Learning Android

268 Pages·2011·9.46 MB·English

by  Marko Gargenta

Learning Android
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Learning Android
Marko Gargenta
Beijing • Cambridge • Farnham • Köln • Sebastopol • Tokyo
Learning Android
by Marko Gargenta
Copyright © 2011 Marko Gargenta. All rights reserved.
Printed in the United States of America.
Published by O’Reilly Media, Inc., 1005 Gravenstein Highway North, Sebastopol, CA 95472.
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Editors: Andy Oram and Brian Jepson Indexer: Jay Marchand
Production Editor: Holly Bauer Cover Designer: Karen Montgomery
Copyeditor: Genevieve d’Entremont Interior Designer: David Futato
Proofreader: Jennifer Knight Illustrator: Robert Romano
Printing History:
March 2011: First Edition.
Nutshell Handbook, the Nutshell Handbook logo, and the O’Reilly logo are registered trademarks of
O’Reilly Media, Inc. Learning Android, the image of a Little Owl, and related trade dress are trademarks
of O’Reilly Media, Inc.
Many of the designations used by manufacturers and sellers to distinguish their products are claimed as
trademarks. Where those designations appear in this book, and O’Reilly Media, Inc., was aware of a
trademark claim, the designations have been printed in caps or initial caps.
While every precaution has been taken in the preparation of this book, the publisher and author assume
no responsibility for errors or omissions, or for damages resulting from the use of the information con-
tained herein.
ISBN: 978-1-449-39050-1
[LSI]
1299702297
Table of Contents
Preface .................................................................... xiii
1. Android Overview ....................................................... 1
Android Overview 1
Comprehensive 1
Open Source Platform 2
Designed for Mobile Devices 2
History 3
Google’s Motivation 3
Open Handset Alliance 4
Android Versions 4
Summary 5
2. The Stack .............................................................. 7
Stack Overview 7
Linux 7
Portability 7
Security 8
Features 8
Native Libraries 9
Dalvik 9
Android and Java 10
Application Framework 11
Applications 12
The APK 12
Application Signing 12
Application Distribution 12
Summary 13
3. Quick Start ............................................................ 15
Installing the Android SDK 15
v
Setting Up a PATH to Tools 16
Installing Eclipse 16
Eclipse Workspace 17
Setting Up Android Development Tools 17
Hello, World 18
Creating a New Project 18
Manifest File 20
Layout XML Code 21
Strings 21
The R File 22
Java Source Code 22
The Emulator 23
An Emulator Versus a Physical Phone 25
Summary 25
4. Main Building Blocks ................................................... 27
What Are Main Building Blocks? 27
A Real-World Example 27
Activities 28
Activity Life Cycle 28
Intents 31
Services 31
Content Providers 32
Broadcast Receivers 34
Application Context 34
Summary 35
5. Yamba Project Overview ................................................ 37
The Yamba Application 37
Design Philosophy 39
Project Design 39
Part 1: Android User Interface 39
Building an Activity 40
Networking and Multithreading 41
Debugging Android Apps 41
Part 2: Preferences, Filesystem, Options Menu, and Intents 41
The Activity 41
Menu System and Intents 42
Filesystem 42
Part 3: Android Services 42
Services 42
Application Object 42
Part 4: Working with Databases 42
vi | Table of Contents
SQLite and Android’s Support for It 42
Refactoring the Code Again 43
Part 5: Lists and Adapters 43
Timeline Activity 43
More Refactoring? 43
Part 6: Broadcast Receivers 43
Boot and Network Receivers 44
Timeline Receiver 44
Permissions 44
Part 7: Content Providers 44
Status Data 44
Android Widgets 44
Part 8: System Services 45
Compass and Location 45
> Intent Service, Alarms, and Notifications 45
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o Summary 45
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Important Widget Properties 54
Strings Resource 55
The StatusActivity Java Class 56
Creating Your Application-Specific Object and Initialization Code 56
Compiling Code and Building Your Projects: Saving Files 59
Adding the jtwitter.jar Library 59
Updating the Manifest File for Internet Permission 61
Logging in Android 62
LogCat 62
Threading in Android 65
Single Thread 65
Multithreaded Execution 66
AsyncTask 67
Table of Contents | vii
Other UI Events 70
Adding Color and Graphics 74
Adding Images 74
Adding Color 76
Alternative Resources 79
Optimizing the User Interface 80
Hierarchy Viewer 81
Summary 82
7. Preferences, the Filesystem, the Options Menu, and Intents .................. 83
Preferences 83
Prefs Resource 84
PrefsActivity 87
Update the Manifest File 88
The Options Menu 89
The Menu Resource 89
Android System Resources 90
Update StatusActivity to Load the Menu 91
Update StatusActivity to Handle Menu Events 92
Strings Resource 92
Shared Preferences 93
The Filesystem Explained 95
Exploring the Filesystem 95
Filesystem Partitions 96
System Partition 96
SDCard Partition 96
The User Data Partition 97
Filesystem Security 98
Summary 99
8. Services ............................................................. 101
The Yamba Application Object 102
The YambaApplication Class 102
Update the Manifest File 104
Simplifying StatusActivity 105
UpdaterService 105
Creating the UpdaterService Java Class 106
Update the Manifest File 107
Add Menu Items 108
Update the Options Menu Handling 109
Testing the Service 109
Looping in the Service 110
Testing the Service 113
viii | Table of Contents