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PROFESSIONAL

ANDROID™ 2 APPLICATION DEVELOPMENT

INTRODUCTION xxvii

CHAPTER 1 Hello, Android 1

CHAPTER 2 Getting Started 17

CHAPTER 3 Creating Applications and Activities 49

CHAPTER 4 Creating User Interfaces 85

CHAPTER 5 Intents, Broadcast Receivers, Adapters, and the Internet 137

CHAPTER 6 Files, Saving State, and Preferences 187

CHAPTER 7 Databases and Content Providers 209

CHAPTER 8 Maps, Geocoding, and Location-Based Services 245

CHAPTER 9 Working in the Background 285

CHAPTER 10 Invading the Phone-Top 327

CHAPTER 11 Audio, Video, and Using the Camera 363

CHAPTER 12 Telephony and SMS 389

CHAPTER 13 Bluetooth, Networks, and Wi-Fi 425

CHAPTER 14 Sensors 457

CHAPTER 15 Advanced Android Development 477

INDEX 529

PROFESSIONAL

Android™ 2 Application Development

Reto Meier

WILEY

Wiley Publishing, Inc.

Professional Android™ 2 Application Development

Published by Wiley Publishing, Inc. 10475 Crosspoint Boulevard Indianapolis, IN 46256 www.wiley.com

Copyright © 2010 by Wiley Publishing, Inc., Indianapolis, Indiana

ISBN: 978-0-470-56552-0

Manufactured in the United States of America

10987654321

No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 646-8600. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) 748-6011, fax (201) 748-6008, or online at http://www.wiley.com/go/permissions.

Limit of Liability/Disclaimer of Warranty: The publisher and the author make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation warranties of fitness for a particular purpose. No warranty may be created or extended by sales or promotional materials. The advice and strategies contained herein may not be suitable for every situation. This work is sold with the understanding that the publisher is not engaged in rendering legal, accounting, or other professional services. If professional assistance is required, the services of a competent professional person should be sought. Neither the publisher nor the author shall be liable for damages arising herefrom. The fact that an organization or Web site is referred to in this work as a citation and/or a potential source of further information does not mean that the author or the publisher endorses the information the organization or Web site may provide or recommendations it may make. Further, readers should be aware that Internet Web sites listed in this work may have changed or disappeared between when this work was written and when it is read.

For general information on our other products and services please contact our Customer Care Department within the United States at (877) 762-2974, outside the United States at (317) 572-3993 or fax (317) 572-4002.

Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books.

Library of Congress Control Number: 2009943638

Trademarks: Wiley, the Wiley logo, Wrox, the Wrox logo, Wrox Programmer to Programmer, and related trade dress are trademarks or registered trademarks of John Wiley & Sons, Inc. and/or its affiliates, in the United States and other countries, and may not be used without written permission. Android is a trademark of Google, Inc. All other trademarks are the property of their respective owners. Wiley Publishing, Inc. is not associated with any product or vendor mentioned in this book.

To Kristy

ABOUT THE AUTHOR

RETO MEIER is originally from Perth, Western Australia, but now lives in London.

He currently works as an Android Developer Advocate at Google, helping Android app developers create the best applications possible. Reto is an experienced software developer with more than 10 years of experience in GUI application development. Before Google, he worked in various industries, including offshore oil and gas and finance.

Always interested in emerging technologies, Reto has been involved in Android since the initial release in 2007. In his spare time, he tinkers with a wide range of development platforms, including Google's plethora of developer tools.

You can check out Reto's web site, The Radioactive Yak, ahttp://blog.radioactiveyak.comor follow him on twitter at http://www.twitter.com/retomeier.

ABOUT THE TECHNICAL EDITOR

MILAN NARENDRASHAH graduated with a BSc Computer Science degree from the University of Southampton. He has been working as a software engineer for more than seven years, with experiences in C#, C/C++, and Java. He is married and lives in Buckinghamshire, United Kingdom.

CREDITS

ACQUISITIONS EDITOR

Scott Meyers

PROJECT EDITOR

William Bridges

TECHNICAL EDITOR

Milan Narendra Shah

PRODUCTION EDITOR

Rebecca Anderson

COPY EDITOR Sadie Kleinman

EDITORIAL DIRECTOR

Robyn B. Siesky

EDITORIAL MANAGER

Mary Beth Wakefield

ASSOCIATE DIRECTOR OF MARKETING

David Mayhew

PRODUCTION MANAGER

Tim Tate

VICE PRESIDENT AND EXECUTIVE GROUP PUBLISHER

Richard Swadley

VICE PRESIDENT AND EXECUTIVE PUBLISHER

Barry Pruett

ASSOCIATE PUBLISHER

Jim Minatel

PROJECT COORDINATOR, COVER

Lynsey Stanford

PROOFREADER

Kyle Schlesinger, Word One INDEXER

Robert Swanson

COVER IMAGE

© Linda Bucklin/istockphoto

COVER DESIGNER

Michael E. Trent

ACKNOWLEDGMENTS

Most importantly I'd like to thank Kristy. Your support makes everything I do possible, and your generous help ensured that this book was the best it could be. Without you it would never have happened.

A big thank-you goes to Google and the Android team, particularly the Android engineers and my colleagues in developer relations. The pace at which Android has grown and developed in the past year is nothing short of phenomenal.

I also thank Scott Meyers for giving me the chance to bring this book up to date; and Bill Bridges, Milan Shah, Sadie Kleinman, and the Wrox team for helping get it done.

Special thanks go out to the Android developer community. Your hard work and exciting applications have helped make Android a great success.

CONTENTS

INTRODUCTION xxvii

CHAPTER 1: HELLO, ANDROID 1

A Little Background 2

The Not-So-Distant Past 2

The Future 3

What It Isn't 3

Android: An Open Platform for Mobile Development 4

Native Android Applications 5

Android SDK Features 6

Access to Hardware, Including Camera, GPS, and Accelerometer 6

Native Google Maps, Geocoding, and Location-Based Services 7

Background Services 7

SQLite Database for Data Storage and Retrieval 7

Shared Data and Interapplication Communication 7 Using Widgets, Live Folders, and Live Wallpaper to Enhance the

Home Screen 8

Extensive Media Support and 2D/3D Graphics 8

Optimized Memory and Process Management 8

Introducing the Open Handset Alliance 9

What Does Android Run On? 9

Why Develop for Mobile? 9

Why Develop for Android? 10

What Has and Will Continue to Drive Android Adoption? 10

What Does It Have That Others Don't? 11

Changing the Mobile Development Landscape 11

Introducing the Development Framework 12

What Comes in the Box 12

Understanding the Android Software Stack 13

The Dalvik Virtual Machine 14

Android Application Architecture 15

Android Libraries 16

Summary 16

CHAPTER 2: GETTING STARTED 17

Developing for Android 18

What You Need to Begin 18

Downloading and Installing the SDK 18

Developing with Eclipse 19

Using the Eclipse Plug-In 20

Creating Your First Android Application 23

Starting a New Android Project 23

Creating a Launch Configuration 24

Running and Debugging Your Android Applications 26

Understanding Hello World 26

Types of Android Applications 29

Foreground Applications 29

Background Services and Intent Receivers 29

Intermittent Applications 30

Widgets 30

Developing for Mobile Devices 30

Hardware-Imposed Design Considerations 30

Be Efficient 31

Expect Limited Capacity 31

Design for Small Screens 32

Expect Low Speeds, High Latency 32

At What Cost? 33

Considering the Users' Environment 34

Developing for Android 35

Being Fast and Efficient 35

Being Responsive 36

Developing Secure Applications 37

Ensuring a Seamless User Experience 37

To-Do List Example 38

Android Development Tools 43

The Android Virtual Device and SDK Manager 44

Android Virtual Devices 44

SDK Manager 45

The Android Emulator 46

Dalvik Debug Monitor Service (DDMS) 47

The Android Debug Bridge (ADB) 47

Summary 48

CHAPTER 3: CREATING APPLICATIONS AND ACTIVITIES 49

What Makes an Android Application? 50

Introducing the Application Manifest 51

Using the Manifest Editor 56

The Android Application Life Cycle 57

Understanding Application Priority and Process States 58

Externalizing Resources 59

Creating Resources 60

Creating Simple Values 60

Styles and Themes 62

Drawables 63

Layouts 63

Animations 64

Menus 66

Using Resources 67

Using Resources in Code 67

Referencing Resources within Resources 68

Using System Resources 69

Referring to Styles in the Current Theme 70

To-Do List Resources Example 70

Creating Resources for Different Languages and Hardware 71

Runtime Configuration Changes 72

Introducing the Android Application Class 74

Extending and Using the Application Class 74

Overriding the Application Life Cycle Events 75

A Closer Look at Android Activities 76

Creating an Activity 77

The Activity Life Cycle 78

Activity Stacks 78

Activity States 79

Monitoring State Changes 80

Understanding Activity Lifetimes 82

Android Activity Classes 84

Summary 84

CHAPTER 4: CREATING USER INTERFACES 85

Fundamental Android UI Design 86

Introducing Views 86

Creating Activity User Interfaces with Views 87

The Android Widget Toolbox 88

Introducing Layouts 89

Using Layouts 89

Optimizing Layouts 91

Creating New Views 91

Modifying Existing Views 92

Customizing Your To-Do List 93

Creating Compound Controls 96

Creating Custom Views 99

Creating a New Visual Interface 99

Handling User Interaction Events 104

Creating a Compass View Example 105

Using Custom Controls 110

Drawable Resources 111

Shapes, Colors, and Gradients 111

Color Drawable 111

Shape Drawable 111

Gradient Drawable 113

Composite Drawables 114

Transformative Drawables 114

Layer Drawable 116

State List Drawables 116

Level List Drawables 116

NinePatch Drawable 117

Resolution and Density Independence 117

The Resource Framework and Resolution Independence 118

Resource Qualifiers for Screen Size and Pixel Density 118

Specifying Supported Screen Sizes 119

Best Practices for Resolution Independence 119

Relative Layouts and Density-Independent Pixels 120

Using Scalable Graphics Assets 120

Provide Optimized Resources for Different Screens 121

Testing, Testing, Testing 121

Emulator Skins 122

Testing for Custom Resolutions and Screen Sizes 122

Creating and Using Menus 123

Introducing the Android Menu System 123

Defining an Activity Menu 124

Menu Item Options 126

Dynamically Updating Menu Items 127

Handling Menu Selections 127

Submenus and Context Menus 128

Creating Submenus 128

Using Context Menus 128

Defining Menus in XML 130

To-Do List Example Continued 131

Summary 136

CHAPTER 5: INTENTS, BROADCAST RECEIVERS, ADAPTERS,

AND THE INTERNET 137

Introducing Intents 138

Using Intents to Launch Activities 138

Explicitly Starting New Activities 139

Implicit Intents and Late Runtime Binding 139

Returning Results from Activities 140

Native Android Actions 143

Using Intent Filters to Service Implicit Intents 144

How Android Resolves Intent Filters 146

Finding and Using the Launch Intent Within an Activity 147

Passing on Responsibility 147

Select a Contact Example 148

Using Intent Filters for Plug-Ins and Extensibility 152

Supplying Anonymous Actions to Applications 153

Incorporating Anonymous Actions in Your Activity's Menu 154

Introducing Linkify 155

The Native Linkify Link Types 155

Creating Custom Link Strings 156

Using the Match Filter 157

Using the Transform Filter 157

Using Intents to Broadcast Events 157

Broadcasting Events with Intents 158

Listening for Broadcasts with Broadcast Receivers 158

Broadcasting Sticky and Ordered Intents 161

Native Android Broadcast Actions 161

Introducing Pending Intents 162

Introducing Adapters 163

Introducing Some Native Adapters 163

Customizing the Array Adapter 163

Using Adapters for Data Binding 164

Customizing the To-Do List Array Adapter 165

Using the Simple Cursor Adapter 169

Using Internet Resources 170

Connecting to an Internet Resource 170

Using Internet Resources 171

Introducing Dialogs 172

Introducing the Dialog Classes 172

The Alert Dialog Class 173

Specialist Input Dialogs 174

Using Activities as Dialogs 174

Managing and Displaying Dialogs 175

Creating an Earthquake Viewer 176

Summary 184

CHAPTER 6: FILES, SAVING STATE, AND PREFERENCES 187

Saving Simple Application Data 188

Creating and Saving Preferences 188

Retrieving Shared Preferences 189

Creating a Settings Activity for the Earthquake Viewer 189

Introducing the Preference Activity and Preferences Framework 197

Defining a Preference Screen Layout in XML 198

Native Preference Controls 199

Using Intents to Import System Preference Screens 200

Introducing the Preference Activity 200

Finding and Using Preference Screen Shared Preferences 201

Introducing Shared Preference Change Listeners 201 Creating a Standard Preference Activity for the Earthquake Viewer 202

Saving Activity State 203

Saving and Restoring Instance State 203

Saving the To-Do List Activity State 205

Saving and Loading Files 207

Including Static Files as Resources 207

File Management Tools 208

Summary 208

CHAPTER 7: DATABASES AND CONTENT PROVIDERS 209

Introducing Android Databases 209

Introducing SQLite Databases 210

Introducing Content Providers 210

Introducing SQLite 210

Cursors and Content Values 211

Working with SQLite Databases 211

Introducing the SQLiteOpenHelper 214

Opening and Creating Databases without SQLiteHelper 215

Android Database Design Considerations 215

Querying a Database 215

Extracting Results from a Cursor 216

Adding, Updating, and Removing Rows 217

Inserting New Rows 217

Updating a Row 218

Deleting Rows 218

Saving Your To-Do List 218

Creating a New Content Provider 224

Exposing Access to the Data Source 225

Registering Your Provider 227

Using Content Providers 227

Introducing Content Resolvers 227

Querying for Content 228

Adding, Updating, and Deleting Content 228

Inserts 228

Deletes 229

Updates 229

Accessing Files in Content Providers 230

Creating and Using an Earthquake Content Provider 230

Creating the Content Provider 230

Using the Provider 236

Native Android Content Providers 238

Using the Media Store Provider 239

Using the Contacts Provider 240

Introducing the Contacts Contract Content Provider 240

Reading Contact Details 240

Modifying and Augmenting Contact Details 243

Summary 244

CHAPTER 8: MAPS, GEOCODING, AND LOCATION-BASED SERVICES 245

Using Location-Based Services 246

Configuring the Emulator to Test Location-Based Services 246

Updating Locations in Emulator Location Providers 246

Selecting a Location Provider 247

Finding the Available Providers 248

Finding Location Providers Using Criteria 248

Finding Your Location 249

'Where Am I?' Example 250

Tracking Movement 252

Updating Your Location in 'Where Am I?' 253

Using Proximity Alerts 255

Using the Geocoder 256

Reverse Geocoding 257

Forward Geocoding 258

Geocoding 'Where Am I?' 259

Creating Map-Based Activities 260

Introducing Map View and Map Activity 260

Getting Your Maps API Key 261

Getting Your Development/Debugging MD5 Fingerprint 261

Getting your Production/Release MD5 Fingerprint 262

Creating a Map-Based Activity 262

Configuring and Using Map Views 263

Using the Map Controller 264

Mapping 'Where Am I?' 265

Creating and Using Overlays 268

Creating New Overlays 268

Introducing Projections 269

Drawing on the Overlay Canvas 269

Handling Map Tap Events 270

Adding and Removing Overlays 271

Annotating 'Where Am I?' 271

Introducing My Location Overlay 275

Introducing Itemized Overlays and Overlay Items 275

Pinning Views to the Map and Map Positions 278

Mapping Earthquakes Example 279

Summary 284

CHAPTER 9: WORKING IN THE BACKGROUND 285

Introducing Services 286

Creating and Controlling Services 287

Creating a Service 287

Registering a Service in the Manifest 289

Self-Terminating a Service 289

Starting, Controlling, and Interacting with a Service 290

An Earthquake Monitoring Service Example 290

Binding Activities to Services 297

Prioritizing Background Services 299

Using Background Threads 300

Using AsyncTask to Run Asynchronous Tasks 301

Creating a New Asynchronous Task 301

Running an Asynchronous Task 302 Moving the Earthquake Service to a Background Thread Using AsyncTask 303

Manual Thread Creation and GUI Thread Synchronization 304

Creating a New Thread 304

Using the Handler for Performing GUI Operations 304

Let's Make a Toast 306

Customizing Toasts 306

Using Toasts in Worker Threads 308

Introducing Notifications 309

Introducing the Notification Manager 310

Creating Notifications 310

Creating a Notification and Configuring the Status Bar Icon 310

Configuring the Extended Status Notification Display 311

Triggering Notifications 313

Adding Notifications and Toasts to the Earthquake Monitor 314

Advanced Notification Techniques 316

Using the Defaults 317

Making Sounds 317

Vibrating the Phone 317

Flashing the Lights 318

Ongoing and Insistent Notifications 319

Using Alarms 320

Setting Repeating Alarms 322

Using Repeating Alarms to Update Earthquakes 323

Summary 325

CHAPTER 10: INVADING THE PHONE-TOP 327

Introducing Home-Screen Widgets 328

Creating App Widgets 328

Creating the Widget Layout 329

Widget Design Guidelines 329

Supported Widget Views and Layouts 330

Defining Your Widget Settings 331

Creating Your Widget Intent Receiver and Adding It to the

Application Manifest 332

Introducing Remote Views and the App Widget Manager 333 Creating Remote Views and Using the App Widget Manager to Apply Them 333 Using a Remote View within the App Widget Provider's onUpdate Handler 334

Using Remote Views to Modify UI 335

Making Your Widgets Interactive 335

Refreshing Your Widgets 337

Using the Minimum Update Rate 337

Listening for Intents 338

Using Alarms 339

Creating and Using a Widget Configuration Activity 340

Creating an Earthquake Widget 341

Introducing Live Folders 346

Creating Live Folders 346

Live Folder Content Providers 347

Live Folder Activity 348

Creating an Earthquake Live Folder 349

Adding Search to Your Applications and the Quick Search Box 351

Adding Search to Your Application 351

Creating a Search Activity 352

Responding to Search Queries from a Content Provider 353

Surfacing Search Results to the Quick Search Box 355

Adding Search to the Earthquake Example 355

Creating Live Wallpaper 358

Creating a Live Wallpaper Definition Resource 359

Creating a Wallpaper Service 359

Creating a Wallpaper Service Engine 360

Summary 361

CHAPTER 11: AUDIO, VIDEO, AND USING THE CAMERA 363

Playing Audio and Video 364

Introducing the Media Player 364

Preparing Audio for Playback 365

Packaging Audio as an Application Resource 365

Initializing Audio Content for Playback 365

Preparing for Video Playback 366

Playing Video Using the Video View 367

Setting up a Surface for Video Playback 367

Initializing Video Content for Playback 369

Controlling Playback 370

Managing Media Playback Output 370

Recording Audio and Video 371

Using Intents to Record Video 371

Using the Media Recorder 372

Configuring and Controlling Video Recording 373

Previewing Video Recording 374

Using the Camera and Taking Pictures 375

Using Intents to Take Pictures 375

Controlling the Camera and Taking Pictures 377

Controlling and Monitoring Camera Settings and Image Options 377

Monitoring Auto Focus 379

Using the Camera Preview 379

Taking a Picture 381

Reading and Writing JPEG EXIF Image Details 381

Adding New Media to the Media Store 382

Using the Media Scanner 382

Inserting Media into the Media Store 383

Raw Audio Manipulation 384

Recording Sound with Audio Record 384

Playing Sound with Audio Track 385

Speech Recognition 386

Summary 388

CHAPTER 12: TELEPHONY AND SMS 389

Telephony 390

Launching the Dialer to Initiate Phone Calls 390

Replacing the Native Dialer 390

Accessing Phone and Network Properties and Status 392

Reading Phone Device Details 392

Reading Data Connection and Transfer State 392

Reading Network Details 393

Reading SIM Details 394 Monitoring Changes in Phone State, Phone Activity, and

Data Connections 395

Monitoring Incoming Phone Calls 396

Tracking Cell Location Changes 396

Tracking Service Changes 397

Monitoring Data Connectivity and Activity 398

Introducing SMS and MMS 398

Using SMS and MMS in Your Application 399 Sending SMS and MMS from Your Application Using Intents and the Native Client 399

Sending SMS Messages Manually 400

Sending Text Messages 400

Tracking and Confirming SMS Message Delivery 401

Conforming to the Maximum SMS Message Size 402

Sending Data Messages 403

Listening for Incoming SMS Messages 403

Simulating Incoming SMS Messages in the Emulator 405

Handling Data SMS Messages 406

Emergency Responder SMS Example 406

Automating the Emergency Responder 415

Summary 423

CHAPTER 13: BLUETOOTH, NETWORKS, AND WI-FI 425

Using Bluetooth 425

Accessing the Local Bluetooth Device Adapter 426

Managing Bluetooth Properties and State 427

Being Discoverable and Remote Device Discovery 430

Managing Device Discoverability 430

Discovering Remote Devices 431

Bluetooth Communications 433

Opening a Bluetooth Server Socket Listener 434

Selecting Remote Bluetooth Devices for Communications 435

Opening a Client Bluetooth Socket Connection 437

Transmitting Data Using Bluetooth Sockets 438

Bluetooth Data Transfer Example 439

Managing Network Connectivity 448

Introducing the Connectivity Manager 448

Reading User Preferences for Background Data Transfer 449

Monitoring Network Details 450 Finding and Configuring Network Preferences and Controlling

Hardware Radios 451

Monitoring Network Connectivity 451

Managing Your Wi-Fi 452

Monitoring Wi-Fi Connectivity 452

Monitoring Active Connection Details 453

Scanning for Hotspots 453

Managing Wi-Fi Configurations 454

Creating Wi-Fi Network Configurations 455

Summary 455

CHAPTER 14: SENSORS 457

Using Sensors and the Sensor Manager 458

Introducing Sensors 458

Supported Android Sensors 458

Finding Sensors 459

Using Sensors 459

Interpreting Sensor Values 461

Using the Compass, Accelerometer, and Orientation Sensors 462

Introducing Accelerometers 462

Detecting Acceleration Changes 463

Creating a G-Forceometer 464

Determining Your Orientation 467

Determining Orientation Using the Orientation Sensor 468 Calculating Orientation Using the Accelerometer and

Magnetic Field Sensors 468

Remapping the Orientation Reference Frame 470

Creating a Compass and Artificial Horizon 470

Controlling Device Vibration 474

Summary 475

CHAPTER 15: ADVANCED ANDROID DEVELOPMENT 477

Paranoid Android 478

Linux Kernel Security 478

Introducing Permissions 478

Declaring and Enforcing Permissions 479

Enforcing Permissions for Broadcast Intents 480

Using Wake Locks 480

Introducing Android Text to Speech 481

Using AIDL to Support IPC for Services 483

Implementing an AIDL Interface 484

Passing Class Objects as Parcelables 484

Creating the AIDL Service Definition 486

Implementing and Exposing the IPC Interface 487

Using Internet Services 488

Building Rich User Interfaces 489

Working with Animations 489

Introducing Tweened Animations 490

Creating Tweened Animations 490

Applying Tweened Animations 492

Using Animation Listeners 492

Animated Sliding User Interface Example 493

Animating Layouts and View Groups 498

Creating and Using Frame-by-Frame Animations 500

Advanced Canvas Drawing 501

What Can You Draw? 501

Getting the Most from Your Paint 502

Improving Paint Quality with Anti-Aliasing 507

Canvas Drawing Best Practice 507

Advanced Compass Face Example 508

Bringing Map Overlays to Life 516

Introducing the Surface View 517

When Should You Use a Surface View? 517

Creating a New Surface View 517

Creating 3D Controls with a Surface View 519

Creating Interactive Controls 520

Using the Touch Screen 520

Using the Device Keys, Buttons, and D-Pad 524

Using the On Key Listener 525

Using the Trackball 526

Summary 526

INDEX 529

INTRODUCTION

Now is an exciting time for mobile developers. Mobile phones have never been more popular, and powerful smartphones are now a popular choice for consumers. Stylish and versatile phones packing hardware features like GPS, accelerometers, and touch screens, combined with fixed-rate, reasonably priced data plans provide an enticing platform upon which to create innovative mobile applications.

A host of Android handsets are now available to tempt consumers, including phones with QVGA screens and powerful WVGA devices like the Motorola Droid and the Google Nexus One. The real win though, is for developers. With much existing mobile development built on proprietary operating systems that restrict the development and deployment of third-party applications, Android offers an open alternative. Without artificial barriers, Android developers are free to write applications that take full advantage of increasingly powerful mobile hardware and distribute them in an open market.

As a result, developer interest in Android devices has exploded as handset sales have continued to grow. In 2009 and the early parts of 2010 more than 20 Android handsets have been released from OEMs including HTC, Motorola, LG, Samsung, and Sony Ericsson. Android devices are now available in over 26 countries on more than 32 carriers. In the United States, Android devices are available on all four major carriers: T-Mobile, Verizon, AT&T, and Sprint. Additionally, you can now buy the unlocked Google Nexus One handset directly from Google at http://www.google.com/phone.

Built on an open source framework, and featuring powerful SDK libraries and an open philosophy, Android has opened mobile phone development to thousands of developers who haven't had access to tools for building mobile applications. Experienced mobile developers can now expand into the Android platform, leveraging the unique features to enhance existing products or create innovative new ones.

Using the Android Market for distribution, developers can take advantage of an open marketplace, with no review process, for distributing free and paid apps to all compatible Android devices.

This book is a hands-on guide to building mobile applications using version 2 of the Android software development kit. Chapter by chapter, it takes you through a series of sample projects, each introducing new features and techniques to get the most out of Android. It covers all the basic functionality as well as exploring the advanced features through concise and useful examples.

Google's philosophy is to release early and iterateoften. Since Android's first full release in October 2008, there have been seven platform and SDK releases. With such a rapid release cycle, there are likely to be regular changes and improvements to the software and development libraries. While the Android engineering team has worked hard to ensure backwards compatibility, future releases are likely to date some of the information provided in this book.

Nonetheless, the explanations and examples included here will give you the grounding and knowledge needed to write compelling mobile applications using the current SDK, along with the flexibility to quickly adapt to future enhancements.

WHOM THIS BOOK IS FOR

This book is for anyone interested in creating applications for the Android mobile phone platform using the SDK. It includes information that will be valuable, whether you're an experienced mobile developer or you're making your first foray, via Android, into writing mobile applications.

It will help if readers have used mobile phones (particularly phones running Android), but it's not necessary, nor is prior experience in mobile phone development. It's expected that you'll have some experience in software development and be familiar with basic development practices. While knowledge of Java is helpful, it's not a necessity.

Chapters 1 and 2 introduce mobile development and contain instructions to get you started in Android. Beyond that, there's no requirement to read the chapters in order, although a good understanding of the core components described in Chapters 3 through 7 is important before you venture into the remaining chapters. Chapters 8 through 15 cover a variety of optional and advanced functionality and can be read in whatever order interest or need dictates.

WHAT THIS BOOK COVERS

Chapter 1 introduces Android, including what it is and how it fits into existing mobile development. What Android offers as a development platform and why it's an exciting opportunity for creating mobile phone applications are then examined in greater detail.

Chapter 2 covers some best practices for mobile development and explains how to download the Android SDK and start developing applications. It also introduces the Android developer tools and demonstrates how to create new applications from scratch.

Chapters 3 through 7 take an in-depth look at the fundamental Android application components. Starting with examining the pieces that make up an Android application and its life cycle, you'll quickly move on to the application manifest and external resources before learning about Activities, their lifetimes, and their life cycles.

You'll then learn how to create user interfaces with layouts and Views, before being introduced to the Intent mechanism used to perform actions and send messages between application components. Internet resources are then covered before a detailed look at data storage, retrieval, and sharing. You'll start with the preference-saving mechanism before moving on to file handling and databases. This section finishes with a look at sharing application data using Content Providers.

Chapters 8 to 14 look at more advanced topics. Starting with maps and location-based services, you'll move on to Services, background Threads, and using Notifications.

Next you'll learn how your applications can interatcwith the user directly from the home screen using widgets, live folders, Live Wallpaper, and the quick search box. After looking at playing and recording multimedia, and using the camera, you'll be introduced to Android's communication abilities.

The telephony API will be examined as well as the APIs used to send and receive SMS messages before going on to Bluetooth and network management (both Wi-Fi and mobile data connections).

Chapter 14 examines the sensor APIs, demonstrating how to use the compass, accelerometers, and other hardware sensors to let your application react to its environment.

Chapter 15 includes several advanced development topics, among them security, IPC, advanced graphics techniques, and user- hardware interactions.

HOW THIS BOOK IS STRUCTURED

This book is structured in a logical sequence to help readers of different development backgrounds learn how to write advanced Android applications.

There's no requirement to read each chapter sequentially, but several of the sample projects are developed over the course of several chapters, adding new functionality and other enhancements at each stage.

Experienced mobile developers with a working Android development environment can skim the first two chapters —which are an introduction to mobile development and instructions for creating your development environment —and dive in at Chapters 3 to 7. These cover the fundamentals of Android development, so it's important to have a solid understanding of the concepts they describe. With this covered, you can move on to the remaining chapters, which look at maps, location-based services, background applications, and more advanced topics such as hardware interaction and networking.

WHAT YOU NEED TO USE THIS BOOK

To use the code samples in this book, you will need to create an Android development environment by downloading the Android SDK, developer tools, and the Java development kit. You may also wish to download and install Eclipse and the Android Developer Tool plug-in to ease your development, but neither is a requirement.

Android development is supported in Windows, MacOS, and Linux, with the SDK available from the Android web site.

You do not need an Android device to use this book or develop Android applications.

Chapter 2 outlines these requirements in more detail as well as describing where to download and how to install each component.

CONVENTIONS

To help you get the most from the text and keep track of what's happening, I've used various conventions throughout the book.

As for styles in the text:

> I show URLs and code within the text like so: persistence.properties.

> To help readability, class names in text are often represented using a regular font but capitalized like so:

Content Provider

> I present code in two different ways:

I use a monofont type with no highlighting for most code examples. I use bold highlighting to emphasize code that's particularly important in the present context.

> In some code samples, you'll see lines marked as follows:

This represents an instruction to replace the entire line (including the square brackets) with actual code, either from a previous code snippet in the former case, or your own implementation in the latter.

> To keep the code sample reasonably concise, I have not always included every import statement required in the code samples. The downloadable code samples described below include all the required import statements.

SOURCE CODE

As you work through the examples in this book, you may choose either to type in all the code manually or to use the source code files that accompany the book. All the source code used in this book is available for download at www.wrox.com. Once at the site, simply locate the book's title (either by using the Search box or by using one of the title lists), and click the Download Code link on the book's detail page to obtain all the source code for the book.

Because many books have similar titles, you may find it easiest to search by ISBN; this book' s ISBN is 978-0-470-56552-0.

Once you download the code, just decompress it with your favorite decompression tool. Alternatively, you can go to the main Wrox code download page at www.wrox.com/dynamic/books/download.aspx to see the code available for this book and all other Wrox books.

ERRATA

We make every effort to ensure that there are no errors in the text or in the code. However, no one is perfect, and mistakes do occur. If you find an error in one of our books, like a spelling mistake or faulty piece of code, we would be very grateful for your feedback. By sending in errata you may save another reader hours of frustration, and at the same time you will be helping us provide even higher quality information.

To find the errata page for this book, go to www.wrox.com and locate the title using the Search box or one of the title lists. Then, on the book details page, click the Book Errata link. On this page, you can view all errata that have been submitted for this book and posted by Wrox editors. A complete book list including links to each book's errata is also available atwww.wrox.com/misc-pages/booklist

If you don't spot''your'' error on the Book Errata page,wwwtorox.com/contact/techsupport .shtml and complete the form there to send us the error you have found. We'll check the information and, if appropriate, post a message to the book's Errata page and fix the problem in subsequent editions of the book.

For author and peer discussion, join the P2P forums at p2p.wrox.com. The forums are a web-based system for you to post messages relating to Wrox books and related technologies and interact with other readers and technology users. The forums offer a subscription feature to e-mail you topics of interest of your choosing when new posts are made to the forums. Wrox authors, editors, other industry experts, and your fellow readers are present on these forums.

At http://p2p.wrox.com, you will find a number of different forums that will help you not only as you read this book, but also as you develop your own applications. To join the forums, just follow these steps:

1. Go to p2p.wrox.com and click the Register link.

2. Read the terms of use and click Agree.

3. Complete the required information to join as well as any optional information you wish to provide, and click Submit.

4. You will receive an e-mail with information describing how to verify your account and complete the joining process.

You can read messages in the forums without joining P2P, but in order to post your own messages, you must join.

Once you join, you can post new messages and respond to messages other users post. You can read messages at any time on the Web. If you would like to have new messages from a particular forum e-mailed to you, click the ''Subscribe to This Forum icon by the forum name in the forum listing.

For more information about how to use the Wrox P2P, be sure to read the P2P FAQs for answers to questions about how the forum software works as well as many common questions specific to P2P and Wrox books. To read the FAQs, click the FAQ link on any P2P page.

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