Hello, Android: Introducing Google's Mobile Development Platform (Pragmatic Programmers)

302 Pages·2010·4.74 MB·English

by  Ed Burnette

What Readers Are Saying About Hello, Android
Learn to develop Android apps with this complete yet gentle introduc-
tion to the Android platform. Out of all the books on Android, Hello,
Android has the best flow and coverage for developers new to this plat-
form. You’ll be writing Android apps in no time!
Marko Gargenta
CEO, , Marakana.com
The third edition of Hello,Android gets you on the fast track of
Android application development, from the basic concepts to pub-
lishing to the Android Market. Ed shows his vast experience on the
subject and even covers hard-to-find topics such as multi-touch and
OpenGL. This is a must-read for everyone starting on the fascinating
journey of Android development.
Diego Torres Milano
Android expert and blogger,
I thoroughly enjoyed the Hello,Android book, and it helped me get on
the right track to releasing my first two apps to the Market.
Nathan Rapp
Founder, , KMBurrito Designs
More than a greeting, Hello,Android welcomes both beginners and
pros to Android development.
Michael Martin PMP
Founder, , GoogleAndBlog and Mobile Martin
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Hello, Android
Introducing Google’s
Mobile Development Platform, 3rd Edition
Ed Burnette
The Pragmatic Bookshelf
Raleigh,NorthCarolina Dallas,Texas
From Library of Wow! eBook
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Contents
Acknowledgments 9
Preface 10
What Makes Android Special? . . . . . . . . . . . . . . . . . . 10
Who Should Read This Book? . . . . . . . . . . . . . . . . . . . 11
What’s in This Book? . . . . . . . . . . . . . . . . . . . . . . . . 12
What’s New in the Third Edition?. . . . . . . . . . . . . . . . . 12
Online Resources . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Fast-Forward >> . . . . . . . . . . . . . . . . . . . . . . . . . . 14
I Introducing Android 16
1 Quick Start 17
1.1 Installing the Tools . . . . . . . . . . . . . . . . . . . . . 17
1.2 Creating Your First Program . . . . . . . . . . . . . . . . 23
1.3 Running on the Emulator . . . . . . . . . . . . . . . . . 23
1.4 Running on a Real Phone . . . . . . . . . . . . . . . . . 28
1.5 Fast-Forward >>. . . . . . . . . . . . . . . . . . . . . . . 29
2 Key Concepts 30
2.1 The Big Picture . . . . . . . . . . . . . . . . . . . . . . . 30
2.2 It’s Alive! . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
2.3 Building Blocks . . . . . . . . . . . . . . . . . . . . . . . 39
2.4 Using Resources . . . . . . . . . . . . . . . . . . . . . . 40
2.5 Safe and Secure . . . . . . . . . . . . . . . . . . . . . . . 40
2.6 Fast-Forward >>. . . . . . . . . . . . . . . . . . . . . . . 41
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CONTENTS 6
II Android Basics 42
3 Designing the User Interface 43
3.1 Introducing the Sudoku Example. . . . . . . . . . . . . 43
3.2 Designing by Declaration . . . . . . . . . . . . . . . . . 44
3.3 Creating the Opening Screen . . . . . . . . . . . . . . . 45
3.4 Using Alternate Resources . . . . . . . . . . . . . . . . . 55
3.5 Implementing an About Box . . . . . . . . . . . . . . . . 57
3.6 Applying a Theme . . . . . . . . . . . . . . . . . . . . . . 61
3.7 Adding a Menu . . . . . . . . . . . . . . . . . . . . . . . 64
3.8 Adding Settings . . . . . . . . . . . . . . . . . . . . . . . 65
3.9 Starting a New Game . . . . . . . . . . . . . . . . . . . . 66
3.10 Debugging . . . . . . . . . . . . . . . . . . . . . . . . . . 69
3.11 Exiting the Game . . . . . . . . . . . . . . . . . . . . . . 71
3.12 Fast-Forward >>. . . . . . . . . . . . . . . . . . . . . . . 71
4 Exploring 2D Graphics 73
4.1 Learning the Basics. . . . . . . . . . . . . . . . . . . . . 73
4.2 Adding Graphics to Sudoku . . . . . . . . . . . . . . . . 78
4.3 Handling Input . . . . . . . . . . . . . . . . . . . . . . . 87
4.4 The Rest of the Story . . . . . . . . . . . . . . . . . . . . 93
4.5 Making More Improvements . . . . . . . . . . . . . . . . 103
4.6 Fast-Forward >>. . . . . . . . . . . . . . . . . . . . . . . 103
5 Multimedia 105
5.1 Playing Audio . . . . . . . . . . . . . . . . . . . . . . . . 105
5.2 Playing Video . . . . . . . . . . . . . . . . . . . . . . . . 112
5.3 Adding Sounds to Sudoku . . . . . . . . . . . . . . . . . 115
5.4 Fast-Forward >>. . . . . . . . . . . . . . . . . . . . . . . 119
6 Storing Local Data 120
6.1 Adding Options to Sudoku . . . . . . . . . . . . . . . . . 120
6.2 Continuing an Old Game . . . . . . . . . . . . . . . . . 122
6.3 Remembering the Current Position . . . . . . . . . . . . 124
6.4 Accessing the Internal File System . . . . . . . . . . . . 126
6.5 Accessing SD Cards . . . . . . . . . . . . . . . . . . . . 127
6.6 Fast-Forward >>. . . . . . . . . . . . . . . . . . . . . . . 128
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CONTENTS 7
III Beyond the Basics 129
7 The Connected World 130
7.1 Browsing by Intent . . . . . . . . . . . . . . . . . . . . . 131
7.2 Web with a View . . . . . . . . . . . . . . . . . . . . . . . 135
7.3 From JavaScript to Java and Back . . . . . . . . . . . . 140
7.4 Using Web Services . . . . . . . . . . . . . . . . . . . . . 147
7.5 Fast-Forward >>. . . . . . . . . . . . . . . . . . . . . . . 160
8 Locating and Sensing 161
8.1 Location, Location, Location . . . . . . . . . . . . . . . . 161
8.2 Set Sensors to Maximum . . . . . . . . . . . . . . . . . 168
8.3 Bird’s-Eye View . . . . . . . . . . . . . . . . . . . . . . . 172
8.4 Fast-Forward >>. . . . . . . . . . . . . . . . . . . . . . . 177
9 Putting SQL to Work 178
9.1 Introducing SQLite . . . . . . . . . . . . . . . . . . . . . 178
9.2 SQL 101 . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
9.3 Hello, Database . . . . . . . . . . . . . . . . . . . . . . . 181
9.4 Data Binding. . . . . . . . . . . . . . . . . . . . . . . . . 189
9.5 Using a ContentProvider . . . . . . . . . . . . . . . . . . 192
9.6 Implementing a ContentProvider . . . . . . . . . . . . . 195
9.7 Fast-Forward >>. . . . . . . . . . . . . . . . . . . . . . . 196
10 3D Graphics in OpenGL 198
10.1 Understanding 3D Graphics . . . . . . . . . . . . . . . . 198
10.2 Introducing OpenGL . . . . . . . . . . . . . . . . . . . . 199
10.3 Building an OpenGL Program . . . . . . . . . . . . . . . 200
10.4 Rendering the Scene . . . . . . . . . . . . . . . . . . . . 202
10.5 Building a Model . . . . . . . . . . . . . . . . . . . . . . 206
10.6 Lights, Camera, ... . . . . . . . . . . . . . . . . . . . . . 209
10.7 Action! . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
10.8 Applying Texture . . . . . . . . . . . . . . . . . . . . . . 212
10.9 Peekaboo . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
10.10 Measuring Smoothness . . . . . . . . . . . . . . . . . . 217
10.11 Fast-Forward >>. . . . . . . . . . . . . . . . . . . . . . . 218
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CONTENTS 8
IV The Next Generation 219
11 Multi-Touch 220
11.1 Introducing Multi-Touch . . . . . . . . . . . . . . . . . . 220
11.2 Building the Touch Example . . . . . . . . . . . . . . . 222
11.3 Understanding Touch Events . . . . . . . . . . . . . . . 225
11.4 Setting Up for Image Transformation . . . . . . . . . . 228
11.5 Implementing the Drag Gesture. . . . . . . . . . . . . . 229
11.6 Implementing the Pinch Zoom Gesture . . . . . . . . . 230
11.7 Fast-Forward >>. . . . . . . . . . . . . . . . . . . . . . . 232
12 There’s No Place Like Home 233
12.1 Hello, Widget . . . . . . . . . . . . . . . . . . . . . . . . . 233
12.2 Live Wallpaper . . . . . . . . . . . . . . . . . . . . . . . . 242
12.3 Fast-Forward >>. . . . . . . . . . . . . . . . . . . . . . . 254
13 Write Once, Test Everywhere 256
13.1 Gentlemen, Start Your Emulators . . . . . . . . . . . . 257
13.2 Building for Multiple Versions . . . . . . . . . . . . . . . 257
13.3 Evolving with Android APIs . . . . . . . . . . . . . . . . 259
13.4 Bug on Parade . . . . . . . . . . . . . . . . . . . . . . . . 265
13.5 All Screens Great and Small . . . . . . . . . . . . . . . . 267
13.6 Installing on the SD Card . . . . . . . . . . . . . . . . . 268
13.7 Fast-Forward >>. . . . . . . . . . . . . . . . . . . . . . . 270
14 Publishing to the Android Market 271
14.1 Preparing . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
14.2 Signing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
14.3 Publishing . . . . . . . . . . . . . . . . . . . . . . . . . . 273
14.4 Updating . . . . . . . . . . . . . . . . . . . . . . . . . . . 275
14.5 Closing Thoughts . . . . . . . . . . . . . . . . . . . . . . 276
V Appendixes 277
A Java vs. the Android Language and APIs 278
A.1 Language Subset . . . . . . . . . . . . . . . . . . . . . . 278
A.2 Standard Library Subset . . . . . . . . . . . . . . . . . . 280
A.3 Third-Party Libraries . . . . . . . . . . . . . . . . . . . . 281
B Bibliography 282
Index 283
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Acknowledgments
I’d like to thank the many people who made this book possible, includ-
ing the readers of the previous editions for all their great suggestions;
my editor, Susannah Pfalzer, for her attention to detail; Javier Collado,
Marilynn Huret, and Staffan Nöteberg for providing valuable review
comments; and especially Lisa, Michael, and Christopher for their con-
tinued patience and support.
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Preface
Android is an open source software toolkit for mobile phones that was
createdbyGoogleandtheOpenHandsetAlliance.It’sinsidemillionsof
cellphonesandothermobiledevices,makingAndroidamajorplatform
for application developers. Whether you’re a hobbyist or a professional
programmer, whether you are doing it for fun or for profit, it’s time to
learn more about developing for Android. This book will help you get
started.
What Makes Android Special?
There are already many mobile platforms on the market today, includ-
ing Symbian, iPhone, Windows Mobile, BlackBerry, Java Mobile Edi-
tion, Linux Mobile (LiMo), and more. When I tell people about Android,
their first question is often, Why do we need another mobile standard?
Where’s the “wow”?
Althoughsomeofitsfeatureshaveappearedbefore,Androidisthefirst
environment that combines the following:
• A truly open, free development platform based on Linux and open
source: Handset makers like it because they can use and cus-
tomize the platform without paying a royalty. Developers like it
because they know that the platform “has legs” and is not locked
into any one vendor that may go under or be acquired.
• A component-based architecture inspired by Internet mashups:
Parts of one application can be used in another in ways not orig-
inally envisioned by the developer. You can even replace built-in
componentswithyourownimprovedversions.Thiswillunleasha
new round of creativity in the mobile space.
• Tonsofbuilt-inservicesoutofthebox:Location-basedservicesuse
GPSorcelltowertriangulationtoletyoucustomizetheuserexpe-
rience depending on where you are. A full-powered SQL database
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