replaced by underscores.
+
+The default generated stubs for the JavaScript build look like this com_mycompany_myapp_MyNative:
+
+592
+
+(function(exports){
+
+var o = {};
+
+    o.helloWorld__java_lang_String = function(param1, callback) {
+        callback.error(new Error("Not implemented yet"));
+    };
+
+    o.isSupported_ = function(callback) {
+        callback.complete(false);
+    };
+
+exports.com_mycompany_myapp_MyNative= o;
+
+})(cn1_get_native_interfaces());
+
+A simple implementation looks like this.
+
+(function(exports){
+
+var o = {};
+
+    o.helloWorld__java_lang_String = function(param1, callback) {
+        callback.complete("Hello World!!!");
+    }
+
+    o.isSupported_ = function(callback) {
+        callback.complete(true);
+    };
+
+exports.com_my_code_MyNative = o;
+
+})(cn1_get_native_interfaces());
+
+Notice that we use the complete() method of the provided callback to pass the return value rather
+than  using  the  return  statement.  This  is  to  work  around  the  fact  that  Javascript  doesn’t  natively
+support threads. The Java thread that is calling your native interface will block until your method
+calls  callback.complete().  This  allows  you  to  use  asynchronous  APIs  inside  your  native  method
+while still allowing Codename One to work use your native interface via a synchronous API.
+
+
+
+Make sure you call either callback.complete() or callback.error() in your method
+at some point, or you will cause a deadlock in your app (code calling your native
+
+method will just sit and "wait" forever for your method to return a value).
+
+The  naming  conventions  for  the  methods  themselves  are  modeled  after  the  naming  conventions
+
+shown in the previous examples:
+
+<method-name>__<param-1-type>_<param-2-type>_…<param-n-type>
+
+593
+
+Where  <method-name>  is  the  name  of  the  method  in  Java,  and  the  `<param-X-type>`s  are  a  string
+representing the parameter type. The general rule for these strings are:
+
+1. Primitive types are mapped to their type name. (E.g. int to "int", double to "double", etc…).
+
+2. Reference  types  are  mapped  to  their  fully-qualified  class  name  with  '.'  replaced  with
+
+underscores. E.g. java.lang.String would be "java_lang_String".
+
+3. Array  parameters  are  marked  by  their  scalar  type  name  followed  by  an  underscore  and
+"1ARRAY". E.g. int[] would be "int_1ARRAY" and String[] would be "java_lang_String_1ARRAY".
+
+JavaScript Examples
+
+Java API:
+
+public void print(String str);
+
+becomes
+
+o.print__java_lang_String = function(param1, callback) {
+    console.log(param1);
+    callback.complete();
+}
+
+Java API:
+
+public int add(int a, int b);
+
+becomes
+
+o.add__int_int = function(param1, param2, callback) {
+    callback.complete(param1 + param2);
+}
+
+public int add(int[] a);
+
+becomes
+
+594
+
+o.add__int_1ARRAY = function(param1, callback) {
+    var c = 0, len = param1.length;
+    for (var i =0; i<len; i++) {
+        c += param1[i];
+    }
+    callback.complete(c);
+}
+
+16.5.4. Native GUI Components
+
+PeerComponent 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/PeerComponent.html] 
+
+return
+
+values are automatically translated to the platform native peer as an expected return value. E.g. for
+a NativeInterface method such as this:
+
+public PeerComponent` createPeer();
+
+Android native implementation would use:
+
+public View createPeer() {
+    return null;
+}
+
+The iphone would need to return a pointer to a view e.g.:
+
+- (UIView*)createPeer;
+
+
+
+Not  all  platforms  support  native  peers.  Specifically  JavaSE  doesn’t  support  them
+
+due to the way the JavaSE native interfaces are mapped to their implementation.
+
+Note that this won’t limit the code from running on an unsupported platform. Only
+
+that specific method won’t work.
+
+Javascript would expect a DOM Element (e.g. a <div> tag to be returned.). E.g.
+
+o.createHelloComponent_ = function(callback) {
+    var c = jQuery('<div>Hello World</div>')
+            .css({'background-color' : 'yellow', 'border' : '1px solid blue'});
+    callback.complete(c.get(0));
+};
+
+Notice that if you want to use a native library (jar, .a file etc.) just places it within the appropriate
+
+native  directory  and  it  will  be  packaged  into  the  final  executable.  You  would  only  be  able  to
+
+reference it from the native code and not from the Codename One code, which means you will need
+
+to build native interfaces to access it.
+
+595
+
+This is discussed further below.
+
+16.5.5. Type Mapping & Rules
+
+Several rules govern the creation of NativeInterfaces and we only briefly covered some of them.
+
+• The implementation class must have a default public constructor or no constructor at all
+
+• Native methods can’t throw exceptions, checked or otherwise
+
+• A native method can’t have the name init as this is a reserved method in Objective-C
+
+• Only the supported types listed below can be used
+
+• Native implementations can’t rely on pass by reference/value semantics as those might change
+
+between platforms
+
+• hashCode, equals & toString are reserved and won’t be mapped to native code
+
+Table 11. NativeInterface Supported Types
+
+Android
+
+JavaSE
+
+Obj-C
+
+C#
+
+byte
+
+boolean
+
+boolean
+
+Java
+
+byte
+
+boolean
+
+int
+
+short
+
+long
+
+float
+
+sbyte[]
+
+char[]
+
+short[]
+
+int[]
+
+byte
+
+BOOL
+
+char
+
+int
+
+long
+
+float
+
+char
+
+bool
+
+short
+
+int
+
+long
+
+float
+
+double
+
+byte[]
+
+sbyte
+
+char
+
+short
+
+int
+
+long long
+
+float
+
+String
+
+byte[]
+
+double
+
+double
+
+NSString*
+
+String
+
+char[]
+
+short[]
+
+char[]
+
+NSData
+
+NSData*
+
+short[]
+
+NSData*
+
+int[]
+
+NSData*
+
+long[]
+
+float[]
+
+long[]
+
+float[]
+
+char
+
+short
+
+int
+
+long
+
+double
+
+String
+
+byte[]
+
+char[]
+
+int[]
+
+long[]
+
+float[]
+
+char
+
+short
+
+int
+
+float
+
+double
+
+String
+
+NSSData*
+
+bool[]
+
+short[]
+
+int[]
+
+long[]
+
+NSData*
+
+boolean[]
+
+boolean[]
+
+boolean[]
+
+NSData*
+
+float[]
+
+double[]
+
+double[]
+
+double[]
+
+NSData*
+
+double[]
+
+
+
+JavaScript is excluded from the table above as it isn’t a type safe language and thus
+
+has no such type mapping
+
+ PeerComponent on iOS is void* but UIView is expected as a result
+
+The examples below demonstrate the signatures for this method on all platforms:
+
+596
+
+Listing 22. NativeInterface definition
+
+public void test(byte b, boolean boo, char c, short s,
+    int i, long l, float f, double d, String ss,
+    byte[] ba, boolean[] booa, char[] ca, short[] sa, int[] ia,
+    long[] la, float[] fa, double[] da,
+    PeerComponent cmp);
+
+Listing 23. Android Version
+
+public void test(byte param, boolean param1, char param2,
+    short param3, int param4, long param5, float param6,
+    double param7, String param8, byte[] param9,
+    boolean[] param10, char[] param11, short[] param12,
+    int[] param13, long[] param14, float[] param15,
+    double[] param16, android.view.View param17) {
+}
+
+Listing 24. iOS Version
+
+-(void)test:(char)param param1:(BOOL)param1
+    param2:(int)param2 param3:(short)param3 param4:(int)param4
+    param5:(long long)param5 param6:(float)param6
+    param7:(double)param7 param8:(NSString*)param8
+��   param9:(NSData*)param9 param10:(NSData*)param10
+    param11:(NSData*)param11 param12:(NSData*)param12
+    param13:(NSData*)param13 param14:(NSData*)param14
+    param15:(NSData*)param15 param16:(NSData*)param16
+    param17:(void*)param17;
+}
+
+ We had to break lines for the print version, the JavaScript version is a really long
+
+method name that literally broke the book!
+
+Listing 25. JavaScript Version
+
+o.test__byte_boolean_char_short_int_long_float_double
+_java_lang_String_byte_1ARRAY_boolean_1ARRAY_char_1ARRAY
+_short_1ARRAY_int_1ARRAY_long_1ARRAY_float_1ARRAY_double
+_1ARRAY_com_codename1_ui_PeerComponent = function(param1, param2, param3, param4, param5, param6, param7, param8, param9,
+param10, param11, param12, param13, param14, param15, param16, param17, param18, callback) {
+    callback.error(new Error("Not implemented yet"));
+};
+
+Listing 26. Java SE Version
+
+public void test(byte param, boolean param1, char param2, short param3, int param4, long param5, float param6, double
+param7, String param8, byte[] param9, boolean[] param10, char[] param11, short[] param12, int[] param13, long[] param14,
+float[] param15, double[] param16, com.codename1.ui.PeerComponent param17) {
+}
+
+597
+
+Listing 27. C# Version
+
+public void test(byte param, bool param1, char param2, short param3, int param4, long param5, float param6, double
+param7, String param8, byte[] param9, boolean[] param10, char[] param11, short[] param12, int[] param13, long[] param14,
+float[] param15, double[] param16, FrameworkElement param17) {
+}
+
+16.5.6. Android Native Permissions
+
+Normally  permissions  in  Codename  One  are  seamless.  Codename  One  traverses  the  bytecode  and
+
+automatically  assigns  permissions  to  Android  applications  based  on  the  API’s  used  by  the
+
+developer.
+
+However, when accessing native functionality this just won’t work since native code might require
+
+specialized  permissions  and  we  don’t/can’t  run  any  serious  analysis  on  it  (it  can  be  just  about
+
+anything).
+
+So  if  you  require  additional  permissions  in  your  Android  native  code  you  need  to  define  them  in
+the  build  arguments  using  android.permission.<PERMISSION_NAME>=true  for  each  permission  you
+want  to  include.  A  full  list  of  permissions  are  listed  in  Android’s  Manifest.permission
+
+documentation [https://developer.android.com/reference/android/Manifest.permission.html].
+
+E.g.
+
+android.permission.ADD_VOICEMAIL=true
+android.permission.BATTERY_STATS=true
+...
+
+You  can  specify  the  maximum  SDK  version  in  which  the  permission  is  needed  using  the
+android.permission.<PERMISSION_NAME>.maxSdkVersion  build  hint.  You  can  also  specify  whether  the
+permission is required for the app to run using the android.permission.<PERMISSION_NAME>.required
+build hint.
+
+E.g.
+
+android.permission.ADD_VOICEMAIL=true
+android.permission.BATTERY_STATS=true
+android.permission.ADD_VOICEMAIL.required=false
+android.permission.ADD_VOICEMAIL.maxSdkVersion=18
+...
+
+You  can  alternatively  use  the  android.xpermissions  build  hint  to  inject  <uses-permission>  tags  into
+the manifest file. E.g.:
+
+android.xpermissions=<uses-permission android:name="android.permission.READ_CALENDAR" />
+
+598
+
+ You need to include the full XML snippet. You can unify multiple lines into a single
+
+line in the GUI as XML allows that.
+
+16.5.7. Native AndroidNativeUtil
+
+If  you  do  any  native  interfaces  programming  in  Android  you  should  be  familiar  with  the
+AndroidNativeUtil class which allows you to access native device functionality more easily from the
+native  code.  E.g.  many  Android  API’s  need  access  to  the  Activity  which  you  can  get  by  calling
+AndroidNativeUtil.getActivity().
+
+The native util class includes quite a few other features such as:
+
+• runOnUiThreadAndBlock(Runnable) - this is such a common pattern that it was generalized into a
+public  static  method.  Its  identical  to  Activity.runOnUiThread  but  blocks  until  the  runnable
+finishes execution.
+
+• addLifecycleListener/removeLifecycleListener - These essentially provide you with a callback to
+
+lifecycle events: onCreate etc. which can be pretty useful for some cases.
+
+• registerViewRenderer 
+
+-  PeerComponent 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/
+
+PeerComponent.html]'s  are  usually  shown  on  top  of  the  UI  since  they  are  rendered  within  their
+
+own 
+
+thread  outside  of 
+
+the  EDT  cycle.  So  when  we  need 
+
+to  show  a  Dialog
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/Dialog.html]  on  top  of  the  peer  we  grab  a
+
+screenshot of the peer, hide it and then show the dialog with the image as the background (the
+
+same applies for transitions). Unfortunately some components (specifically the MapView) might
+
+not  render  properly  and  require  custom  code  to  implement  the  transferal  to  a  native  Bitmap,
+
+this API allows you to do just that.
+
+You can work with AndroidNativeUtil using native code such as this:
+
+import com.codename1.impl.android.AndroidNativeUtil;
+
+class NativeCallsImpl {
+     public void nativeMethod() {
+        AndroidNativeUtil.getActivity().runOnUiThread(new Runnable() {
+            public void run() {
+               ...
+            }
+        });
+     }
+    ....
+}
+
+16.5.8. Broadcast Receiver
+
+A  common  way  to  implement  features  in  Android  is  the  BroadcastReceiver  API.  This  allows
+intercepting operating system events for common use cases.
+
+A  good  example  is  intercepting  incoming  SMS  which  is  specific  to  Android  so  we’d  need  a
+
+599
+
+broardcast receiver to implement that. This is often confusing to developers who sometimes derive
+
+the impl class from broadcast receiver. That’s a mistake…
+
+The  solution  is  to  place  any  native  Android  class  into  the  native/android  directory.  It  will  get
+compiled  with  the  rest  of  the  native  code  and  "just  works".  So  you  can  place  this  class  under
+native/android/com/codename1/sms/intercept:
+
+package com.codename1.sms.intercept;
+
+import android.content.*;
+import android.os.Bundle;
+import android.telephony.*;
+import com.codename1.io.Log;
+
+public class SMSListener extends BroadcastReceiver {
+
+    @Override
+    public void onReceive(Context cntxt, Intent intent) {
+        // based on code from https://stackoverflow.com/questions/39526138/broadcast-receiver-for-receive-sms-is-not-
+working-when-declared-in-manifeststat
+        if(intent.getAction().equals("android.provider.Telephony.SMS_RECEIVED")) {
+            Bundle bundle = intent.getExtras();
+            SmsMessage[] msgs = null;
+            if (bundle != null){
+                try{
+                    Object[] pdus = (Object[]) bundle.get("pdus");
+                    msgs = new SmsMessage[pdus.length];
+                    for(int i=0; i<msgs.length; i++){
+                        msgs[i] = SmsMessage.createFromPdu((byte[])pdus[i]);
+                        String msgBody = msgs[i].getMessageBody();
+                        SMSCallback.smsReceived(msgBody);
+                    }
+                } catch(Exception e) {
+                    Log.e(e);
+                    SMSCallback.smsReceiveError(e);
+                }
+            }
+        }
+    }
+}
+
+The code above is pretty standard native Android code, it’s just a callback in which most of the logic
+
+is 
+
+similar 
+
+to 
+
+the  native  Android  code  mentioned 
+
+in 
+
+this 
+
+stackoverflow  question
+
+[https://stackoverflow.com/questions/39526138/broadcast-receiver-for-receive-sms-is-not-working-when-declared-in-
+
+manifeststat].
+
+But there is still more you need to do. In order to implement this natively we need to register the
+permission and the receiver in the manifest.xml file as explained in that question. This is how their
+native manifest looked:
+
+600
+
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.bulsy.smstalk1">
+    <uses-permission android:name="android.permission.RECEIVE_SMS" />
+    <uses-permission android:name="android.permission.READ_SMS" />
+    <uses-permission android:name="android.permission.SEND_SMS"/>
+    <uses-permission android:name="android.permission.READ_CONTACTS" />
+
+    <application
+        android:allowBackup="true"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:supportsRtl="true"
+        android:theme="@style/AppTheme">
+        <activity android:name=".MainActivity">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+        <receiver android:name="com.bulsy.smstalk1.SmsListener"
+               android:enabled="true"
+               android:permission="android.permission.BROADCAST_SMS"
+               android:exported="true">
+            <intent-filter android:priority="2147483647">//this doesnt work
+                <category android:name="android.intent.category.DEFAULT" />
+                <action android:name="android.provider.Telephony.SMS_RECEIVED" />
+            </intent-filter>
+        </receiver>
+    </application>
+</manifest>
+
+We only need the broadcast permission XML and the permission XML. Both are doable via the build
+
+hints. The former is pretty easy:
+
+android.xpermissions=<uses-permission android:name="android.permission.RECEIVE_SMS" />
+
+The  latter  isn’t  much  harder,  notice  I  took  multiple  lines  and  made  them  into  a  single  line  for
+
+convenience:
+
+android.xapplication=<receiver android:name="com.codename1.sms.intercept.SMSListener"  android:enabled="true"
+android:permission="android.permission.BROADCAST_SMS"  android:exported="true">                    <intent-filter
+android:priority="2147483647"><category android:name="android.intent.category.DEFAULT" />        <action
+android:name="android.provider.Telephony.SMS_RECEIVED" />                 </intent-filter>             </receiver>
+
+Here it is formatted nicely:
+
+601
+
+<receiver android:name="com.codename1.sms.intercept.SMSListener"
+              android:enabled="true"
+              android:permission="android.permission.BROADCAST_SMS"
+              android:exported="true">
+                   <intent-filter android:priority="2147483647">
+                          <category android:name="android.intent.category.DEFAULT" />
+                          <action android:name="android.provider.Telephony.SMS_RECEIVED" />
+                   </intent-filter>
+</receiver>
+
+Listening & Permissions
+
+You will notice that these don’t include the actual binding or permission prompts you would expect
+
+for something like this. To do this we need a native interface.
+
+The  native  sample  in  stack  overflow  bound  the  listener  in  the  activity  but  here  we  want  the  app
+
+code to decide when we should bind the listening:
+
+public interface NativeSMSInterceptor extends NativeInterface {
+    public void bindSMSListener();
+    public void unbindSMSListener();
+}
+
+That’s easy!
+
+Notice  that  isSupported()  returns  false  for  all  other  OS’s  so  we  won’t  need  to  ask  whether  this  is
+"Android" we can just use isSupported().
+
+The implementation is pretty easy too:
+
+602
+
+package com.codename1.sms.intercept;
+
+import android.Manifest;
+import android.content.IntentFilter;
+import com.codename1.impl.android.AndroidNativeUtil;
+
+public class NativeSMSInterceptorImpl {
+    private SMSListener smsListener;
+    public void bindSMSListener() {
+        if(AndroidNativeUtil.checkForPermission(Manifest.permission.RECEIVE_SMS, "We can automatically enter the SMS code
+for you")) { ①
+            smsListener = new SMSListener();
+            IntentFilter filter = new IntentFilter();
+            filter.addAction("android.provider.Telephony.SMS_RECEIVED");
+            AndroidNativeUtil.getActivity().registerReceiver(smsListener, filter); ②
+        }
+    }
+
+    public void unbindSMSListener() {
+        AndroidNativeUtil.getActivity().unregisterReceiver(smsListener);
+    }
+
+    public boolean isSupported() {
+        return true;
+    }
+}
+
+① This will trigger the permission prompt on Android 6 and newer. Even though the permission is
+declared in XML this isn’t enough for 6+. Notice that even when you run on Android 6 you still
+
+need to declare permissions in XML!
+
+② Here we actually bind the listener, this allows us to grab one SMS and not listen in on every SMS
+
+coming thru
+
+16.5.9. Native Code Callbacks
+
+Native  interfaces  standardize  the  invocation  of  native  code  from  Codename  One,  but  it  doesn’t
+
+standardize  the  reverse  of  callbacks  into  Codename  One  Java  code.  The  reverse  is  naturally  more
+
+complicated since its platform specific and more error prone.
+
+A common "trick" for calling back is to just define a static method and then trigger it from native
+
+code. This works nicely for Android, Java SE, Blackberry & Java ME since those platforms use Java
+
+for their "native code". Mapping this to iOS requires some basic understanding of how the iOS VM
+
+works.
+
+For  the  purpose  of  this  explanation  lets  pretend  we  have  a  class  called  NativeCallback  in  the  src
+hierarchy under the package com.mycompany that has the method: public static void callback().
+
+package com.mycompany;
+public class NativeCallback {
+    public static void callback() {
+        // do stuff
+    }
+}
+
+603
+
+So  if  I  want  to  call  it  from  Android  or  all  of  the  Java  based  platforms  I  can  just  write  this  in  the
+
+"native" code:
+
+com.mycompany.NativeCallback.callback();
+
+I can also pass a argument as we do later on:
+
+com.mycompany.NativeCallback.callback("My Arg");
+
+Accessing Callbacks from Objective-C
+
+If we want to invoke that method from Objective-C we need to do the following.
+
+Add an include statement as such:
+
+#include "com_mycompany_NativeCallback.h"
+#include "CodenameOne_GLViewController.h"
+
+that 
+
+Notice 
+CN1_THREAD_STATE_PASS_SINGLE_ARG.
+
+the  CodenameOne_GLViewController.h 
+
+include  defines  various  macros  such  as
+
+Then when we want to trigger the method just do:
+
+com_mycompany_NativeCallback_callback__(CN1_THREAD_STATE_PASS_SINGLE_ARG);
+
+
+
+most 
+
+For 
+macro
+CN1_THREAD_GET_STATE_PASS_SINGLE_ARG  instead  of  CN1_THREAD_STATE_PASS_SINGLE_ARG
+also make sure to add `#include "cn1_globals.h" in the file
+
+callbacks 
+
+should 
+
+you 
+
+use 
+
+the 
+
+The VM passes the thread context along method calls to save on API calls (thread context is heavily
+
+used in Java for synchronization, gc and more).
+
+We can easily pass arguments like:
+
+public static void callback(int arg)
+
+Which maps to native as (notice the extra _ before the int):
+
+com_mycompany_NativeCallback_callback___int(CN1_THREAD_GET_STATE_PASS_ARG intValue);
+
+Notice that there is no comma between the CN1_THREAD_GET_STATE_PASS_ARG and the value!
+
+604
+
+Why No Comma?
+
+The comma is included as part of the macro which makes for code that isn’t as readable.
+
+The  reason  for  this  dates  to  the  migration  from  XMLVM  [10]  to  the  current  ParparVM
+implementation. CN1_THREAD_GET_STATE_PASS_ARG is defined as nothing in XMLVM since
+
+it didn’t use that concept. Yet under ParparVM it will include the necessary comma.
+
+A  common  use  case  is  passing  string  values  to  the  Java  side,  or  really  NSString*  which  is  iOS
+
+equivalent. Assuming a method like this:
+
+public static void callback(String arg)
+
+You  would  need  to  convert  the  NSString*  value  you  already  have  to  a  java.lang.String  which  the
+callback expects.
+
+The fromNSString function also needs this special argument so you will need to modify the method
+as such:
+
+com_mycompany_NativeCallback_callback___java_lang_String(CN1_THREAD_GET_STATE_PASS_ARG
+fromNSString(CN1_THREAD_GET_STATE_PASS_ARG nsStringValue));
+
+And finally you might want to return a value from callback as such:
+
+public static int callback(int arg)
+
+This  is  tricky  since  the  method  name  changes  to  support  covariant  return  types  and  so  the
+
+signature would be:
+
+com_mycompany_NativeCallback_callback___int_R_int(intValue);
+
+The upper case R allows us to differentiate between void callback(int,int) and int callback(int).
+
+
+
+Covariant  return  types  are  a  little  known  Java  5  feature.  E.g.  the  method  Object
+getX()  can  be  overriden  by  MyObject  getX().  However,  in  the  VM  level  they  can
+both exist side by side.
+
+Accessing Callbacks from Javascript
+
+The mechanism for invoking static callback methods from Javascript (for the Javascript port only) is
+similar to Objective-C’s. The this object in your native interface method contains a property named
+$GLOBAL$  that  provides  access  to  static  java  methods.  This  object  will  contain  Javascript  mirror
+objects  for  each  Java  class  (though  the  property  name  is  mangled  by  replacing  "."  with
+
+underscores).  Each  mirror  object  contains  a  wrapper  method  for  its  underlying  class’s  static
+
+605
+
+methods where the method name follows the same naming convention as is used for the Javascript
+
+native methods themselves (and very similar to the naming conventions used in Objective-C).
+
+For example, the Google Maps project includes the static callback method:
+
+static void fireMapChangeEvent(int mapId, final int zoom, final double lat, final double lon) { ... }
+
+defined in the com.codename1.googlemaps.MapContainer class.
+
+This method is called from Javascript inside a native interface using the following code:
+
+var fireMapChangeEvent = this.$GLOBAL$.com_codename1_googlemaps_MapContainer.fireMapChangeEvent__int_int_double_double;
+google.maps.event.addListener(this.map, 'bounds_changed', function() {
+    fireMapChangeEvent(self.mapId, self.map.getZoom(), self.map.getCenter().lat(), self.map.getCenter().lng());
+});
+
+In this example we first obtain a reference to the fireMapChangeEvent method, and then call it later.
+However, we could have called it directly also.
+
+code 
+
+MUST 
+
+Your 
+path
+this.$GLOBAL$.your_class_name.your_method_name  or  the  build  server  will  not  be
+able  to  recognize  that  your  code  requires  this  method.  The  $GLOBAL$  object  is
+populated  by  the  build  server  only  with  those  classes  and  methods  that  are  used
+
+contain 
+
+string 
+
+full 
+
+the 
+
+
+
+inside your native methods. If the build server doesn’t recognize that the methods
+
+are being used (via this pattern) it won’t generate the necessary wrappers for your
+
+Javascript code to access the Java methods.
+
+Callbacks of the SMS Receiver
+
+The SMS Broadcast Receiver code from before also used callbacks such as this:
+
+606
+
+package com.codename1.sms.intercept; ①
+
+import com.codename1.util.FailureCallback;
+import com.codename1.util.SuccessCallback;
+import static com.codename1.ui.CN.*;
+
+/**
+ * This is an internal class, it's package protect to hide that
+ */
+class SMSCallback {
+    static SuccessCallback<String> onSuccess;
+    static FailureCallback onFail;
+
+    public static void smsReceived(String sms) {
+        if(onSuccess != null) {
+            SuccessCallback<String> s = onSuccess;
+            onSuccess = null;
+            onFail = null;
+            SMSInterceptor.unbindListener();
+            callSerially(() -> s.onSucess(sms)); ②
+        }
+    }
+
+    public static void smsReceiveError(Exception err) {
+        if(onFail != null) {
+            FailureCallback f = onFail;
+            onFail = null;
+            SMSInterceptor.unbindListener();
+            onSuccess = null;
+            callSerially(() -> f.onError(null, err, 1, err.toString()));
+        } else {
+            if(onSuccess != null) {
+                SMSInterceptor.unbindListener();
+                onSuccess = null;
+            }
+        }
+    }
+}
+
+① Notice  that  the  package  is  the  same  as  the  native  code  and  the  other  classes.  This  allows  the
+callback class to be package protected so it isn’t exposed via the API (the class doesn’t have the
+
+public modifier)
+
+② We wrap the callback in call serially to match the Codename One convention of using the EDT by
+default.  The  call  will  probably  arrive  on  the  Android  native  thread  so  it  makes  sense  to
+
+normalize it and not expose the Android native thread to the user code
+
+Asynchronous Callbacks & Threading
+
+One  of  the  problematic  aspects  of  calling  back  into  Java  from  Javascript  is  that  Javascript  has  no
+
+607
+
+notion of multi-threading. Therefore, if the method you are calling uses Java’s threads at all (e.g. It
+includes a wait(), notify(), sleep(), callSerially(), etc…) you need to call it asynchronously from
+Javascript.  You  can  call  a  method  asynchronously  by  appending  $async  to  the  method  name.  E.g.
+With the Google Maps example above, you would change :
+
+this.$GLOBAL$.com_codename1_googlemaps_MapContainer.fireMapChangeEvent__int_int_double_double;
+
+to
+
+this.$GLOBAL$.com_codename1_googlemaps_MapContainer.fireMapChangeEvent__int_int_double_double$async;
+
+This  will  cause  the  call  to  be  wrapped  in  the  appropriate  bootstrap  code  to  work  properly  with
+
+threads - and it is absolutely necessary in cases where the method may use threads of any kind. The
+side-effect  of  calling  a  method  with  the  $async  suffix  is  that  you  can’t  use  return  values  from  the
+method.
+
+
+
+In most cases you should use the async version of a method when calling it from
+
+your  native  method.  Only  use  the  synchronous  (default)  version  if  you  are
+
+absolutely sure that the method doesn’t use any threading primitives.
+
+16.6. Libraries - cn1lib
+
+Support for JAR files in Codename One has been a source of confusion so its probably a good idea to
+
+revisit this subject again and clarify all the details.
+
+The first source of confusion is changing the classpath. You should NEVER change the classpath or
+
+add an external JAR via the IDE classpath UI. The reasoning here is very simple, these IDE’s don’t
+
+package  the  JAR’s  into  the  final  executable  and  even  if  they  did  these  JAR’s  would  probably  use
+features unavailable or inappropriate for the device (e.g. java.io.File etc.).
+
+Figure 477. Don’t change the classpath, this is how it should look for a typical Java 8 Codename One
+
+application
+
+Cn1libs  are  Codename  One’s  file  format  for  3rd  party  extensions.  It’s  physicially  a  zip  file
+
+containing other zip files and some meta-data.
+
+608
+
+16.6.1. Why Not Use JAR?
+
+A jar can be compiled with usage of any Java API that might not be supported, it can be compiled
+
+with a Java target version that isn’t tested.
+
+Jars  don’t  include  support  for  writing  native  code,  you  could  use  JNI  in  jars  (awkwardly)  but  that
+
+doesn’t match Codename One’s needs for native support (see section above).
+
+Jars don’t support "proper" code completion, a common developer trick is to stick source code into
+
+the  jar  but  that  prevents  usage  with  proprietary  code.  Cn1libs  provide  full  IDE  code  completion
+
+(with JavaDoc hints) without exposing the sources.
+
+There are two use cases for wanting JAR’s and they both have very different solutions:
+
+1. Modularity
+
+2. Working with an existing JARs
+
+Cn1lib’s  address  the  modularity  aspect  allowing  you  to  break  that  down.  Existing  jars  can
+
+sometimes be used native code settings but for the most part you would want to adapt the code to
+
+abide by Codename One restrictions.
+
+16.6.2. How To Use cn1libs?
+
+Codename One has a large repository of 3rd party cn1libs [https://www.codenameone.com/cn1libs.html],
+
+you  can  install  a  cn1lib  by  placing  it  in  the  lib  directory  of  your  project  then  right  clicking  the
+
+project and selecting Codename One → Refresh cn1lib files.
+
+Figure 478. Refresh cn1lib files menu option
+
+Once refreshed the content of the cn1lib will be available to code completion and you could just use
+
+it.
+
+
+
+Notice that some cn1libs require additional configurations such as build hints etc.
+
+so  make  sure  to  read  the  developers  instructions  when  integrating  a  3rd  party
+
+library.
+
+609
+
+Under the Hood of cn1lib Install
+
+Refresh cn1lib files  invokes  the  ant  task  refresh-libs.  You  could  automatically  trigger  a
+refresh as part of your build process by invoking that ant task manually.
+
+Technically that task invokes a custom task that unzips the content of the cn1lib into a set of
+
+directories  accessible  to  the  build  process.  Classes  and  stub  sources  are  installed  in
+lib/impl/cls & lib/impl/stubs respectively.
+
+The native files are extracted to lib/impl/native. The classpath for the main project and the
+ant build process know about these directories and include them within their path.
+
+16.6.3. Creating a Simple cn1lib
+
+Creating a cn1lib is trivial, we will get into more elaborate uses soon enough but for a hello world
+
+cn1lib we can just use this 2 step process:
+
+Figure 479. Select the CodenameOne Library Option
+
+Figure 480. Select the file name/destination. Notice that a Java 8 cn1lib requires Java 8 support in the parent
+
+project!
+
+Once  we  go  thru  these  steps  we  can  define  any  source  file  within  the  library  and  it  will  be
+
+accessible to the users of the library.
+
+16.6.4. Build Hints in cn1libs
+
+Some  cn1libs  are  pretty  simple  to  install,  just  place  them  under  the  lib  directory  and  refresh.
+
+However, many of the more elaborate cn1libs need some pretty complex configurations. This is the
+
+case when native code is involved where we need to add permissions or plist entries for the various
+
+native platforms to get everything to work. This makes the cn1lib’s helpful but less than seamless
+
+which is where we want to go.
+
+Codename  One 
+
+cn1libs 
+
+include 
+
+two 
+
+files 
+
+that 
+
+can  be  placed 
+
+into 
+
+the 
+
+root:
+
+610
+
+codenameone_library_required.properties & codenameone_library_appended.properties.
+
+In  these  files  you  can  just  write  a  build  hint  as  codename1.arg.ios.plistInject=…  for  the  various
+hints.
+
+
+
+Notice the usage of the properties syntax for the build hint with the codename1.arg
+prefix you would also need to escape reserved characters for properties files.
+
+The best way to discover the right syntax for such build hints is to set them via the
+
+build  hints  GUI 
+in  a 
+codenameone_settings.properties into the cn1lib file.
+
+regular  project  and 
+
+copy/paste 
+
+them 
+
+from
+
+The obvious question is why do we need two files?
+
+There are two types of build hints: required and appended.
+
+Required build hints can be something like ios.objC=true which we want to always work. E.g. if a
+cn1lib defines ios.objC=true and another cn1lib defines ios.objC=false things won’t work since one
+cn1lib won’t get what it needs…
+
+In this case we’d want the build to fail so we can remove the faulty cn1lib.
+
+ If two cn1libs define ios.objC=true there will be no collision as the value would be
+
+identical
+
+An 
+ios.plistInject=<key>UIBackgroundModes</key><array><string>audio</string> </array>
+
+appended 
+
+property 
+
+something 
+
+would 
+
+be 
+
+like
+
+Notice that this can still collide e.g. if a different cn1lib defines its own background mode. However,
+there  are  many  valid  cases  where  ios.plistInject  can  be  used  for  other  things.  In  this  case  we’ll
+append the content of the ios.plistInject into the build hint if it’s not already there.
+
+There are a couple of things you need to keep in mind:
+
+• Properties are merged with every "refresh libs" call not dynamically on the server. This means
+
+it should be pretty simple for the developer to investigate issues in this process.
+
+• Changing flags is problematic - there is no "uninstall" process. Since the data is copied into the
+codenameone_settings.properties  file.  If  you  need  to  change  a  flag  later  on  you  might  need  to
+alert users to make changes to their properties essentially negating the value of this feature…
+
+So be very careful when adding properties here.
+
+It’s your responsibility as a library developer to decide which build hint goes into which file!
+
+Codename One can’t automate this process as the whole process of build hints is by definition an ad
+
+hoc process.
+
+The  rule  of  thumb  is  that  a  build  hint  with  a  numeric  or  boolean  value  is  always  a  required
+
+property.  If  an  entry  has  a  string  that  you  can  append  with  another  string  then  its  probably  an
+
+appended entry.
+
+These build hints are probably of the "required" type:
+
+611
+
+android.debug
+android.release
+android.installLocation
+android.licenseKey
+android.stack_size
+android.statusbar_hidden
+android.googleAdUnitId
+android.includeGPlayServices
+android.headphoneCallback
+android.gpsPermission
+android.asyncPaint
+android.supportV4
+android.theme
+android.cusom_layout1
+android.versionCode
+android.captureRecord
+android.removeBasePermissions
+android.blockExternalStoragePermission
+android.min_sdk_version
+android.smallScreens
+android.streamMode
+android.enableProguard
+android.targetSDKVersion
+android.web_loading_hidden
+facebook.appId
+ios.keyboardOpen
+ios.project_type
+ios.newStorageLocation
+ios.prerendered_icon
+ios.application_exits
+ios.themeMode
+ios.xcode_version
+javascript.inject_proxy
+javascript.minifying
+javascript.proxy.url
+javascript.sourceFilesCopied
+javascript.teavm.version
+rim.askPermissions
+google.adUnitId
+ios.includePush
+ios.headphoneCallback
+ios.enableAutoplayVideo
+ios.googleAdUnitId
+ios.googleAdUnitIdPadding
+ios.enableBadgeClear
+ios.locationUsageDescription
+ios.bundleVersion
+ios.objC
+ios.testFlight
+desktop.width
+desktop.height
+
+612
+
+desktop.adaptToRetina
+desktop.resizable
+desktop.fontSizes
+desktop.theme
+desktop.themeMac
+desktop.themeWin
+desktop.windowsOutput
+noExtraResources
+j2me.iconSize
+android.permission.<PERMISSION_NAME>
+
+These build hints should probably be appended:
+
+android.xapplication
+android.xpermissions
+android.xintent_filter
+android.facebook_permissions
+android.stringsXml
+android.style
+android.nonconsumable
+android.xapplication_attr
+android.xactivity
+android.pushVibratePattern
+android.proguardKeep
+android.sharedUserId
+android.sharedUserLabel
+ios.urlScheme
+ios.interface_orientation
+ios.plistInject
+ios.facebook_permissions
+ios.applicationDidEnterBackground
+ios.viewDidLoad
+ios.glAppDelegateHeader
+ios.glAppDelegateBody
+ios.beforeFinishLaunching
+ios.afterFinishLaunching
+ios.add_libs
+
+613
+
+cn1lib Structure/File Format
+
+The  cb1lib  file  format  is  quite  simple,  it’s  a  zip  file  containing  zip  files  within  it  with  fixed
+
+names to support the various features.
+
+The table below covers the files that can/should be a part of a cn1lib file:
+
+Table 12. cn1lib structure
+
+File Name
+
+main.zip
+
+stubs.zip
+
+manifest.properties
+
+codenameone_ library_
+
+appended.properties
+
+codenameone_ library_
+
+required.properties
+
+nativeios.zip
+
+nativeand.zip
+
+nativejavascript.zip
+
+nativerim.zip
+
+nativese.zip
+
+nativewin.zip
+
+nativeme.zip
+
+Required
+
+Purpose
+
+✓
+
+✓
+
+×
+
+×
+
+×
+
+×
+
+×
+
+×
+
+×
+
+×
+
+×
+
+×
+
+Contains the bytecode and the library binary
+
+data. This is effectively the portable portion
+
+of the jar
+
+Stub source files (auto-generated) containing
+
+javadocs to provide code completion
+
+General properties of the library, this isn’t
+
+used for much at the moment
+
+Discussed above
+
+Discussed above
+
+Native iOS sources if applicable
+
+Native Android sources if applicable
+
+Native JavaScript sources if applicable
+
+Native RIM sources if applicable
+
+Native JavaSE sources if applicable
+
+Native Windows sources if applicable
+
+Native Java ME sources if applicable
+
+16.7. Integrating Android 3rd Party Libraries & JNI
+
+While  its  pretty  easy  to  use  native  interfaces  to  write  Android  native  code  some  things  aren’t
+
+necessarily as obvious. E.g. if you want to integrate a 3rd party library, specifically one that includes
+
+native C JNI code this process isn’t as straightforward.
+
+If you need to integrate such a library into your native calls you have the following options:
+
+1. The  first  option  (and  the  easiest  one)  is  to  just  place  a  Jar  file  in  the  native/android  directory.
+
+This will link your binary with the jar file. Just place the jar under the native/android and the
+
+build server will pick it up and will add it to the classpath.
+
+Notice that Android release apps are obfuscated by default which might cause issues with such
+
+libraries  if  they  reference  API’s  that  are  unavailable  on  Android.  You  can  workaround  this  by
+
+adding  a  build  hint  to  the  proguard  obfuscation  code  that  blocs  the  obfuscation  of  the
+
+614
+
+problematic classes using the build hint:
+android.proguardKeep=-keep class com.mypackage.ProblemClass { *; }`
+
+2. Another  option  is  the  aar  file  is  a  binary  format  Google  introduced  to  represent  an  Android
+Library  project  (similarly  to  the  cn1lib  format).  One  of  the  problem  with  the  Android  Library
+
+projects  was  the  fact  that  it  required  the  project  sources  which  made  it  difficult  for  3rd  party
+
+vendors to publish libraries.
+As a result so android introduced the aar file which is a binary format that represents a Library
+project.  To  learn  more  about  arr  you  can  read  this  [https://developer.android.com/studio/projects/
+
+android-library.html#aar-contents].
+
+You can link an aar file by placing it under the native/android and the build server will link it to
+the project.
+
+3. There  is  another  obsolete  approach  that  we  are  mentioning  for  legacy  purposes  (e.g.  if  you
+need to port code written with this legacy option). This predated the aar option from Google…
+Not  all  3rd  party  tools  can  be  packaged  as  a  simple  jar,  some  3rd  party  tools  need  to  declare
+activities add permissions, resources, assets, and/or even add native code (.so files).
+To link a Library project to your Codename One project open the Library project in Eclipse or
+
+Android Studio and make sure the project builds, after the project was built successfully remove
+
+the bin directory from the project and zip the whole project.
+
+Rename  the  extension  from  .zip  to  .andlib  and  place  the  andlib  file  under  the  native/android
+directory. The build server will pick it up and will link it to the project.
+
+16.8. Drag & Drop
+
+Unlike  other  platforms  that  tried  to  create  overly  generic  catch  all  API’s  Codename  One  tried  to
+
+make things as simple as possible.
+
+In Codename One only components can be dragged and drop targets are always components. The
+
+logic of actually performing the operation indicated by the drop is the responsibility of the person
+
+implementing the drop.
+
+
+
+Some  platforms  e.g.  AWT  allow  dragging  abstract  concepts  such  as  mime  type
+
+elements. This allows dragging things like a text file into the app, but that use case
+
+isn’t realistic in mobile
+
+The code below allows you to rearrange the items based on a sensible order. Notice it relies on the
+default Container drop behavior.
+
+615
+
+Form hi = new Form("Rearrangeable Items", new BorderLayout());
+String[] buttons = {"A Game of Thrones", "A Clash Of Kings",  "A Storm Of Swords",
+    "A Feast For Crows", "A Dance With Dragons", "The Winds of Winter", "A Dream of Spring" };
+
+Container box = new Container(BoxLayout.y());
+box.setScrollableY(true);
+box.setDropTarget(true);
+java.util.List<String> got = Arrays.asList(buttons);
+Collections.shuffle(got);
+for(String current : got) {
+    MultiButton mb = new MultiButton(current);
+    box.add(mb);
+    mb.setDraggable(true);
+}
+
+hi.add(BorderLayout.NORTH, "Arrange The Titles").add(BorderLayout.CENTER, box);
+hi.show();
+
+Figure 481. Drag and drop demo
+
+To enable dragging a component it must be flagged as draggable using setDraggable(true), to allow
+dropping  the  component  onto  another  component  you  must  first  enable  the  drop  target  with
+setDropTarget(true) and override some methods (more on that later).
+
+When  dragging  on  top  of  a  child  component  of  a  drop  target  the  code  recursively  searches  for  a
+
+drop target parent. Dropping a component on the child will automatically find the right drop target,
+
+hence there is no need to make "everything" into a drop target.
+
+You can override these methods in the draggable components:
+
+• getDragImage  -  this  generates  an  image  preview  of  the  component  that  will  be  dragged.  This
+
+automatically generates a sensible default so you don’t need to override it.
+
+• drawDraggedImage - this method will be invoked to draw the dragged image at a given location, it
+might  be  useful  to  override  it  if  you  want  to  display  some  drag  related  information  such  an
+
+additional icon based on location etc. (e.g. a move/copy icon).
+
+In the drop target you can override the following methods:
+
+• draggingOver - returns true if a drop operation at this point is permitted. Otherwise releasing the
+
+component will have no effect.
+
+616
+
+• dragEnter/Exit - useful to track and cleanup state related to dragging over a specific component.
+
+• drop - the logic for dropping/moving the component must be implemented here!
+
+16.9. Continuous Integration & Release Engineering
+
+Codename  One  was  essentially  built  for  continuous  integration  since  the  build  servers  are
+
+effectively  a  building  block  for  such  an  architecture.  However,  there  are  several  problems  with
+
+that: the first of which is limited server capacity.
+
+If  all  users  would  start  sending  builds  with  every  commit  the  servers  would  instantly  become
+
+unusable  due  to  the  heavy  load.  To  circumvent  this  CI  support  is  limited  only  on  the  Enterprise
+
+level which allows Codename One to stock more servers and cope with the rise in demand related
+
+to the feature.
+
+To integrate with any CI solution just use the standard Ant targets such as build-for-android-device,
+build-for-iphone-device etc.
+
+Normally, this would be a problem since the build is sent but since it isn’t blocking you wouldn’t get
+
+the build result and wouldn’t be able to determine if the build passed or failed. To enable this just
+edit  the  build  XML  and  add  the  attribute  automated="true"  to  the  codeNameOne  tag  in  the
+appropriate targets.
+
+This will deliver a result.zip file under the dist folder containing the binaries of a successful build.
+It  will  also  block  until  the  build  is  completed.  This  should  be  pretty  easy  to  integrate  with  any  CI
+
+system together with our automated testing solutions .
+
+E.g. we can do a synchronous build like this:
+
+<target name="build-for-javascript-sync" depends="clean,copy-javascript-override,copy-libs,jar,clean-override">
+    <codeNameOne
+        jarFile="${dist.jar}"
+        displayName="${codename1.displayName}"
+        packageName = "${codename1.packageName}"
+        mainClassName = "${codename1.mainName}"
+        version="${codename1.version}"
+        icon="${codename1.icon}"
+        vendor="${codename1.vendor}"
+        subtitle="${codename1.secondaryTitle}"
+        automated="true"
+        targetType="javascript"
+        />
+</target>
+
+This allows us to build a JavaScript version of the app automatically as part of a release build script.
+
+16.10. Android Lollipop ActionBar Customization
+
+When running on Android Lollipop (5.0 or newer) the native action bar will use the Lollipop design.
+
+This  isn’t  applicable  if  you  use  the  Toolbar  [https://www.codenameone.com/javadoc/com/codename1/ui/
+
+Toolbar.html]  or  SideMenuBar  [https://www.codenameone.com/javadoc/com/codename1/ui/SideMenuBar.html]
+
+617
+
+this will be used only in the task switcher.
+
+To  customize  the  colors  of  the  native  ActionBar  on  Lollipop  define  a  colors.xml  file  in  the
+native/android directory of your project. It should look like this:
+
+<resources>
+   <color name="colorPrimary">#ff00ff00</color>
+   <color name="colorPrimaryDark">#80ff0000</color>
+   <color name="colorAccent">#800000ff</color>
+</resources>
+
+16.11. Intercepting URL’s On iOS & Android
+
+A  common  trick  in  mobile  application  development,  is  communication  between  two  unrelated
+
+applications.
+
+In  Android  we  can  use  intents  which  are  pretty  elaborate  and  can  be  used  via  Display.execute,
+however  what  if  you  would  like  to  expose  the  functionality  of  your  application  to  a  different
+
+application running on the device. This would allow that application to launch your application.
+
+This isn’t something we builtin to Codename One, however it does expose enough of the platform
+
+capabilities to enable that functionality rather easily on Android.
+
+On  Android  we  need  to  define  an  intent  filter  which  we  can  do  using  the  android.xintent_filter
+build hint, this accepts the XML to filter whether a request is relevant to our application:
+
+android.xintent_filter=<intent-filter>   <action android:name="android.intent.action.VIEW" />    <category
+android:name="android.intent.category.DEFAULT" />    <category android:name="android.intent.category.BROWSABLE" />
+<data android:scheme="myapp" />  </intent-filter>
+
+You can read more about it in this stack overflow question [http://stackoverflow.com/questions/11421048/
+
+android-ios-custom-uri-protocol-handling].
+
+To bind the myapp:// URL to your application. As a result typing myapp://x into the Android browser
+will launch the application.
+
+16.11.1. Passing Launch Arguments To The App
+
+You can access the value of the URL that launched the app using:
+
+String arg = Display.getInstance().getProperty("AppArg");
+
+This value would be null if the app was launched via the icon.
+
+iOS is practically identical to Android with some small caveats, iOS’s equivalent of the manifest is
+
+the plist.
+
+618
+
+You can inject more data into the plist by using the ios.plistInject build hint.
+
+So the equivalent in the iOS side would be
+
+ios.plistInject=<key>CFBundleURLTypes</key>     <array>         <dict>             <key>CFBundleURLName</key>
+<string>com.yourcompany.myapp</string>         </dict>         <dict>             <key>CFBundleURLSchemes</key>
+<array>                 <string>myapp</string>             </array>         </dict>     </array>
+
+However,  that  can  conflict  with  the  Facebook  integration  if  you  use  FacebookConnect  which  needs
+access to the schemes. To workaround it you can use the build hint ios.urlScheme e.g.:
+
+ios.urlScheme=<string>myapp</string>
+
+16.12. Native Peer Components
+
+Many  Codename  One  developers  don’t  truly  grasp  the  reason  for  the  separation  between  peer
+
+(native)  components  and  Codename  One  components.  This  is  a  crucial  thing  you  need  to
+
+understand especially if you plan on working with native widgets e.g. Web Browser, native maps,
+text input, media and native interfaces (which can return a PeerComponent).
+
+Codename One draws all of its widgets on its own, this is a concept which was modeled in part after
+
+Swing. This allows functionality that can’t be achieved in native widget platforms:
+
+1. The Codename One GUI builder & simulator are almost identical to the device - notice that this
+
+also enables the build cloud, otherwise device specific bugs would overwhelm development and
+
+make the build cloud redundant.
+
+2. Ability  to  override  everything  -  paint,  pointer,  key  events  are  all  overridable  and  replaceable.
+
+Developers can also paint over everything e.g. glasspane and layered pane.
+
+3. Consistency - provides identical functionality on all platforms for the most part.
+
+This  all  contributes  to  our  ease  of  working  with  Codename  One  and  maintaining  Codename  One.
+
+More  than  95%  of  Codename  One’s  code  is  in  Java  hence  its  really  portable  and  pretty  easy  to
+
+maintain!
+
+16.12.1. Why does Codename One Need Native Widgets at all?
+
+We need the native device to do input, html rendering etc. these are just too big and too complex
+
+tasks for Codename One to do from scratch.
+
+They  are  sometimes  impossible  to  perform  without  the  native  platform.  E.g.  the  virtual  keyboard
+
+input on the devices is tied directly to the native text input. It’s impractical to implement everything
+
+from scratch for all languages, dictionaries etc. The result would be sub-par.
+
+A web browser can’t be implemented in this day and age without a JavaScript JIT and including a
+
+JIT within an iOS app is prohibited by Apple.
+
+619
+
+16.12.2. So what’s the problems with native widgets?
+
+Codename One does pretty much everything on the EDT (Event Dispatch Thread), this provides a lot
+
+of cool features e.g. modal dialogs, invokeAndBlock etc.
+
+However native widgets have to be drawn on the devices native UI thread.
+
+This means that drawing looks something like this:
+
+1. Loop over all Codename One components and paint them.
+
+2. Loop over all native peer components and paint them.
+
+This  effectively  means  that  all  peer  components  are  drawn  on  top  of  the  Codename  One
+
+components.
+
+ This was also the case in AWT/Swing to one degree or another…
+
+16.12.3. So how do we show dialogs on top of Peer Components?
+
+Codename  One  grabs  a  screenshot  of  the  peer,  hide  it  and  then  we  can  just  show  the  screenshot.
+
+Since  the  screenshot  is  static  it  can  be  rendered  via  the  standard  UI.  Naturally  we  can’t  do  that
+
+always since grabbing a screenshot is an expensive process on all platforms and must be performed
+
+on the native device thread.
+
+16.12.4. Why can’t we combine peer component scrolling and Codename
+One scrolling?
+
+Since the form title/footer etc. are drawn by Codename One the peer component might paint itself
+
+on top of them. Clipping a peer component is often pretty difficult. Furthermore, if the user drags
+
+his  finger  within  the  peer  component  he  might  trigger  the  native  scroll  within  the  might  collide
+
+with our scrolling?
+
+16.12.5. Native Components In The First Form
+
+There  is  also  another  problem  that  might  be  counter  intuitive.  iOS  has  screenshot  images
+
+representing the first form. If your first page is an HTML or a native map (or other peer widget) the
+
+screenshot  process  on  the  build  server  will  show  fallback  code  instead  of  the  real  thing  thus
+
+providing sub-par behavior.
+
+Its impractical to support something like HTML for the screenshot process since it would also look
+
+completely different from the web component running on the device.
+
+
+
+You can read more about the screenshot process here [https://www.codenameone.com/
+
+manual/appendix-ios.html#section-ios-screenshots].
+
+16.13. Integrating 3rd Party Native SDKs
+
+The  following  is  a  description  of  the  procedure  that  was  used  to  create  the  Codename  One
+
+FreshDesk  library  [http://shannah.github.io/cn1-freshdesk/].  This  process  can  be  easily  adapted  to  wrap
+
+620
+
+any native SDK on Android and iOS.
+
+16.13.1. Step 1 : Review the FreshDesk SDKs
+
+Before we begin, we’ll need to review the Android and iOS SDKs.
+
+1. FreshDesk  Android  SDK: 
+
+Integration  Guide 
+
+[http://developer.freshdesk.com/mobihelp/android/
+
+integration_guide/] | API Docs [http://developer.freshdesk.com/mobihelp/android/api/reference/com/freshdesk/
+
+mobihelp/package-summary.html]
+
+2. FreshDesk  iOS  SDK:  Integration  Guide  [http://developer.freshdesk.com/mobihelp/ios/integration_guide/]
+
+| API Docs [http://developer.freshdesk.com/mobihelp/ios/api/]
+
+In reviewing the SDKs, we are looking for answers to two questions:
+
+1. What should my Codename One FreshDesk API look like?
+
+2. What will be involved in integrating the native SDK in my app or lib?
+
+16.13.2. Step 2: Designing the Codename One Public API
+
+When  designing  the  Codename  One  API,  we  should  begin  by  looking  at  the  Javadocs
+
+[http://developer.freshdesk.com/mobihelp/android/api/reference/com/freshdesk/mobihelp/package-summary.html]
+
+for  the  native  Android  SDK.  If  the  class  hierarchy  doesn’t  look  too  elaborate,  we  may  decide  to
+
+model  our  Codename  One  public  API  fairly  closely  on  the  Android  API.  On  the  other  hand,  if  we
+
+only need a small part of the SDK’s functionality, we may choose to create my abstractions around
+
+just the functionality that we need.
+
+In  the  case  of  the  FreshDesk  SDK,  it  looks  like  most  of  the  functionality  is  handled  by  one  central
+class Mobihelp, with a few other POJO classes for passing data to and from the service. This is a good
+candidate for a comprehensive Codename One API.
+
+Before  proceeding,  we  also  need  to  look  at  the  iOS  API  to  see  if  there  are  any  features  that  aren’t
+
+included. While naming conventions in the iOS API are a little different than those in the Android
+
+API, it looks like they are functionally the same.
+
+Therefore, I choose to create a class hierarchy and API that closely mirrors the Android SDK.
+
+16.13.3. Step 3: The Architecture and Internal APIs
+
+A Codename One library that wraps a native SDK, will generally consist of the following:
+
+1. Public  Java  API,  consisting  of  pure  Java  classes  that  are  intended  to  be  used  by  the  outside
+
+world.
+
+2. Native  Interface(s).  The  Native  Interface(s)  act  as  a  conduit  for  the  public  Java  API  to
+
+communicate to the native SDK. Parameters in native interface methods are limited to primitive
+
+types, arrays of primitive types, and Strings, as are return values.
+
+3. Native  code.  Each  platform  must  include  an  implementation  of  the  Native  Interface(s).  These
+
+implementations are written in the native language of the platform (e.g. Java for Android, and
+
+Objective-C for iOS).
+
+621
+
+4. Native dependencies. Any 3rd party libraries required for the native code to work, need to be
+
+included for each platform. On android, this may mean bundling .jar files, .aar files, or .andlib
+
+files. On iOS, this may mean bundling .h files, .a files, .framework, and .bundle files.
+
+5. Build hints. Some libraries will require you to add some extra build hints to your project. E.g.
+
+On  Android  you  may  need  to  add  permissions  to  the  manifest,  or  define  services  in  the
+<Application>  section  of  the  manifest.  On  iOS,  this  may  mean  specifying  additional  core
+frameworks for inclusion, or adding build flags for compilation.
+
+The following diagram shows the dependencies in a native library:
+
+Figure 482. Relationship between native & Codename One API UML Diagram
+
+In the specific case of our FreshDesk API, the public API and classes will look like:
+
+Figure 483. Freshdesk API Integration
+
+622
+
+Things to Notice
+
+1. The  public  API  consists  of  the  main  class  (Mobihelp  [https://github.com/shannah/cn1-freshdesk/blob/
+master/cn1-freshdesk-demo/src/com/codename1/freshdesk/Mobihelp.java]),  and  a  few  supporting  classes
+(FeedbackRequest 
+[https://github.com/shannah/cn1-freshdesk/blob/master/cn1-freshdesk-demo/src/com/
+codename1/freshdesk/FeedbackRequest.java],  FeedbackType  [https://github.com/shannah/cn1-freshdesk/blob/
+MobihelpConfig
+master/cn1-freshdesk-demo/src/com/codename1/freshdesk/FeedbackType.java], 
+
+[https://github.com/shannah/cn1-freshdesk/blob/master/cn1-freshdesk-demo/src/com/codename1/freshdesk/
+MobihelpConfig.java],  MobihelpCallbackStatus  [https://github.com/shannah/cn1-freshdesk/blob/master/cn1-
+freshdesk-demo/src/com/codename1/freshdesk/MobihelpCallbackStatus.java]),  which  were  copied  almost
+
+directly from the Android SDK.
+
+2. The only way for the public API to communicate with the native SDK is via the MobihelpNative
+[https://github.com/shannah/cn1-freshdesk/blob/master/cn1-freshdesk-demo/src/com/codename1/freshdesk/
+
+MobihelpNative.java] interface.
+
+3. We  introduced  the  MobihelpNativeCallback  [https://github.com/shannah/cn1-freshdesk/blob/master/cn1-
+freshdesk-demo/src/com/codename1/freshdesk/MobihelpNativeCallback.java]  class  to  facilitate  native  code
+
+calling back into the public API. This was necessary for a few methods that used asynchronous
+
+callbacks.
+
+16.13.4. Step 4: Implement the Public API and Native Interface
+
+We have already looked at the final product of the public API in the previous step, but let’s back up
+
+and walk through the process step-by-step.
+
+I wanted to model my API closely around the Android API, and the central class that includes all of
+
+the 
+
+functionality 
+
+of 
+
+the 
+
+SDK 
+
+is 
+
+the 
+
+com.freshdesk.mobihelp.Mobihelp 
+
+class
+
+[http://developer.freshdesk.com/mobihelp/android/api/reference/com/freshdesk/mobihelp/Mobihelp.html],  so  we
+
+begin there.
+
+We’ll  start  by  creating  our  own  package  (com.codename1.freshdesk)  and  our  own  Mobihelp  class
+inside it.
+
+Adapting Method Signatures
+
+The Context parameter
+
+In  a  first  glance  at  the  com.freshdesk.mobihelp.Mobihelp  API  [http://developer.freshdesk.com/mobihelp/
+
+android/api/reference/com/freshdesk/mobihelp/Mobihelp.html]  we  see  that  many  of  the  methods  take  a
+
+parameter  of 
+
+type  android.content.Context 
+
+[http://developer.android.com/reference/android/content/
+
+Context.html].  This  class  is  part  of  the  core  Android  SDK,  and  will  not  be  accessible  to  any  pure
+
+Codename One APIs. Therefore, our public API cannot include any such references. Luckily, we’ll be
+
+able  to  access  a  suitable  context  in  the  native  layer,  so  we’ll  just  omit  this  parameter  from  our
+
+public API, and inject them in our native implementation.
+
+Hence, the method signature public static final void setUserFullName (Context context, String
+name)  will  simply  become  public  static  final  void  setUserFullName  (String  name)  in  our  public
+API.
+
+623
+
+Non-Primitive Parameters
+
+Although our public API isn’t constrained by the same rules as our Native Interfaces with respect to
+
+parameter  and  return  types,  we  need  to  be  cognizant  of  the  fact  that  parameters  we  pass  to  our
+
+public  API  will  ultimately  be  funnelled  through  our  native  interface.  Therefore,  we  should  pay
+
+attention to any parameters or return types that can’t be passed directly to a native interface, and
+
+start  forming  a  strategy  for  them.  E.g.  consider  the  following  method  signature  from  the  Android
+Mobihelp class:
+
+public static final void showSolutions (Context activityContext, ArrayList<String> tags)
+
+We’ve already decided to just omit the Context parameter in our API, so that’s a non-issue. But what
+about the ArrayList<String> tags parameter? Passing this to our public API is no problem, but when
+we implement the public API, how will we pass this ArrayList to our native interface, since native
+interfaces don’t allow us to arrays of strings as parameters?
+
+I generally use one of three strategies in such cases:
+
+1. Encode the parameter as either a single String (e.g. using JSON or some other easily parseable
+
+format) or a byte[] array (in some known format that can easily be parsed in native code).
+
+2. Store the parameter on the Codename One side and pass some ID or token that can be used on
+
+the native side to retrieve the value.
+
+3. If the data structure can be expressed as a finite number of primitive values, then simply design
+
+the  native  interface  method  to  take  the  individual  values  as  parameters  instead  of  a  single
+
+object. E.g. If there is a User [https://www.codenameone.com/javadoc/com/codename1/facebook/User.html]
+class  with  properties  name  and  phoneNumber,  the  native  interface  can  just  have  name  and
+phoneNumber parameters rather than a single `user parameter.
+
+In this case, because an array of strings is such a simple data structure, I decided to use a variation
+
+on strategy number 1: Merge the array into a single string with a delimiter.
+
+In any case, we don’t have to come up with the specifics right now, as we are still on the public API,
+
+but it will pay dividends later if we think this through ahead of time.
+
+Callbacks
+
+It is quite often the case that native code needs to call back into Codename One code when an event
+
+occurs. This may be connected directly to an API method call (e.g. as the result of an asynchronous
+
+method invocation), or due to something initiated by the operating system or the native SDK on its
+
+own (e.g. a push notification, a location event, etc..).
+
+Native code will have access to both the Codename One API and any native APIs in your app, but on
+
+some platforms, accessing the Codename One API may be a little tricky. E.g. on iOS you’ll be calling
+
+from  Objective-C  back  into  Java  which  requires  knowledge  of  Codename  One’s  java-to-objective  C
+
+conversion process. In general, I have found that the easiest way to facilitate callbacks is to provide
+
+abstractions  that  involve  static  java  methods  (in  Codename  One  space)  that  accept  and  return
+
+primitive types.
+
+624
+
+In the case of our Mobihelp class, the following method hints at the need to have a "callback plan":
+
+public static final void getUnreadCountAsync (Context context, UnreadUpdatesCallback callback)
+
+The interface definition for UnreadUpdatesCallback is:
+
+public interface UnreadUpdatesCallback {
+    //This method is called once the unread updates count is available.
+    void onResult(MobihelpCallbackStatus status, Integer count);
+
+}
+
+I.e. If we were to implement this method (which I plan to do), we need to have a way for the native
+code to call the callback.onResult() method of the passed parameter.
+
+So we have two issues that will need to be solved here:
+
+1. How to pass the callback object through the native interface.
+
+2. How to call the callback.onResult() method from native code at the right time.
+
+For the first issue, we’ll use strategy #2 that we mentioned previously: (Store the parameter on the
+
+Codename One side and pass some ID or token that can be used on the native side to retrieve the
+
+value).
+
+For the second issue, we’ll create a static method that can take the token generated to solve the first
+issue, and call the stored callback object’s onResult() method. We abstract both sides of this process
+using  the  MobihelpNativeCallback  class  [https://github.com/shannah/cn1-freshdesk/blob/master/cn1-freshdesk-
+demo/src/com/codename1/freshdesk/MobihelpNativeCallback.java].
+
+625
+
+public class MobihelpNativeCallback {
+    private static int nextId = 0;
+    private static Map<Integer,UnreadUpdatesCallback> callbacks = new HashMap<Integer,UnreadUpdatesCallback>();
+
+    static int registerUnreadUpdatesCallback(UnreadUpdatesCallback callback) {
+        callbacks.put(nextId, callback);
+        return nextId++;
+    }
+
+    public static void fireUnreadUpdatesCallback(int callbackId, final int status, final int count) {
+        final UnreadUpdatesCallback cb = callbacks.get(callbackId);
+        if (cb != null) {
+            callbacks.remove(callbackId);
+            Display.getInstance().callSerially(new Runnable() {
+
+                public void run() {
+                    MobihelpCallbackStatus status2 = MobihelpCallbackStatus.values()[status];
+                    cb.onResult(status2, count);
+                }
+
+            });
+        }
+    }
+
+}
+
+Things to notice here:
+
+1. This  class  uses  a  static  Map<Integer,UnreadUpdatesCallback>  member  to  keep  track  of  all
+
+callbacks, mapping a unique integer ID to each callback.
+
+2. The registerUnreadUpdatesCallback() method takes an UnreadUpdatesCallback object, places it in
+the callbacks map, and returns the integer token that can be used to fire the callback later. This
+method  would  be  called  by  the  public  API  inside  the  getUnreadCountAsync()  method
+implementation to convert the callback into an integer, which can then be passed to the native
+API.
+
+3. The  fireUnreadUpdatesCallback()  method  would  be  called  later  from  native  code.  Its  first
+
+parameter is the token for the callback to call.
+
+4. We  wrap  the  onResult()  call  inside  a  Display.callSerially()  invocation  to  ensure  that  the
+callback  is  called  on  the  EDT.  This  is  a  general  convention  that  is  used  throughout  Codename
+
+One,  and  you’d  be  well-advised  to  follow  it.  Event  handlers  should  be  run  on  the  EDT  unless
+
+there  is  a  good  reason  not  to  -  and  in  that  case  your  documentation  and  naming  conventions
+
+should make this clear to avoid accidentally stepping into multithreading hell!
+
+Initialization
+
+Most  Native  SDKs  include  some  sort  of  initialization  method  where  you  pass  your  developer  and
+
+application  credentials  to  the  API.  When  I  filled  in  FreshDesk’s  web-based  form  to  create  a  new
+
+application, it generated an application ID, an app "secret", and a "domain". The SDK requires me to
+pass all three of these values to its init() method via the MobihelpConfig class.
+
+Note, however, that FreshDesk (and most other service provides that have native SDKs) requires me
+
+to  create  different  Apps  for  each  platform.  This  means  that  my  App  ID  and  App  secret  will  be
+
+626
+
+different on iOS than they will be on Android.
+
+Therefore our public API needs to enable us to provide multiple credentials in the same app, and
+
+our  API  needs  to  know  to  use  the  correct  credentials  depending  on  the  device  that  the  app  is
+
+running on.
+
+There are many solutions to this problem, but the one I chose was to provide two different init()
+methods:
+
+public final static void initIOS(MobihelpConfig config)
+
+and
+
+public final static void initAndroid(MobihelpConfig config)
+
+Then I can set up the API with code like:
+
+MobihelpConfig config = new MobihelpConfig();
+config.setAppSecret("xxxxxxx");
+config.setAppId("freshdeskdemo-2-xxxxxx");
+config.setDomain("codenameonetest1.freshdesk.com");
+Mobihelp.initIOS(config);
+
+config = new MobihelpConfig();
+config.setAppSecret("yyyyyyyy");
+config.setAppId("freshdeskdemo-1-yyyyyyyy");
+config.setDomain("https://codenameonetest1.freshdesk.com");
+Mobihelp.initAndroid(config);
+
+The Resulting Public API
+
+public class Mobihelp {
+
+    private static char[] separators = new char[]{',','|','/','@','#','%','!','^','&','*','=','+','*','<'};
+    private static MobihelpNative peer;
+
+    public static boolean isSupported() {
+        ....
+    }
+
+    public static void setPeer(MobihelpNative peer) {
+        ....
+    }
+
+    //Attach the given custom data (key-value pair) to the conversations/tickets.
+    public final static void    addCustomData(String key, String value) {
+        ...
+    }
+    //Attach the given custom data (key-value pair) to the conversations/tickets with the ability to flag sensitive data.
+    public final static void    addCustomData(String key, String value, boolean isSensitive) {
+        ...
+    }
+
+627
+
+    //Clear all breadcrumb data.
+    public final static void    clearBreadCrumbs() {
+        ...
+    }
+    //Clear all custom data.
+    public final static void    clearCustomData() {
+        ...
+    }
+    //Clears User information.
+    public final static void    clearUserData() {
+        ...
+    }
+    //Retrieve the number of unread items across all the conversations for the user synchronously i.e.
+    public final static int getUnreadCount() {
+        ...
+    }
+
+    //Retrieve the number of unread items across all the conversations for the user asynchronously, count is delivered to
+the supplied UnreadUpdatesCallback instance Note : This may return 0 or stale value when there is no network connectivity
+etc
+    public final static void    getUnreadCountAsync(UnreadUpdatesCallback callback) {
+        ...
+    }
+    //Initialize the Mobihelp support section with necessary app configuration.
+    public final static void    initAndroid(MobihelpConfig config) {
+        ...
+    }
+
+    public final static void initIOS(MobihelpConfig config) {
+        ...
+    }
+
+    //Attaches the given text as a breadcrumb to the conversations/tickets.
+    public final static void    leaveBreadCrumb(String crumbText) {
+        ...
+    }
+    //Set the email of the user to be reported on the Freshdesk Portal
+    public final static void    setUserEmail(String email) {
+        ...
+    }
+
+    //Set the name of the user to be reported on the Freshdesk Portal.
+    public final static void    setUserFullName(String name) {
+        ...
+    }
+
+    //Display the App Rating dialog with option to Rate, Leave feedback etc
+    public static void  showAppRateDialog() {
+        ...
+    }
+    //Directly launch Conversation list screen from anywhere within the application
+    public final static void    showConversations() {
+        ...
+    }
+    //Directly launch Feedback Screen from anywhere within the application.
+    public final static void    showFeedback(FeedbackRequest feedbackRequest) {
+        ...
+    }
+    //Directly launch Feedback Screen from anywhere within the application.
+    public final static void    showFeedback() {
+        ...
+    }
+    //Displays the Support landing page (Solution Article List Activity) where only solutions tagged with the given tags
+are displayed.
+    public final static void    showSolutions(ArrayList<String> tags) {
+        ...
+
+628
+
+    }
+
+    private static String findUnusedSeparator(ArrayList<String> tags) {
+        ...
+
+    }
+
+    //Displays the Support landing page (Solution Article List Activity) from where users can do the following
+    //View solutions,
+    //Search solutions,
+    public final static void    showSolutions() {
+        ...
+    }
+    //Displays the Integrated Support landing page where only solutions tagged with the given tags are displayed.
+    public final static void    showSupport(ArrayList<String> tags) {
+        ...
+    }
+
+    //Displays the Integrated Support landing page (Solution Article List Activity) from where users can do the following
+    //View solutions,
+    //Search solutions,
+    //  Start a new conversation,
+    //View existing conversations update/ unread count etc
+    public final static void    showSupport() {
+        ...
+    }
+
+}
+
+The Native Interface
+
+The final native interface is nearly identical to our public API, except in cases where the public API
+
+included non-primitive parameters.
+
+public interface MobihelpNative extends NativeInterface {
+
+    /**
+     * @return the appId
+     */
+    public String config_getAppId();
+
+    /**
+     * @param appId the appId to set
+     */
+    public void config_setAppId(String appId);
+
+    /**
+     * @return the appSecret
+     */
+    public String config_getAppSecret();
+
+    /**
+     * @param appSecret the appSecret to set
+     */
+    public void config_setAppSecret(String appSecret);
+    /**
+     * @return the domain
+     */
+    public String config_getDomain();
+    /**
+     * @param domain the domain to set
+     */
+    public void config_setDomain(String domain) ;
+
+629
+
+    /**
+     * @return the feedbackType
+     */
+    public int config_getFeedbackType() ;
+
+    /**
+     * @param feedbackType the feedbackType to set
+     */
+    public void config_setFeedbackType(int feedbackType);
+
+    /**
+     * @return the launchCountForReviewPrompt
+     */
+    public int config_getLaunchCountForReviewPrompt() ;
+    /**
+     * @param launchCountForReviewPrompt the launchCountForReviewPrompt to set
+     */
+    public void config_setLaunchCountForReviewPrompt(int launchCountForReviewPrompt);
+    /**
+     * @return the prefetchSolutions
+     */
+    public boolean config_isPrefetchSolutions();
+    /**
+     * @param prefetchSolutions the prefetchOptions to set
+     */
+    public void config_setPrefetchSolutions(boolean prefetchSolutions);
+    /**
+     * @return the autoReplyEnabled
+     */
+    public boolean config_isAutoReplyEnabled();
+
+    /**
+     * @param autoReplyEnabled the autoReplyEnabled to set
+     */
+    public void config_setAutoReplyEnabled(boolean autoReplyEnabled) ;
+
+    /**
+     * @return the enhancedPrivacyModeEnabled
+     */
+    public boolean config_isEnhancedPrivacyModeEnabled() ;
+
+    /**
+     * @param enhancedPrivacyModeEnabled the enhancedPrivacyModeEnabled to set
+     */
+    public void config_setEnhancedPrivacyModeEnabled(boolean enhancedPrivacyModeEnabled) ;
+
+    //Attach the given custom data (key-value pair) to the conversations/tickets.
+    public void addCustomData(String key, String value);
+    //Attach the given custom data (key-value pair) to the conversations/tickets with the ability to flag sensitive data.
+    public void addCustomDataWithSensitivity(String key, String value, boolean isSensitive);
+    //Clear all breadcrumb data.
+    public void clearBreadCrumbs() ;
+    //Clear all custom data.
+    public void clearCustomData();
+    //Clears User information.
+    public void clearUserData();
+    //Retrieve the number of unread items across all the conversations for the user synchronously i.e.
+    public int getUnreadCount();
+
+    //Retrieve the number of unread items across all the conversations for the user asynchronously, count is delivered to
+the supplied UnreadUpdatesCallback instance Note : This may return 0 or stale value when there is no network connectivity
+etc
+    public void getUnreadCountAsync(int callbackId);
+
+630
+
+    public void initNative();
+
+    //Attaches the given text as a breadcrumb to the conversations/tickets.
+    public  void leaveBreadCrumb(String crumbText);
+    //Set the email of the user to be reported on the Freshdesk Portal
+
+    public void setUserEmail(String email);
+
+    //Set the name of the user to be reported on the Freshdesk Portal.
+    public void setUserFullName(String name);
+
+    //Display the App Rating dialog with option to Rate, Leave feedback etc
+    public void showAppRateDialog();
+    //Directly launch Conversation list screen from anywhere within the application
+    public void showConversations();
+
+    //Directly launch Feedback Screen from anywhere within the application.
+    public void showFeedbackWithArgs(String subject, String description);
+    //Directly launch Feedback Screen from anywhere within the application.
+    public void showFeedback();
+
+    //Displays the Support landing page (Solution Article List Activity) where only solutions tagged with the given tags
+are displayed.
+    public void showSolutionsWithTags(String tags, String separator);
+
+    //Displays the Support landing page (Solution Article List Activity) from where users can do the following
+    //View solutions,
+    //Search solutions,
+    public void showSolutions();
+    //Displays the Integrated Support landing page where only solutions tagged with the given tags are displayed.
+    public void showSupportWithTags(String tags, String separator);
+
+    //Displays the Integrated Support landing page (Solution Article List Activity) from where users can do the following
+    //View solutions,
+    //Search solutions,
+    //  Start a new conversation,
+    //View existing conversations update/ unread count etc
+    public void showSupport();
+}
+
+Notice also, that the native interface includes a set of methods with names prefixed with config__.
+This is just a naming conventions I used to identify methods that map to the MobihelpConfig class. I
+could have used a separate native interface for these, but decided to keep all the native stuff in one
+
+class for simplicity and maintainability.
+
+Connecting the Public API to the Native Interface
+
+So we have a public API, and we have a native interface. The idea is that the public API should be a
+
+thin wrapper around the native interface to smooth out rough edges that are likely to exist due to
+
+the  strict  set  of  rules  involved  in  native  interfaces.  We’ll,  therefore,  use  delegation  inside  the
+Mobihelp class to provide it a reference to an instance of MobihelpNative:
+
+public class Mobihelp {
+    private static MobihelpNative peer;
+    //...
+}
+
+We’ll initialize this peer inside the init() method of the Mobihelp class. Notice, though that init() is
+
+631
+
+private since we have provided abstractions for the Android and iOS apps separately:
+
+    //Initialize the Mobihelp support section with necessary app configuration.
+    public final static void initAndroid(MobihelpConfig config) {
+        if ("and".equals(Display.getInstance().getPlatformName())) {
+            init(config);
+        }
+    }
+
+    public final static void initIOS(MobihelpConfig config) {
+        if ("ios".equals(Display.getInstance().getPlatformName())) {
+            init(config);
+        }
+    }
+
+    private static void init(MobihelpConfig config) {
+        peer = (MobihelpNative)NativeLookup.create(MobihelpNative.class);
+        peer.config_setAppId(config.getAppId());
+        peer.config_setAppSecret(config.getAppSecret());
+        peer.config_setAutoReplyEnabled(config.isAutoReplyEnabled());
+        peer.config_setDomain(config.getDomain());
+        peer.config_setEnhancedPrivacyModeEnabled(config.isEnhancedPrivacyModeEnabled());
+        if (config.getFeedbackType() != null) {
+            peer.config_setFeedbackType(config.getFeedbackType().ordinal());
+        }
+        peer.config_setLaunchCountForReviewPrompt(config.getLaunchCountForReviewPrompt());
+        peer.config_setPrefetchSolutions(config.isPrefetchSolutions());
+        peer.initNative();
+
+    }
+
+Things to Notice:
+
+1. The  initAndroid()  and  initIOS()  methods  include  a  check  to  see  if  they  are  running  on  the
+
+correct platform. Ultimately they both call init().
+
+2. The  init()  method,  uses  the  NativeLookup  [https://www.codenameone.com/javadoc/com/codename1/
+
+system/NativeLookup.html] class to instantiate our native interface.
+
+Implementing the Glue Between Public API and Native Interface
+
+For  most  of  the  methods  in  the  Mobihelp  class,  we  can  see  that  the  public  API  will  just  be  a  thin
+wrapper around the native interface. E.g. the public API implementation of setUserFullName(String)
+is:
+
+public final static void setUserFullName(String name) {
+    peer.setUserFullName(name);
+}
+
+For some other methods, the public API needs to break apart the parameters into a form that the
+
+632
+
+native interface can accept. E.g. the init() method, shown above, takes a MobihelpConfig object as a
+parameter, but it passed the properties of the config object individually into the native interface.
+
+Another  example,  is  the  showSupport(ArrayList<String>  tags)  method.  The  corresponding  native
+interface  method  that  is  wraps  is  showSupport(String  tags,  `String  separator)`  -  i.e  it  needs  to
+merge  all  tags  into  a  single  delimited  string,  and  pass  then  to  the  native  interface  along  with  the
+
+delimiter used. The implementation is:
+
+public final static void showSupport(ArrayList<String> tags) {
+    String separator = findUnusedSeparator(tags);
+    StringBuilder sb = new StringBuilder();
+    for (String tag : tags) {
+        sb.append(tag).append(separator);
+    }
+    peer.showSupportWithTags(sb.toString().substring(0, sb.length()-separator.length()), separator);
+}
+
+The only other non-trivial wrapper is the getUnreadCountAsync() method that we discussed before:
+
+   public final static void getUnreadCountAsync(UnreadUpdatesCallback callback) {
+        int callbackId = MobihelpNativeCallback.registerUnreadUpdatesCallback(callback);
+        peer.getUnreadCountAsync(callbackId);
+    }
+
+16.13.5. Step 5: Implementing the Native Interface in Android
+
+Now that we have set up our public API and our native interface, it is time to work on the native
+
+side of things. You can generate stubs for all platforms in your IDE (Netbeans in my case), by right
+clicking on the MobihelpNative class in the project explorer and selecting "Generate Native Access".
+
+Figure 484. Generate Native Access Menu Item
+
+This will generate a separate directory for each platform inside your project’s native directory:
+
+Figure 485. Native generated sources directory view
+
+Inside the android directory, this generates a com/codename1/freshdesk/MobihelpNativeImpl class with
+stubs for each method.
+
+633
+
+Our  implementation  will  be  a  thin  wrapper  around  the  native  Android  SDK.  See  the  source  here
+
+[https://github.com/shannah/cn1-freshdesk/blob/master/cn1-freshdesk-demo/native/android/com/codename1/
+
+freshdesk/MobihelpNativeImpl.java].
+
+Some highlights:
+
+1. Context : The native API requires us to pass a context object as a parameter on many methods.
+This  should  be  the  context  for  the  current  activity.  It  will  allow  the  FreshDesk  API  to  know
+
+where  to  return  to  after  it  has  done  its  thing.  Codename  One  provides  a  class  called
+AndroidNativeUtil that allows us to retrieve the app’s Activity (which includes the Context). We’ll
+wrap this with a convenience method in our class as follows:
+
+private static Context context() {
+    return com.codename1.impl.android.AndroidNativeUtil.getActivity().getApplicationContext();
+}
+
+This will enable us to easily wrap the freshdesk native API. E.g.:
+
+public void clearUserData() {
+    com.freshdesk.mobihelp.Mobihelp.clearUserData(context());
+}
+
+2. runOnUiThread()  -  Many  of  the  calls  to  the  FreshDesk  API  may  have  been  made  from  the
+Codename One EDT. However, Android has its own event dispatch thread that should be used
+
+for interacting with native Android UI. Therefore, any API calls that look like they initiate some
+sort of native Android UI process should be wrapped inside Android’s runOnUiThread() method
+which is similar to Codename One’s Display.callSerially() method. E.g. see the showSolutions()
+method:
+
+    public void showSolutions() {
+        activity().runOnUiThread(new Runnable() {
+            public void run() {
+                com.freshdesk.mobihelp.Mobihelp.showSolutions(context());
+            }
+        });
+
+    }
+
+(Note  here  that  the  activity()  method  is  another  convenience  method  to  retrieve  the  app’s
+current Activity from the AndroidNativeUtil class).
+
+3. Callbacks. We discussed, in detail, the mechanisms we put in place to enable our native code to
+
+perform  callbacks  into  Codename  One.  You  can  see  the  native  side  of  this  by  viewing  the
+getUnreadCountAsync() method implementation:
+
+634
+
+    public void getUnreadCountAsync(final int callbackId) {
+        activity().runOnUiThread(new Runnable() {
+            public void run() {
+                com.freshdesk.mobihelp.Mobihelp.getUnreadCountAsync(context(), new
+com.freshdesk.mobihelp.UnreadUpdatesCallback() {
+                    public void onResult(com.freshdesk.mobihelp.MobihelpCallbackStatus status, Integer count) {
+                        MobihelpNativeCallback.fireUnreadUpdatesCallback(callbackId, status.ordinal(), count);
+                    }
+                });
+            }
+        });
+
+    }
+
+16.13.6. Step 6: Bundling the Native SDKs
+
+The last step (at least on the Android side) is to bundle the FreshDesk SDK. For Android, there are a
+
+few different scenarios you’ll run into for embedding SDKs:
+
+1. The SDK includes only Java classes - NO XML UI files, assets, or resources that aren’t included
+
+inside  a  simple  .jar  file.  In  this  case,  you  can  just  place  the  .jar  file  inside  your  project’s
+native/android directory.
+
+2. The SDK includes some XML UI files, resources, and assets. In this case, the SDK is generally
+
+distributed as an Android project folder that can be imported into an Eclipse or Android studio
+
+workspace. In general, in this case, you would need to zip the entire directory and change the
+extension  of  the  resulting  .zip  file  to  ".andlib",  and  place  this  in  your  project’s  native/android
+directory.
+
+3. The  SDK  is  distributed  as  an  .aar  file  -  In  this  case  you  can  just  copy  the  .aar  file  into  your
+
+native/android directory.
+
+The FreshDesk SDK
+
+The FreshDesk (aka Mobihelp) SDK is distributed as a project folder (i.e. scenario 2 from the above
+
+list).  Therefore,  our  procedure  is  to  download  the  SDK  (download  link  [https://s3.amazonaws.com/
+assets.mobihelp.freshpo.com/sdk/mobihelp_sdk_android.zip]), and rename it from mobihelp_sdk_android.zip
+to mobihelp_sdk_android.andlib, and copy it into our native/android directory.
+
+Dependencies
+
+Unfortunately, in this case there’s a catch. The Mobihelp SDK includes a dependency:
+
+Mobihelp SDK depends on AppCompat-v7 (Revision 19.0+) Library. You will
+
+need to update project.properties to point to the Appcompat library.
+
+If we look inside the project.properties file (inside the Mobihelp SDK directory--- i.e. you’d need to
+extract it from the zip to view its contents), you’ll see the dependency listed:
+
+android.library.reference.1=../appcompat_v7
+
+635
+
+I.e.  it  is  expecting  to  find  the  appcompat_v7  library  located  in  the  same  parent  directory  as  the
+Mobihelp  SDK  project.  After  a  little  bit  of  research  (if  you’re  not  yet  familiar  with  the  Android
+AppCompat  support  library),  we  find  that  the  AppCompat_v7  library  is  part  of  the  Android  Support
+library,  which  can  can  installed  into  your  local  Android  SDK  using  Android  SDK  Manager.
+
+Installation processed specified here [https://developer.android.com/tools/support-library/setup.html].
+
+After  installing  the  support  library,  you  need  to  retrieve  it  from  your  Android  SDK.  You  can  find
+
+that 
+the
+file 
+ANDROID_HOME/sdk/extras/android/m2repository/com/android/support/appcompat-v7/19.1.0/  directory
+(for version 19.1.0). The contents of that directory on my system are:
+
+inside 
+
+.aar 
+
+appcompat-v7-19.1.0.aar     appcompat-v7-19.1.0.pom
+appcompat-v7-19.1.0.aar.md5 appcompat-v7-19.1.0.pom.md5
+appcompat-v7-19.1.0.aar.sha1    appcompat-v7-19.1.0.pom.sha1
+
+There are two files of interest here:
+
+1. appcompat-v7-19.1.0.aar  -  This  is  the  actual  library  that  we  need  to  include  in  our  project  to
+
+satisfy the Mobisdk dependency.
+
+2. appcompat-v7-19.1.0.pom  -  This  is  the  Maven  XML  file  for  the  library.  It  will  show  us  any
+
+dependencies that the appcompat library has. We will also need to include these dependencies:
+
+  <dependencies>
+    <dependency>
+      <groupId>com.android.support</groupId>
+      <artifactId>support-v4</artifactId>
+      <version>19.1.0</version>
+      <scope>compile</scope>
+    </dependency>
+  </dependencies>
+
+i.e. We  need  to  include  the  support-v4  library  version  19.1.0  in  our  project.  This  is  also  part  of
+the  Android 
+to:
+couple  of  directories 
+ANDROID_HOME/sdk/extras/android/m2repository/com/android/support, we’ll see it listed there:
+
+If  we  back  up  a 
+
+Support 
+
+library. 
+
+appcompat-v7            palette-v7
+cardview-v7         recyclerview-v7
+gridlayout-v7           support-annotations
+leanback-v17            support-v13
+mediarouter-v7          support-v4
+multidex            test
+multidex-instrumentation
+
++  And 
+(in
+ANDROID_HOME/sdk/extras/android/m2repository/com/android/support/support-v4/19.1.0), we see:
+
+the  appropriate  version  directory  of  support-v4 
+
+if  we 
+
+inside 
+
+look 
+
+636
+
+support-v4-19.1.0-javadoc.jar       support-v4-19.1.0.jar
+support-v4-19.1.0-javadoc.jar.md5   support-v4-19.1.0.jar.md5
+support-v4-19.1.0-javadoc.jar.sha1  support-v4-19.1.0.jar.sha1
+support-v4-19.1.0-sources.jar       support-v4-19.1.0.pom
+support-v4-19.1.0-sources.jar.md5   support-v4-19.1.0.pom.md5
+support-v4-19.1.0-sources.jar.sha1  support-v4-19.1.0.pom.sha1
+
+Looks like this library is pure Java classes, so we only need to include the support-v4-19.1.0.jar
+file into our project. Checking the .pom file we see that there are no additional dependencies we
+need to add.
+
+So,  to  summarize  our  findings,  we  need  to  include  the  following  files  in  our  native/android
+directory:
+
+1. appcompat-v7-19.1.0.aar
+
+2. support-v4-19.1.0.jar
+
+And  since  our  Mobihelp  SDK  lists  the  appcompat_v7  dependency  path  as  "../appcompat_v7"  in  its
+project.properties file, we are going to rename appcompat-v7-19.1.0.aar to appcompat_v7.aar.
+
+When all is said and done, our native/android directory should contain the following:
+
+appcompat_v7.aar    mobihelp.andlib
+com         support-v4-19.1.0.jar
+
+16.13.7. Step 7 : Injecting Android Manifest and Proguard Config
+
+The final step on the Android side is to inject necessary permissions and services into the project’s
+
+AndroidManifest.xml file.
+
+We can find the manifest file injections required by opening the AndroidManifest.xml file from the
+MobiHelp SDK project. Its contents are as follows:
+
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.freshdesk.mobihelp"
+    android:versionCode="1"
+    android:versionName="1.0" >
+
+     <uses-sdk
+        android:minSdkVersion="10" />
+
+    <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.READ_LOGS" />
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
+
+    <application>
+        <activity
+
+637
+
+            android:name="com.freshdesk.mobihelp.activity.SolutionArticleListActivity"
+            android:configChanges="orientation|screenSize"
+            android:theme="@style/Theme.Mobihelp"
+            android:windowSoftInputMode="adjustPan" >
+        </activity>
+        <activity
+            android:name="com.freshdesk.mobihelp.activity.FeedbackActivity"
+            android:configChanges="keyboardHidden|orientation|screenSize"
+            android:theme="@style/Theme.Mobihelp"
+            android:windowSoftInputMode="adjustResize|stateVisible" >
+        </activity>
+        <activity
+            android:name="com.freshdesk.mobihelp.activity.InterstitialActivity"
+            android:configChanges="orientation|screenSize"
+            android:theme="@style/Theme.AppCompat">
+        </activity>
+        <activity
+            android:name="com.freshdesk.mobihelp.activity.TicketListActivity"
+            android:parentActivityName="com.freshdesk.mobihelp.activity.SolutionArticleListActivity"
+            android:theme="@style/Theme.Mobihelp" >
+
+            <!-- Parent activity meta-data to support 4.0 and lower -->
+            <meta-data
+                android:name="android.support.PARENT_ACTIVITY"
+                android:value="com.freshdesk.mobihelp.activity.SolutionArticleListActivity" />
+        </activity>
+        <activity
+            android:name="com.freshdesk.mobihelp.activity.SolutionArticleActivity"
+            android:parentActivityName="com.freshdesk.mobihelp.activity.SolutionArticleListActivity"
+            android:theme="@style/Theme.Mobihelp"
+            android:configChanges="orientation|screenSize|keyboard|keyboardHidden" >
+
+            <!-- Parent activity meta-data to support 4.0 and lower -->
+            <meta-data
+                android:name="android.support.PARENT_ACTIVITY"
+                android:value="com.freshdesk.mobihelp.activity.SolutionArticleListActivity" />
+        </activity>
+        <activity
+            android:name="com.freshdesk.mobihelp.activity.ConversationActivity"
+            android:parentActivityName="com.freshdesk.mobihelp.activity.SolutionArticleListActivity"
+            android:theme="@style/Theme.Mobihelp"
+            android:windowSoftInputMode="adjustResize|stateHidden" >
+
+            <!-- Parent activity meta-data to support 4.0 and lower -->
+            <meta-data
+                android:name="android.support.PARENT_ACTIVITY"
+                android:value="com.freshdesk.mobihelp.activity.SolutionArticleListActivity" />
+        </activity>
+        <activity
+            android:name="com.freshdesk.mobihelp.activity.AttachmentHandlerActivity"
+            android:configChanges="keyboardHidden|orientation|screenSize"
+            android:parentActivityName="com.freshdesk.mobihelp.activity.SolutionArticleListActivity"
+            android:theme="@style/Theme.Mobihelp" >
+
+            <!-- Parent activity meta-data to support 4.0 and lower -->
+            <meta-data
+                android:name="android.support.PARENT_ACTIVITY"
+
+638
+
+                android:value="com.freshdesk.mobihelp.activity.SolutionArticleListActivity" />
+        </activity>
+
+        <service android:name="com.freshdesk.mobihelp.service.MobihelpService" />
+
+        <receiver android:name="com.freshdesk.mobihelp.receiver.ConnectivityReceiver" >
+            <intent-filter>
+                <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
+            </intent-filter>
+        </receiver>
+    </application>
+
+</manifest>
+
+We’ll need to add the <uses-permission> tags and all of the contents of the <application> tag to our
+manifest file. Codename One provides the following build hints for these:
+
+1. android.xpermissions  -  For  your  <uses-permission>  directives.  Add  a  build  hint  with  name
+
+android.xpermissions, and for the value, paste the actual <uses-permission> XML tag.
+
+2. android.xapplication - For the contents of your <application> tag.
+
+Proguard Config
+
+For  the  release  build,  we’ll  also  need  to  inject  some  proguard  configuration  so  that  important
+
+classes don’t get stripped out at build time. The FreshDesk SDK instructions state:
+
+If  you  use  Proguard,  please  make  sure  you  have  the  following  included  in
+
+your project’s proguard-project.txt
+
+-keep class android.support.v4.** { *; }
+-keep class android.support.v7.** { *; }
+
+In addition, if you look at the proguard-project.txt file inside the Mobihelp SDK, you’ll see the rules:
+
+-keep public class * extends android.app.Service
+-keep public class * extends android.content.BroadcastReceiver
+-keep public class * extends android.app.Activity
+-keep public class * extends android.preference.Preference
+-keep public class com.freshdesk.mobihelp.exception.MobihelpComponentNotFoundException
+
+-keepclassmembers class * implements android.os.Parcelable {
+  public static final android.os.Parcelable$Creator *;
+}
+
+We’ll  want  to  merge  this  and  then  paste  them  into  the  build  hint  android.proguardKeep  of  our
+project.
+
+639
+
+Troubleshooting Android Stuff
+
+If, after doing all this, your project fails to build, you can enable the "Include Source" option of the
+
+build  server,  then  download  the  source  project,  open  it  in  Eclipse  or  Android  Studio,  and  debug
+
+from there.
+
+16.14. Part 2: Implementing the iOS Native Code
+
+Part 1 of this tutorial focused on the Android native integration. Now we’ll shift our focus to the iOS
+
+implementation.
+
+After selecting "Generate Native Interfaces" for our "MobihelpNative" class, you’ll find a native/ios
+directory in your project with the following files:
+
+1. com_codename1_freshdesk_MobihelpNativeImpl.h 
+
+[https://github.com/shannah/cn1-freshdesk/blob/master/
+
+cn1-freshdesk-demo/native/ios/com_codename1_freshdesk_MobihelpNativeImpl.h]
+
+2. com_codename1_freshdesk_MobihelpNativeImpl.m 
+
+[https://github.com/shannah/cn1-freshdesk/blob/master/
+
+cn1-freshdesk-demo/native/ios/com_codename1_freshdesk_MobihelpNativeImpl.m]
+
+These files contain stub implementations corresponding to our MobihelpNative class.
+
+We make use of the API docs [http://developer.freshdesk.com/mobihelp/ios/api/] to see how the native SDK
+needs to be wrapped. The method names aren’t the same. E.g. instead of a method showFeedback(), it
+has a message -presentFeedback:
+
+We  more-or-less  just  follow  the  iOS  integration  guide  [http://developer.freshdesk.com/mobihelp/ios/
+
+integration_guide/#getting-started] for wrapping the API. Some key points include:
+
+1. Remember to import the Mobihelp.h file in your header file:
+
+#import "Mobihelp.h"
+
+2. Similar  to  our  use  of  runOnUiThread()  in  Android,  we  will  wrap  all  of  our  API  calls  in  either
+dispatch_async()  or  dispatch_sync()  calls  to  ensure  that  we  are  interacting  with  the  Mobihelp
+API on the app’s main thread rather than the Codename One EDT.
+
+3. Some  methods/messages  in  the  Mobihelp  SDK  require  us  to  pass  a  UIViewController  as  a
+parameter.  In  Codename  One,  the  entire  application  uses  a  single  UIViewController:
+CodenameOne_GLViewController.  You 
+can 
+[CodenameOne_GLViewController instance] message. We need to import its header file:
+
+this  using 
+
+reference 
+
+obtain 
+
+the
+
+to 
+
+a 
+
+#import "CodenameOne_GLViewController.h"
+
+As an example, let’s look at the showFeedback() method:
+
+640
+
+-(void)showFeedback{
+
+    dispatch_async(dispatch_get_main_queue(), ^{
+        [[Mobihelp sharedInstance] presentFeedback:[CodenameOne_GLViewController instance]];
+    });
+}
+
+16.14.1. Using the MobihelpNativeCallback
+
+We  described  earlier  how  we  created  a  static  method  on  the  MobihelpNativeCallback  class  so  that
+native code could easily fire a callback method. Now let’s take a look at how this looks from the iOS
+side of the fence. Here is the implementation of getUnreadCountAsync():
+
+-(void)getUnreadCountAsync:(int)param{
+  dispatch_async(dispatch_get_main_queue(), ^{
+    [[Mobihelp sharedInstance]
+      unreadCountWithCompletion:^(NSInteger count){
+        com_codename1_freshdesk_MobihelpNativeCallback_fireUnreadUpdatesCallback___int_int_int(
+                CN1_THREAD_GET_STATE_PASS_ARG param, 3 /*SUCCESS*/, count);
+      }];
+  });
+}
+
+In our case the iOS SDK version of this method is +unreadCountWithCompletion: which takes a block
+(which is like an anonymous function) as a parameter.
+
+The callback to our Codename One function occurs on this line:
+
+com_codename1_freshdesk_MobihelpNativeCallback_fireUnreadUpdatesCallback___int_int_int(
+    CN1_THREAD_GET_STATE_PASS_ARG param, 3 /*SUCCESS*/, count);
+
+Some things worth mentioning here:
+
+1. The 
+
+is 
+
+name 
+
+method 
+
+taking 
+(MobihelpNativeCallback.fireUpdateUnreadUpdatesCallback(int,  int,  int) 
+the  package
+com.codename1.freshdesk)  and  replacing  all  .  characters  with  underscores,  suffixing  two
+underscores  after  the  end  of  the  method  name,  then  appending  _int  once  for  each  of  the  int
+arguments.
+
+result 
+
+FQN
+
+the 
+
+the 
+
+in 
+
+of 
+
+2. We also need to import the header file for this class:
+
+#import "com_codename1_freshdesk_MobihelpNativeCallback.h"
+
+16.14.2. Bundling Native iOS SDK
+
+Now that we have implemented our iOS native interface, we need to bundle the Mobihelp iOS SDK
+
+641
+
+into our project. There are a few different scenarios you may face when looking to include a native
+
+SDK:
+
+1. The  SDK  includes  .bundle  resource  files.  In  this  case,  just  copy  the  .bundle  file(s)  into  your
+
+native/ios directory.
+
+2. The  SDK  includes  .h  header  files.  In  this  case,  just  copy  the  .h  file(s)  into  your  native/ios
+
+directory.
+
+3. The SDK includes .a files. In this case, just copy the .a file(s) into your native/ios directory.
+
+4. The SDK includes .framework files. In this case, you’ll need to zip up the framework, and copy it
+into your native/ios directory. E.g. If the framework is named, MyFramework.framework, then
+the  zip  file  should  be  named  MyFramework.framework.zip,  and  should  be  located  at
+native/ios/MyFramework.framework.zip.
+
+The FreshDesk SDK doesn’t include any .framework files, so we don’t need to worry about that last
+scenario.  We  simply  download  the  iOS  SDK  [https://s3.amazonaws.com/assets.mobihelp.freshpo.com/sdk/
+mobihelp_sdk_ios.zip],  copy  the  libFDMobihelpSDK.a,  Mobihelp.h.  MHModel.bundle,  MHResources.bundle,
+and MHLocalization/en.proj/MHLocalizable.strings into native/ios.
+
+16.14.3. Troubleshooting iOS
+
+If  you  run  into  problems  with  the  build,  you  can  select  "Include  Sources"  in  the  build  server  to
+
+download the resulting Xcode Project. You can then debug the Xcode project locally, make changes
+
+to  your  iOS  native  implementation  files,  and  copy  them  back  into  your  project  once  it  is  building
+
+properly.
+
+16.14.4. Adding Required Core Libraries and Frameworks
+
+The  iOS  integration  guide  for  the  FreshDesk  SDK  lists  the  following  core  frameworks  as
+
+dependencies:
+
+Figure 486. IOS link options
+
+We can add these dependencies to our project using the ios.add_libs build hint. E.g.
+
+Figure 487. iOS’s "add libs" build hint
+
+I.e.  we  just  list  the  framework  names  separated  by  semicolons.  Notice  that  my  list  in  the  above
+
+image  doesn’t  include  all  of  the  frameworks  that  they  list  because  many  of  the  frameworks  are
+
+already included by default (I obtained the default list by simply building the project with "include
+
+sources" checked, then looked at the frameworks that were included).
+
+642
+
+16.15. Part 3 : Packaging as a cn1lib
+
+During the initial development, I generally find it easier to use a regular Codename One project so
+
+that I can run and test as I go. But once it is stabilized, and I want to distribute the library to other
+
+developers, I will transfer it over to a Codename One library project. This general process involves:
+
+1. Create a Codename One Library project.
+
+2. Copy the .java files from my original project into the library project.
+
+3. Copy the native directory from the original project into the library project.
+
+4. Copy  the  relevant  build  hints  from  the  original  project’s  codenameone_settings.properties  file
+
+into the library project’s codenameone_library_appended.properties file.
+
+In  the  case  of  the  FreshDesk  .cn1lib,  I  modified  the  original  project’s  build  script  to  generate  and
+
+build a library project automatically. But that is beyond the scope of this tutorial.
+
+16.16. Building Your Own Layout Manager
+
+A  Layout  [https://www.codenameone.com/javadoc/com/codename1/ui/layouts/Layout.html]  contains  all  the
+
+logic  for  positioning  Codename  One  components.  It  essentially  traverses  a  Codename  One
+
+Container 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/Container.html] 
+
+and 
+
+positions
+
+components absolutely based on internal logic.
+
+When we build the layout we need to take margin into consideration and make sure to add it into
+
+the  position/size  calculations.  Building  a 
+layoutContainer & getPreferredSize.
+
+layout  manager  involves  two  simple  methods:
+
+layoutContainer  is  invoked  whenever  Codename  One  decides  the  container  needs  rearranging,
+Codename  One  tries  to  avoid  calling  this  method  and  only  invokes  it  at  the  last  possible  moment.
+
+Since  this  method  is  generally  very  expensive  (imagine  the  recursion  with  nested  layouts).
+
+Codename  One  just  marks  a  flag  indicating  layout  is  "dirty"  when  something  important  changes
+
+and tries to avoid "reflows".
+
+getPreferredSize allows the layout to determine the size desired for the container. This might be a
+difficult call to make for some layout managers that try to provide both flexibility and simplicity.
+
+Most  of  FlowLayout  bugs  stem  from  the  fact  that  this  method  is  just  impossible  to  implement
+correctly & efficiently for all the use cases of a deeply nested FlowLayout. The size of the final layout
+won’t necessarily match the requested size (it probably won’t) but the requested size is taken into
+
+consideration, especially when scrolling and also when sizing parent containers.
+
+This is a layout manager that just arranges components in a center column aligned to the middle.
+
+We then show the proper usage of margin to create a stair like effect with this layout manager:
+
+643
+
+class CenterLayout extends Layout {
+    public void layoutContainer(Container parent) {
+        int components = parent.getComponentCount();
+        Style parentStyle = parent.getStyle();
+        int centerPos = parent.getLayoutWidth() / 2 + parentStyle.getMargin(Component.LEFT);
+        int y = parentStyle.getMargin(Component.TOP);
+        boolean rtl = parent.isRTL();
+        for (int iter = 0; iter < components; iter++) {
+            Component current = parent.getComponentAt(iter);
+            Dimension d = current.getPreferredSize();
+            Style currentStyle = current.getStyle();
+            int marginRight = currentStyle.getMarginRight(rtl);
+            int marginLeft = currentStyle.getMarginLeft(rtl);
+            int marginTop = currentStyle.getMarginTop();
+            int marginBottom = currentStyle.getMarginBottom();
+            current.setSize(d);
+            int actualWidth = d.getWidth() + marginLeft + marginRight;
+            current.setX(centerPos - actualWidth / 2 + marginLeft);
+            y += marginTop;
+            current.setY(y);
+            y += d.getHeight() + marginBottom;
+        }
+    }
+
+    public Dimension getPreferredSize(Container parent) {
+        int components = parent.getComponentCount();
+        Style parentStyle = parent.getStyle();
+        int height = parentStyle.getMargin(Component.TOP) + parentStyle.getMargin(Component.BOTTOM);
+        int marginX = parentStyle.getMargin(Component.RIGHT) + parentStyle.getMargin(Component.LEFT);
+        int width = marginX;
+        for (int iter = 0; iter < components; iter++) {
+            Component current = parent.getComponentAt(iter);
+            Dimension d = current.getPreferredSize();
+            Style currentStyle = current.getStyle();
+            width = Math.max(d.getWidth() + marginX + currentStyle.getMargin(Component.RIGHT)
+                    + currentStyle.getMargin(Component.LEFT), width);
+            height += currentStyle.getMargin(Component.TOP) + d.getHeight()
+                    + currentStyle.getMargin(Component.BOTTOM);
+        }
+        Dimension size = new Dimension(width, height);
+        return size;
+    }
+}
+
+Form hi = new Form("Center Layout", new CenterLayout());
+for(int iter = 1 ; iter < 10 ; iter++) {
+    Label l = new Label("Label: " + iter);
+    l.getUnselectedStyle().setMarginLeft(iter * 3);
+    l.getUnselectedStyle().setMarginRight(0);
+    hi.add(l);
+}
+hi.add(new Label("Really Wide Label Text!!!"));
+hi.show();
+
+644
+
+Figure 488. Center layout staircase effect with margin
+
+16.16.1. Porting a Swing/AWT Layout Manager
+
+The  GridBagLayout 
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/layouts/GridBagLayout.html]
+
+was  ported  to  Codename  One  relatively  easily  considering  the  complexity  of  that  specific  layout
+
+manager.  Here  are  some  tips  you  should  take  into  account  when  porting  a  Swing/AWT  layout
+
+manager:
+
+1. Codename One doesn’t have Insets, we added some support for them in order to port GridBag
+but  components  in  Codename  One  have  a  margin  they  need  to  consider  instead  of  the  Insets
+(the padding is in the preferred size and is thus hidden from the layout manager).
+
+2. AWT  layout  managers  also  synchronize  a  lot  on  the  AWT  thread.  This  is  no  longer  necessary
+
+since Codename One is single threaded, like Swing.
+
+3. AWT considers the top left position of the Container to be 0,0 whereas Codename One considers
+the  position  based  on  its  parent  Container.  The  top  left  position  in  Codename  One  is  getX(),
+getY().
+
+Other  than  those  things  it’s  mostly  just  fixing  method  and  import  statements,  which  are  slightly
+
+different. Pretty trivial stuff.
+
+16.17. Port a Language to Codename One
+
+As  you  may  have  already  read,  we  have  just  added  support  for  Kotlin  in  Codename  One.  This  is
+
+something  that  you  can  achieve  without  the  help  of  Codename  One.  You  could  port  a  3rd  party
+
+language like Scala, Ruby, Python etc. to Codename One.
+
+16.17.1. What is a JVM Language?
+
+A JVM Language is any programming language that can be compiled to byte-codes that will run on
+
+the JVM (Java Virtual Machine). Java was the original JVM language, but many others have sprung
+
+up  over  the  years.  Kotlin  [https://kotlinlang.org/],  Scala  [https://www.scala-lang.org/],  Groovy  [http://groovy-
+
+lang.org/],  and  JRuby  [http://jruby.org/]  come  to  mind  as  well-established  and  mature  languages,  but
+
+there are many others [https://en.wikipedia.org/wiki/List_of_JVM_languages].
+
+645
+
+16.17.2. How Hard is it to Port a JVM Language to Codename One?
+
+The  difficulty  of  porting  a  particular  language  to  Codename  One  will  vary  depending  on  such
+
+factors as:
+
+1. Does it require a runtime library?
+
+a. How  complex  is  the  runtime  library?  (E.g.  Does  it  require  classes  that  aren’t  currently
+
+offered in Codename One’s subset of the java standard libraries?)
+
+2. Does it need reflection?
+
+a. Codename One doesn’t support reflection because it would result in a very large application
+
+size.  If  a  JVM  language  requires  reflection  just  to  get  off  the  ground  then  adding  it  to
+
+Codename one would be tricky.
+
+3. Does it perform any runtime byte-code manipulation?
+
+a. Some  dynamic  languages  may  perform  byte-code  manipulation  at  runtime.  This  is
+
+problematic on iOS (and possibly other platforms) which prohibits such runtime behavior.
+
+Step 1: Assess the Language
+
+The  more  similar  a  language,  and  its  build  outputs  are  to  Java,  the  easier  it  will  be  to  port
+
+(probably). Most JVM languages have two parts:
+
+1. A compiler, which compiles source files to JVM byte-code (usually as .class files).
+
+2. A runtime library.
+
+Currently I’m only aware of one language (other than Java) that doesn’t require a runtime library,
+
+and that is Mirah [http://www.mirah.org/].
+
+ Codename  One  also  supports  Mirah  [https://www.codenameone.com/blog/mirah-for-
+
+codename-one.html]
+
+Assessing the Byte-Code
+
+The first thing I do is take a look at the byte-code that is produced by the compiler. I use javap to
+print out a nice version.
+
+Consider this sample Kotlin class:
+
+646
+
+package com.codename1.hellokotlin2
+
+import com.codename1.ui.Button
+import com.codename1.ui.Form
+import com.codename1.ui.Label
+import com.codename1.ui.layouts.BoxLayout
+
+/**
+ * Created by shannah on 2017-07-10.
+ */
+class KotlinForm : Form {
+
+    constructor() : super("Hello Kotlin", BoxLayout.y()) {
+        val label = Label("Hello Kotlin")
+        val clickMe = Button("Click Me")
+        clickMe.addActionListener {
+            label.setText("You Clicked Me");
+            revalidate();
+        }
+
+        add(label).add(clickMe);
+
+    }
+
+}
+
+Let’s take a look at the bytecode that Kotlin produced for this class:
+
+$ javap -v com/codename1/hellokotlin2/KotlinForm.class
+
+  Last modified 10-Jul-2017; size 1456 bytes
+  MD5 checksum 1cb00f6e63b918bb5a9f146ca8b0b78e
+  Compiled from "KotlinForm.kt"
+public final class com.codename1.hellokotlin2.KotlinForm extends com.codename1.ui.Form
+  SourceFile: "KotlinForm.kt"
+  InnerClasses:
+       static final #31; //class com/codename1/hellokotlin2/KotlinForm$1
+  RuntimeVisibleAnnotations:
+    0: #56(#57=[I#58,I#58,I#59],#60=[I#58,I#61,I#58],#62=I#58,#63=[s#64],#65=[s#55,s#66,s#6,s#67])
+  minor version: 0
+  major version: 50
+  flags: ACC_PUBLIC, ACC_FINAL, ACC_SUPER
+Constant pool:
+   #1 = Utf8               com/codename1/hellokotlin2/KotlinForm
+   #2 = Class              #1             //  com/codename1/hellokotlin2/KotlinForm
+   #3 = Utf8               com/codename1/ui/Form
+   #4 = Class              #3             //  com/codename1/ui/Form
+   #5 = Utf8               <init>
+   #6 = Utf8               ()V
+   #7 = Utf8               Hello Kotlin
+   #8 = String             #7             //  Hello Kotlin
+   #9 = Utf8               com/codename1/ui/layouts/BoxLayout
+
+647
+
+  #10 = Class              #9             //  com/codename1/ui/layouts/BoxLayout
+  #11 = Utf8               y
+  #12 = Utf8               ()Lcom/codename1/ui/layouts/BoxLayout;
+  #13 = NameAndType        #11:#12        //  y:()Lcom/codename1/ui/layouts/BoxLayout;
+  #14 = Methodref          #10.#13        //  com/codename1/ui/layouts/BoxLayout.y:()Lcom/codename1/ui/layouts/BoxLayout;
+  #15 = Utf8               com/codename1/ui/layouts/Layout
+  #16 = Class              #15            //  com/codename1/ui/layouts/Layout
+  #17 = Utf8               (Ljava/lang/String;Lcom/codename1/ui/layouts/Layout;)V
+  #18 = NameAndType        #5:#17         //  "<init>":(Ljava/lang/String;Lcom/codename1/ui/layouts/Layout;)V
+  #19 = Methodref          #4.#18         //
+com/codename1/ui/Form."<init>":(Ljava/lang/String;Lcom/codename1/ui/layouts/Layout;)V
+  #20 = Utf8               com/codename1/ui/Label
+  #21 = Class              #20            //  com/codename1/ui/Label
+  #22 = Utf8               (Ljava/lang/String;)V
+  #23 = NameAndType        #5:#22         //  "<init>":(Ljava/lang/String;)V
+  #24 = Methodref          #21.#23        //  com/codename1/ui/Label."<init>":(Ljava/lang/String;)V
+  #25 = Utf8               com/codename1/ui/Button
+  #26 = Class              #25            //  com/codename1/ui/Button
+  #27 = Utf8               Click Me
+  #28 = String             #27            //  Click Me
+  #29 = Methodref          #26.#23        //  com/codename1/ui/Button."<init>":(Ljava/lang/String;)V
+  #30 = Utf8               com/codename1/hellokotlin2/KotlinForm$1
+  #31 = Class              #30            //  com/codename1/hellokotlin2/KotlinForm$1
+  #32 = Utf8               (Lcom/codename1/hellokotlin2/KotlinForm;Lcom/codename1/ui/Label;)V
+  #33 = NameAndType        #5:#32         //  "<init>":(Lcom/codename1/hellokotlin2/KotlinForm;Lcom/codename1/ui/Label;)V
+  #34 = Methodref          #31.#33        //
+com/codename1/hellokotlin2/KotlinForm$1."<init>":(Lcom/codename1/hellokotlin2/KotlinForm;Lcom/codename1/ui/Label;)V
+  #35 = Utf8               com/codename1/ui/events/ActionListener
+  #36 = Class              #35            //  com/codename1/ui/events/ActionListener
+  #37 = Utf8               addActionListener
+  #38 = Utf8               (Lcom/codename1/ui/events/ActionListener;)V
+  #39 = NameAndType        #37:#38        //  addActionListener:(Lcom/codename1/ui/events/ActionListener;)V
+  #40 = Methodref          #26.#39        //
+com/codename1/ui/Button.addActionListener:(Lcom/codename1/ui/events/ActionListener;)V
+  #41 = Utf8               com/codename1/ui/Component
+  #42 = Class              #41            //  com/codename1/ui/Component
+  #43 = Utf8               add
+  #44 = Utf8               (Lcom/codename1/ui/Component;)Lcom/codename1/ui/Container;
+  #45 = NameAndType        #43:#44        //  add:(Lcom/codename1/ui/Component;)Lcom/codename1/ui/Container;
+  #46 = Methodref          #2.#45         //
+com/codename1/hellokotlin2/KotlinForm.add:(Lcom/codename1/ui/Component;)Lcom/codename1/ui/Container;
+  #47 = Utf8               com/codename1/ui/Container
+  #48 = Class              #47            //  com/codename1/ui/Container
+  #49 = Methodref          #48.#45        //
+com/codename1/ui/Container.add:(Lcom/codename1/ui/Component;)Lcom/codename1/ui/Container;
+  #50 = Utf8               clickMe
+  #51 = Utf8               Lcom/codename1/ui/Button;
+  #52 = Utf8               label
+  #53 = Utf8               Lcom/codename1/ui/Label;
+  #54 = Utf8               this
+  #55 = Utf8               Lcom/codename1/hellokotlin2/KotlinForm;
+  #56 = Utf8               Lkotlin/Metadata;
+  #57 = Utf8               mv
+  #58 = Integer            1
+  #59 = Integer            6
+  #60 = Utf8               bv
+  #61 = Integer            0
+  #62 = Utf8               k
+  #63 = Utf8               d1
+  #64 = Utf8
+                           \n\n\20¢¨
+  #65 = Utf8               d2
+  #66 = Utf8               Lcom/codename1/ui/Form;
+  #67 = Utf8               HelloKotlin2
+  #68 = Utf8               KotlinForm.kt
+  #69 = Utf8               Code
+  #70 = Utf8               LocalVariableTable
+
+648
+
+  #71 = Utf8               LineNumberTable
+  #72 = Utf8               SourceFile
+  #73 = Utf8               InnerClasses
+  #74 = Utf8               RuntimeVisibleAnnotations
+{
+  public com.codename1.hellokotlin2.KotlinForm();
+    descriptor: ()V
+    flags: ACC_PUBLIC
+    Code:
+      stack=5, locals=3, args_size=1
+         0: aload_0
+         1: ldc           #8                  // String Hello Kotlin
+         3: invokestatic  #14                 // Method
+com/codename1/ui/layouts/BoxLayout.y:()Lcom/codename1/ui/layouts/BoxLayout;
+         6: checkcast     #16                 // class com/codename1/ui/layouts/Layout
+         9: invokespecial #19                 // Method
+com/codename1/ui/Form."<init>":(Ljava/lang/String;Lcom/codename1/ui/layouts/Layout;)V
+        12: new           #21                 // class com/codename1/ui/Label
+        15: dup
+        16: ldc           #8                  // String Hello Kotlin
+        18: invokespecial #24                 // Method com/codename1/ui/Label."<init>":(Ljava/lang/String;)V
+        21: astore_1
+        22: new           #26                 // class com/codename1/ui/Button
+        25: dup
+        26: ldc           #28                 // String Click Me
+        28: invokespecial #29                 // Method com/codename1/ui/Button."<init>":(Ljava/lang/String;)V
+        31: astore_2
+        32: aload_2
+        33: new           #31                 // class com/codename1/hellokotlin2/KotlinForm$1
+        36: dup
+        37: aload_0
+        38: aload_1
+        39: invokespecial #34                 // Method
+com/codename1/hellokotlin2/KotlinForm$1."<init>":(Lcom/codename1/hellokotlin2/KotlinForm;Lcom/codename1/ui/Label;)V
+        42: checkcast     #36                 // class com/codename1/ui/events/ActionListener
+        45: invokevirtual #40                 // Method
+com/codename1/ui/Button.addActionListener:(Lcom/codename1/ui/events/ActionListener;)V
+        48: aload_0
+        49: aload_1
+        50: checkcast     #42                 // class com/codename1/ui/Component
+        53: invokevirtual #46                 // Method add:(Lcom/codename1/ui/Component;)Lcom/codename1/ui/Container;
+        56: aload_2
+        57: checkcast     #42                 // class com/codename1/ui/Component
+        60: invokevirtual #49                 // Method
+com/codename1/ui/Container.add:(Lcom/codename1/ui/Component;)Lcom/codename1/ui/Container;
+        63: pop
+        64: return
+      LocalVariableTable:
+        Start  Length  Slot  Name   Signature
+           32      32     2 clickMe   Lcom/codename1/ui/Button;
+           22      42     1 label   Lcom/codename1/ui/Label;
+            0      65     0  this   Lcom/codename1/hellokotlin2/KotlinForm;
+      LineNumberTable:
+        line 13: 0
+        line 14: 12
+        line 15: 22
+        line 16: 32
+        line 21: 48
+}
+
+That’s a big mess of stuff, but it’s pretty easy to pick through it when you know what you’re looking
+
+for.  The  layout  of  this  output  is  pretty  straight  forward.  The  beginning  shows  that  this  is  a  class
+
+definition:
+
+649
+
+public final class com.codename1.hellokotlin2.KotlinForm extends com.codename1.ui.Form {
+    //...
+}
+
+Even  just  comparing  this  line  with  the  class  definition  from  the  source  file  we  have  learned
+something  about  the  Kotlin  compiler.  It  has  made  the  class  final  by  default.  That  observation
+shouldn’t affect our assessment here, but it is kind of interesting.
+
+After the class definition, it shows the internal classes:
+
+InnerClasses:
+     static final #31; //class com/codename1/hellokotlin2/KotlinForm$1
+
+The Constant Pool
+
+And the constants that are used in the class:
+
+Constant pool:
+   #1 = Utf8               com/codename1/hellokotlin2/KotlinForm
+   #2 = Class              #1             //  com/codename1/hellokotlin2/KotlinForm
+   #3 = Utf8               com/codename1/ui/Form
+   #4 = Class              #3             //  com/codename1/ui/Form
+   #5 = Utf8               <init>
+   #6 = Utf8               ()V
+   #7 = Utf8               Hello Kotlin
+   #8 = String             #7             //  Hello Kotlin
+   #9 = Utf8               com/codename1/ui/layouts/BoxLayout
+   ... etc...
+
+The  constant  pool  will  consist  of  class  names,  and  strings  mostly.  You’ll  want  to  peruse  this  list  to
+
+see  if  the  compiler  has  added  any  classes  that  aren’t  in  the  source  code.  In  the  example  above,  it
+
+looks like Kotlin is pretty faithful to the original source’s dependencies. It didn’t inject any classes
+
+that aren’t in the original source.
+
+Even if the compiler does inject other dependencies into the bytecode, it might not be a problem. It
+
+is  only  a  problem  if  those  classes  aren’t  supported  by  Codename  One.  Keep  your  eyes  peeled  for
+anything  in  the  java.lang.reflect  package  or  unsolicited  use  of  java.net,  java.nio,  or  any  other
+package  that  aren’t  part  of  the  Codename  One  standard  library.  If  you’re  not  sure  if  a  class  or
+
+package 
+
+is  available 
+
+in 
+
+the  Codename  One 
+
+standard 
+
+library,  check 
+
+the 
+
+javadocs
+
+[https://www.codenameone.com/javadoc/].
+
+The ByteCode Instructions:
+
+After  the  constant  pool,  we  see  each  of  the  methods  of  the  class  written  out  as  a  list  of  bytecode
+
+instructions. E.g.
+
+650
+
+public com.codename1.hellokotlin2.KotlinForm();
+  descriptor: ()V
+  flags: ACC_PUBLIC
+  Code:
+    stack=5, locals=3, args_size=1
+       0: aload_0
+       1: ldc           #8                  // String Hello Kotlin
+       3: invokestatic  #14                 // Method
+com/codename1/ui/layouts/BoxLayout.y:()Lcom/codename1/ui/layouts/BoxLayout;
+       6: checkcast     #16                 // class com/codename1/ui/layouts/Layout
+       9: invokespecial #19                 // Method
+com/codename1/ui/Form."<init>":(Ljava/lang/String;Lcom/codename1/ui/layouts/Layout;)V
+      12: new           #21                 // class com/codename1/ui/Label
+      15: dup
+      16: ldc           #8                  // String Hello Kotlin
+      etc...
+
+In  the  above  snippet,  the  first  instruction  is  aload_0  (which  adds  this  to  the  stack).  The  2nd
+instruction  is  ldc,  (which  loads  constant  #8 — the  string  "Hello  Kotlin"  to  the  stack).  The  3rd
+instruction is invokestatic which calls the static method define by Constant #14 from the constant
+pool, with the two parameters that had just been added to the stack.
+
+ You  don’t  need  to  understand  what  all  of  these  instructions  do.  You  just  need  to
+
+look for instructions that may be problematic.
+
+The  only  instruction  that  I  think  might  be  problematic  is  "invokedynamic".  All  other  instructions
+
+should work find in Codename One. (I don’t know for a fact that invokedynmic won’t work - I just
+
+suspect it might not work on some platforms).
+
+Summary of Byte-code Assessment
+
+So to summarize, the byte-code assessment phase, we’re basically just looking to make sure that the
+
+compiler doesn’t tend to add dependencies to parts of the JDK that Codename One doesn’t currently
+
+support. And we want to make sure that it doesn’t use invokedynamic.
+
+If you find that the compiler does use invokedynamic or add references to classes that Codename
+
+One doesn’t support, don’t give up just yet. You might be able to create your own "porting" runtime
+
+library that will provide these dependencies at runtime.
+
+Assessing the Runtime Library
+
+The  process  for  assessing  the  runtime  library  is  pretty  similar  to  the  process  for  the  bytecodes.
+You’ll want to get your hands on the language’s runtime library, and use javap to inspect the .class
+files.  You’re  looking  for  the  same  things  as  you  were  looking  for  in  the  compiler’s  output:
+
+"invokedynamic" and classes that aren’t supported in Codename One.
+
+Step 2: Convert the Runtime Library into a CN1Lib
+
+Once you have assessed the language and are optimistic that it is a good candidate for porting, you
+
+can  proceed  to  port  the  runtime  library  into  Codename  One.  Usually  that  language’s  runtime
+
+library will be distributed in .jar format. You need to convert this into a cn1lib so that it can be used
+
+in a Codename One project. If you can get your hands on the source code for the runtime library
+
+651
+
+then the best approach is to paste the source files into a Codename One Library project, and try to
+
+build  it.  This  has  the  advantage  that  it  will  validate  the  source  during  compile  to  ensure  that  it
+
+doesn’t depend on any classes that Codename One doesn’t support.
+
+If you can’t find the sources of the runtime library or they don’t seem to be easily "buildable", then
+
+the next best thing is to just get the binary distribution’s jar file and convert it to a cn1lib. This is
+
+what we did for the Kotlin runtime library [https://github.com/shannah/codenameone-kotlin].
+
+This procedure exploits the fact that a cn1lib file is just a zip file with a specific file structure inside
+
+it. The cross-platform Java .class files are all contained inside a file named "main.zip", inside the zip
+
+file. This is the only mandatory file that must be inside a cn1lib.
+
+To  make  the  library  easier  to  use  the  cn1lib  file  can  also  contain  a  file  named  "stubs.zip"  which
+
+includes stubs of the Java sources. When you build a cn1lib using a Codename One Library project,
+
+it will automatically generate stubs of the source so that the IDE will have access to nice things like
+
+Javadoc when using the library. The kotlin distribution includes a separate jar file with the runtime
+
+sources, named "kotlin-runtime-sources.jar", so we used this as the "stubs". It contains full sources,
+
+which isn’t necessary, but it also doesn’t hurt.
+
+So now that we had my two jar files: kotlin-runtime.jar and kotlin-runtime-sources.jar, I created a
+
+new  empty  directory,  and  copied  them  inside.  I  renamed  the  jars  "main.zip"  and  "stubs.zip"
+
+respectively. Then I zipped up the directory and renamed the zip file "kotlin-runtime.cn1lib".
+
+
+
+Building  cn1libs  manually  in  this  way  is  a  very  bad  habit,  as  it  bypasses  the  API
+
+verification  step  that  normally  occurs  when  building  a  library  project.  It  is
+
+possible,  even  likely,  that  the  jar  files  that  you  convert  depend  on  classes  that
+
+aren’t  in  the  Codename  One  library,  so  your  library  will  fail  at  runtime  in
+
+unexpected  ways.  The  only  reason  we  could  do  this  with  kotlin’s  runtime  (with
+
+some confidence) is because I already analyzed the bytecodes to ensure that they
+
+didn’t include anything problematic.
+
+Step 3: Hello World
+
+For  our  "Hello  World"  test  we  will  need  to  create  a  separate  project  in  our  JVM  language  and
+
+produce  class  files  that  we  will  manually  copy  into  an  appropriate  location  of  our  project.  We’ll
+
+want  to  use  the  normal  tools  for  the  language  and  not  worry  about  how  it  integrates  with
+
+Codename One. For Kotlin, I just followed the getting started tutorial on the Kotlin site to create a
+
+new Kotlin project in IntelliJ. When Steve ported Mirah, he just used a text editor and the mirahc
+
+command-line  compiler  to  create  my  Hello World  class.  The  tools  and  process  will  depend  on  the
+
+language.
+
+Here is the "hello world" we created in Kotlin:
+
+652
+
+package com.mycompany.myapp
+
+class HelloKotlin {
+
+    fun hello() {
+        System.out.println("Hello from Kotlin");
+    }
+}
+
+After building this, I have a directory that contains "com/mycompany/myapp/HelloKotlin.class".
+
+It also produced a .jar file that contains this class.
+
+The easiest way to integrate external code into a Codename One project, is just to wrap it as a cn1lib
+
+file  and  place  it  into  my  Codename  One  project’s  lib  directory.  That  way  you  don’t  have  to  mess
+
+with  any  of  the  build  files.  So,  using  roughly  the  same  procedure  as  we  used  to  create  the  kotlin-
+
+runtime.cn1lib, I wrap my hellokotlin.jar as a cn1lib to produce "hellokotlin.cn1lib" and copy it to
+
+the "lib" directory of a Codename One project.
+
+ Remember to select "Codename One" → "Refresh CN1Libs" after placing the cn1lib
+
+in your lib directory or it won’t get picked up.
+
+Finally, I call my library from the start() method of my app:
+
+HelloKotlin hello = new HelloKotlin();
+hello.hello();
+
+If we run this in the Simulator, it should print "Hello from Kotlin" in the output console. If we get an
+
+error,  then  we  can  dig  in  and  try  to  figure  out  what  went  wrong  using  my  standard  debugging
+
+techniques.  EXPECT  an  error  on  the  first  run.  Hopefully  it  will  just  be  a  missing  import  or
+
+something simple.
+
+Step 4: A More Complex Hello World
+
+In the case of Kotlin, the hello world example app would actually run without the runtime library
+
+because it was so simple. So it was necessary to add a more complex example to prove the need for
+
+the runtime library. It doesn’t matter what you do with your more complex example, as long as it
+
+doesn’t require classes that aren’t in Codename One.
+
+If  you  want  to  use  the  Codename  One  inside  your  project,  you  should  add  the  CodenameOne.jar
+
+(found inside any Codename One project) to your classpath so that it will compile.
+
+Step 5: Automation and Integration
+
+At  this  point  we  already  have  a  manual  process  for  incorporating  files  built  with  our  alternate
+
+language into a Codename One project. The process looks like:
+
+1. Use standard tools for your JVM language to write your code.
+
+653
+
+2. Use the JVM language’s standard build tools (e.g. command-line compiler, etc..) to compile your
+
+code so that you have .class files (and optionally a .jar file).
+
+3. Wrap your .class files in a cn1lib.
+
+4. Add the cn1lib to the lib directory of a Codename One project.
+
+5. Use your library from the Codename One project.
+
+When  Steve  first  developed  Mirah  support  he  automated  this  process  using  an  ANT  script
+
+[https://github.com/shannah/CN1MirahNBM/blob/master/src/ca/weblite/codename1/mirah/build.xml].  He 
+
+also
+
+automatically generated some bootstrap code so that he could develop the whole app in Mirah and
+
+he woudn’t have to write any Java. However, this level of integration has limitations.
+
+For  example,  with  this  approach  alone,  you  couldn’t  have  two-way  dependencies  between  Java
+
+source  and  Mirah  source.  Yes,  Mirah  code  could  use  Java  libraries  (and  it  did  depend  on
+
+CodenameOne.jar), and my Java code could use my Mirah code. However, Mirah source code could
+
+not depend on the Java source code in my project. This has to do with the order in which code is
+
+compiled. It’s a bit of a chicken and egg issue. If we are building a project that has Java source code
+
+and  Mirah  source  code,  we  are  using  two  different  compilers:  mirahc  to  compile  the  Mirah  files,
+
+and javac to compile the Java files. If we are starting from a clean build, and we run mirahc first,
+
+then the .java files haven’t yet been compiled to .class files - and thus mirahc can’t reference them -
+
+and any mirah code that depends on those uncompiled Java classes will fail. If we compile the .java
+
+files first, then we have the opposite problem.
+
+Steve worked around this problem in Mirah by writing my own pseudo-compiler [https://github.com/
+
+shannah/mirah-ant/blob/master/src/ca/weblite/asm/JavaExtendedStubCompiler.java]  that  produced  stub  class
+
+files for the java source that would be referenced by mirahc when compiling the Mirah files. In this
+
+way he was able to have two-way dependencies between Java and Mirah in the same project.
+
+Kotlin also supports two-way dependencies, probably using a similar mechanism.
+
+How Seamless Can You Make It?
+
+For both the Kotlin and Mirah support, we wanted integration to be seamless. We didn’t want users
+
+to  have  to  create  a  separate  project  for  their  Kotlin/Mirah  code. We  wanted  them  to  simply  add  a
+
+Kotlin/Mirah  file  into  their  project  and  have  it  just  work.  Achieving  this  level  of  integration  in
+
+Kotlin  was  quite  easy,  since  they  provide  an  ANT  plugin  [https://kotlinlang.org/docs/reference/using-
+ant.html] that essentially allowed me to just add one tag inside my <javac/> tags:
+
+<withKotlin/>
+
+And it would automatically handle Kotlin and Java files together: Seamlessly. There are a few places
+
+in a Codename One’s build.xml file where we call "javac" so we just needed to inject these tags in
+
+those places. This injection is performed automatically by the Codename One IntelliJ plugin.
+
+For  Mirah,  Steve  developed  his  own  ANT  plugins  [https://github.com/shannah/mirah-ant]  and  Netbeans
+
+module [https://github.com/shannah/mirah-nbm] that do something similar in Netbeans.
+
+654
+
+16.18. Update Framework
+
+When we launched Codename One in 2012 we needed a way to ship updates and fixes faster than
+
+the plugin update system. So we built the client lib update system. Then we needed a way to update
+
+the designer tool (resource editor), the GUI builder & the skins… We also needed a system to update
+the builtin builder code (CodeNameOneBuildClient.jar so we built a tool for that too).
+
+The Update Framework [https://github.com/codenameone/UpdateCodenameOne] solves several problems in
+
+the old systems:
+
+• Download  once  -  if  you  have  multiple  projects  the  library  will  only  download  once  to  the
+
+.codenameone directory. All the projects will update from local storage
+
+• Skins  update  automatically  -  this  is  hugely  important.  When  we  change  a  theme  we  need  to
+
+update it in the skins and if you don’t update the skin you might see a difference between the
+
+simulator and the device
+
+• Update of settings/designer without IDE plugin update - The IDE plugin update process is slow
+
+and tedious. This way we can push out a bug fix for the GUI builder without going through the
+
+process of releasing a new plugin version
+
+For the most part this framework should be seamless. You should no longer see the "downloading"
+
+message  whenever  we  push  an  update  after  your  build  client  is  updated.  Your  system  would  just
+
+poll for a new version daily and update when new updates are available.
+
+You can also use the usual method of  Codename One Settings →  Basic →  Update Client Libs which
+
+will force an update check. Notice that the UI will look a bit different after this update.
+
+16.18.1. How does it Work?
+
+You can see the full code here [https://github.com/codenameone/UpdateCodenameOne] the gist of it is very
+simple.  We  create  a  jar  called  UpdateCodenameOne.jar  under  ~/.codenameone  (~  represents  the  users
+home directory).
+
+An update happens by running this tool with a path to a Codename One project e.g.:
+
+java -jar ~/.codenameone/UpdateCodenameOne.jar path_to_my_codenameone_project
+
+E.g.:
+
+655
+
+java -jar ~/.codenameone/UpdateCodenameOne.jar ~/dev/AccordionDemo
+Checking: JavaSE.jar
+Checking: CodeNameOneBuildClient.jar
+Checking: CLDC11.jar
+Checking: CodenameOne.jar
+Checking: CodenameOne_SRC.jar
+Checking: designer_1.jar
+Checking: guibuilder_1.jar
+Updating the file: /Users/shai/dev/AccordionDemo/JavaSE.jar
+Updating the file: /Users/shai/dev/AccordionDemo/CodeNameOneBuildClient.jar
+Updating the file: /Users/shai/dev/AccordionDemo/lib/CLDC11.jar
+Updating the file: /Users/shai/dev/AccordionDemo/lib/CodenameOne.jar
+Updated project files
+
+Notice  that  no  download  happened  since  the  files  were  up  to  date.  You  can  also  force  a  check
+
+against the server by adding the force argument as such:
+
+java -jar ~/.codenameone/UpdateCodenameOne.jar path_to_my_codenameone_project
+
+The way this works under the hood is thought a Versions.properties within your directory that lists
+the versions of local files. That way we know what should be updated.
+
+
+
+Exclude Versions.properties from Git
+
+Under  the  ~/.codenameone  directory  we  have  a  more  detailed  UpdateStatus.properties  file  that
+includes  versions  of  the  locally  downloaded  files.  Notice  you  can  delete  this  file  and  it  will  be
+
+recreated as all the jars get downloaded over again.
+
+16.18.2. What isn’t Covered
+
+You will notice 3 big things that aren’t covered in this unified framework:
+
+• We don’t update cn1libs - I’m not sure if this is something we would like to update automatically
+
+• Versioned  builds  -  there  is  a  lot  of  complexity  in  the  versioned  build  system.  This  might  be
+
+something we address in the future but for now I wanted to keep the framework simple.
+
+• Offline  builds  -  Offline  builds  work  through  manual  download  and  aren’t  subjected  to  this
+
+framework
+
+[10] The old Codename One VM
+
+656
+
+17. Signing, Certificates & Provisioning
+
+In this section we attempt to explain how to acquire certificates for the various platforms and how
+
+to set them up.
+
+The good news is that this is usually a "one time issue" and once it’s done the work becomes easier
+
+(except for the case of iOS where a provisioning profile should be maintained).
+
+17.1. Common Terms In Signing & Distribution
+
+This section uses some terms that you might not be familiar with if you haven’t used cryptography
+
+or  built  mobile  apps  before.  Here  is  a  quick  "FAQ"  covering  some  common  terms/concepts  in  this
+
+section.
+
+17.1.1. What Is A Certificate?
+
+Certificates  use  cryptographic  principals  to  "sign"  data  (e.g.  an  application).  Think  of  them  as  you
+
+would think of a company stamp, you use them to sign an app so users know who it’s from.
+
+17.1.2. What Is Provisioning?
+
+Provisioning  provides  the  hints/guidelines  for  the  application  install.  E.g.  if  an  application  needs
+
+some service from the OS such as push it can usually request that with provisioning.
+
+In iOS provisioning is separate from the app and you need to also define the devices supported by
+
+the app during development.
+
+17.1.3. What’s a Signing Authority?
+
+Normally  certificates  are  issued  by  a  signing  authority  which  is  a  body  that  certifies  that  you  are
+
+who you say you are. Apple issues certificates for iOS and is in effect a signing authority.
+
+Android  uses  self  signed  certificates  which  don’t  use  a  signing  authority  so  anyone  can  ship  an
+
+Android app.
+
+The logic with the Android approach is that a signature indicates that you are the same person who
+
+previously shipped the app. Hence an app will be updated only with the exact same certificate.
+
+17.1.4. What is UDID?
+
+The UDID is the Universal Device Identifier. It identifies mobile devices uniquely, notice that some
+
+operating systems e.g. iOS block access to this value due to privacy concerns.
+
+You need the iOS device UDID value during development to add the device into the list of allowed
+
+devices.
+
+657
+
+
+
+Don’t use an app to get the UDID!
+
+Most  return  the  wrong  value,  the  official  way  to  get  the  UDID  is  thru  itunes.  We
+
+can also recommend trying http://get.udid.io/ which seems to work rather well
+
+17.1.5. Should I Reuse the Same Certificate for All Apps?
+
+For iOS yes. It’s designed to work in that way.
+
+We  would  recommend  it  for  all  platforms  for  simplicity  but  some  developers  prefer  creating  per-
+
+application certificates for Android. The advantage here is that you can transfer ownership of the
+
+application later on without giving away what is effectively "you house keys".
+
+17.2. iOS Signing Wizard
+
+Codename One features a wizard to generate certificates/provisioning for iOS without requiring a
+
+Mac  or  deep  understanding  of  the  signing  process  for  iOS.  There  is  still  support  for  manually
+
+generating the P12/provisioning files when necessary but for most intents and purposes using the
+
+wizard will simplify this error prone process significantly.
+
+To  generate  your  certificates  and  profiles,  open  project’s  properties  and  click  on  "iOS"  in  the  left
+
+menu.  This  will  show  the  "iOS  Signing"  panel  that  includes  fields  to  select  your  certificates  and
+
+mobile provisioning profiles.
+
+Figure 489. Netbeans iOS Signing properties panel
+
+If  you  already  have  valid  certificates  and  profiles,  you  can  just  enter  their  locations  here.  If  you
+
+don’t, then you can use the wizard by clicking the Generate button in the lower part of the form.
+
+17.2.1. Logging into the Wizard
+
+After clicking Generate you’ll be shown a login form. Log into this form using your iTunes Connect
+
+user ID and password. NOT YOUR CODENAME ONE LOGIN.
+
+658
+
+Figure 490. Wizard login form
+
+17.2.2. Selecting Devices
+
+Once  you  are  logged  in  you  will  be  shown  a  list  of  all  of  the  devices  that  you  currently  have
+
+registered on your Apple developer account.
+
+Figure 491. Devices form
+
+Select the ones that you want to include in your provisioning profile and click next.
+
+ Apple supports up to 100 devices for testing purposes so if you want to install the
+
+built app on your device you need to add it here
+
+Figure 492. After selecting devices
+
+If you don’t have any devices registered yet, you can click the "Add New Device" button, which will
+
+prompt you to enter the UDID for your device.
+
+659
+
+17.2.3. Decisions & Edge Cases
+
+ If you already have iOS P12 development/distribution certificates you should reuse
+
+them for all your apps from that account and you shouldn’t regenerate them
+
+After  you  click  Next  on  the  device  form,  the  wizard  checks  to  see  if  you  already  have  a  valid
+
+certificate.  If  your  project  already  has  a  valid  certificate  and  it  matches  the  one  that  is  currently
+
+active  in  your  apple  developer  account,  then  it  will  just  use  the  same  certificate.  If  the  certificate
+
+doesn’t match the currently-active one, or you haven’t provided a certificate, you will be prompted
+
+to overwrite the old certificate with a new one.
+
+Figure 493. Prompt to overwrite existing certificate
+
+Figure 494. Prompt to overwrite other certificate
+
+The same decision need to be made twice: Once for the development certificate, and once for the
+
+Apptore certificate.
+
+
+
+You  can  revoke  a  certificate  when  you  have  an  application  in  the  store  shipping
+
+with said certificate!
+
+This won’t affect the shipping app see this [http://stackoverflow.com/questions/6320255/if-
+
+i-revoke-an-existing-distribution-certificate-will-it-mess-up-anything-with].
+
+660
+
+Why Two Certificates?
+
+A typical iOS app has at least two certificates:
+
+• Development  -  this  is  used  during  development  and  can’t  be  shipped  to  3rd  parties.  An
+
+application  signed  with  this  certificate  can  only  be  installed  on  one  of  the  up  to  100
+
+devices listed above.
+
+• Distribution  -  this  is  used  when  you  are  ready  to  upload  your  app  to  itunes  whether  for
+
+final  shipping  or  beta  testing.  Notice  that  you  can’t  install  a  distribution  build  on  your
+
+own device. You need to upload it to itunes.
+
+• There  are  two  push  certificates,  they  are  separate  from  the  signing  certificates.  Don’t
+
+confuse them!
+
+They are used to authenticate with Apple when sending push messages.
+
+17.2.4. App IDs and Provisioning Profiles
+
+The  next  form  in  the  wizard  asks  for  your  app’s  bundle  ID.  This  should  have  been  pre-filled,  but
+
+you can change the app ID to a wildcard ID if you prefer.
+
+Figure 495. Enter the app bundle ID
+
+661
+
+Wildcard Card Provisioning
+
+Wildcard ids such as com.mycompany.\* or even \* allow you to create one generic certificate
+
+to use with all applications. This is remarkably useful for the global settings dialog and allows
+
+you  to  create  an  app  without  launching  the  wizard.  Notice  that  wildcards  apps  can’t  use
+
+features such as push etc.
+
+You  can  set  the  global  defaults  for  the  IDE  by  going  to  IDE  settings/preferences  and  setting
+
+default values e.g.:
+
+Figure 496. Setting the development certificate and a global \* provisioning profile allows you to
+
+create a new app and built it to device without running the certificate wizard. Notice that you will
+
+need to run it when going into production
+
+17.2.5. Installing Files Locally
+
+Once the wizard is finished generating your provisioning profiles, you should click "Install Locally",
+
+which will open a file dialog for you to navigate to a folder in which to store the generated files.
+
+Figure 497. Install files locally
+
+662
+
+Figure 498. Select directory to save files in
+
+Figure 499. Final Done Message
+
+
+
+You can see the password for the P12 files in the codenameone_settings.properties
+file. You can use the values defined there when creating a new application
+
+17.2.6. Building Your App
+
+After  selecting  your  local  install  location,  and  closing  the  wizard,  you  should  see  the  fields  of  the
+
+"iOS  Signing"  properties  panel  filled  in  correctly.  You  should  now  be  able  to  send  iOS  debug  or
+
+Appstore builds without the usual hassles.
+
+Figure 500. Filled in signing panel after wizard complete
+
+17.3. Advanced iOS Signing
+
+
+
+You  should  use  the  certificate  wizard,  especially  if  you  don’t  have  a  Mac.  This
+
+section  is  here  mostly  for  reference  and  edge  cases  that  don’t  work  with  the
+
+certificate wizard
+
+iOS signing has two distinct modes: App Store signing which is only valid for distribution via iTunes
+
+(you won’t be able to run the resulting application without submitting it to Apple) and development
+
+mode signing.
+
+663
+
+You have two major files to keep track of:
+
+1. Certificate - your signature
+
+2. Provisioning Profile - details about the application and who is allowed to execute it
+
+You need two versions of each file (4 total files) one pair is for development and the other pair is for
+
+uploading to the itunes App Store.
+
+ You need to use a Mac in order to create a certificate file for iOS
+
+The  first  step  you  need  to  accomplish  is  signing  up  as  a  developer  to  Apple’s  iOS  development
+
+program [http://developer.apple.com/], even for testing on a device this is required!
+
+This step requires that you pay Apple on an annual basis.
+
+The Apple website will guide you through the process of applying for a certificate at the end of this
+
+process you should have a distribution and development certificate pair. After that point you can
+
+login  to  the  iOS  provisioning  portal  [https://developer.apple.com/ios/manage/overview/index.action]  where
+
+there  are  plenty  of  videos  and  tutorials  to  guide  you  through  the  process.  Within  the  iOS
+
+provisioning portal you need to create an application ID and register your development devices.
+
+You can then create a provisioning profile which comes in two flavors:
+
+• Distribution - for building the release version of your application
+
+• Development - the development provisioning profile needs to contain the devices on which you
+
+want to test.
+
+You can then configure the 4 files in the IDE and start sending builds to the Codename One cloud.
+
+17.4. Provisioning Profile & Certificates Visual Guide
+
+One of the hardest parts in developing for iOS is the certificate & provisioning process. In this step
+
+by  step  guide  we  walk  over  the  manual  certificate  generation  process.  Notice  that  the  UI  for  the
+
+Apple website changes occasionally but the basic process remains the same…
+
+Start by logging in to the iOS-provisioning portal
+
+Figure 501. Login for the iOS provisioning portal
+
+In the certificates section you can download your development and distribution certificates.
+
+664
+
+Figure 502. Download development provisioning profile
+
+Figure 503. Download distribution provisioning profile
+
+In  the  devices  section  add  device  ids  for  the  development  devices  you  want  to  support.  Notice  no
+
+more than 100 devices are supported!
+
+Figure 504. Add devices
+
+Create an application id; it should match the package identifier of your application perfectly!
+
+Figure 505. Create application id
+
+Create a provisioning profile for development, make sure to select the right app and make sure to
+
+add the devices you want to use during debug.
+
+Figure 506. Create provisioning profile step 1
+
+665
+
+Figure 507. Create provisioning profile step 2
+
+Refresh the screen to see the profile you just created and press the download button to download
+
+your development provisioning profile.
+
+Figure 508. Create provisioning profile step 3
+
+Create a distribution provisioning profile; it will be used when uploading to the app store. There is
+
+no need to specify devices here.
+
+Figure 509. Create distribution provisioning profile
+
+Download the distribution provisioning profile.
+
+Figure 510. Download distribution provisioning profile
+
+We  can  now  import  the  cer  files  into  the  key  chain  tool  on  a  Mac  by  double  clicking  the  file,  on
+
+Windows the process is slightly more elaborate
+
+Figure 511. Import cer files
+
+We can export the p12 files for the distribution and development profiles through the keychain tool
+
+666
+
+Figure 512. Export p12 files
+
+In the IDE we enter the project settings, configure our provisioning profile, the password we typed
+
+when exporting and the p12 certificates. It is now possible to send the build to the server.
+
+Figure 513. IOS Project Settings
+
+17.4.1. iOS Code Signing Failure Checklist
+
+Below is a list of common issues when singing and a set of suggestions for things to check. Notice
+
+that some of these signing failures will sometimes manifest themselves during build and sometimes
+
+will manifest during the install of the application.
+
+
+
+Most  of  these  issues  aren’t  applicable  when  using  the  wizard  e.g.  a  Mac  isn’t
+
+required for the certificate wizard as it uses the Codename One cloud
+
+• You must use a Mac to generate P12 certificates manually. The only workaround we found is
+
+the certificate wizard!
+
+Notice that this is something you need to do once a year (generate P12), you will also need a Mac
+
+to upload your final app to the store at this time.
+
+• When  exporting  the  P12  certificate  make  sure  that  you  selected  BOTH  the  public  and  the
+
+private keys as illustrated here. If you only see one entry (no private key) then you created the
+
+CSR  (singing  request)  on  a  different  machine  than  the  one  where  you  imported  the  resulting
+
+CER file.
+
+Figure 514. p12 export
+
+• Make  sure  the  package  matches  between  the  main  preferences  screen  in  the  IDE  and  the  iOS
+
+settings screen.
+
+667
+
+Figure 515. Package ID matching App ID
+
+• Make sure the prefix for the app id in the iOS section of the preferences matches the one you
+
+have from Apple
+
+Figure 516. App prefix
+
+• Make sure your provisioning profile’s app id matches your package name or is a * provisioning
+
+profile. Both are sampled in the pictures below, notice that you would need an actual package
+
+name for push/in-app-purchase support as well as for app store distribution.
+
+Figure 517. The star (*) Provisioning Profile
+
+Figure 518. Provisioning Profile with app id
+
+• Make sure the certificate and provisioning profile are from the same source (if you work with
+
+multiple accounts), notice that provisioning profiles and certificates expire so you will need to
+
+regenerate provisioning when your certificate expires or is revoked.
+
+• If  you  declare  push  in  the  provisioning  profile  then  ios.includePush  (in  the  build  arguments)
+MUST  be  set  to  true,  otherwise  it  MUST  be  set  to  false  (see  pictures  below).  Notice  that  this
+
+should be configured via the UI in the iOS section.
+
+668
+
+Figure 519. Include push build hint
+
+17.5. Android
+
+Signing Android applications is trivial when compared to the pain of iOS signing.
+
+The  NetBeans  and  Eclipse  plugins  have  a  simple  wizard  to  generate  the  certificate  that  you  can
+
+launch by pressing this button:
+
+Figure 520. Android keystore generation wizard
+
+Then fill out your details and password in the form:
+
+Figure 521. UI for Android certificate details
+
+This  will  seamlessly  generate  a  certificate  for  your  project,  you  can  reuse  it  for  other  projects  as
+
+well.
+
+17.5.1. Generating an Android Certificate Manually
+
+You need the JDK’s keytool executable (it should be under the JDK’s bin directory) and execute the
+
+following command:
+
+keytool -genkey -keystore Keystore.ks -alias [alias_name] -keyalg RSA -keysize 2048 -validity 15000 -dname "CN=[full
+name], OU=[ou], O=[comp], L=[City], S=[State], C=[Country Code]" -storepass [password] -keypass [password]
+
+669
+
+The elements in the brackets should be filled up based on this:
+
+Alias: [alias_name] (just use your name/company name without spaces)
+Full name: [full name]
+Organizational Unit: [ou]
+Company: [comp]
+City: [City]
+State: [State]
+CountryCode: [Country Code]
+Password: [password] (we expect both passwords to be identical)
+
+Executing  the  command  will  produce  a  Keystore.ks  file  in  that  directory  which  you  need  to  keep
+
+since if you lose it you will no longer be able to upgrade your applications! Fill in the appropriate
+
+details in the project properties or in the CodenameOne section in the Netbeans preferences dialog.
+
+For more details see http://developer.android.com/guide/publishing/app-signing.html
+
+17.6. RIM/BlackBerry
+
+You  can  now  get  signing  keys  for  free  from  Blackberry  by  going  here  [https://www.blackberry.com/
+
+SignedKeys/].  Once  you  obtain  the  certificates  you  need  to  install  them  on  your  machine  (you  will
+need  the  Blackberry  development  environment  for  this).  You  will  have  two  files:  sigtool.db  and
+sigtool.csk  on  your  machine  (within  the  JDE  directory  hierarchy).  We  need  them  and  their
+associated password to perform the signed build for Blackberry application.
+
+17.7. J2ME
+
+Currently  signing  J2ME  applications  isn’t  supported.  You  can  use  tools  such  as  the  Sprint  WTK  to
+sign the resulting jad/jar produced by Codename One.  
+
+670
+
+18. Working with iOS
+
+18.1. Troubleshooting iOS Debug Build installs
+
+In 9 cases out of 10 if you have a problem installing an app make sure your device is a 64 bit device.
+If  not  you  will  need  to  add  the  build  hint  ios.debug.archs=armv7.  Notice  that  a  32  bit  app  will  still
+work on a 64 bit device it will just display a performance warning.
+
+If you have access to a Mac you can connect a cable and open xcode where you can use the device
+
+explorer console to look at messages which sometimes give a clue about what went wrong. If not
+
+here is a laundry list of a few things that might fail:
+
+• Make sure you built the debug version and not the appstore version. The appstore version won’t
+
+install on the device and can only be distributed via Apple’s store or testflight
+
+• Verify  that  you  are  sending  a  32  bit  build  in  the  build  hints  using  the  build  hint
+ios.debug.archs=armv7.  It’s  only  necessary  if  you  have  an  older  32  bit  device,  see  this
+[https://www.codenameone.com/blog/moving-to-64bit-by-default.html].  Notice  that  this  only  applies  for
+
+debug builds, release builds include both 32 and 64 bit versions
+
+
+
+Devices prior to iPad Air & iPhone 5s were 32 bit devices so iPhone 5s won’t need
+
+that flag but iPhone 5 or iPhone 5c will need it
+
+• Check the the UDID is correct - if you got the UDID from an app then it’s probably wrong as apps
+
+don’t  have  access  to  the  device  UDID  anymore.  The  way  to  get  the  UDID  is  either  thru  iOS
+
+Settings app or itunes
+
+• Make  sure  the  device  isn’t  locked  for  installing  3rd  party  apps.  I’ve  had  this  when  trying  to
+
+install on my kids tablet which I configured to be child safe. This is configured in the settings as
+
+parental controls
+
+• Check that you "own" the package name. E.g. if you previously installed an app with the same
+
+package name but a different certificate a new install will fail (this is true for Android too). So if
+
+you installed the kitchen sink from the store then built one of your own and installed it there
+
+will be a collision.
+
+Notice that this might be problematic if you use overly generic package names as someone else
+
+might have used them which is why you must always use your own domain
+
+• Make  sure  the  device  has  a  modern  enough  version  of  iOS  for  the  dependencies.  I  think  the
+
+current  minimum  for  hello  world  is  6.0.1  but  some  apps  might  require  a  newer  version  e.g.
+
+Intercom requires OS 8 or newer
+
+• Verify that you are using Safari when installing on the device (if you tried via cable that’s not a
+
+problem), some developers had issues with firefox not launching the install process
+
+• Check that the build hint ios.includePush is set in a way that matches your iOS provisioning. So
+
+it must be false if you don’t have push within the provisioning profile
+
+671
+
+18.2. The iOS Screenshot/Splash Screen Process
+
+
+
+As of version 5.0 (September 2018), screenshot generation is no longer enabled by
+
+default.  Instead,  the  launch  storyboard  is  used.  Therefore  much  of  the  following
+
+section is no longer relevant.
+
+iOS apps seem to start almost instantly in comparison to Android apps.
+There is a trick to that, iOS applications have a file traditionally called Default.png that includes a
+320x480 pixel image of the first screen of the application. This creates an "illusion" of the application
+instantly coming to life and filling up with data, this is rather clever but is a source trouble as the
+platform grows [11].
+
+
+
+You can disable the screenshot process entirely with the ios.fastBuild=true build
+hint.  This  will  only  apply  for  debug  builds  so  you  don’t  need  to  worry  about
+
+accidentally forgetting it in production.
+
+The screenshot process was a pretty clever workaround but as Apple introduced the retina display
+640x960 it required a higher resolution Default@2x.png file, then it added the iPad, iPad Retina and
+iPhone 5 [12] iPhone 6 & 6+ all of which required images of their own.
+
+To  make  matters  worse  iPad  apps  (and  iPhone  6+  apps)  can  be  launched  in  landscape  mode  so
+
+that’s two more resolutions for the horizontal orientation iPad. Overall as of this writing (or until
+
+Apple adds more resolutions) we need 16 screenshots for a typical iOS app:
+
+Table 13. iOS Device Screenshot Resolutions
+
+Resolution
+
+320x480
+
+640x960
+
+640x1136
+
+1024x768
+
+768x1024
+
+2048x1536
+
+1536x2048
+
+750x1334
+
+1242x2208
+
+2208x1242
+
+2048×2732
+
+2732x2048
+
+1668×2224
+
+672
+
+File Name
+
+Default.png
+
+Default@2x.png
+
+Default-568h@2x.png
+
+Default-Portrait.png
+
+Devices
+
+iPhone 3gs
+
+iPhone 4x
+
+iPhone 5x
+
+Non-retina ipads in portrait
+
+mode
+
+Default-Landscape.png
+
+Non-retina ipads in landscape
+
+Default-Portrait@2x.png
+
+Default-Landscape@2x.png
+
+Default-667h@2x.png
+
+Default-736h@3x.png
+
+mode
+
+Retina ipads in portrait mode
+
+Retina ipads in landscape mode
+
+iPhone 6
+
+iPhone 6 Plus Portrait
+
+Default-736h-Landscape@3x.png
+
+iPhone 6 Plus Landscape
+
+Default-iPadPro@2.png
+
+Default-iPadPro-
+Landscape@2.png
+
+iPad Pro Portrait
+
+iPad Pro Landscape
+
+Default-iPadProSmall@2.png
+
+10.5" iPad Pro Portrait
+
+Resolution
+
+2224x1668
+
+1125×2436
+
+2436x1125
+
+File Name
+
+Devices
+
+Default-iPadProSmall-
+Landscape@2.png
+
+Default-iPhoneX@3.png
+
+Default-iPhoneX-
+Landscape@3.png
+
+10.5" iPad Pro Landscape
+
+iPhone X Portrait
+
+iPhone X Landscape
+
+
+
+You can predefine any of these files within the native/ios directory in your project.
+If  the  build  server  sees  a  file  matching  that  exact  name  it  will  not  generate  a
+
+screenshot for that resolution
+
+Native iOS developers can run their applications 16 times with blank data to grab these screenshots
+
+every time they change something in the first view of their application!
+
+With  Codename  One  this  will  not  be  feasible  since  the  fonts  and  behavior  might  not  match  the
+
+device. Thus Codename One runs the application 16 times in the build servers, grabs the right sized
+
+screenshots in the simulator and then builds the app!
+
+This  means  the  process  of  the  iPhone  splash  screen  is  almost  seamless  to  the  developer,  however
+
+like every abstraction this too leaks.
+
+The  biggest  problem  developers  have  with  this  approach  is  for  apps  that  use  a  web  browser  or
+
+native maps in the first screen of their app. This won’t work well as those are native widgets. They
+
+will look different during the screenshot process.
+
+Another  problem  is  with  applications  that  require  a  connection  immediately  on  startup,  this  can
+
+fail for the build process.
+
+A solution to both problems is to create a special case for the first launch of the app where no data
+
+exists. This will setup the screenshot process correctly and let you proceed with the app as usual.
+
+18.2.1. Size
+
+One of the first things we ran into when building one of our demos was a case where an app that
+
+wasn’t very big in terms of functionality took up 30mb!
+
+After inspecting the app we discovered that the iPad retina PNG files were close to 5mb in size…
+
+Since we had 2 of them (landscape and portrait) this was the main problem.
+
+The  iPad  retina  is  a  2048x1536  device  and  with  the  leather  theme  the  PNG  images  are  almost
+
+impossible  to  compress  because  of  the  richness  of  details  within  that  theme.  This  produced  the
+
+huge screenshots that ballooned the application.
+
+18.2.2. Mutable first screen
+
+A  very  common  use  case  is  to  have  an  application  that  pops  up  a  login  dialog  on  first  run.  This
+
+doesn’t  work  well  since  the  server  takes  a  picture  of  the  login  screen  and  the  login  screen  will
+
+appear briefly for future loads and will never appear again.
+
+673
+
+18.2.3. Unsupported component
+
+One of the biggest obstacles is with heavyweight components, e.g. if you use a browser or maps on
+
+the  first  screen  of  the  app  you  will  see  a  partially 
+
+loaded/distorted  MapComponent
+
+[https://www.codenameone.com/javadoc/com/codename1/maps/MapComponent.html]  and  the  native  webkit
+
+browser obviously can’t be rendered properly by our servers.
+
+The workaround for such issues is to have a splash screen that doesn’t include any of the above. Its
+
+OK to show it for a very brief amount of time since the screenshot process is pretty fast.
+
+18.3. Launch Screen Storyboards
+
+With  the  shift  to  Xcode  9,  which  is  the  default  version  on  the  Codename  One  build  servers  as  of
+
+February  2018  [https://www.codenameone.com/blog/xcode-9-on-by-default.html],  it  is  now  possible  to  use  a
+
+launch-screen storyboard as the splash screen instead of launch images. This will potentially solve
+
+the issue of the proliferation of screenshots, as you can supply a single storyboard which will work
+
+on  all  devices.  Launch  screen  storyboards  are  enabled  by  default  (as  of  version  5.0/September
+2018). You can disable them by adding the ios.generateSplashScreens=true build hint.
+
+18.3.1. Launch Storyboard vs Launch Images
+
+The key benefit of using a launch storyboard right now is that it allows your app to be used in split-
+
+screen  mode.  Storyboards,  however,  work  a  little  bit  differently  than  launch  images.  They  don’t
+
+show  a  screenshot  of  the  first  page  of  your  app.  The  default  Codename  One  launch  storyboard
+
+simply shows your app’s icon in the middle of the screen. You can customize the launch screen by
+
+providing one or more of the following files in your project’s native/ios directory
+
+1. Launch.Foreground.png - Will be shown instead of your app’s icon in the center of the screen.
+
+2. Launch.Background.png - Will fill the background of the screen.
+
+3. LaunchScreen.storyboard - A custom storyboard developed in Xcode, that will be used instead of
+
+the default storyboard.
+
+ Make sure to add the ios.multitasking=true build hint, or your launch storyboard
+
+will not be used.
+
+
+
+Changes  to  the  launch  screen  will  not  take  effect  until  the  device  has  been
+
+restarted.  I.e.  If  you  install  your  app  on  a  device,  then  you  make  changes  to  the
+
+launch screen and update the app, the launch screen won’t change until the device
+
+is restarted.
+
+18.4. Local Notifications on iOS and Android
+
+Local notifications are similar to push notifications, except that they are initiated locally by the app,
+
+rather than remotely. They are useful for communicating information to the user while the app is
+
+running  in  the  background,  since  they  manifest  themselves  as  pop-up  notifications  on  supported
+
+devices.
+
+674
+
+
+
+the  notification 
+
+To  set 
+icon  named
+ic_stat_notify.png  under  the  native/android  folder  of  the  app.  The  icon  can  be
+white with transparency areas
+
+icon  on  Android  place  a  24x24 
+
+18.4.1. Sending Notifications
+
+The process for sending a notification is:
+
+1. Create 
+
+a 
+
+LocalNotification 
+
+[https://www.codenameone.com/javadoc/com/codename1/notifications/
+
+LocalNotification.html] object with the information you want to send in the notification.
+
+2. Pass the object to Display.scheduleLocalNotification().
+
+Notifications can either be set up as one-time only or as repeating.
+
+Example Sending Notification
+
+LocalNotification n = new LocalNotification();
+n.setId("demo-notification");
+n.setAlertBody("It's time to take a break and look at me");
+n.setAlertTitle("Break Time!");
+n.setAlertSound("beep-01a.mp3");
+
+Display.getInstance().scheduleLocalNotification(
+        n,
+        System.currentTimeMillis() + 10 * 1000, // fire date/time
+        LocalNotification.REPEAT_MINUTE  // Whether to repeat and what frequency
+);
+
+The resulting notification will look like
+
+Figure 522. Resulting notification in iOS
+
+18.4.2. Receiving Notifications
+
+The  API  for  receiving/handling  local  notifications  is  also  similar  to  push.  Your  application’s  main
+lifecycle  class  needs  to  implement  the  com.codename1.notifications.LocalNotificationCallback
+
+675
+
+interface which includes a single method:
+
+public void localNotificationReceived(String notificationId)
+
+The  notificationId  parameter  will  match  the  id  value  of  the  notification  as  set  using
+LocalNotification.setId().
+
+Example Receiving Notification
+
+public class BackgroundLocationDemo implements LocalNotificationCallback {
+    //...
+
+    public void init(Object context) {
+        //...
+    }
+
+    public void start() {
+        //...
+
+    }
+
+    public void stop() {
+        //...
+    }
+
+    public void destroy() {
+        //...
+    }
+
+    public void localNotificationReceived(String notificationId) {
+        System.out.println("Received local notification "+notificationId);
+    }
+}
+
+
+
+localNotificationReceived()  is  only  called  when  the  user  responds  to  the
+notification  by  tapping  on  the  alert.  If  the  user  doesn’t  click  on  the  notification,
+
+then this event handler will never be fired.
+
+18.4.3. Canceling Notifications
+
+Repeating  notifications  will  continue  until  they  are  canceled  by  the  app.  You  can  cancel  a  single
+
+notification by calling:
+
+Display.getInstance().cancelLocalNotification(notificationId);
+
+Where 
+
+notificationId 
+
+is 
+
+the 
+
+string 
+
+id 
+
+that  was 
+
+set 
+
+for 
+
+the  notification  using
+
+676
+
+LocalNotification.setId().
+
+18.5. iOS Beta Testing (Testflight)
+
+Apple  provides  the  ability  to  distribute  beta  versions  of  your  application  to  beta  testers  using
+
+testflight. This allows you to recruit up to 1000 beta testers without the typical UDID limits a typical
+
+Apple account has.
+
+ This is supported for pro users as part of the crash protection feature.
+
+To take advantage of that capability use the build hint ios.testFlight=true and then submit the app
+to the store for beta testing. Make sure to use a release build target.
+
+18.6. Accessing Insecure URL’s
+
+Due  to  security  exploits  Apple  blocked  some  access  to  insecure  URL’s  which  means  that  http  code
+
+that worked before could stop working for you on iOS 9+. This is generally a good move, you should
+
+use  https  and  avoid  http  as  much  as  possible  but  that’s  sometimes  impractical  especially  when
+
+working with an internal or debug environment.
+
+You can disable the strict URL checks from Apple by using the venerable ios.plistInject build hint
+and setting it to:
+
+<key>NSAppTransportSecurity</key><dict><key>NSAllowsArbitraryLoads</key><true/></dict>
+
+However,  it  seems  that  Apple  will  reject  your  app  if  you  just  include  that  and  don’t  have  a  good
+
+reason.
+
+18.7. Using Cocoapods
+
+CocoaPods [https://cocoapods.org/] is a dependency manager for Swift and Objective-C Cocoa projects.
+
+It  has  over  eighteen  thousand  libraries  and  can  help  you  scale  your  projects  elegantly.  Cocoapods
+
+can  be  used  in  your  Codename  One  project  to  include  native  iOS  libraries  without  having  to  go
+
+through the hassle of bundling the actual library into your project. Rather than bundling .h and .a
+files in your ios/native directory, you can specify which "pods" your app uses via the ios.pods build
+hint. (There are other build hints also if you need more advanced features).
+
+Examples
+
+Include the AFNetworking [https://github.com/AFNetworking/AFNetworking] library in your app:
+
+ios.pods=AFNetworking
+
+Include the AFNetworking [https://github.com/AFNetworking/AFNetworking] version 3.0.x library in your
+
+app:
+
+677
+
+ios.pods=AFNetworking ~> 3.0
+
+For  full  versioning  syntax  specifying  pods  see  the  Podfile  spec  for  the  "pod"  directive
+
+[https://guides.cocoapods.org/syntax/podfile.html#pod].
+
+18.7.1. Including Multiple Pods
+
+Multiple pods can be separated by either commas or semi-colons in the value of the ios.pods build
+hint. E.g. To include GoogleMaps and AFNetworking, you could:
+
+ios.pods=GoogleMaps,AFNetworking
+
+Or specifying versions:
+
+ios.pods=AFNetworking ~> 3.0,GoogleMaps
+
+18.7.2. Other Pod Related Build Hints
+
+ios.pods.platform  :  The  minimum  platform  to  target.  In  some  cases,  Cocoapods  require
+functionality that is not in older version of iOS. For example, the GoogleMaps pod requires iOS 7.0
+or higher, so you would need to add the ios.pods.platform=7.0 build hint.
+
+ios.pods.sources  :  Some  pods  require  that  you  specify  a  URL  for  the  source  of  the  pod  spec.  This
+may  be  optional  if  the  spec  is  hosted  in  the  central  CocoaPods  source  (https://github.com/
+CocoaPods/Specs.git).
+
+18.7.3. Converting PodFile To Build Hints
+
+Most  documentation  for  Cocoapods  "pods"  provide  instructions  on  what  you  need  to  add  to  your
+
+Xcode  project’s  PodFile.  Here  is  an  example  from  the  GoogleMaps  cocoapod  to  show  you  how  a
+
+PodFile can be converted into equivalent build hints in a Codename One project.
+
+The GoogleMaps cocoapod directs you to add the following to your PodFile:
+
+source 'https://github.com/CocoaPods/Specs.git'
+platform :ios, '7.0'
+pod 'GoogleMaps'
+
+This would translate to the following build hints in your Codename One project:
+
+ios.pods.sources=https://github.com/CocoaPods/Specs.git
+ios.pods.platform=7.0
+ios.pods=GoogleMaps
+
+678
+
+(Note that the ios.pods.sources directive is optional).
+
+18.8. Including Dynamic Frameworks
+
+If  you  need  to  use  a  dynamic  framework  (e.g.  SomeThirdPartySDK.framework),  and  it  isn’t
+
+available  via  cocoapods,  then  you  can  add  it  to  your  project  by  simply  zipping  up  the  framework
+
+and copying it to your native/ios directory.
+
+e.g. native/ios/SomeThirdPartySDK.framework.zip
+
+There are no build hints necessary for this approach. The build server will automatically detect the
+
+framework and link it into your app.
+
+[11] Apple provided another trick with XIB files starting with iOS 8 but that doesn’t apply to games or Codename One. It has its own
+
+set of problems
+
+[12] slightly larger screen and different aspect ratio
+
+679
+
+680
+
+19. Working with JavaScript
+
+This  section  covers  the  Codename  One  Javascript  port,  which  allows  you  to  compile  your  app  as
+
+native  javascript  and  run  it  inside  a  browser.  This  is  different  from  the  BrowserComponent
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/BrowserComponent.html]  and  other  methods  of
+
+displaying HTML/Javascript inside a Codename One app.
+
+19.1. Limitations of the Javascript Port
+
+19.1.1. No Multithreaded Code inside Static Initializers
+
+ This section pertains to Codename One 3.6 and older. Newer versions of Codename
+
+One support multithreaded code inside static initializers now.
+
+Codename One’s Javascript port uses TeaVM [http://teavm.org/] to compile your application directly to
+
+Javascript so that it can run inside modern web browsers without the need for any plugins (i.e. NOT
+
+as  an  applet).  One  of  the  revolutionary  features  that  TeaVM  provides  is  the  ability  to  run  multi-
+
+threaded  code  (i.e.  it  has  full  support  for  Object.wait(),  Object.notify(),  Object.notifyAll(),  and  the
+synchronized  keyword).  The  one  caveat  to  be  aware  of  is  that  you  cannot  use  any  threading
+primitives  inside  static  initializers.  This  is  due  to  technical  limitations  in  the  browser
+
+environment  and  the  way  that  TeaVM  compiles  class  definitions  into  Javascript.  The  workaround
+
+for this issue is to do lazy initialization in cases where you need to use multithreaded code.
+
+Example
+
+The following code will result in a build error when deploying a Javascript build:
+
+Class1.java
+
+import com.codename1.io.Log;
+class Class1 {
+    public static int getValue() {
+        Log.p("Hello world");
+        return 1;
+    }
+}
+
+Class2.java
+
+class Class2 {
+    public static int value = Class1.getValue();
+
+}
+
+This fails because Class2 calls Class1.getValue() in its static initializer, and getValue() calls Log.p(),
+which, underneath the covers, writes to Storage - which involves some synchronous network access
+
+681
+
+in the Javascript port (i.e. it uses wait() and notify() under the hood.
+
+If we simply remove the call to Log.p() from getValue(), as follows:
+
+    public static int getValue() {
+        return 1;
+    }
+
+Then everything would be fine.
+
+But How do we Know if A method includes wait()/notify somewhere along the line?
+
+When you try to build your app as a Javascript app, it will fail (if code in your static initializers uses
+wait()/notify() somewhere along the line).
+
+How to Work Around this Issue
+
+Use  lazy  initialization  wherever  you  can.  You  don’t  need  to  worry  about  this  for  setting  static
+variables to literal values. E.g.: static int someVal = 20; will always be fine. But static int someVal
+=  OtherClass.calculateSomeVal();  may  or  may  not  be  fine,  because  you  don’t  know  whether
+calculateSomeVal()  uses  a  wait/notify.  So  instead  of  initializing  someVal  in  the  static  initializer,
+create a static accessor that lazily initializes it. Or initialize it inside your app’s init() method. Or
+initialize it inside the class constructor.
+
+19.2. Troubleshooting Build Errors
+
+If your Javascript build fails, you should download the error log and see what the problem is. The
+
+most common errors are:
+
+1. "[ERROR]  Method  XXX.<clinit>()V  is  claimed  to  be  synchronous,  but  it  is  has  invocations  of
+
+asynchronous methods"
+
+This  error  will  occur  if  you  have  static  initializers  that  use  multithreaded  code  (e.g.
+
+wait/notify/sleep, etc…). See Static Initializers for information about troubleshooting this error.
+
+In  some  cases  TeaVM  may  give  a  false-positive  here  (i.e.  it  thinks  you  are  doing  some
+
+multithreaded stuff, but you’re really not), then you can force the build to "succeed" by adding
+the javascript.stopOnErrors=false build hint.
+
+2. "Method XXX was not found"
+
+TeaVM  uses  its  own  Java  runtime  library.  It  is  mostly  complete,  but  you  may  occasionally  run
+
+into methods that haven’t been implemented. If you run into errors saying that certain classes
+
+or  methods  were  not  found,  please  post  them  to  the  Codename  One  issue  tracker
+
+[https://github.com/codenameone/CodenameOne/issues].  You  can  also  work  around  these  by  changing
+
+your own code to not use such functions. If this missing method doesn’t fall on a critical path on
+
+your  app,  you  can  also  force  the  app  to  still  build  despite  this  error  by  adding  the
+javascript.stopOnErrors=false build hint.
+
+682
+
+19.3. ZIP, WAR, or Preview.  What’s the difference?
+
+The Javascript build target will result in up to three different bundles being generated:
+
+1. YourApp-1.0.war
+
+2. YourApp-1.0.zip
+
+3. YourApp-1.0-Preview.html
+
+YourApp-1.0.war is a self contained application bundle that can be installed in any JavaEE servlet
+
+container. If you haven’t customized any proxy settings, then the application will be configured to
+
+use a proxy servlet that is embedded into the .war file.
+
+As an example, the PropertyCross .war file contains the following files:
+
+$ jar tvf PropertyCross-1.0.war
+     0 Thu Apr 30 15:57:38 PDT 2015 META-INF/
+   132 Thu Apr 30 15:57:36 PDT 2015 META-INF/MANIFEST.MF
+     0 Thu Apr 30 15:57:36 PDT 2015 assets/
+     0 Thu Apr 30 15:57:36 PDT 2015 assets/META-INF/
+     0 Thu Apr 30 15:57:36 PDT 2015 js/
+     0 Thu Apr 30 15:57:36 PDT 2015 teavm/
+     0 Thu Apr 30 15:57:36 PDT 2015 WEB-INF/
+     0 Thu Apr 30 15:57:36 PDT 2015 WEB-INF/classes/
+     0 Thu Apr 30 15:57:36 PDT 2015 WEB-INF/classes/com/
+     0 Thu Apr 30 15:57:36 PDT 2015 WEB-INF/classes/com/codename1/
+     0 Thu Apr 30 15:57:36 PDT 2015 WEB-INF/classes/com/codename1/corsproxy/
+     0 Thu Apr 30 15:57:36 PDT 2015 WEB-INF/lib/
+ 27568 Thu Apr 30 15:57:12 PDT 2015 assets/CN1Resource.res
+306312 Thu Apr 30 15:57:12 PDT 2015 assets/iOS7Theme.res
+427737 Thu Apr 30 15:57:12 PDT 2015 assets/iPhoneTheme.res
+   350 Thu Apr 30 15:57:12 PDT 2015 assets/META-INF/MANIFEST.MF
+ 92671 Thu Apr 30 15:57:12 PDT 2015 assets/theme.res
+ 23549 Thu Apr 30 15:57:14 PDT 2015 icon.png
+  2976 Thu Apr 30 15:57:14 PDT 2015 index.html
+ 30695 Thu Apr 30 15:57:12 PDT 2015 js/fontmetrics.js
+ 84319 Thu Apr 30 15:57:12 PDT 2015 js/jquery.min.js
+ 13261 Thu Apr 30 15:57:12 PDT 2015 progress.gif
+  2816 Thu Apr 30 15:57:12 PDT 2015 style.css
+1886163 Thu Apr 30 15:57:36 PDT 2015 teavm/classes.js
+359150 Thu Apr 30 15:57:36 PDT 2015 teavm/classes.js.map
+1147502 Thu Apr 30 15:57:36 PDT 2015 teavm/classes.js.teavmdbg
+ 30325 Thu Apr 30 15:57:36 PDT 2015 teavm/runtime.js
+  1011 Thu Apr 30 15:57:18 PDT 2015 WEB-INF/classes/com/codename1/corsproxy/CORSProxy.class
+232771 Wed Nov 05 17:35:12 PST 2014 WEB-INF/lib/commons-codec-1.6.jar
+ 62050 Wed Apr 15 14:35:56 PDT 2015 WEB-INF/lib/commons-logging-1.1.3.jar
+590004 Wed Apr 15 14:35:58 PDT 2015 WEB-INF/lib/httpclient-4.3.4.jar
+282269 Wed Apr 15 14:35:56 PDT 2015 WEB-INF/lib/httpcore-4.3.2.jar
+ 14527 Wed Apr 15 14:35:56 PDT 2015 WEB-INF/lib/smiley-http-proxy-servlet-1.6.jar
+   903 Thu Apr 30 15:57:12 PDT 2015 WEB-INF/web.xml
+  9458 Thu Apr 30 15:57:14 PDT 2015 META-INF/maven/com.propertycross/PropertyCross/pom.xml
+   113 Thu Apr 30 15:57:36 PDT 2015 META-INF/maven/com.propertycross/PropertyCross/pom.properties
+
+683
+
+Some things to note in this file listing:
+
+1. The index.html file is the entry point to the application.
+
+2. CORSProxy.class is the proxy servlet for making network requests to other domains.
+
+3. The  assets  directory  contains  all  of  your  application’s  jar  resources.  All  resource  files  in  your
+
+app will end up in this directory.
+
+4. The  teavm  directory  contains  all  of  the  generated  javascript  for  your  application.  Notice  that
+there are some debugging files generated (classes.js.map and classes.js.teavmdbg). These are
+
+not  normally  loaded  by  the  browser  when  your  app  is  run,  but  they  can  be  used  by  Chrome
+
+when you are doing debugging.
+
+5. The jar files in the WEB-INF/lib directory are dependencies of the proxy servlet. They are not
+
+required for your app to run - unless you are using the proxy.
+
+YourApp-1.0.zip is appropriate for deploying the application on any web server. It contains all of
+
+the same files as the .war file, excluding the WEB-INF directory (i.e. it doesn’t include any servlets,
+
+class files, or Java libraries - it contains purely client-side javascript files and HTML).
+
+As an example, this is a listing of the files in the zip distribution of the PropertyCross demo:
+
+$ unzip -vl PropertyCross-1.0.zip
+Archive:  /path/to/PropertyCross-1.0.zip
+ Length   Method    Size  Ratio   Date   Time   CRC-32    Name
+--------  ------  ------- -----   ----   ----   ------    ----
+   27568  Defl:N    26583   4%  04-30-15 15:57  9dc91739  assets/CN1Resource.res
+  306312  Defl:N   125797  59%  04-30-15 15:57  0b5c1c3a  assets/iOS7Theme.res
+  427737  Defl:N   218975  49%  04-30-15 15:57  3de499c8  assets/iPhoneTheme.res
+     350  Defl:N      241  31%  04-30-15 15:57  7e7e3714  assets/META-INF/MANIFEST.MF
+   92671  Defl:N    91829   1%  04-30-15 15:57  004ad9d7  assets/theme.res
+   23549  Defl:N    23452   0%  04-30-15 15:57  acd79066  icon.png
+    2903  Defl:N     1149  60%  04-30-15 15:57  e5341de1  index.html
+   30695  Defl:N     7937  74%  04-30-15 15:57  2e008f6c  js/fontmetrics.js
+   84319  Defl:N    29541  65%  04-30-15 15:57  15b91689  js/jquery.min.js
+   13261  Defl:N    11944  10%  04-30-15 15:57  51b895c7  progress.gif
+    2816  Defl:N      653  77%  04-30-15 15:57  a12159c7  style.css
+ 1886163  Defl:N   315437  83%  04-30-15 15:57  2b34c50f  teavm/classes.js
+  359150  Defl:N    92874  74%  04-30-15 15:57  30abdf13  teavm/classes.js.map
+ 1147502  Defl:N   470472  59%  04-30-15 15:57  e5c456f7  teavm/classes.js.teavmdbg
+   30325  Defl:N     5859  81%  04-30-15 15:57  46651f06  teavm/runtime.js
+--------          -------  ---                            -------
+ 4435321          1422743  68%                            15 files
+
+You’ll  notice  that  it  has  many  of  the  same  files  as  the  .war  distribution.  It  is  just  missing  the  the
+
+proxy servlet and dependencies.
+
+YourApp-1.0-Preview.html  is  a  single-page  HTML  file  with  all  of  the  application’s  resources
+
+embedded  into  a  single  page.  This  is  generated  for  convenience  so  that  you  can  preview  your
+
+application  on  the  build  server  directly.  While  you  could  use  this  file  in  production,  you  are
+
+probably  better  to  use  the  ZIP  or  WAR  distribution  instead  as  some  mobile  devices  have  file  size
+
+684
+
+limitations that may cause problems for the "one large single file" approach. If you do decide to use
+
+this file for your production app (i.e. copy the file to your own web server), you will need to change
+
+the proxy settings, as it is configured to use the proxy on the Codename One build server - which
+
+won’t be available when the app is hosted on a different server.
+
+19.4. Setting up a Proxy for Network Requests
+
+The 
+
+Codename 
+
+One 
+
+API 
+
+includes 
+
+a 
+
+network 
+
+layer 
+
+(the  NetworkManager
+
+[https://www.codenameone.com/javadoc/com/codename1/io/NetworkManager.html]  and  ConnectionRequest
+
+[https://www.codenameone.com/javadoc/com/codename1/io/ConnectionRequest.html] classes) that allows you to
+
+make HTTP requests to arbitrary destinations. When an application is running inside a browser as
+
+a Javascript app, it is constrained by the same origin policy. You can only make network requests to
+
+the same host that served the app originally.
+
+E.g.  If  your  application  is  hosted  at  http://example.com/myapp/index.html,  then  your  app  will  be
+
+able to perform network requests to retrieve other resources under the example.com domain, but
+
+it won’t be able to retrieve resources from example2.com, foo.net, etc..
+
+
+
+The  HTTP  standard  does  support  cross-origin  requests  in  the  browser  via  the
+Access-Control-Allow-Origin  HTTP  header.  Some  web  services  supply  this  header
+when serving resources, but not all. The only way to be make network requests to
+
+arbitrary resources is to do it through a proxy.
+
+Luckily  there  is  a  solution.  The  .war  javascript  distribution  includes  an  embedded  proxy  servlet,
+
+and  your  application  is  configured,  by  default,  to  use  this  servlet.  If  you  intend  to  use  the  .war
+
+distribution, then it should just work. You shouldn’t need to do anything to configure the proxy.
+
+If, however, you are using the .zip distribution or the single-file preview, you will need to set up a
+
+Proxy servlet and configure your application to use it for its network requests.
+
+19.4.1. Step 1: Setting up a Proxy
+
+
+
+This section is only relevant if you are using the .zip or single-file distributions of
+
+your  app.  You  shouldn’t  need  to  set  up  a  proxy  for  the  .war  distribution  since  it
+
+includes a proxy built-in.
+
+The easiest way to set up a proxy is to use the Codename One cors-proxy [https://github.com/shannah/
+
+cors-proxy] project. This is the open-source project from which the proxy in the .war distribution is
+
+derived.  Simply  download  and  install  the  cors-proxy  .war  file  in  your  JavaEE  compatible  servlet
+
+container.
+
+If  you  don’t  want  to  install  the  .war  file,  but  would  rather  just  copy  the  proxy  servlet  into  an
+
+existing web project, you can do that also. See the cors-proxy wiki for more information about this
+
+[https://github.com/shannah/cors-proxy/wiki/Embedding-Servlet-into-Existing-Project].
+
+19.4.2. Step 2: Configuring your Application to use the Proxy
+
+There are three ways to configure your application to use your proxy.
+
+685
+
+1. Using the javascript.proxy.url build hint.
+
+E.g.:
+
+javascript.proxy.url=http://example.com/myapp/cn1-cors-proxy?_target=
+
+2. By modifying your app’s index.html file after the build.
+
+E.g.:
+
+<script type="text/javascript">
+    window.cn1CORSProxyURL='http://example.com/myapp/cn1-cors-proxy?_target=';
+</script>
+
+3. By setting the javascript.proxy.url property in your Java source. Generally you would do this
+inside  your  init()  method,  but  it  just  has  to  be  executed  before  you  make  a  network  request
+that requires the proxy.
+
+Display.getInstance().setProperty(
+        "javascript.proxy.url",
+        "http://example.com/myapp/cn1-cors-proxy?_target="
+);
+
+The method you choose will depend on the workflow that you prefer. Options #1 and #3 will almost
+
+always result in fewer changes than #2 because you only have to set them up once, and the builds
+
+will retain the settings each time you build your project.
+
+19.5. Using the CORS Proxy for Same Origin Requests
+
+By default, the CORS proxy is only used for HTTP requests to URLS at a different domain than the
+
+one that the app is running in. There are some circumstances where you may want to even use the
+proxy  for  same  domain  requests.  You  can  do  this  by  setting  the  javascript.useProxyForSameDomain
+display property to true. E.g.
+
+Display.getInstance().setProperty("javascript.useProxyForSameDomain", "true");
+
+Why would you want to do this?
+
+The browser shields some HTTP headers (e.g. "Set-Cookie") from Javascript so that your app cannot
+
+access them. Going through the proxy works around this limitation by copying and encoding such
+
+headers in a format that the browser will allow, and then decoding them client-side to make them
+
+available to your app seamlessly.
+
+686
+
+Using Apache as a Proxy
+
+If you are hosting your application on an Apache 2 web server with mod_proxy installed, and you
+
+only  need  to  make  CORS  requests  to  a  single  domain  (or  a  limited  set  of  domains),  you  can  use
+
+Apache  to  serve  as  your  proxy.  One  sample  configuration  (which  you  would  place  either  in  your
+
+VirtualHost definition or your .htaccess file is as follows:
+
+SSLProxyEngine on
+ProxyPass /app https://www.myexternaldomain.com
+ProxyPassReverse /app https://www.myexternaldomain.com
+
+This tells Apache to proxy all requests for '/app' to the domain https://www.myexternaldomain.com.
+
+You would then need to set your CORS proxy URL in your CN1 app to "/app/".
+
+The syntax is the same if you have multiple domains, but keep attention to the order of the lines to
+
+make the proxy working correctly. For example:
+
+SSLProxyEngine on
+ProxyPass /app https://www.myexternaldomain1.com
+ProxyPassReverse /app https://www.myexternaldomain1.com
+ProxyPass /storage https://www.myexternaldomain2.com
+ProxyPassReverse /storage https://www.myexternaldomain2.com
+
+This 
+
+tells 
+
+Apache 
+
+to 
+
+proxy 
+
+all 
+
+requests 
+
+for 
+
+'/app' 
+
+to 
+
+the 
+
+domain
+
+https://www.myexternaldomain1.com  and  all 
+
+requests 
+
+for 
+
+'/storage' 
+
+to 
+
+the  domain
+
+https://www.myexternaldomain2.com
+
+19.6. Customizing the Splash Screen
+
+Since  your  application  may  include  many  resource  files,  videos,  etc..,  the  the  build-server  will
+
+generate a splash screen for your app to display while it is loading. This basically shows a progress
+
+indicator with your app’s icon.
+
+You can customize this splash screen by simply modifying the HTML source inside the cn1-splash
+div tag of your app’s index.html file:
+
+<div id="cn1-splash">
+    <img class="icon" src="icon.png"/>
+
+    <img class="progress" src="progress.gif"/>
+    <p>...Loading...</p>
+</div>
+
+19.7. Debugging
+
+If you run into problems with your app that only occur in the Javascript version, you may need to
+
+687
+
+do a little bit of debugging. There are many debugging tools for Javascript, but the preferred tool for
+
+debugging Codename One apps is Chrome’s debugger.
+
+If your application crashes and you don’t have a clue where to begin, follow these steps:
+
+1. Load your application in Chrome.
+
+2. Open the Chrome debugger.
+
+3. Enable the "Pause on Exceptions" feature, then click the "Refresh" button to reload your app.
+
+4. Step  through  each  exception  until  you  reach  the  one  you  are  interested  in.  Chrome  will  then
+
+show you a stack trace that includes the name of the Java source file and line numbers.
+
+Figure 523. Debugging using Chrome tools
+
+19.8. Including Third-Party Javascript Libraries
+
+Codename  One  allows  you  to  interact  directly  with  Javascript  using  native  interfaces.  Native
+interfaces  are  placed  inside  your  project’s  native/javascript  directory  using  a  prescribed  naming
+convention. If you want to, additionally, include third-party Javascript libraries in your application
+you  should  also  place  these  libraries  inside  the  native/javascript  directory  but  you  must  specify
+which  files  should  be  treated  as  "libraries"  and  which  files  are  treated  as  "resources".  You  can  do
+this  by  adding  a  file  with  extension  .cn1mf.json  file  either  the  root  of  your  native/javascript
+directory or the root level of the project’s src directory.
+
+19.8.1. Libraries vs Resources
+
+A  resource  is  a  file  whose  contents  can  be  loaded  by  your  application  at  runtime  using
+Display.getInstance().getResourceAsStream().  In  a  typical  Java  environment,  resources  would  be
+stored  on  the  application’s  classpath  (usually  inside  a  Jar  file).  On  iOS,  resources  are  packaged
+inside the application bundle. In the Javascript port, resources are stored inside the APP_ROOT/assets
+directory. Historically, javascript files have always been treated as resources in Codename One, and
+
+688
+
+many  apps 
+
+include  HTML  and  Javascript  files  for  use 
+
+inside  the  BrowserComponent
+
+[https://www.codenameone.com/javadoc/com/codename1/ui/BrowserComponent.html].
+
+With the Javascript port, it isn’t quite so clear whether a Javascript file is meant to be a resource or
+
+a library that the application itself uses. Most of the time you probably want Javascript files to be
+
+used as libraries, but you might also have Javascript files in your app that are meant to be loaded at
+
+runtime and displayed inside a Web View - these would be considered resources.
+
+19.8.2. The Javascript Manifest File
+
+In order to differentiate libraries from resources, you should provide a cn1mf.json file inside your
+native/javascript directory that specifies any files or directories that should be treated as libraries.
+This  file  can  be  named  anything  you  like,  as  long  as  its  name  ends  with  cn1mf.json.  Any  files  or
+directories that you list in this manifest file will be packaged inside your app’s includes directory
+instead  of  the  assets  directory.  Additionally  it  add  appropriate  <script>  tags  to  include  your
+libraries as part of the index.html page of your app.
+
+
+
+If you include the cn1mf.json file in your project’s src directory it could potentially
+be  used  to  add  configuration  parameters  to  platform’s  other  than  Javascript
+
+(although currently no other platforms use this feature). If you place it inside your
+native/javascript  directory, 
+configuration contained therein.
+
+Javascript  port  will  use 
+
+then  only 
+
+the 
+
+the
+
+A simple manifest file might contain the following JSON:
+
+{
+    "javascript" : {
+        "libs" : [
+            "mylib1.js"
+        ]
+    }
+}
+
+I.e. It contains a object with key libs whose value is a list of files that should be treated as libraries.
+In the above example, we are declaring that the file native/javascript/mylib1.js should be treated
+as a library. This will result in the following <script> tag being added to the index.html file:
+
+<script src="includes/mylib1.js"></script>
+
+ This  also  caused  the  mylib1.js  file  to  be  packaged  inside  the  includes  directory
+
+instead of the assets directory.
+
+
+
+A  project  may  contain  more  than  one  manifest  file.  This  allows  you  to  include
+
+manifest files with your cn1libs also. You just need to make sure that each manifest
+
+file has a different name.
+
+689
+
+How to NOT generate the <script> tag
+
+In some cases you may want a Javascript file to be treated as a library (i.e. packaged in the includes
+directory) but not automatically included in the index.html page. Rather than simply specifying the
+name of the file in the libs list, you can provide a structure with multiple options about the file. E.g.
+
+{
+    "javascript" : {
+        "libs" : [
+            "mylib1.js",
+            {
+                "file" : "mylib2.js",
+                "include" : false
+            }
+        ]
+    }
+}
+
+In the above example, the mylib2.js file will be packaged inside the includes directory, but the build
+server won’t insert its <script> tag in the index.html page.
+
+Library Directories
+
+You  can  also  specify  directories  in  the  manifest  file.  In  this  case,  the  entire  directory  will  be
+packaged inside the includes directory of your app.
+
+If  you  are  including  Javascript  files  in  your  app  that  are  contained  inside  a
+
+directory hierarchy, you should specify the root directory of the hierarchy in your
+
+manifest file and use the sub "includes" property of the directory entry to specify
+which files should be included with <script> tags. Specifying the file directly inside
+the "libs" list will result in the file being packed directly in the your app’s includes
+directory. This may or may not be what you want.
+
+
+
+E.g.
+
+690
+
+{
+    "javascript" : {
+        "libs" : [
+            "mylib1.js",
+            {
+                "file" : "mylib2.js",
+                "include" : false
+            },
+            {
+                "file" : "mydir1",
+                "includes" : ["subfile1.js", "subfile2.js"]
+            }
+        ]
+    }
+}
+
+In this example the entire mydir1 directory would be packed inside the app’s includes directory, and
+the following script tags would be inserted into the index.html file:
+
+<script src="includes/mydir1/subfile1.js"></script>
+<script src="includes/mydir1/subfile2.js"></script>
+
+
+
+Libraries  included  from  a  directory  hierarchy  may  not  work  correctly  with  the
+
+single file preview that the build server generates. For that version, it will embed
+the contents of each included Javascript file inside the index.html file, but the rest
+of  the  directory  contents  will  be  omitted.  If  your  the  library  depends  on  the
+
+directory hierarchy and supporting files and you require the single-file preview to
+
+work,  then  you  may  consider  hosting  the  library  on  a  separate  server,  and
+
+including  the  library  directly  from  there,  rather  than  embedding  it  inside  your
+
+project’s "native/javascript" directory.
+
+Including Remote Libraries
+
+The  examples  so  far  have  only  demonstrated  the  inclusion  of  libraries  that  are  part  of  the  app
+
+bundle.  However,  you  can  also  include  libraries  over  the  network  by  specifying  the  URL  to  the
+
+library directly. This is handy for including common libraries that are hosted by a CDN.
+
+E.g.  The  Google  Maps  library  requires  the  Google  maps  API  to  be  included.  This  is  accomplished
+
+with the following manifest file contents:
+
+691
+
+{
+    "javascript" : {
+        "libs" : [
+            "//maps.googleapis.com/maps/api/js?v=3.exp"
+        ]
+    }
+}
+
+This  example  uses  the  "//"  prefix  for  the  URL  instead  of  specifying  the  protocol
+
+directly. This allow the library to work for both http and https hosting. You could
+
+however specify the protocol as well:
+
+
+
++
+
+{
+    "javascript" : {
+        "libs" : [
+            "https://maps.googleapis.com/maps/api/js?v=3.exp"
+        ]
+    }
+}
+
+Including CSS Files
+
+CSS files can be included using the same mechanism as is used for Javascript files. If the file name
+ends  with  ".css",  then  it  will  be  treated  as  a  CSS  file  (and  included  with  a  <link>  tag  instead  of  a
+<script> tag. E.g.
+
+{
+    "javascript" : {
+        "libs" : [
+            "mystyles.css"
+        ]
+    }
+}
+
+or
+
+{
+    "javascript" : {
+        "libs" : [
+            "https://example.com/mystyles.css"
+        ]
+    }
+}
+
+692
+
+Embedding Variables in URLs
+
+In some cases the URL for a library may depend on the values of some build hints in the project. For
+
+example, in the Google Maps cn1lib, the API key must be appended to the URL for the API as a GET
+
+parameter.  E.g. 
+
+https://maps.googleapis.com/maps/api/js?v=3.exp&key=SOME_API_KEY,  but 
+
+the
+
+developer of the library doesn’t want to put his own API key in the manifest file for the library. It
+
+would  be  better  for  the  API  key  to  be  supplied  by  the  developer  of  the  actual  app  that  uses  the
+
+library and not the library itself.
+
+The solution for this is to add a variable into the URL as follows:
+
+{
+    "javascript" : {
+        "libs" : [
+            "//maps.googleapis.com/maps/api/js?v=3.exp&key={{javascript.googlemaps.key}}"
+        ]
+    }
+}
+
+The  {{javascript.googlemaps.key}}  variable  will  be  replaced  with 
+the
+javascript.googlemaps.key  build  hint  by  the  build  server,  so  the  resulting  include  you  see  in  the
+index.html page will be something like:
+
+the  value  of 
+
+<script src="//maps.googleapis.com/maps/api/js?v=3.exp&key=XYZ"></script>
+
+19.9. Browser Environment Variables
+
+Native  interfaces  allow  you  to  interact  with  the  Javascript  environment  in  unlimited  ways,  but
+
+Codename  One  provide’s  a  simpler  method  of  obtaining  some  common  environment  information
+from the browser via the Display.getInstance().getProperty() method. The following environment
+variables are currently available:
+
+Table 14. Property hints for the JavaScript port
+
+Name
+
+Description
+
+browser.window.location.href
+
+browser.window.location.search
+
+browser.window.location.host
+
+browser.window.location.hash
+
+A String, representing the entire URL of the
+
+page, including the protocol (like http://)
+
+A String, representing the querystring part of a
+
+URL, including the question mark (?)
+
+A String, representing the domain name and
+
+port number, or the IP address of a URL
+
+A String, representing the anchor part of the
+
+URL, including the hash sign (#)
+
+693
+
+Name
+
+Description
+
+browser.window.location.origin
+
+browser.window.location.pathname
+
+browser.window.location.protocol
+
+browser.window.location.port
+
+A String, representing the protocol (including
+
+://), the domain name (or IP address) and port
+
+number (including the colon sign (:) of the URL.
+
+For URL’s using the "file:" protocol, the return
+
+value differs between browsers
+
+A String, representing the pathname
+
+A String, representing the protocol of the
+
+current URL, including the colon (:)
+
+A String, representing the port number of a URL.
+
++ Note: If the port number is not specified or if it
+
+is the scheme’s default port (like 80 or 443), an
+
+empty string is returned
+
+browser.window.location.hostname
+
+A String, representing the domain name, or the
+
+User-Agent
+
+browser.language
+
+browser.name
+
+Platform
+
+browser.codeName
+
+browser.version
+
+javascript.deployment.type
+
+IP address of a URL
+
+The User-agent string identifying the browser,
+
+version etc..
+
+The language code that the browser is currently
+
+set to. (e.g. en-US)
+
+the name of the browser as a string.
+
+a string that must be an empty string or a string
+
+representing the platform on which the browser
+
+is executing. + For example: "MacIntel", "Win32",
+
+"FreeBSD i386", "WebTV OS"
+
+the internal name of the browser
+
+the version number of the browser
+
+Specifies the deployment type of the app. This
+
+will be "file" for the single-file preview,
+
+"directory" for the zip distribution, and "war" for
+
+the war distribution.
+
+19.10. Changing the Native Theme
+
+Since  a  web  application  could  potentially  be  run  on  any  platform,  it  isn’t  feasible  to  bundle  all
+
+possible themes into the application (at least it wouldn’t be efficient for most use cases). By default
+
+we have bundled the iOS7 theme for javascript applications. This means that the app will look like
+
+iOS7 on all devices: desktop, iOS, Android, WinPhone, etc…
+
+You  can  override  this  behavior  dynamically  by  setting  the  javascript.native.theme  Display
+[https://www.codenameone.com/javadoc/com/codename1/ui/Display.html]  property  to  a  theme  that  you  have
+
+included in your app. All of the native themes are available on GitHub, so you can easily copy these
+into  your  application.  The  best  place  to  add  the  theme  is  in  your  native/javascript  directory  -  so
+that they won’t be included for other platforms.
+
+694
+
+19.10.1. Example:  Using Android Theme on Android
+
+
+
+As of Codename One 6.0, apps will automatically use the Android theme when run
+
+on an Android device, so this example is not necessary. However the technique of
+
+changing the native theme at runtime is still applicable.
+
+First,  download 
+
+androidTheme.res 
+
+[https://github.com/codenameone/CodenameOne/raw/master/Ports/
+
+Android/src/androidTheme.res]  from  the  Android  port  on  GitHub,  and  copy  it  into  your  app’s
+native/javascript directory.
+
+Then in your app’s init() method, add the following:
+
+Display d = Display.getInstance();
+if (d.getProperty("User-Agent", "Unknown").indexOf("Android") != -1) {
+    d.setProperty("javascript.native.theme", "/androidTheme.res");
+}
+
+19.11. Disabling the 'OnBeforeUnload' Handler
+
+By default, apps will display warning/confirm dialog when the user attempts to leave the page.
+
+can 
+
+explicitly 
+
+You 
+the
+disable 
+"platformHint.javascript.beforeUnloadMessage"  display  property.  Setting  the  property  to  null  will
+disable this behaviour, so that users will not be harassed by this dialog when they navigate away
+
+behaviour 
+
+enable 
+
+setting 
+
+this 
+
+by 
+
+or 
+
+from the app. Setting it to a string value, like "leaving so soon?", will re-enable this behaviour.
+
+
+
+Some  browsers  don’t  allow  you  to  specify  the  message  that  is  displayed  in  this
+
+dialog. In those browsers, this property can be viewed as boolean: A null value will
+
+result  in  no  prompt  being  shown,  and  a  non-null  value  will  result  in  a  prompt
+
+being shown.
+
+19.11.1. Example: Toggling the BeforeUnload Prompt On/Off
+
+Form f = new Form("Test Before Unload", BoxLayout.y());
+CheckBox enableBeforeUnload = new CheckBox("Enable Before Unload");
+enableBeforeUnload.setSelected(true);
+enableBeforeUnload.addActionListener(e->{
+    if (enableBeforeUnload.isSelected()) {
+        CN.setProperty("platformHint.javascript.beforeUnloadMessage", "Are you sure you want to leave this page?  It
+might be bad");
+    } else {
+        CN.setProperty("platformHint.javascript.beforeUnloadMessage", null);
+    }
+});
+f.add(enableBeforeUnload);
+f.show();
+
+695
+
+19.12. Deploying as a Progressive Web App
+
+Out of the box, your app is ready to be deployed as a progressive web app (PWA). That means that
+
+users can access the app directly in their browser, but once the browser determines that the user is
+
+frequenting the app, it will "politely" prompt the user to install the app on their home screen. Once
+
+installed  on  the  home  screen,  the  app  will  behave  just  like  a  native  app.  It  will  continue  to  work
+
+while offline, and if the user launches the app, it will open without the browser’s navigation bar. If
+
+you  were  to  install  the  native  and  PWA  versions  of  your  app  side  by  side,  you  would  be  hard
+
+pressed to find the difference - especially on newer devices.
+
+Below  is  a  screenshot  from  Chrome  for  Android  where  the  browser  is  prompting  the  user  to  add
+
+the app to their home screen.
+
+Figure 524. Add app to homescreen banner
+
+If  the  app  is  available  as  a  native  app,  in  the  Play  store,  you  can  indicate  this  using  the
+javascript.manifest.related_applications  and  javascript.manifest.prefer_related_applications
+build hints. Then, instead of prompting the user to add the web app to their home screen, they’ll be
+
+prompted to install the native app from the Play store, as shown below.
+
+Figure 525. Add native app banner
+
+696
+
+
+
+The  PWA  standard  requires  that  you  host  your  app  on  over  HTTPS.  For  testing
+purposes, it will also work when accessed at a localhost address. You can use the
+Lighthoust  PWA  analysis  tool  [https://developers.google.com/web/ilt/pwa/lighthouse-pwa-
+
+analysis-tool] to ensure compliance.
+
+For  more  information  about  Progressive  Web  Apps  see  Google’s  introduction  to  the  subject
+
+[https://developers.google.com/web/progressive-web-apps/].
+
+19.12.1. Customizing the App Manifest File
+
+At the heart of a progressive web app is the web app manifest [https://developer.mozilla.org/en-US/docs/
+
+Web/Manifest].  It  specifies  things  like  the  app’s  name,  icons,  description,  preferred  orientation,
+
+display  mode  (e.g.  whether  to  display  browser  navigation  or  to  open  with  the  full  screen  like  a
+
+native  app),  associated  native  apps,  etc..  The  Codename  One  build  server  will  automatically
+
+generate a manifest file for your app but you can (and should) customize this file via build hints.
+
+Build hints of the form javascript.manifest.XXX will be injected into the app manifest. E.g. To set the
+app’s description, you could add the build hint:
+
+javascript.manifest.description=An app for doing cool stuff
+
+You  can  find  a  full  list  of  available  manifest  keys  here  [https://developer.mozilla.org/en-US/docs/Web/
+
+Manifest].  The  build  server  will  automatically  generate  all  of  the  icons  so  you  don’t  need  to  worry
+
+about  those.  The  "name"  and  "short_name"  properties  will  default  to  the  app’s  display  name,  but
+they can be overridden via the javascript.manifest.name and javascript.manifest.short_name build
+hints respectively.
+
+ The javascript.manifest.related_applications build hint expects a JSON formatted
+
+list, just like in the raw manifest file.
+
+19.12.2. Related Applications
+
+One  nice  feature  (discussed  above)  of  progressive  web  apps,  is  the  ability  to  specify  related
+
+applications  in  the  app  manifest.  Browsers  that  support  the  PWA  standard  use  some  heuristics  to
+
+"offer" the user to install the associated native app when it is clear that the user is using the app on
+a regular basis. Use the javascript.manifest.related_applications build hint to specify the location
+of the native version of your app. E.g.
+
+javascript.manifest.related_applications=[{"platform":"play", "id":"my.app.id"}]
+
+You  can  declare  that  the  native  app  is  the  preferred  way  to  use  the  app  by  setting  the
+javascript.manifest.prefer_related_applications build hint to "true".
+
+
+
+According  to  the  app  manifest  documentation  [https://developer.mozilla.org/en-US/docs/
+
+Web/Manifest],  this  should  only  be  used  if  the  related  native  apps  really  do  offer
+
+something that the web application can’t do.
+
+697
+
+19.12.3. Device/Browser Support for PWAs
+
+Chrome and Firefox both support PWAs on desktop and on Android. iOS doesn’t support the PWA
+
+standard, however, many aspects of it are supported. E.g. On iOS you can add the app to your home
+
+screen, after which time it will appear and behave like a native app - and it will continue to work
+
+while  offline.  However,  many  other  nice  features  of  PWA  like  "Install  this  app  on  your  home
+
+screen" banners, push notifications, and invitations to install the native version of the app, are not
+
+supported. It is unclear when, or even, whether Apple will ever add full support; but most experts
+
+predict that they will join the rest of the civilized world and add PWA support in the near future.
+
+On the desktop, Chrome provides an analogous feature to "add to your homescreen": "Add to shelf".
+
+If it looks like the user is using the app on a regular basis, and it isn’t yet installed, it will show a
+
+banner at the top of the page asking the user if they want to add to their shelf.
+
+Figure 526. Add to shelf banner
+
+Clicking the "Add button" prompts the user for the name they wish the app to appear as:
+
+Figure 527. Add to shelf prompt
+
+Upon submission, Chrome will generate a real application (on Mac, it will be a ".app", on Windows,
+
+an  "exe",  etc..)  which  the  user  can  double  click  to  open  the  app  directly  in  the  Chrome.  And,
+
+importantly, the app will still work when the user is offline.
+
+The  app  will  also  appear  in  their  "Shelf"  which  you  can  always  access  at  chrome://apps,  or  by
+opening  the  "Chrome  App  Launcher"  app  (on  OS  X  this  is  located  in  "~/Applications/Chrome
+
+Apps/Application Launcher").
+
+Figure 528. Chrome App Launcher
+
+698
+
+The Chrome App Launcher lists apps installed both via the Chrome Web Store and
+
+
+
+via the "Add to Shelf" feature that we discuss here. The features we describe in this
+
+article  are  orthogonal  to  the  Chrome  Web  Store  and  will  not  be  affected  by  its
+
+closure.
+
+19.13. Playing Media and Opening Links
+
+People don’t like it when the browser automatically starts playing sounds, or opening links without
+
+their  permission.  For  this  reason,  modern  browsers  generally  restrict  your  ability  to
+
+programmatically do these things, unless they are in response to a user action, like a mouse click.
+
+If  your  app  needs  to  play  media  (e.g.  Media.play()),  or  open  a  link  (e.g.  Display.execute("…"))
+without the user actually interacting physically (e.g. key press or pointer press), then it will display
+
+a popup dialog confirming that the user actually wants to perform this action.
+
+In some cases this dialog may affect the utility of the app. For example, suppose you want to play a
+
+video in response to a voice command. Having to press an "OK" button after the command, may be
+annoying. For such cases, you can use the platformHint.javascript.backsideHooksInterval property
+to poll for media play requests on an authorized event.
+
+For example:
+
+CN.setProperty("platformHint.javascript.backsideHooksInterval", "1000");
+
+// Now your app will process media.play() and Display.execute(...) calls
+// once per second (1000ms).  If play() or execute() has been called anytime
+// in that second (since the last poll), it will seamlessly process the
+// request.
+
+// To disable polling, just set it to an interval 0 or lower.
+// e.g.
+CN.setProperty("platformHint.javascript.backsideHooksInterval", "0");
+
+
+
+Do not abuse this feature. You should enable this polling only when necessary. E.g.
+
+If your app enables the user to listen for voice commands, only enable polling for
+
+the  period  of  time  that  it  is  listening.  When  the  user  wants  to  stop  listening,  you
+
+should also stop the polling by setting the interval to "0".
+
+699
+
+700
+
+20. Working with UWP
+
+UWP Apps may distributed in 2 different ways:
+
+1. In the Windows App Store. (This should be used for deployment of any production app).
+
+2. Outside of the Windows App Store via sideloading directly onto a device. This should only be
+
+used for development.
+
+20.1. Deploying Outside of the Windows App Store
+(Sideloading)
+
+UWP apps may be deployed directly to Windows 10 desktop and mobile devices without any need
+
+to involve the Windows Store. This process is only realistic, though, for testing and debugging your
+
+app during development because it requires you to enable "Development" mode on the device. In
+
+addition,  installation  is  a  little  bit  more  complicated  than  simply  downloading  an  app  over  the
+
+internet. The process for deploying to Windows 10 desktop devices is different than the process for
+
+mobile devices. These are described in the following sections.
+
+20.1.1. Side-loading to Windows 10 Mobile Devices
+
+Enabling Developer Mode on Device
+
+Before you can side-load apps onto your phone, you’ll need to set up your phone for development.
+
+1. In "Settings", select "Update & Security" > "For developers"
+
+701
+
+2. Select "Developer mode"
+
+3. Under "Device Discovery", make sure that the "Make your device visible to USB connections and
+
+your local network" is set to "On".
+
+4. Make sure that "Device Portal" is set to "On"
+
+5. When you switch "Device Portal" to "On" it should show you an address that you can access the
+
+Phone at via wifi. (E.g. https://10.0.1.11). Remember this address, you’re going to use it to install
+
+all of your apps onto the device.
+
+ This will be a local address within your local network. It won’t be available to
+
+the outside world.
+
+702
+
+At this point, your phone should be ready to receive "Side-loaded" apps. This was a one-time setup,
+
+so you shouldn’t have to do it again, until you set up another device.
+
+Building App for UWP
+
+Now that your device is set up for development, you can proceed to build your app.
+
+1. Select the "Mobile Debug Build" option in the UWP Codename One Settings.
+
+2. Select the "Send Windows UWP Build" option in the Codename One menu of your IDE. This will
+
+initiate the build on the Codename One build server.
+
+3. Log into the Codename One dashboard to watch the build progress. When it is complete, you’ll
+
+be able to download the ".appxbundle" file to your desktop.
+
+
+
+You  cannot  simply  download  the  .appxbundle  file  directly  to  your  Windows
+
+Phone 10 mobile device and install it. It will indeed allow you to download it,
+
+and will give you an option to install it, but the install will silently fail.
+
+Installing App On Device
+
+1. Point your computer’s web browser to the address for your mobile device. (This is the address
+
+listed  when  you  turned  on  the  "Device  Portal"  in  the  "Enabling  Developer  Mode  on  Device"
+
+section above. This will open the App Manager page.
+
+2. Click on the "Apps" item in the left menu.
+
+703
+
+3. If this is the first time installing a UWP (debug) app on your device, you will need to install the
+
+dependencies.  You  can  find  the  dependencies  for  mobile/ARM  apps  here  [https://github.com/
+
+codenameone/cn1-binaries/tree/master/uwp/Dependencies/ARM]. 
+both
+Microsoft.NET.CoreRuntime.1.0.appx  and  Microsoft.VCLibs.ARM.Debug.14.00.appx.  If  this  is  not
+the first time installing a UWP app, you can skip to the next step.
+
+install 
+
+You’ll 
+
+need 
+
+to 
+
+a. Under the "Install App" section, click the "Choose File" button and navigate through the file
+
+chooser to select the "Microsoft.NET.CoreRuntime.1.0.appx" file. Then click "Go".
+
+b. Do the same for the "Microsoft.VCLibs.ARM.Debug.14.00.appx" file.
+
+4. Under  the  "Install  App"  section,  click  the  "Choose  File"  button  and  navigate  through  the  file
+
+chooser to select the .appxbundle file for your app.
+
+5. Once you have the appxbundle selected, you should press "Go" under the "Deploy" subheading.
+
+This  will  install  the  app  and,  if  all  went  well,  your  app  will  appear  in  the  "Recently  Added"
+
+section in the apps list of the phone.
+
+20.1.2. Side-loading to Windows 10 Desktop Devices
+
+Enabling Developer Mode on PC
+
+The  easiest  way  to  be  able  to  run  your  development  apps  on  a  Windows  10  PC  is  to  enable
+
+developer mode. This will allow you to install any app even if it is just "self-signed".
+
+To  enable  developer  mode,  open  "Settings",  then  select  "Updates  an  Security".  Under  the  "For
+
+Developers" menu item, select "Developer Mode" as shown below:
+
+704
+
+Building the App
+
+Before building the app, you’ll need to ensure that the build target is set to "Debug Desktop" in the
+
+Codename One Settings panel for Windows apps.
+
+Steps:
+
+1. Open  Codename  One  Settings  (steps  vary  by  IDE).  On  Netbeans  you  will  find  "Codename  One
+
+Settings"  by  right  clicking  your  project’s  node  in  the  project  explorer,  and  look  in  the
+
+"Codename One" submenu:
+
+2. Click on "Windows Settings":
+
+3. Under "Build Type", make sure that "Desktop Debug Build" is selected, as shown below:
+
+4. Save the changes by clicking the "Disk" icon in the upper right:
+
+Now you can proceed to send the build to the build server.
+
+1. Select the "Send Windows UWP Build" option in the Codename One menu of your IDE. This will
+
+initiate the build on the Codename One build server.
+
+705
+
+2. Log into the Codename One dashboard to watch the build progress. When it is complete, you’ll
+
+be able to download the ".zip" file to the Windows 10 PC on which you wish to install the app.
+
+Installing the App
+
+Start by extracting the .zip file. (Navigate to the folder where the zip was downloaded, right click it,
+
+and select "Extract all" as shown below:
+
+Figure 529. Extract UWP zip file
+
+After extraction, open the resulting directory. You should see contents similar to the following:
+
+Figure 530. UWP Zip file contents
+
+Downloading Dependencies
+
+If  this  is  your  first  time  installing  a  UWP  app  on  this  PC,  you  may  need  to  add  the  dependencies
+
+before  you  can  install.  You  can  download  the  dependencies  here  [https://github.com/codenameone/cn1-
+
+binaries/raw/master/uwp/Dependencies.zip].  Extract 
+
+"Dependencies.zip"  and  copy 
+
+the  resulting
+
+"Dependencies" directory into the app install directory. Your app install directory should now look
+
+like:
+
+Figure 531. UWP Zip file contents with dependencies
+
+706
+
+Running the Powershell Script
+
+We are finally at the point where we can run the installer.
+
+Right-click on the "Add-AppDevPackage" icon, and select "Run in Powershell", as shown:
+
+Figure 532. UWP Install by run in powershell
+
+You may be prompted that you need to change the execution policy, in Powershell:
+
+Figure 533. UWP Powershell change execution policy
+
+Enter "Y" at the prompt to allow this.
+
+If all goes well, you should see a message saying that the app as successfully installed.
+
+Figure 534. UWP Powershell app successfully installed
+
+And if you look in your "Windows Menu" under "All Apps", you should see your app listed there:
+
+Figure 535. Windows 10 App listed in All Apps
+
+20.1.3. Building for the Windows Store
+
+If you want to be able to distribute your app to the public, the Windows Store is your best channel.
+
+707
+
+Building for the Windows store involves roughly 3 steps:
+
+1. Reserve a name for your app in the Windows Store
+
+2. Build your app using the "Windows Store Upload" build type.
+
+3. Upload the resulting .appxupload file to the Windows store.
+
+Let’s  go  through  these  steps  in  more  detail.  Start  here  [https://developer.microsoft.com/en-us/windows/
+
+publish].
+
+Figure 536. Publish windows apps webpage
+
+If you don’t already have an account, sign up for one. Then log in. Once logged in, you can click the
+
+"Dashboard" link on the toolbar.
+
+Figure 537. Windows Store dashboard
+
+Under  the  "Your  apps"  section  (on  the  left  in  the  above  screenshot),  click  the  "Create  new  app"
+
+button.
+
+Figure 538. Reserve name form
+
+708
+
+Enter a name for your app, and click "Reserve app name".
+
+If the name was available, it should take you to the app overview page for your new app. There’s
+
+quite a few options there to play with, but we’re not going to worry about any of them for now. All
+
+we need to know is:
+
+1. Your App’s ID
+
+2. Your App’s Publisher ID
+
+You  can  get  this  information  by  scrolling  down  to  the  bottom  of  the  "App  overview"  page  and
+
+clicking the "View app identity details" under the "App Management" > "App identity" section:
+
+Figure 539. App Identity section
+
+You’ll see a page with the information we need shown below:
+
+Figure 540. App identity details
+
+The next step is to copy this information into your Codename One project.
+
+Open up the Codename One Settings for your project and go to the "Windows Settings" section.
+
+Copy  and  paste  the  "Package/Identity/Name"  and  "Package/Properties/PublisherDisplayName"
+
+values from the windows store into the "App ID" and "Publisher Display Name" fields respectively.
+
+
+
+It is important that your App ID and Publisher Display Name match exactly what
+
+you have in the store, or your app will fail at the validation stage when you try to
+
+upload your app to the store.
+
+Next, click on the "Generate" button next to the Certificate field.
+
+This  will  open  a  dialog 
+
+titled 
+
+"Certificate  Generator".  Paste 
+
+the  value 
+
+from 
+
+the
+
+"Package/Identity/Publisher"  listed  in  the  Windows  Store  into  the  Publisher  ID  field  as  shown
+
+below:
+
+709
+
+Figure 541. Certificate Generator
+
+Then click OK. This will generate a .pfx file inside your project folder.
+
+The "Display Name" must also match that app name in the store.
+
+Finally,  make  sure  that  "Windows  Store  Upload"  is  selected  in  the  "Build  Type"  field.  For  the
+
+example above, my settings form looks like the following screenshot when I am done.
+
+Figure 542. Settings for Windows Store uploads
+
+When  you  are  done,  hit  the  "Save"  icon  in  the  upper  right  corner  of  the  window  to  save  your
+
+changes.
+
+Finally, select "Codename One" > "Send Windows UWP Build" in your IDE’s project explorer.
+
+This will produce an .appxupload file that you can upload to the Windows Store.
+
+See  the  Microsoft’s  documentation  on  uploading  app  packages  [https://msdn.microsoft.com/en-us/
+
+windows/uwp/publish/upload-app-packages] for more information on the remaining steps.
+
+20.2. Debugging UWP Apps
+
+On  most  platforms,  there  is  a  device  log  that  records  errors,  exceptions,  and  messages  written  to
+
+STDOUT. UWP, unfortunately, doesn’t seem to provide this. If you are running on Windows Phone
+
+10, there doesn’t seem to be any device log at all. There is a separate program called "Field Medic"
+
+that you can use to do some logging, but it doesn’t capture application errors or STDOUT messages.
+
+The best way to debug apps on device is to enable crash protection in your app. This can be enabled
+by adding the following to your app’s init() method:
+
+Log.bindCrashProtection(true);
+
+With crash protection enabled, you’ll receive an email whenever an exception is thrown that isn’t
+
+caught in your application code. The email will include the stack trace of the error along with any
+output you had previously provided using the com.codename1.io.Log class (e.g. Log.p() and Log.e()).
+
+ A Pro account (or higher) is required to receive crash protection emails.
+
+20.2.1. No Line Numbers in Stack Traces
+
+One  major  annoyance  of  UWP  is  that  it  doesn’t  provide  line  numbers  in  its  stack  traces.  Here  is
+
+what you can expect to see in a stack trace:
+
+710
+
+[EDT] 0:0:7,683 - Results null
+[EDT] 0:0:7,799 - Exception: java.lang.NullPointerException - null
+   at com.codename1.ui.Display.invokeAndBlock(Runnable r, Boolean dropEvents)[EDT] 0:0:7,815 - Exception in AppName
+version 1.1
+[EDT] 0:0:7,830 - OS win
+[EDT] 0:0:7,836 - Error java.lang.NullPointerException
+[EDT] 0:0:7,836 - Current Form null
+[EDT] 0:0:7,836 - Exception: java.lang.NullPointerException - null
+at System.Environment.GetStackTrace(Exception e, Boolean needFileInfo)
+   at System.Environment.get_StackTrace()
+   at UWPApp.IKVMReflectionHelper.getCurrentStackTrace()
+   at java.lang.ThrowableHelper.getCurrentStackTrace()
+   at java.lang.Throwable..ctor()
+   at java.lang.Exception..ctor()
+   at java.lang.RuntimeException..ctor()
+   at java.lang.NullPointerException..ctor()
+   at java.lang.Throwable.__mapImpl(Exception )
+   at IKVM.Internal.ExceptionHelper.MapException[T](Exception x, Boolean remap, Boolean unused)
+   at IKVM.Runtime.ByteCodeHelper.MapException[T](Exception x, MapFlags mode)
+   at com.codename1.ui.Display.invokeAndBlock(Runnable r, Boolean dropEvents)
+   at com.codename1.ui.Display.invokeAndBlock(Runnable r)
+   at com.codename1.impl.SilverlightImplementation.editString(Component n1, Int32 n2, Int32 n3, String n4, Int32 n5)
+   at com.codename1.impl.CodenameOneImplementation.editStringImpl(Component cmp, Int32 maxSize, Int32 constraint, String
+text, Int32 initiatingKeycode)
+   at com.codename1.ui.Display.editString(Component cmp, Int32 maxSize, Int32 constraint, String text, Int32
+initiatingKeycode)
+   at com.codename1.ui.Display.editString(Component cmp, Int32 maxSize, Int32 constraint, String text)
+   at com.codename1.ui.TextArea.editString()
+   at com.codename1.ui.TextArea.pointerReleased(Int32 x, Int32 y)
+   at com.codename1.ui.TextField.pointerReleased(Int32 x, Int32 y)
+   at com.codename1.ui.Form.pointerReleased(Int32 x, Int32 y)
+   at com.codename1.ui.Component.pointerReleased(Int32[] x, Int32[] y)
+   at com.codename1.ui.Display.handleEvent(Int32 offset)
+   at com.codename1.ui.Display.edtLoopImpl()
+   at com.codename1.ui.Display.mainEDTLoop()
+   at com.codename1.ui.RunnableWrapper.run()
+   at com.codename1.impl.CodenameOneThread.run()
+   at java.lang.Thread.threadProc2()
+   at java.lang.Thread.threadProc()
+   at java.lang.Thread.1.Invoke()
+   at com.codename1.impl.NativeThreadImpl.<>c__DisplayClass6_0.<init>b__0()
+   at System.Threading.Tasks.Task.InnerInvoke()
+   at System.Threading.Tasks.Task.Execute()
+   at System.Threading.Tasks.Task.ExecutionContextCallback(Object obj)
+   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
+   at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot)
+   at System.Threading.Tasks.Task.ExecuteEntry(Boolean bPreventDoubleExecution)
+   at System.Threading.Tasks.ThreadPoolTaskScheduler.LongRunningThreadWork(Object obj)
+   at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
+   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
+   at System.Threading.ThreadHelper.ThreadStart(Object obj)
+Originating from:
+Message=Object reference not set to an instance of an object.
+   at com.propertycross.codename1.PropertyCross.1.run()
+   at com.codename1.ui.Display.processSerialCalls()
+   at com.codename1.ui.Display.edtLoopImpl()
+   at com.codename1.ui.Display.invokeAndBlock(Runnable r, Boolean dropEvents)
+
+It  will  show  you  the  call  stack  with  the  names  of  the  methods.  But  it  won’t  show  you  the  line
+numbers.  If  the  stack  trace  isn’t  specific  enough,  you  can  add  Log.p()  statements  in  various
+positions in my code to help narrow down the source of the exception.
+
+711
+
+20.3. Customizing the Status Bar
+
+On mobile, the status bar (the bar across the top of the screen with the time, battery level etc…) is
+
+updated  each  time  a  form  is  shown.  The  foreground  color,  background  color,  and  background
+
+opacity are set using the unselected style of the form being shown.
+
+You can override these colors application-wide using the following display properties:
+
+1. windows.StatusBar.ForegroundColor - A string representation of an integer RGB color.
+
+2. windows.StatusBar.BackgroundColor - A string representation of an integer RGB color.
+
+3. windows.StatusBar.BackgroundTransparency - A string representation of 0-255 integer.
+
+e.g.
+
+Display d = Display.getInstance();
+d.setProperty("windows.StatusBar.ForegroundColor", String.valueOf(0xff0000));  // red
+d.setProperty("windows.StatusBar.BackgroundColor", String.valueOf(0xffffff));  // white
+d.setProperty("windows.StatusBar.BackgroundOpacity", String.valueOf(255));  // fully opaque
+
+20.4. Associating App with File Types
+
+It is possible to associate your application with file types on UWP using the standard Codename One
+"AppArg"  method  in  conjunction  with  the  windows.extensions  build  hint.  Any  content  you  place  in
+the  windows.extensions  build  hint  will  be  embedded  inside  the  <Extensions/>  section  of  the
+Package.appxmanifest  file.  Then  if  the  app  is  opened  as  a  result  of  the  user  opening  a  file  of  the
+
+specified 
+Display.getProperty("AppArg").
+
+type, 
+
+then 
+
+the  path 
+
+to 
+
+that 
+
+file  will  be  made  available 
+
+to 
+
+the  app  via
+
+Example windows.extensions Value:
+
+The following value would associate the app with the file extension ".alsdk". This example is taken
+
+from 
+
+this  MSDN  document 
+
+[https://msdn.microsoft.com/vi-vn/windows/uwp/launch-resume/handle-file-
+
+activation?f=255&MSPPError=-2147217396].
+
+<uap:Extension Category="windows.fileTypeAssociation">
+  <uap:FileTypeAssociation Name="alsdk">
+    <uap:Logo>images\icon.png</uap:Logo>
+    <uap:SupportedFileTypes>
+      <uap:FileType>.alsdk</uap:FileType>
+    </uap:SupportedFileTypes>
+  </uap:FileTypeAssociation>
+</uap:Extension>
+
+To register your app to be able to handle PDFs, you would add:
+
+712
+
+<uap:Extension Category="windows.fileTypeAssociation">
+    <uap:FileTypeAssociation Name="pdf">
+        <uap:Logo>images\icon.png</uap:Logo>
+        <uap:SupportedFileTypes>
+            <uap:FileType ContentType="application/pdf">.pdf</uap:FileType>
+        </uap:SupportedFileTypes>
+    </uap:FileTypeAssociation>
+</uap:Extension>
+
+For  more 
+
+information  about  using 
+
+the 
+
+"AppArg"  property, 
+
+see 
+
+this  blog  post
+
+[https://www.codenameone.com/blog/intercepting-urls-on-ios-android.html]  which  describes  its  usage  on  iOS
+
+and Android for intercepting URL types.
+
+713
+
+714
+
+21. Working with Mac OS X
+
+21.1. Mac OS Desktop Build Options
+
+You can configure Desktop Mac OS build settings, by opening Codename One Settings, and clicking
+
+the "Mac Desktop Settings" button:
+
+Figure 543. Mac Desktop settings
+
+This will bring you to the following form:
+
+Figure 544. Mac Desktop settings form
+
+Here you can provide your certificate(s) as a .p12 file, and select a bundle type.
+
+21.1.1. Bundle Types
+
+There are three bundle types which dictate what the build server produces for you when you build
+
+your project as a Desktop Mac OS App.
+
+1. DMG - Produces a .DMG disk image with your app. This is the preferred format for distributing
+
+your app outside of the Mac Appstore. If you provide a Developer ID Application certificate (see
+
+"Understanding  Certificates"  below),  this  the  app  will  be  signed  so  that  users  won’t  receive
+
+warnings about "Unidentified developer" when they install your app.
+
+2. Sandboxed  DMG  -  Same  as  DMG  bundle  type  except  that  your  app  is  set  up  to  use  the  app
+
+sandbox. Generally this would be used to test an app that is being distributed via the Appstore,
+
+since Appstore apps must use the sandbox. If you select this bundle type, you are required to
+
+provide  a  Mac  App  Distribution  Certificate,  and  you  should  additionally  specify  entitlements
+
+required  for  your  app  to  function  properly.  For  more  information  about  the  app  sandbox,  see
+
+Apple’s documentation on the subject [https://developer.apple.com/app-sandboxing/].
+
+3. Mac  Appstore  Upload  (PKG)  -  Produces  a  .PKG  file  that  you  can  upload  to  the  Mac  appstore.
+
+This requires that you provide both a Mac App Distribution certificate, and a Mac App Installer
+
+certificate  (see  "Understanding  Certificates"  below).  Both  of  these  certificates  should  be
+
+embedded into a single .p12 file (See "Exporting Certificates as p12" below).
+
+21.1.2. Understanding Mac Certificates
+
+For  the  purposes  of  Mac  application  distribution,  there  are  3  types  of  certificates  that  we  will  be
+
+interested  in.  The  type(s)  of  certificate  required  will  depend  on  the  type  of  bundle  you  generate.
+
+The certificate types are:
+
+1. Developer ID Application Certificate (Mac applications)
+
+715
+
+This type of certificate is used to sign an app to be distributed outside of the Mac Appstore as a
+
+DMG  image.  This  corresponds  to  the  "DMG"  bundle  type  in  Codename  one  settings.  You  can
+
+easily  identity  this  kind  of  certificate  because  its  identity  will  be  of  the  form  "Developer  ID
+
+Application:  YOUR  COMPANY  NAME  (SOMECODE)".  E.g.  Developer  ID  Application:  Acme
+
+Widgets Corp. (XYSD5YF).
+
+2. Mac App Distribution Certificate (Mac Appstore)
+
+This type of certificate is used to sign the .app bundle for an app that is to be distributed in the
+
+Mac  Appstore.  This  certificate  is  required  for  both  the  "Sandboxed  DMG",  and  "Mac  Appstore
+
+Upload (PKG)" bundle types. You can easily identify this kind of certificate because its identity
+
+will  be  of  the  form  "3rd  Party  Mac  Developer  Application:  YOUR  COMPANY  NAME
+
+(SOMECODE)". E.g. 3rd Party Mac Developer Application: Acme Widgets Corp. (XYSD5YF).
+
+3. Mac App Installer Certificate (Mac Appstore)
+
+This type of certificate is used to sign the .pkg installer for an app that is being submitted to the
+
+Mac Appstore. This certificate is required for the "Mac Appstore Upload (PKG)" bundle type only.
+
+You can easily identify this kind of certificate because its identity will be of the form "3rd Party
+
+Mac  Developer  Installer:  YOUR  COMPANY  NAME  (SOMECODE)".  E.g.  3rd  Party  Mac  Developer
+
+Installer: Acme Widgets Corp. (XYXD5YF).
+
+21.1.3. Obtaining Certificates
+
+
+
+Apple  provides  documentation  on  obtaining  certificates  on 
+
+its  website
+
+[https://developer.apple.com/library/content/documentation/IDEs/Conceptual/
+AppDistributionGuide/MaintainingCertificates/MaintainingCertificates.html#//apple_ref/doc/uid/
+
+TP40012582-CH31-SW6]  but  the  process  described  there  involves  Xcode.  This  section
+
+describes an alternate process that doesn’t require Xcode.
+
+If  you  have  an  Apple  developer  account,  you  can  manage  your  certificates  here
+
+[https://developer.apple.com/account/mac/certificate].
+
+Figure 545. Mac Developer portal certificates
+
+The  screenshot  above  shows  an  account  that  already  has  the  three  kinds  of  certificates  we  will
+
+require:
+
+1. Developer ID Application - Used for the DMG bundle type.
+
+2. Mac App Distribution - Used for the Sandboxed DMG and Mac Appstore Upload (PKG) bundle
+
+types.
+
+3. Mac App Installer - Used for the Mac Appstore Upload (PKG) bundle type.
+
+If your account doesn’t yet have a certificate of the required type, you should begin by pressing the
+
+716
+
+"+" button in the upper right. This will bring you to a page asking "What type of Certificate do you
+
+need?". There are only two options on this page that we’ll be interested in:
+
+Figure 546. Creating a new certificate
+
+1. Production  >  Mac  App  Store  -  For  both  the  Mac  App  Distribution  and  Mac  App  Installer
+
+certificates.
+
+2. Production > Developer ID - For the Developer ID Application certificate.
+
+Select  the  option  corresponding  to  the  certificate  you  wish  to  generate.  In  either  case,  you’ll  be
+
+taken to a form to select whether you want an "Installer" certificate or an "Application" certificate.
+
+Select the appropriate type.
+
+You  will  then  be  prompted  to  upload  a  Certificate  Signing  Request  (CSR)  file,  and  it  will  provide
+
+instructions on how to do this via the Keychain app.
+
+
+
+You can reuse the same CSR file for generating all 3 certificates.
+
+After  generating  the  certificates,  you  should  download  them  to  your  Mac,  and  import  them  into
+
+your  keychain.  You  should  be  able  to  accomplish  this  by  simply  double-clicking  the  downloaded
+
+".cer" file, and following the prompts.
+
+21.1.4. Exporting Certificates as P12
+
+ The following section requires access to a Mac, and assumes that you have already
+
+generated your 3 certificates
+
+Notice  that  Mac  apps  may  require  three  different  kinds  of  certificates,  yet  the  settings  page  only
+
+provides  space  for  a  single  certificate  (P12)  file.  This  is  not  a  mistake.  P12  files  may  contain  more
+
+than one certificate, and you are expected to include all of the certificates that the build server may
+
+require  inside  a  single  P12.  The  build  server  will  automatically  extract  the  certificates  it  needs
+
+according to the bundle type.
+
+When  building  the  "DMG"  bundle  type,  the  build  server  will  look  for  a  "Developer  ID  Application
+
+717
+
+Certificate" inside the P12. If one is found, it will be used to sign the app bundle.
+
+The "Sandboxed DMG" target will look for a "Mac App Distribution Certificate" certificate in the P12.
+
+The "Mac Appstore Upload (PKG)" target will require both a "Mac App Distribution Certificate" and
+
+a "Mac App Installer Certificate" to be included in the P12.
+
+The easiest way to produce a P12 that includes all 3 kinds of certificates is to export them from the
+
+Keychain Access app (Requires a Mac). Select all 3 certificates at once (using CMD-click), then right
+
+click and select "Export 3 Items…"
+
+You will then be prompted to select a location to save the .p12 file, as well as selecting a password
+
+for the file.
+
+21.1.5. Entitlements
+
+When  distributing  apps  in  the  Mac  Appstore,  or  when  using  the  "Sandboxed  DMG"  bundle  type,
+
+your app is run inside a sandboxed environment, meaning that it doesn’t have access to the outside
+
+world.  It  is  provided  its  own  "sandboxed"  container  for  file  system  access,  and  it  doesn’t  get  any
+
+network access. If your app requires access to the "outside world", you need to request entitlements
+
+for that access. If you select a bundle type that uses the sandbox, you you will be shown a list of all
+
+of the available entitlements from which you can "check" the ones that you wish to include.
+
+Figure 547. App sandbox entitlements
+
+For  more  information  about  the  app  sandbox,  and  a  full  list  of  entitlements,  see  Apple’s
+
+documentation  on  the  subject  [https://developer.apple.com/library/content/documentation/Miscellaneous/
+
+Reference/EntitlementKeyReference/Chapters/EnablingAppSandbox.html].
+
+718
+
+22. Security
+
+Security is a "big word". It implies many things and that is also true for the mobile app development
+
+so before we get started lets try to define the scope of security.
+
+We  will  deal  only  with  application  security  and  its  communication  mechanisms  while  ignoring
+
+everything beyond that scope. Let’s start with a simple fact:
+
+Codename One applications are secure on the devices by the nature of the
+
+mobile OS security.
+
+For  most  intents  and  purposes  this  will  be  enough,  unless  you  are  specifically  concerned  about
+
+security this section isn’t for you. Mobile OS’s isolate applications from one another so it’s hard for
+
+an application to damage the OS or even damage/spy on a different app.
+
+The restrictions laid on apps are here to make them extra secure and on top of that Codename One
+
+lays a few big advantages in terms of security:
+
+• Codename One code is compiled (unlike e.g. PhoneGap/Cordova)
+
+• We obfuscate by default which makes the binaries harder to reverse engineer
+
+• We compile the UI to native code too which means typical reverse engineering code will have a
+
+harder time following
+
+• We disable debug flags so a hacker won’t be able to debug your production app on the device
+
+Despite that you still need to keep in mind that the binary could still be reverse engineered and so it
+
+is  important  to  avoid  storing  keys  in  the  client  side  code.  E.g.  if  you  have  an  API  key  to  access  a
+
+service  (e.g.  Google  Cloud  key)  it  needs  to  be  stored  in  your  server  and  not  as  a  constant  in  your
+
+app!
+
+Each  section  below  discusses  some  attack  vectors  against  applications  and  how  they  can  be
+
+stopped. Pretty much all of these attacks require a very sophisticated attacker which will only exist
+
+for high value targets (e.g. bank apps, government etc.).
+
+22.1. Constant Obfuscation
+
+One  of  the  first  things  a  hacker  will  do  when  compromising  an  app  is  look  at  it.  E.g.  if  I  want  to
+
+exploit  a  bank’s  login  UI  I  would  look  at  the  label  next  to  the  login  and  then  search  for  it  in  the
+
+decompiled code. So if the UI has the String "enter user name and password" I can search for that.
+
+It  won’t  lead  directly  to  a  hack  or  exploit  but  it  will  show  you  the  approximate  area  of  the  code
+
+where we should look and it makes the first step that much easier. Obfuscation helps as it removes
+
+descriptive method names but it can’t hide the Strings we use in constants. If an app has a secret
+
+key within obfuscating it can make a difference (albeit a slight difference).
+
+Notice that this is a temporary roadblock as any savvy hacker would compile the app and connect a
+
+debugger eventually (although this is blocked in release builds) and would be able to inspect values
+
+of variables/flow. But the road to reverse engineering the app would be harder even with a simple
+
+719
+
+xor obfuscation.
+
+ We’re  not  calling  this  encoding  or  encryption  since  it’s  neither.  It’s  a  simple
+
+obfuscation of the data
+
+There are two simple methods in the Util class:
+
+public static String xorDecode(String s);
+public static String xorEncode(String s);
+
+They use a simple xor based obfuscation to make a String less readable. E.g. if you have code like
+
+this:
+
+private static final String SECRET = "Don't let anyone see this....";
+
+You might be concerned about the secret, then this would make it slightly harder to find out:
+
+// Don't let anyone see this....
+private static final String SECRET = Util.xorDecode("RW1tI3Ema219KmpidGFhdTFhdnE1Yn9xajQ1MjM=");
+
+Notice that this is not secure, if you have a crucial value that must not be found you need to store it
+
+in the server. There is no alternative as everything that is sent to the client can be compromised by
+
+a determined hacker
+
+
+
+Use the comment to help you find the string in the code
+
+Our builtin user specific constants are obfuscated with this method, e.g. normally an app built with
+
+Codename One carries some internal data such as the user who built the app etc. This is obfuscated
+
+now. We built this small app to encode strings easily so we can copy and paste them into our app
+
+easily:
+
+Form hi = new Form("Encoder", BoxLayout.y());
+TextField bla = new TextField("", "Type Text Here", 20, TextArea.ANY);
+TextArea encoded = new TextArea();
+SpanLabel decoded = new SpanLabel();
+hi.addAll(bla, encoded, decoded);
+bla.addDataChangedListener((a, b) -> {
+    String s = bla.getText();
+    String e = Util.xorEncode(s);
+    encoded.setText(e);
+    decoded.setText(Util.xorDecode(e));
+    hi.getContentPane().animateLayout(100);
+});
+
+hi.show();
+
+720
+
+This allows you to type in the first text field and the second text area shows the encoded result. We
+
+used a text area so copy/paste would be easy.
+
+For  your  convenience  this  app  can  be  accessed  here:  https://www.codenameone.com/demos/
+
+StringEncoder/index.html
+
+22.2. Storage Encryption
+
+Codename One had support for bouncy castle encryption for quite a while but it’s not as intuitive as
+
+we’d like it to be. This makes securing/encrypting your app more painful than it should.
+
+Codename  One  supports  full  encryption  of  the  Storage  (notice  the  distinction,  Storage  is  not
+FileSystemStorage).  This  is  available  by  installing  the  bouncy  castle  cn1lib  from  the  extensions
+menu then using one line of code
+
+EncryptedStorage.install("your-pass-encryption-key");
+
+
+
+Normally you would want that code within your init(Object) method
+
+Notice  that  you  can’t  use  storage  or  preferences  to  store  this  data  as  it  would  be  encrypted
+(Preferences uses Storage internally). You can use a password for this key and it would make it way
+more secure but if a user changes his password you might have a problem. In that case you might
+
+need the old password to migrate to a new password.
+
+This  works  thru  a  new  mechanism  in  storage  where  you  can  replace  the  storage  instance  with
+
+another instance using:
+
+Storage.setStorageInstance(new MyCustomStorageSubclass());
+
+We  can  leverage  that  knowledge  to  change  the  encryption  password  on  the  encryption  storage
+
+using pseudo code like this:
+
+EncryptedStorage.install(oldKey);
+InputStream is = Storage.getInstance().createInputStream(storageFileName);
+byte[] data = Util.readInputStream(is);
+EncryptedStorage.install(newKey);
+OutputStream o = Storage.getInstance().createOutputStream("TestEncryption");
+o.write(data);
+o.close();
+
+ It’s  not  a  good  idea  to  replace  storage  objects  when  an  app  is  running  so  this  is
+
+purely for this special case…
+
+If you use preferences it might be a good idea to set their builtin location to a different path using
+something like Preferences.setPreferencesLocation("EncryptedPreferences");.
+
+721
+
+This is useful as it prevents the encrypted preferences from colliding with the regular preferences.
+
+22.3. Disabling Screenshots
+
+One of the common security features some apps expect is the ability to block a screenshot. In the
+
+past  apps  like  snapchat  required  that  you  touch  the  screen  to  view  a  photo  to  block  the  ability  to
+
+grab a screenshot (on iOS). This no longer works…
+
+Blocking  screenshots  is  an  Android  specific  feature  that  can’t  be  implemented  on  iOS.  This  is
+
+implemented  by  classifying  the  app  window  as  secure  and  you  can  do  that  via  the  build  hint
+android.disableScreenshots=true. Once that is added screenshots should no longer work for the app,
+this  might  impact  other  things  as  well  such  as  the  task  view  which  will  no  longer  show  the
+
+screenshot either.
+
+22.4. Blocking Copy & Paste
+
+Blocking copy & paste is useful for cases where a device might have spyware installed that monitors
+
+the clipboard. This also prevents a user from using a password manager (which usually rely on the
+
+clipboard), those managers could be compromised and thus if you are building a very secure app
+
+this might be necessary.
+
+You can block copy & paste on Android & iOS. Blocking of copy & paste can be implemented globally
+
+or on a specific field.
+
+To block copy & paste globally use:
+
+Display.getInstance().setProperty("blockCopyPaste", "true");
+
+To block copy & paste on a specific field do:
+
+textCmp.putClientProperty("blockCopyPaste", Boolean.TRUE);
+
+ Notice that the inverse of using false might not work as expected
+
+22.5. Blocking Jailbreak
+
+iOS & Android are walled gardens which is both a blessing and a curse. Looking at the bright side
+
+the walled garden aspect of locked down devices means the devices are more secure by nature. E.g.
+
+on a PC that was compromised we can detect the banking details of a user logging into a bank. But
+
+on a phone it would be much harder due to the deep process isolation.
+
+This  isn’t  true  for  jailbroken  or  rooted  devices.  In  these  devices  security  has  been  compromised
+
+often with good intentions (opening up the ecosystem) but it can also be used as a step in a serious
+
+attack on an application!
+
+For  obvious  reasons  it’s  really  hard  to  accurately  detect  a  jailbroken  or  rooted  device  but  when
+
+722
+
+possible if you have a high security app you might want to block the functionality or even raise a
+"silent alarm" in such a case. To detect this you can use the isJailbrokenDevice method as such:
+
+if(Display.getInstance().isJailbrokenDevice()) {
+    // probably jailbroken or rooted
+} else {
+   // probably not
+}
+
+Notice  that  this  isn’t  accurate,  we  can’t  be  100%  sure  as  there  are  no  official  ways  to  detect
+
+jailbreak. That is why it’s crucial to encrypt everything and assume the device was compromised to
+
+begin with when dealing with very sensitive data. Still it’s worthwhile to use these API’s to make the
+
+life of an attacker just a little bit harder.
+
+22.6. Strong Android Certificates
+
+When  Android  launched  RSA1024  with  SHA1  was  considered  strong  enough  for  the  foreseeable
+
+future, this hasn’t changed completely but the recommendation today is to use stronger cyphers for
+
+signing & encrypting as those can be compromised.
+
+APK’s are signed as part of the build process when we upload an app to the Google Play Store. This
+
+process  seems  redundant  as  we  generate  the  signature/certificate  ourselves  (unlike  Apple  which
+
+generates  it  for  us).  However,  this  is  a  crucial  step  as  it  allows  the  device  to  verify  upgrades  and
+
+make sure a new update is from the same original author!
+
+This  means  that  if  a  hacker  takes  over  your  account  on  Google  Play,  he  still  won’t  be  able  to  ship
+
+fake updates to your apps without your certificate. That’s important since if a hacker would have
+
+access  to  your  certificate  he  could  create  an  app  update  that  would  just  send  him  all  the  users
+
+private information e.g. if you are a bank this could be a disaster.
+
+Android launched with RSA1024/SHA1 as the signing certificates. This was good enough at the time
+
+and  is  still  pretty  secure.  However,  these  algorithms  are  slowly  eroding  and  it  is  conceivable  that
+
+within the 10-15 year lifetime of an app they might be compromised using powerful hardware. That
+
+is  why  Google  introduced  support  for  stronger  cryptographic  signing  into  newer  versions  of
+
+Android and you can use that.
+
+22.6.1. The Bad News
+
+There is a downside…
+
+Google  only  introduced  that  capability  in  Android  4.3  so  using  these  new  keys  will  break
+
+compatibility with older devices. If you are building a highly secure app this is probably a tradeoff
+
+you should accept. If not this might not be worth it for some theoretical benefit.
+
+Furthermore,  if  your  app  is  already  shipping  you  are  out  of  luck.  Due  to  the  obvious  security
+
+implications  once  you  shipped  an  app  the  certificate  is  final.  Google  doesn’t  provide  a  way  to
+
+update the certificate of a shipping app. Thus this feature only applies to apps that aren’t yet in the
+
+play store.
+
+723
+
+22.6.2. The Good
+
+If you are building a new app this is pretty easy to integrate and requires no changes on your part.
+
+Just  a  new  certificate.  You  can  generate  the  new  secure  key  using  instructions  in  articles  like  this
+
+one [https://guardianproject.info/2015/12/29/how-to-migrate-your-android-apps-signing-key/].
+
+If you are using Codename One Setting  you can check the box to generate an SHA512 key which will
+
+harden the security for the APK.
+
+22.7. Certificate Pinning
+
+When we connect to HTTPS servers our networking code checks the certificate on the server. If the
+
+certificate was issued by a trusted certificate authority then the connection goes thru otherwise it
+
+fails.  Let’s  imagine  a  case  where  I’m  sitting  in  a  coffee  shop  connected  to  the  local  wifi,  I  try  to
+
+connect to gmail to check my email. Since I use HTTPS to Google I trust my connection is secure.
+
+
+
+What if the coffee shop was hacked and the router is listening in on everything?
+
+So HTTPS is encrypted and the way encryption works is thru the certificate. The server sends me a
+
+certificate and we can use that to send encrypted data to it.
+
+
+
+What if the router grabs the servers certificate and communicates with Google in
+
+my name?
+
+This  won’t  work  since  the  data  we  send  to  the  server  is  encrypted  with  the  certificate  from  the
+
+server.
+
+
+
+So what if the router sends its own "fake certificate"?
+
+That  won’t  work  either.  All  certificates  are  signed  by  a  "certificate  authority"  indicating  that  a
+
+google.com certificate is valid.
+
+
+
+What  if  I  was  able  to  get  my  fake  certificate  authorized  by  a  real  certificate
+
+authority?
+
+That’s a problem!
+
+It’s obviously hard to do but if someone was able to do this he could execute a "man in the middle"
+
+attack as described above. People were able to fool certificate authorities in the past and gain fake
+
+certificates using various methods so this is possible and probably doable for any government level
+
+attacker.
+
+22.7.1. Certificate Pinning
+
+This  is  the  attack  certificate  pinning  (or  SSL  pinning)  aims  to  prevent.  We  code  into  our  app  the
+
+"fingerprint"  of  the  certificate  that  is  "good"  and  thus  prevent  the  app  from  working  when  the
+
+certificate is changed. This might break the app if we replace the certificate at some point but that
+
+might be reasonable in such a case.
+
+724
+
+To  do  this  we  have  a  cn1lib  [https://github.com/codenameone/SSLCertificateFingerprint/].  that  fetches  the
+
+certificate  fingerprint  from  the  server,  we  can  just  check  this  fingerprint  against  a  list  of
+"authorized" keys to decide whether it is valid. You can install the SSLCertificateFingerprint from
+the extensions section in Codename One Settings and use something like this to verify your server:
+
+if(CheckCert.isCertCheckingSupported()) {
+    String f = CheckCert.getFingerprint(myHttpsURL);
+    if(validKeysList.contains(f)) {
+        // OK it's a good certificate proceed
+    } else {
+       if(Dialog.show("Security Warning", "WARNING: it is possible your commmunications are being tampered! We suggest
+quitting the app at once!", "Quit", "Continue")) {
+          Display.getInstance().exitApplication();
+       }
+    }
+} else {
+    // certificate fingerprint checking isn't supported on this platform... It's your decision whether to proceed or not
+}
+
+Notice that once connection is established you don’t need to verify again for the current application
+
+run.
+
+725
+
+726
+
+23. Travis CI Integration
+
+This  page  includes  instructions  on  setting  up  continuous  integration  for  Codename  One
+
+applications using GitHub and Travis-CI.
+
+Travis  CI  is  a  hosted,  distributed  continuous  integration  service  used  to
+
+build and test software projects hosted at GitHub.
+
+Open  source  projects  may  be  tested  at  no  charge  via  travis-ci.org.  Private
+
+projects  may  be  tested  at  travis-ci.com  on  a  fee  basis.  TravisPro  provides
+
+custom  deployments  of  a  proprietary  version  on  the  customer’s  own
+
+hardware.
+
+Although the source is technically free software and available piecemeal on
+
+GitHub under permissive licenses, the company notes that it is unlikely that
+
+casual users could successfully integrate it on their own platforms.
+
+— Wikipedia
+
+Codename One provides single-click integration with Travis-CI via the Codename One Settings tool.
+
+Once integration is set up, Travis will automatically build your project and run unit tests following
+
+each commit of your project to GitHub.
+
+23.1. Quick Start
+
+Assuming  you  already  have  a  Codename  One  project,  you  only  need  to  do  three  things  to  enable
+
+Travis:
+
+1. Enable Travis in Codename One Settings
+
+2. Push the project to GitHub.
+
+3. Turn on your repository on travis-ci.org [https://travis-ci.org] if your repository is public or travis-
+
+ci.com [https://travis-ci.com] if your repository is private.
+
+
+
+Travis  CI  is  free  for  public  Github  repositories.  If  your  repository  is  private,  then
+
+you’ll need a travis-ci.com [https://travis-ci.com/] account. See their plans and pricing
+
+here [https://travis-ci.com/plans].
+
+23.1.1. Enabling Travis
+
+Open  Codename  One  settings  by  right  clicking  the  project,  and  selecting  "Codename  One"  >
+
+Codename One Settings"
+
+727
+
+Then click on the "Travis CI Integration" button
+
+If your project isn’t already configured for travis, you’ll see a form as follows:
+
+728
+
+Click the "Enable Travis CI" button.
+
+This  will  install  some  travis  scripts  from  the  cn1-travis-template  [https://github.com/shannah/cn1-travis-
+
+template] project. In particular, it will add the following files to your project:
+
+1. .travis.yml - A travis script that is set up to build your project and run its unit tests.
+
+2. .travis/ - A directory containing some utility shell scripts that are used the .travis.yml script.
+
+Activating/Deactivating Jobs
+
+The .travis.yml script that was installed in the previous step includes jobs for testing your app on
+many  different  platforms.  Currently  JavaSE  (the  Codename  One  simulator),  and  a  selection  of  iOS
+
+and Android versions are included, but we will be adding more platforms as time goes on. The goal
+
+is to provide jobs for every platform that Codename One supports.
+
+You can select the platforms you want Travis to test against by selecting or deselecting the platform,
+
+as shown below.
+
+729
+
+
+
+
+
+Only  the  JavaSE  job  is  available  for  non-enterprise  subscribers.  If  you  don’t  have
+
+an  enterprise  subscription,  the  Android  and  iOS  options  will  be  disabled  in  your
+
+settings. If you have an enterprise subscription, and your Android and iOS options
+
+are disabled, then you may not be logged in correctly. Check on the main menu of
+
+settings to ensure that you’re logged into the correct account.
+
+On-device  jobs  such  as  Android  and  iOS  require  that  you  have  the  CN1USER  and
+CN1PASS environment variables set in your Travis settings. These are used to build
+your project on the build server.
+
+23.1.2. Pushing to GitHub
+
+The process of setting up a Github repository is beyond the scope of this document. Please refer to
+
+github’s documentation [https://guides.github.com/activities/hello-world/] for details on this process.
+
+Add a .gitignore file to your project to prevent you from committing all of your .jar
+
+
+
+files  along  with  your  project.  Take  a  look  at  the  .gitignore  file  from  the  Kitchen
+
+Sink  demo  app  [https://github.com/codenameone/KitchenSink/blob/master/.gitignore]  for  a
+
+sample .gitignore file that is suitable for a typical Codename One project.
+
+730
+
+23.1.3. Activate Repository On Travis
+
+Now  that  your  project  is  in  a  Github  repository,  you  just  need  to  activate  the  repository  within
+
+Travis. For this part, you’ll need an account on travis-ci.org (for public repositories) or travis-ci.com
+
+(for private repositories).
+
+Steps to activate your repository in Travis.
+
+1. Go to travis-ci [https://travis-ci.org], and login.
+
+2. Click on your name in the upper right corner, to go to your profile page.
+
+3. Click the "Sync account" button in the upper right to load your Github repositories.
+
+4. Flip the switch next to the repository you want to activate in the list.
+
+23.1.4. Setting Environment Variables
+
+If you have any Android or iOS jobs activated in your travis script, you’ll need to set the CN1PASS and
+CN1USER  environment  variables  in  Travis.  Do  this  by  first  clicking  on  the  repository,  then  select
+
+731
+
+"More Options" in the upper right, and "Settings".
+
+The settings form will allow you to enter environment variables.
+
+23.1.5. Testing Travis Script
+
+To test the travis script, all you need to do is commit a change to your project in it, then push it to
+
+github.
+
+$ git add .
+$ git commit -m "Some changes"
+$ git push origin master
+
+Then go to https://travis-ci.org, and you should see your repository listed in the left menu. Click on it
+
+to follow your build status
+
+732
+
+23.1.6. Writing Unit Tests
+
+In order to make the most out of continuous integration, you’ll want to write unit tests for your app.
+
+See this video/post [https://www.codenameone.com/blog/test-it.html] for a light introduction to Codename
+
+One  unit  testing,  and  also  check  out  the  javadocs  for  the  com.codename1.testing  package
+
+[https://www.codenameone.com/javadoc/com/codename1/testing/package-summary.html].
+
+Disabling Travis
+
+If  you  want  to  disable  travis,  or  start  fresh  with  a  new  travis  script,  you  can  simply  delete  the
+.travis directory and .travis.yml file from your project. If you want to reactivate travis later, you
+can do so through the Codename One settings using the same procedure as described above. That
+
+will re-download the latest travis script from the online template [https://github.com/shannah/cn1-travis-
+
+733
+
+template].
+
+734
+
+24. Working with Codename One Sources
+
+24.1. Checking out the Sources
+
+$ mkdir workspace
+$ cd workspace
+$ git clone https://github.com/codenameone/CodenameOne
+
+Creating  a  clean  "workspace"  directory  is  optional,  and  there  is  nothing  special
+
+
+
+about  the  name  "workspace".  It  is  just  recommended  to  create  a  clean  directory
+
+into  which  you  check  out  Codename  One,  because  building  Codename  One  will
+
+check  out  a  few  dependent  projects  and  place  then  at  the  same  level  as  the
+
+CodenameOne folder, so having a clean workspace will make it easier to manage.
+
+24.2. Building Sources
+
+$ cd CodenameOne
+$ ant
+
+
+
+The cd CodenameOne command should take you to the root project directory which
+contains  subfolders  "CodenameOne",  "Ports",  etc..  -  not  the  subfolder  named
+
+"CodenameOne".
+
+24.3. Running Unit Tests
+
+You  can  run  the  unit  test  suite  locally  in  the  Codename  One  simulator  using  the  "test-javase"  ant
+
+target.
+
+$ ant test-javase
+
+24.4. Running iOS Unit Tests
+
+ Running iOS Unit tests is currently limited to interal use only by Codename One.
+
+TLDR: You can run Codename One’s unit tests on a local iOS simulator by running the "test-ios" ant
+
+target in the main CodenameOne directory. E.g.
+
+ant test-ios
+
+This assumes the following requirements
+
+735
+
+1. You are running Mac OS X with Xcode 7.3 or higher installed.
+
+2. You have npm installed and in your environment PATH.
+
+3. You have appium installed and running.
+
+24.4.1. Installing npm
+
+Either download the installer from https://nodejs.org/en/ OR run brew install node from terminal.
+
+24.4.2. Installing and Running Appium
+
+Open a new terminal window, then
+
+$ mkdir appium
+$ cd appium
+$ npm install appium
+$ ./node_modules/.bin/appium
+
+ You may want to run the last command ./node_modules/.bin/appium as a daemon so
+
+terminal  window.  E.g.
+
+to  use 
+
+same 
+
+the 
+
+that  you 
+continue 
+can 
+./node_modules/.bin/appium &
+
+24.4.3. Running the Unit tests
+
+$ cd CodenameOne
+$ ant test-ios
+
+24.4.4. Overriding the Codename One Build Server Target
+
+$ ant test-ios -Dcn1.iphone.target=iphone_new
+
+This will send to the "iphone_new" build server instead of the default "iphone" server.
+
+736
+
+
\ No newline at end of file