Programming Android

523 Pages·2012·8.22 MB·English

by  Zigurd Mednieks

SECOND EDITION
Programming Android
Zigurd Mednieks, Laird Dornin, G. Blake Meike, and Ma-
sumi Nakamura
Beijing • Cambridge • Farnham • Köln • Sebastopol • Tokyo
Programming Android, Second Edition
by Zigurd Mednieks, Laird Dornin, G. Blake Meike, and Masumi Nakamura
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2012-03-09 Early release revision 1
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ISBN: 978-1-449-31664-8
[LSI]
1331160433
Table of Contents
Preface .................................................................... xiii
Part I. Tools and Basics
1. Installing the Android SDK and Prerequisites ................................ 3
Installing the Android SDK and Prerequisites 3
The Java Development Kit (JDK) 4
The Eclipse Integrated Development Environment (IDE) 5
The Android SDK 7
Adding Build Targets to the SDK 8
The Android Development Toolkit (ADT) Plug-in for Eclipse 9
Test Drive: Confirm That Your Installation Works 13
Making an Android Project 13
Making an Android Virtual Device (AVD) 16
Running a Program on an AVD 19
Running a Program on an Android Device 20
Troubleshooting SDK Problems: No Build Targets 21
Components of the SDK 21
The Android Debug Bridge (adb) 21
The Dalvik Debug Monitor Server (DDMS) 21
Components of the ADT Eclipse Plug-in 23
Android Virtual Devices 25
Other SDK Tools 26
Keeping Up-to-Date 28
Keeping the Android SDK Up-to-Date 28
Keeping Eclipse and the ADT Plug-in Up-to-Date 29
Keeping the JDK Up-to-Date 29
Example Code 30
SDK Example Code 30
Example Code from This Book 30
On Reading Code 32
iii
2. Java for Android ....................................................... 33
Android Is Reshaping Client-Side Java 33
The Java Type System 34
Primitive Types 34
Objects and Classes 35
Object Creation 35
The Object Class and Its Methods 37
Objects, Inheritance, and Polymorphism 39
Final and Static Declarations 41
Abstract Classes 45
Interfaces 46
Exceptions 48
The Java Collections Framework 52
Garbage Collection 55
Scope 56
Java Packages 56
Access Modifiers and Encapsulation 57
Idioms of Java Programming 59
Type Safety in Java 59
Using Anonymous Classes 62
Modular Programming in Java 65
Basic Multithreaded Concurrent Programming in Java 68
Synchronization and Thread Safety 68
Thread Control with wait() and notify() Methods 71
Synchronization and Data Structures 73
3. The Ingredients of an Android Application ................................. 75
Traditional Programming Models Compared to Android 75
Activities, Intents, and Tasks 77
Other Android Components 79
Service 79
Content Providers 79
BroadcastReceiver 83
Component Life Cycles 83
The Activity Life Cycle 83
On Porting Software to Android 85
Static Application Resources and Context 86
Organizing Java Source 87
Resources 88
Application Manifests 90
Initialization Parameters in AndroidManifest.xml 91
Packaging an Android Application: The .apk File 94
The Android Application Runtime Environment 94
iv | Table of Contents
The Dalvik VM 95
Zygote: Forking a New Process 95
Sandboxing: Processes and Users 95
The Android Libraries 96
Extending Android 98
The Android Application Template 98
Overrides and callbacks 98
Polymorphism and composition 101
Extending Android classes 102
Concurrency in Android 104
AsyncTask and the UI Thread 105
Threads in an Android Process 117
Serialization 118
Java Serialization 119
Parcelable 121
Classes That Support Serialization 124
Serialization and the Application Life Cycle 125
4. Getting Your Application into Users’ Hands ................................ 127
Application Signing 127
Public Key Encryption and Cryptographic Signing 127
How Signatures Protect Software Users, Publishers, and
Secure Communications 129
Signing an Application 130
Placing an Application for Distribution in the Android Market 137
Becoming an Official Android Developer 138
Uploading Applications in the Market 138
Getting Paid 139
Google Maps API Keys 140
Specifying API-Level Compatibility 141
Compatibility with Many Kinds of Screens 141
Testing for Screen Size Compatibility 142
Resource Qualifiers and Screen Sizes 142
5. Eclipse for Android Software Development ................................ 143
Eclipse Concepts and Terminology 144
Plug-ins 144
Workspaces 145
Java Environments 146
Projects 147
Builders and Artifacts 147
Extensions 147
Associations 149
Table of Contents | v
Eclipse Views and Perspectives 149
The Package Explorer View 150
The Task List View 150
The Outline View 151
The Problems View 152
Java Coding in Eclipse 152
Editing Java Code and Code Completion 152
Refactoring 153
Eclipse and Android 154
Preventing Bugs and Keeping Your Code Clean 154
Static Analyzers 155
Applying Static Analysis to Android Code 159
Limitations of Static Analysis 162
Eclipse Idiosyncrasies and Alternatives 162
Part II. About the Android Framework
6. Building a View ....................................................... 167
Android GUI Architecture 167
The Model 167
The View 168
The Controller 169
Putting It Together 169
Assembling a Graphical Interface 171
Wiring Up the Controller 176
Listening to the Model 178
Listening for Touch Events 183
Multiple Pointers and Gestures 187
Listening for Key Events 189
Choosing an Event Handler 189
Advanced Wiring: Focus and Threading 191
The Menu and the Action Bar 195
View Debugging and Optimization 199
7. Fragments and Multiplatform Support ................................... 203
Creating a Fragment 204
Fragment Life Cycle 207
The Fragment Manager 208
Fragment Transactions 209
The Support Package 214
Fragments and Layout 215
vi | Table of Contents
8. Drawing 2D and 3D Graphics ............................................ 223
Rolling Your Own Widgets 223
Layout 224
Canvas Drawing 229
Drawables 240
Bitmaps 245
Bling 246
Shadows, Gradients, Filters and Hardware Acceleration 249
Animation 251
OpenGL Graphics 256
9. Handling and Persisting Data ........................................... 261
Relational Database Overview 261
SQLite 262
The SQL Language 262
SQL Data Definition Commands 263
SQL Data Manipulation Commands 266
Additional Database Concepts 268
Database Transactions 269
Example Database Manipulation Using sqlite3 269
SQL and the Database-Centric Data Model for Android Applications 273
The Android Database Classes 274
Database Design for Android Applications 275
Basic Structure of the SimpleVideoDbHelper Class 275
Using the Database API: MJAndroid 278
Android and Social Networking 278
The Source Folder (src) 280
Loading and Starting the Application 281
Database Queries and Reading Data from the Database 281
Modifying the Database 285
Part III. A Skeleton Application for Android
10. A Framework for a Well-Behaved Application .............................. 293
Visualizing Life Cycles 294
Visualizing the Activity Life Cycle 294
Visualizing the Fragment Life Cycle 306
The Activity Class and Well-Behaved Applications 309
The Activity Life Cycle and the User Experience 310
Life Cycle Methods of the Application Class 310
Table of Contents | vii
11. Building a User Interface ............................................... 315
Top-level design 315
Fragment, Activity, and scalable design 315
Action Bar 315
Tabs and swipe navigation 315
Visual editing of user interfaces 316
Starting With a Blank Slate 316
Picking a Simple Strategy 316
Create "Stub" Fragment Subclasses 316
Laying-out the Fragments 316
Lay-out Fragments Using the Visual Editor 316
Create Layouts Within Fragments 317
Folding and Unfolding a Scalable UI 317
Implementing and Scaling an Action Bar 317
Refactoring a User Interface Specification 317
Creating and Editing Assets 317
A Flowing and Intuitive User Experience Across Activities 317
Multitasking in a Small-Screen Environment 317
Tasks and Applications 318
Specifying Launch and Task Behavior 318
Creating a user interface for our example 322
Declarative and Programmatic UI creation 322
12. Using Content Providers ............................................... 325
Understanding Content Providers 326
Implementing a Content Provider 327
Browsing Video with Finch 328
Defining a Provider Public API 329
Defining the CONTENT_URI 330
Creating the Column Names 332
Declaring Column Specification Strings 332
Writing and Integrating a Content Provider 334
Common Content Provider Tasks 334
File Management and Binary Data 336
Android MVC and Content Observation 338
A Complete Content Provider: The SimpleFinchVideoContentProvider
Code 339
The SimpleFinchVideoContentProvider Class and Instance Variables 339
Implementing the onCreate Method 341
Implementing the getType Method 342
Implementing the Provider API 342
Determining How Often to Notify Observers 347
Declaring Your Content Provider 347
viii | Table of Contents
13. A Content Provider As a Facade for a RESTful Web Service .................... 349
Developing RESTful Android Applications 350
A “Network MVC” 351
Summary of Benefits 353
Code Example: Dynamically Listing and Caching YouTube
Video Content 354
Structure of the Source Code for the Finch YouTube Video Example 355
Stepping Through the Search Application 356
Step 1: Our UI Collects User Input 357
Step 2: Our Controller Listens for Events 357
Step 3: The Controller Queries the Content Provider with a managedQuery
on the Content Provider/Model 358
Step 4: Implementing the RESTful Request 358
Constants and Initialization 358
Creating the Database 359
A Networked Query Method 359
insert and ResponseHandlers 372
File Management: Storing Thumbnails 373
14. Remote Procedure Calls - Building Android APIs ............................ 377
Part IV. Advanced Topics
15. Search .............................................................. 381
Search Interface 381
Search Basics 381
Search Dialog 387
Search Widget 388
Query Suggestions 389
Recent Query Suggestions 390
Custom Query Suggestions 391
16. Location and Mapping ................................................. 397
Location-Based Services 398
Mapping 399
The Google Maps Activity 399
The MapView and MapActivity 400
Working with MapViews 401
MapView and MyLocationOverlay Initialization 401
Pausing and Resuming a MapActivity 404
Controlling the Map with Menu Buttons 405
Controlling the Map with the Keypad 407
Table of Contents | ix