Beginning Android 3 ■ ■ ■ Mark Murphy I n t e l ’ s R e c o m m e n d e d R e a d i n g L i s t S e l e c t e d F o r Beginning Android 3 Copyright © 2011 by Mark Murphy All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval system, without the prior written permission of the copyright owner and the publisher. ISBN-13 (pbk): 978-1-4302-3297-1 ISBN-13 (electronic): 978-1-4302-3298-8 Trademarked names, logos, and images may appear in this book. Rather than use a trademark symbol with every occurrence of a trademarked name, logo, or image we use the names, logos, and images only in an editorial fashion and to the benefit of the trademark owner, with no intention of infringement of the trademark. 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Contents Part I: Core Concept 1 ■Chapter 1: The Big Picture 3 Benefits and Drawbacks of Smartphone Programming 3 What Androids Are Made Of 4 Stuff at Your Disposal 5 The Big Picture of This Book 6 ■Chapter 2: How to Get Started 7 Step 1: Set Up Java 7 Install the JDK 7 Learn Java 8 Step 2: Install the Android SDK 8 Install the Base Tools 8 Install the SDKs and Add-ons 9 Step 3: Install the ADT for Eclipse 12 Step 4: Install Apache Ant 14 Step 5: Set Up the Emulator 15 Step 6: Set Up the Device 21 Windows 21 M ac OS X and Linux 22 ■Chapter 3: Your First Android Project 23 Step 1: Create the New Project 23 Eclipse 23 Com mand Line 26 Step 2: Build, Install, and Run the Application in Your Em ulator or Device 27 Eclipse 27 Com mand Line 28 ■Chapter 4: Examining Your First Project 31 Project Structure 31 Root Contents 31 The Sweat Off Your Brow 32 And Now, the Rest of the Story 32 What You Get Out of It 33 Inside Your Manifest 33 In the Beginning, There Was the Root, and It Was Good 34 An Application for Your Application 35 ■Chapter 5: A Bit About Eclipse 37 What the ADT Gives You 37 Coping with Eclipse 38 How to Import a Non- Eclipse Project 38 How to Get to DDM S 42 How to Create an Em ulator 43 How to Run a Project 44 How Not to Run Your Project 45 Alternative IDEs 45 IDEs and This Book 46 ■Chapter 6: Enhancing Your First Project 47 Supporting Multiple Screen Sizes 47 Specifying Versions 48 Part II: Activities 49 ■Chapter 7: Rewriting Your First Project 51 The Activity 51 Dissecting the Activity 52 Building and Running the Acti vity 53 ■Chapter 8: Using XML-Based Layouts 55 What Is an XML-Based Layout? 55 Why Use XML-Based Layouts? 55 OK, So What Does It Look Like? 56 What’s with the @ Signs? 57 And How Do We Attach These to the Java? 57 The Rest of the Story 58 ■Chapter 9: Employing Basic Widgets 61 Assigning Labels 61 Button, Button, Who’s Got the Button? 62 Fleeting Images 63 Fields of Green…or Other Colors 64 Just Another Box to Check 66 Turn the Radio Up 68 It’s Quite a View 70 Padding 70 Other Useful Properties 71 Useful Me thods 71 Colors 71 ■Chapter 10: Working with Containers 73 Thinking Linearly 73 LinearLayout Concepts and Properties 74 LinearLayout Example 76 The Box Model 80 All Things Are Relative 81 RelativeLayout Concepts and Properties 82 RelativeLayout Example 84 Overlap 86 Tabula Rasa 87 TableLayout Concepts and Pr operties 87 TableLayout Example 89 Scrollwork 90 ■Chapter 11: The Input Method Framework 93 Keyboards, Hard and Soft 93 Tailored to Your Needs 94 Tell Android Where It Can Go 98 Fitting In 100 Jane, Stop This Crazy Thing! 101 ■Chapter 12: Using Selection Widgets 103 Adapting to the Circumstances 103 Using ArrayAdapter 104 Lists of Naughty and Nice 104 Selection Modes 106 Spin Control 108 Grid Your Lions (or Som ething Like That ) 111 Fields: Now with 35% Less Typing! 115 Galleries, Give or Take the Art 118 ■Chapter 13: Getting Fancy with Lists 119 Getting to First Base 119 A Dynamic Presentation 121 Inflating Rows Ourselves 123 A Sidebar About Inflation 123 And Now, Back to Our Story 125 Better. Stronger. Faster. 125 Using convertView 125 Using the Holder Pattern 127 Interactive Rows 129 ■Chapter 14: Still More Widgets and Containers 135 Pick and Choose 135 Time Keeps Flowing Like a River 140 Seeking Resolution 141 Putting It on My Tab 142 The Pieces 143 Wiring It Together 144 Adding Them Up 146 Flipping Them Off 149 Getting in Somebody’s Drawer 154 Other Good Stuff 156 ■Chapter 15: Embedding the WebKit Browser 159 A Browser, Writ Small 159 Loading It Up 161 Navigating the W aters 162 Entertaining the Client 163 Settings, Preferences, and Options (Oh, My !) 165 ■Chapter 16: Applying Menus 167 Flavors of Menu 167 Menus of Options 168 Menus in Context 169 Taking a Peek 170 Yet Mo re Inflation 175 Menu XM L Structure 175 Menu Options and XM L 176 Inflating the Menu 177 In the Land of Menus and Honey 178 ■Chapter 17: Showing Pop-Up Messages 179 Raising Toasts 179 Alert! Alert! 180 Checking Them Out 181 ■Chapter 18: Handling Activity Lifecycle Events 183 Schroedinger’s Activity 183 Life, Death, and Your Activity 184 onCreate() and onDestroy() 184 onStart(), onRestart(), and onStop() 185 onPause() and onResume() 185 The Grace of State 185 ■Chapter 19: Handling Rotation 187 A Philosophy of Destruction 187 It’s All the Same, Just Different 188 Picking and Viewing a C ontact 189 Saving Your State 190 Now with Mo re Savings! 193 DIY Rotation 195 But Google Does Not Recommend This 198 Forcing the Issue 198 Making Sense of It All 200 ■Chapter 20: Dealing with Threads 203 The Main Application Thread 203 Making Progress with ProgressBars 204 Getting Through the Handlers 204 Messages 205 Runnables 208 Where Oh Where Has My UI Thread Gone? 208 Asyncing Feeling 208 The Theory 208 AsyncTask, Generics, and Varargs 209 The Stages of AsyncTask 209 A Samp le Task 210 Threads and Rotation 214 Manual Activity Association 215 Flow of Events 217 Why This W orks 218 And Now, the Caveats 218 ■Chapter 21: Creating Intent Filters 221 What’s Your Intent? 221 Pieces of Intents 222 Intent Routing 222 Stating Your Intent(ions) 223 Narrow Receivers 224 The Pause Caveat 225 ■Chapter 22: Launching Activities and Subactivities 227 Peers and Subs 227 Start ’Em Up 228 M ake an Intent 228 Make the Call 228 Tabbed Browsing, Sort Of 232 ■Chapter 23: Working with Resources 235 The Resource Lineup 235 String Theory 235 Plain Strings 236 String Forma ts 236 Styled Text 237 Styled Text and Forma ts 237 Got the Picture? 240 XML: The Resource W ay 241 Miscellaneous Values 243 Dimensions 244 Colors 244 Arrays 245 Different Strokes for Different Folks 246 RTL Languages: Going Both Ways 250 ■Chapter 24: Defining and Using Styles 251 Styles: DIY DRY 251 Elements of Style 253 Where to Apply a Style 253 The Available Attributes 254 Inheriting a Style 254 The Possible Values 255 Themes: A Style by Any Other Name 256 ■Chapter 25: Handling Multiple Screen Sizes 257 Taking the Default 257 Whole in One 258 Think About Rules, Not Positions . 259 Consider Physical Dimensions . 260 Avoid “Real” Pixels . 260 Choose Scalable Drawables . 260 Tailor-Made, Just for You (and You, and You, and ) 261 Adding the <supports-screens> Element 261 Resources and Resource Sets . 262 Finding Your Size . 263 Ain’t Nothing Like the Real Thing . 263 Density Differs 264 Adjusting the Density . 264 Ruthlessly Exploiting the Situation . 265 Replace Menus with Buttons . 265 Replace Tabs with a Simple Activity . 266 Consolidate Multiple Activities . 266 Example: EU4You 266 The First Cut 267 Fixing the Fonts 272 Fixing the Icons 274 Using the Space 274 What If It Is Not a Browser? . 276 Part III: Honeycomb and Tablets . 279 ■Chapter 26: Introducing the Honeycomb UI . 281 Why Honeycomb? 281 What the User Sees 282 The Holographic Theme . 285 Dealing with the Rest of the Devices . 286 ■Chapter 27: Using the Action Bar 289 Enabling the Action Bar . 289 Promoting Menu Items to the Action Bar 290 Responding to the Logo . 291 Adding Custom Views to the Action Bar 291 Defining the Layout . 292 Putting the Layout in the Menu . 293 Getting Control of User Input . 294 Don’t Forget the Phones! . 295 ■Chapter 28: Fragments 297 Introducing Fragments . 297 The Problem Addressed by Fragments . 297 The Fragments Solution . 298 The Android Compatibility Library . 299 Creating Fragment Classes . 300 General Fragments . 300 ListFragment 301 Other Fragment Base Classes 306 Fragments, Layouts, Activities, and Multiple Screen Sizes 306 EU4You 307 DetailsActivity 311 Fragments and Configuration Changes 312 Designing for Fragments 312 ■Chapter 29: Handling Platform Changes 313 Things That Make You Go Boom 313 View Hierarchy 313 Changing Resources 314 Handling API Changes 314 Mi nimum, Maximum, Target, and Build Versions 315 Detecting the Version 316 Wr apping the API 317 Patterns for Honeycomb 318 The Action Bar 319 Wr iting Tablet-Only Apps 321 ■Chapter 30: Accessing Files 323 You and the Horse You Rode in On 323 Readin’ ’n Writin’ 326 External Storage: Giant Economy - Size Space 330 Where to Write 330 When to W rite 331 StrictMode: Avoiding Janky Code 331 Setting Up StrictM ode 332 Seeing StrictMode in Action 332 Development Only, Please! 333 Conditionally Being Strict 333 Linux File Systems: You Sync, You W in 335 Part IV: Data Stores, Network Services, and APIs 337 ■Chapter 31: Using Preferences 339 Getting What You Want 339 Stating Your Preference 340 Introducing PreferenceActivity 340 Letting Users Have Their Say 341 Adding a Wee Bit o’ Structure 345 The Kind of Pop-Ups You Like 347 Preferences via Fragments 350 The Honeycomb W ay 351 Adding Backward Compatibility 354 ■Chapter 32: Managing and Accessing Local Databases 357 A Quick SQLite Primer 359 Start at the Beginning 359 Setting the Table 362 Makin’ Data 362 W hat Goes Around, Comes Around 364 Raw Queries 364 Regular Queries 364 Using Cursors 365 Custom CursorAdapters 366 Making Your Own Cursors 366 Flash: Sounds Faster Than It Is 367 Data, Data, Everywhere 367 ■Chapter 33: Leveraging Java Libraries 369 Ants and JARs 369 The Outer Limits 370 Following the Script 371 Reviewing the Script 374 ■Chapter 34: Communicating via the Internet 377 REST and Relaxation 377 HTTP Operations via Apache HttpClient 378 Parsing Responses 379 Stuff to Consider 381 AndroidHttpClient 382 Leveraging Internet-Aware Android Components 382 Downloading Files 383 Continuing Our Escape from Janky Code 391 Part V: Services 393 ■Chapter 35: Services: The Theory 395 Why Services? 395 Setting Up a Service 396 Service Class 396 Lifecycle Me thods 396 Manifest Entry 397 Comm unicating to Services 397 Sending Comm ands with startService() 397 Binding with bindService() 398 Comm unicating from Services 399 Callback/Listener Objects 400 Broadcast Intents 400 Pending Results 400 Messenger 401 Notifications 401 ■Chapter 36: Basic Service Patterns 403 The Downloader 403 The Design 403 The Service Implem entation 404 Using the Service 406 The Music Player 407 The Design 407 The Service Implem entation 408 Using the Service 409 The Web Service Interface 410 [...]... . 531 Explicit Feature Requests 531 Implied Feature Requests 532 A Guaranteed Market 533 Other Stuff That Varies 534 Bugs, Bugs, Bugs 534 Device Testing 535 ■Chapter 49: Where Do We Go from Here? 537 Questions, Sometimes with Answers 537 Heading to the Source 538 Getting... trivial) Android application The process differs depending on whether you are using Eclipse or the command line Eclipse From the Eclipse main menu, choose File ➤ New ➤ Project to open the New Project dialog box, which gives you a list of project type wizards to choose from Expand the Android option and click Android Project, as shown in Figure 3 1 23 24 CHAPTER 3: Your First Android Project Figure 3 1 Selecting... ■Chapter 37 : Alerting Users via Notifications 4 23 Notification Configuration 4 23 Hardware Notifications 424 Icons 424 Notifications in Action 425 Staying in the Foreground 429 FakePlayer, Redux 430 Notifications and Honeycomb . 431 Part VI: Other Android Capabilities 435 ■Chapter... knowledge is to read Learn Java for Android Development by Jeff Friesen (Apress, 2010) Step 2: Install the Android SDK The Android SDK gives you all the tools you need to create and test Android applications It comes in two parts: the base tools, and version-specific SDKs and related add-ons Install the Base Tools You can find the Android developer tools on the Android Developers web site Download... necessary to run an Android emulator To address this, click the Available packages option on the left to open the screen shown in Figure 2–2 9 10 CHAPTER 2: How to Get Started Figure 2–2 Android SDK and AVD Manager available packages Open the Android Repository branch of the tree After a short pause, you will see a screen similar to Figure 2 3 Figure 2 3 Android SDK and AVD Manager available Android packages... 5 03 Signing and Distribution 5 03 Updates 5 03 Issues You May Encounter 5 03 Android Device Versions 5 03 Screen Sizes and Densities 504 Limited Platform Integration 504 Performance and Battery .505 Look and Feel .505 Distribution 505 HTML5 and Alternative Android. .. will go through a few startup phases, the first of which displays a plain-text ANDROID label, as shown in Figure 2–12 17 18 CHAPTER 2: How to Get Started Figure 2–12 Android emulator, initial startup segment The second phase displays a graphical Android logo, as shown in Figure 2– 13 CHAPTER 2: How to Get Started Figure 2– 13 Android emulator, secondary startup segment Finally, the emulator reaches the... 38 : Requesting and Requiring Permissions 437 Mother, May I? 437 Halt! Who Goes There? . 438 Enforcing Permissions via the Manifest . 439 Enforcing Permissions Elsewhere 440 May I See Your Documents? .440 New Permissions in Old Applications 440 Permissions: Up Front or Not at All .441 ■Chapter 39 :... Your News Fix . 539 Index 541 Part Core Concept I Chapter 1 The Big Picture Android is everywhere Phones Tablets TVs and set-top boxes powered by Google TV Soon, Android will be in cars and all sort of other places as well However, the general theme of Android devices will be smaller screens and/or no hardware keyboard And, by the numbers, Android will probably be associated... Platform” for all Android SDK releases you want to test against “Documentation for Android SDK” for the latest Android SDK release “Samples for SDK” for the latest Android SDK release, and perhaps for older releases if you wish Then, open the Third party Add-ons branch of the tree After a short pause, you will see a screen similar to Figure 2–4 CHAPTER 2: How to Get Started Figure 2–4 Android SDK and . Write 33 0 When to W rite 33 1 StrictMode: Avoiding Janky Code 33 1 Setting Up StrictM ode 33 2 Seeing StrictMode in Action 33 2 Development Only, Please! 33 3 Conditionally Being Strict 33 3 Linux. You W in 33 5 Part IV: Data Stores, Network Services, and APIs 33 7 ■Chapter 31 : Using Preferences 33 9 Getting What You Want 33 9 Stating Your Preference 34 0 Introducing PreferenceActivity 34 0 Letting. 37 9 Stuff to Consider 38 1 AndroidHttpClient 38 2 Leveraging Internet-Aware Android Components 38 2 Downloading Files 38 3 Continuing Our Escape from Janky Code 39 1 Part V: Services 39 3 ■Chapter