professional android 4 application development

Reto currently works as a Developer Advocate on the Android team at Google, helping Android developers create the best applications possible.. INTRODUCTION xxxvii Android: An Open Platfo

ANDROID™ 4 APPLICATION DEVELOPMENT

INTRODUCTION xxxvii

CHAPTER 1 Hello, Android 1

CHAPTER 2 Getting Started 19

CHAPTER 3 Creating Applications and Activities 53

CHAPTER 4 Building User Interfaces 95

CHAPTER 5 Intents and Broadcast Receivers 165

CHAPTER 6 Using Internet Resources 201

CHAPTER 7 Files, Saving State, and Preferences 221

CHAPTER 8 Databases and Content Providers 251

CHAPTER 9 Working in the Background 331

CHAPTER 10 Expanding the User Experience 359

CHAPTER 11 Advanced User Experience 425

CHAPTER 12 Hardware Sensors 481

CHAPTER 13 Maps, Geocoding, and Location-Based Services 513

CHAPTER 14 Invading the Home Screen 565

CHAPTER 15 Audio, Video, and Using the Camera 621

CHAPTER 16 Bluetooth, NFC, Networks, and Wi-Fi 665

CHAPTER 17 Telephony and SMS 701

CHAPTER 18 Advanced Android Development 739

CHAPTER 19 Monetizing, Promoting, and Distributing Applications 771

INDEX 787

PROFESSIONAL

Android ™ 4 Application Development

PROFESSIONAL

Android ™ 4 Application Development

Reto Meier

Professional Android™ 4 Application Development

Copyright © 2012 by John Wiley & Sons, Inc., Indianapolis, Indiana

Published simultaneously in Canada

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in this book.

To Kris

ABOUT THE AUTHOR

RETO MEIER grew up in Perth, Western Australia, and then lived in London for 6 years before moving to the San Francisco Bay Area in 2011

Reto currently works as a Developer Advocate on the Android team at Google, helping Android developers create the best applications possible Reto is an experienced software developer with more than 10 years of experience in GUI application development Before coming to Google, he worked in various industries, including offshore oil and gas and fi nance

Always interested in emerging technologies, Reto has been involved in Android since the initial release in 2007

You can fi nd out entirely too much about Reto’s interests and hobbies on his web site, The Radioactive Yak (http://blog.radioactiveyak.com), or on Google+ (http://profiles google.com/reto.meier) or Twitter (www.twitter.com/retomeier), where he shares more than

he probably should

ABOUT THE TECHNICAL EDITOR

DAN ULERY is a software engineer with experience in NET, Java, and PHP development, as well as

in deployment engineering He graduated from the University of Idaho with a Bachelor of Science degree in computer science and a minor in mathematics

Mary Beth Wakefi eld

FREELANCER EDITORIAL MANAGER

FIRST, I’D LIKE TO THANK KRISTY, whose love, patience, and understanding are pushed to new limits every time I forget what’s involved in writing a book and agree to do another one Your support makes everything I do possible

A big thank you to my friends and colleagues at Google, particularly the Android engineers and my colleagues in developer relations The pace at which Android grows makes life diffi cult for those of

us who choose to write books, but the opportunities it creates for developers makes the stress and rewrites easy to bear

I also thank Dan Ulery for his sharp eye and valuable insights; Robert Elliot and John Sleeva for their patience in waiting for me to get this book fi nished; San Dee Phillips; and the whole team at Wrox for helping to get it done

A special shout-out goes out to the entire Android developer community Your passion, hard work, and excellent applications have helped make Android the huge success that it is Thank you

INTRODUCTION xxxvii

Android: An Open Platform for Mobile Development 4

Using Widgets and Live Wallpaper to Enhance the Home Screen 9

Developing for Mobile and Embedded Devices 38

Introducing the Application Manifest File 55

Creating Resources for Diff erent Languages and Hardware 77

Understanding an Application’s Priority and Its Process’ States 82 Introducing the Android Application Class 83

Using Layouts to Create Device Independent User Interfaces 100

Creating Intent Filters and Broadcast Receivers 183

Finding and Using Intents Received Within an Activity 186

Discovering New Actions from Third-Party Intent Receivers 194

Monitoring Device State Changes Using Broadcast Intents 197

Downloading and Parsing Internet Resources 201

Best Practices for Downloading Data Without Draining

Creating a Settings Activity for the Earthquake Viewer 223 Introducing the Preference Framework and the

Using Intents to Import System Preferences into Preference Screens 234

Defi ning the Preference Fragment Hierarchy

Finding and Using the Shared Preferences Set by Preference Screens 238

Creating a Standard Preference Activity for the Earthquake Viewer 238 Persisting the Application Instance State 242

Saving and Restoring Activity Instance State

Saving and Restoring Fragment Instance State

Opening and Creating Databases Without the SQLite Open Helper 257

Querying for Content Asynchronously Using the Cursor Loader 277

Making Your Search Activity the Default Search Provider

Creating a Searchable Earthquake Content Provider 301

Executing a Service and Controlling Its Restart Behavior 333

Using the Intent Service to Simplify the Earthquake

Customizing the Action Bar to Control Application Navigation Behavior 364

Adding an Action Bar to the Earthquake Monitor 370 Creating and Using Menus and Action Bar Action Items 377

Managing and Displaying Dialogs Using Activity Event Handlers 400

Creating a Notifi cation and Confi guring the Status Bar Display 407Using the Default Notifi cation Sounds, Lights, and Vibrations 408

Adding Notifi cations and Dialogs to the Earthquake Monitor 418

Designing for Every Screen Size and Density 426

xxvii

Managing Hardware Acceleration Use in Your Applications 466

Monitoring a Device’s Movement and Orientation 489

Calculating Orientation Using the Accelerometer and

Determining Orientation Using the Deprecated Orientation Sensor 501

CHAPTER 13: MAPS, GEOCODING, AND

Using the Emulator with Location-Based Services 515

Confi guring the Emulator to Test Location-Based Services 516

Creating Your Widget Intent Receiver and Adding It to the

Populating Collection View Widgets Using a Remote Views Service 594Adding Interactivity to the Items Within a Collection View Widget 595

Surfacing Application Search Results Using the Quick Search Box 614

Adding the Earthquake Example Search Results to the

Controlling Auto Focus, Focus Areas, and Metering Areas 650

Selecting Remote Bluetooth Devices for Communications 675

Managing Network and Internet Connectivity 679

Supporting User Preferences for Background Data Transfers 679

Monitoring Changes in Phone State Using the Phone State Listener 708

Monitoring Data Connectivity and Data Transfer Status Changes 711

Sending SMS and MMS from Your Application Using Intents 713

Implementing Copy Protection Using the License

Finding Your Public Key and Defi ning Your Purchasable Items 754

Using AIDL to Support Inter-Process Communication for Services 759

Implementing and Exposing the AIDL Service Defi nition 762

Dealing with Diff erent Hardware and Software Availability 765

Optimizing UI Performance with Strict Mode 769

CHAPTER 19: MONETIZING, PROMOTING, AND DISTRIBUTING

APPLICATIONS 771

Signing Applications Using the Export Android Application Wizard 772

An Introduction to Monetizing Your Applications 779 Application Marketing, Promotion, and Distribution Strategies 780

Internationalization 782

INDEX 787

THIS IS AN EXCITING TIME FOR ANDROID DEVELOPERS Mobile phones have never been more lar; powerful smartphones are now a regular choice for consumers; and the Android ecosystem has expanded to include tablet and TV devices to further expand the audience of your Android applications

popu-Hundreds of stylish and versatile devices — packing hardware features such as GPS, accelerometers, NFC, and touch screens, combined with reasonably priced data plans — provide an enticing plat-form upon which to create innovative applications for all Android devices

Android offers an open alternative for mobile application development Without artifi cial 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 As of 2012, there are hundreds of handset and tablet OEMs, including HTC, Motorola, LG, Samsung, ASUS, and Sony Ericsson

More than 300 million Android devices have been activated, and that number is growing at a rate of over 850,000 activations every day

Using Google Play for distribution, developers can take advantage of an open marketplace, with no review process, for distributing free and paid applications to all compatible Android devices Built

on an open-source framework, and featuring powerful SDK libraries, Android has enabled more than 450,000 applications to be launched in Google Play

This book is a hands-on guide to building mobile applications using version 4 of the Android SDK 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 to get started, as well as the information for experienced mobile developers to leverage the unique features of Android

to enhance existing products or create innovative new ones

Google’s philosophy is to release early and iterate often Since Android’s fi rst full release in December 2008, there have been 19 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 works hard to ensure backward compatibility, future releases are likely to date some of the information provided in this book Similarly, not all active Android devices will be running the latest platform release

Wherever possible, I have included details on which platform releases support the functionality described, and which alternatives may exist to provide support for users of older devices Further, the explanations and examples included will give you the grounding and knowledge needed to write compelling mobile applications using the current SDK, along with the fl exibility to quickly adapt to future enhancements

WHO THIS BOOK IS FOR

This book is for anyone interested in creating applications for the Android platform It includes

information that will be valuable, whether you’re an experienced mobile developer or making your

fi rst foray, via Android, into writing mobile applications

It will help if you have used smartphones (particularly phones running Android), but it’s not

neces-sary, nor is prior experience in mobile application development

It’s expected that you’ll have some experience in software development and be familiar with basic

object-oriented development practices An understanding of Java syntax is a requirement, and

detailed knowledge and experience is a distinct advantage, though not a strict 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

under-standing of the core components described in Chapters 3–9 is important before you venture into

the remaining chapters Chapters 10 and 11 cover important details on how to create an application

that provides a rich and consistent user experience, while Chapters 12–19 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 fi ts 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 3–9 take an in-depth look at the fundamental Android application components Starting

with examining the pieces that make up an Android application and its lifecycle, you’ll quickly move

on to the application manifest and external resources before learning about “Activities,” their

life-times, and their lifecycles

You’ll then learn how to create basic user interfaces with layouts, Views, and Fragments, before being

introduced to the Intent and Broadcast Receiver mechanisms used to perform actions and send

mes-sages between application components Internet resources are then covered, followed by a detailed

look at data storage, retrieval, and sharing You’ll start with the preference-saving mechanism and

then move on to fi le handling, databases, and Cursors You’ll also learn how share application data

using Content Providers and access data from the native Content Providers This section fi nishes with

an examination of how to work in the background using Services and background Threads

Chapters 10 and 11 build on the UI lessons you learned in Chapter 4, examining how to enhance

the user experience through the use of the Action Bar, Menu System, and Notifi cations You’ll

learn how to make your applications display-agnostic (optimized for a variety of screen sizes and