The Busy Coder's Guide to Android Development

1792 Pages·2012·35.72 MB·English

by  Mark L. Murphy

The Busy Coder's Guide to Android Development
by Mark L. Murphy
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The Busy Coder's Guide to Android Development
by Mark L. Murphy
Copyright © 2008-2012 CommonsWare, LLC. All Rights Reserved.
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Printing History:
September 2012: Version 4.2 ISBN: 978-0-9816780-0-9
The CommonsWare name and logo, “Busy Coder's Guide”, and related trade dress are trademarks of CommonsWare,
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The publisher and author(s) assume no responsibility for errors or omissions or for damages resulting from the use of
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Table of Contents
Headings formatted in bold-italic have changed since the last version.
• Preface
◦ Welcome to the Book! ....................................................................... xxv
◦ The Book’s Structure ......................................................................... xxv
◦ The Trails ............................................................................... xxvi
◦ Warescription .................................................................................... xxx
◦ Getting Help ...................................................................................... xxxi
◦ Book Bug Bounty .............................................................................. xxxi
◦ Source Code And Its License ........................................................... xxxii
◦ Creative Commons and the Four-to-Free (42F) Guarantee .......... xxxii
◦ Acknowledgments .......................................................................... xxxiii
• Key Android Concepts
◦ Android Applications ............................................................................ 1
◦ Android Devices .................................................................................... 7
◦ Don’t Be Scared .................................................................................... 10
• Choosing Your IDE
◦ Eclipse .................................................................................................... 11
◦ Alternative IDEs ................................................................................... 12
◦ IDEs… And This Book ........................................................................... 13
◦ About App Inventor .............................................................................. 13
• Tutorial #1 - Installing the Tools
◦ Step #1 - Checking Your Hardware Requirements ............................. 15
◦ Step #2 - Setting Up Java ..................................................................... 16
◦ Step #3 - Install the Android SDK ...................................................... 16
◦ Step #4 - Install the ADT for Eclipse .................................................. 18
◦ Step #5 - Install Apache Ant ............................................................... 20
◦ Step #6 - Set Up the Emulator ............................................................ 21
◦ Step #7 - Set Up the Device ................................................................. 28
◦ In Our Next Episode… .......................................................................... 31
• Tutorial #2 - Creating a Stub Project
◦ About Our Tutorial Project ...................................................... 33
◦ About the Rest of the Tutorials ........................................................... 34
◦ About the Eclipse Instructions ........................................................... 34
◦ Step #1: Creating the Project ............................................................... 35
◦ Step #2: Running the Project ............................................................. 40
◦ Step #3: Perform Some Minor Cleanup ............................................. 44
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◦ In Our Next Episode… ........................................................................ 44
• Contents of Android Projects
◦ Root Contents ........................................................................... 45
◦ The Sweat Off Your Brow ................................................................... 46
◦ Resources ............................................................................................. 46
◦ What You Get Out Of It ............................................................ 47
• Inside the Manifest
◦ An Application For Your Application ................................................. 51
◦ Specifying Versions .............................................................................. 51
◦ Supporting Multiple Screens .............................................................. 52
◦ Other Stuff ........................................................................................... 53
• Tutorial #3 - Changing Our Manifest
◦ Step #1: Supporting Screens ................................................................ 55
◦ Step #2: Validating our Minimum SDK Version ....................... 59
◦ In Our Next Episode… ........................................................................ 60
• Some Words About Resources
◦ String Theory ....................................................................................... 61
◦ Got the Picture? ........................................................................ 64
◦ Dimensions ......................................................................................... 66
◦ The Resource That Shall Not Be Named… Yet ................................... 67
• Tutorial #4 - Adjusting Our Resources
◦ Step #1: Changing the Name ..................................................... 69
◦ Step #2: Changing the Icon ................................................................. 72
◦ In Our Next Episode… ........................................................................ 80
• The Theory of Widgets
◦ What Are Widgets? ............................................................................. 81
◦ Size, Margins, and Padding ................................................................. 83
◦ What Are Containers? ......................................................................... 83
◦ The Absolute Positioning Anti-Pattern ............................................. 84
• The Android User Interface
◦ The Activity .......................................................................................... 87
◦ Dissecting the Activity ....................................................................... 88
◦ Using XML-Based Layouts ................................................................. 89
• Basic Widgets
◦ Common Concepts .............................................................................. 95
◦ Assigning Labels .................................................................................. 97
◦ A Commanding Button ..................................................................... 102
◦ Fleeting Images ...................................................................... 106
◦ Fields of Green. Or Other Colors. ...................................................... 111
◦ More Common Concepts ................................................................... 114
◦ Visit the Trails! .................................................................................... 116
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• Debugging Crashes
◦ Get Thee To a Stack Trace ................................................................. 120
◦ The Case of the Confounding Class Cast .......................................... 123
◦ Point Break .......................................................................................... 123
• LinearLayout and the Box Model
◦ Concepts and Properties .................................................................... 125
◦ Eclipse Graphical Layout Editor ....................................................... 129
• Other Common Widgets and Containers
◦ Just a Box to Check ............................................................................. 131
◦ Don’t Like Checkboxes? How About Toggles? .................................. 134
◦ Turn the Radio Up ............................................................................. 136
◦ All Things Are Relative ...................................................................... 138
◦ Tabula Rasa ......................................................................................... 145
◦ Scrollwork ........................................................................................... 149
◦ Making Progress with ProgressBars .................................................. 152
◦ Visit the Trails! .................................................................................... 153
• Tutorial #5 - Making Progress
◦ Step #1: Removing The “Hello, World” .............................................. 155
◦ Step #2: Adding a ProgressBar ........................................................... 157
◦ Step #3: Seeing the Results ............................................................... 159
◦ In Our Next Episode… ....................................................................... 160
• GUI Building, Continued
◦ Making Your Selection ....................................................................... 161
◦ Including Includes .............................................................................. 161
◦ Wrap It Up (In a Container) ............................................................. 163
◦ Morphing Widgets ............................................................................. 163
◦ Preview of Coming Attractions ......................................................... 164
• AdapterViews and Adapters
◦ Adapting to the Circumstances ........................................................ 165
◦ Lists of Naughty and Nice ................................................................. 167
◦ Clicks versus Selections ..................................................................... 169
◦ Spin Control ........................................................................................ 173
◦ Grid Your Lions (Or Something Like That…) .................................. 176
◦ Fields: Now With 35% Less Typing! ................................................. 180
◦ Galleries, Give Or Take The Art ........................................................ 185
◦ Customizing the Adapter .................................................................. 186
◦ Visit the Trails! ................................................................................... 194
• The WebView Widget
◦ Role of WebView ............................................................................... 195
◦ WebView and WebKit ....................................................................... 196
◦ Adding the Widget ............................................................................ 196
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◦ Loading Content Via a URL .............................................................. 197
◦ Supporting JavaScript ........................................................................ 199
◦ Alternatives for Loading Content .................................................... 200
◦ Listening for Events ........................................................................... 201
◦ Visit the Trails! ................................................................................... 205
• Defining and Using Styles
◦ Styles: DIY DRY .................................................................................. 207
◦ Elements of Style .............................................................................. 209
◦ Themes: Would a Style By Any Other Name… ................................. 212
• JARs and Library Projects
◦ The Dalvik VM ................................................................................... 214
◦ The Easy Part ..................................................................................... 214
◦ The Outer Limits ................................................................................ 215
◦ OK, So What is a Library Project? .................................................... 216
◦ Creating a Library Project ................................................................. 216
◦ Using a Library Project ....................................................................... 217
◦ Limitations of Library Projects ......................................................... 218
◦ The Android Support Package .......................................................... 218
◦ JAR Dependency Management .......................................................... 221
• Tutorial #6 - Adding a Library
◦ Step #1: Downloading and Unpacking ActionBarSherlock ............. 223
◦ Step #2: Adding the Library to Your Project .................................... 224
◦ In Our Next Episode… ....................................................................... 227
• Options Menus and the Action Bar
◦ Terminology ....................................................................................... 229
◦ A Wee Spot O’ History ....................................................................... 231
◦ Your Action Bar Options ................................................................... 232
◦ Setting the Target .............................................................................. 235
◦ Minding Narrow ................................................................................ 236
◦ Defining the Resource ............................................................ 236
◦ Applying the Resource ...................................................................... 241
◦ Responding to Events ........................................................................ 241
◦ Attaching to Action Layouts .................................................. 242
◦ The Rest of the Sample Activity ....................................................... 242
◦ Visit the Trails! ................................................................................... 250
• Tutorial #7 - Adding the Action Bar
◦ Step #1: Setting Up the Target SDK Version ...................................... 251
◦ Step #2: Setting the Theme and Splitting the Bar ........................... 253
◦ Step #3: Changing to SherlockFragmentActivity ............................ 255
◦ Step #4: Defining Some Options ...................................................... 256
◦ Step #5: Loading and Responding to Our Options ......................... 259
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◦ In Our Next Episode… ....................................................................... 262
• Android’s Process Model
◦ When Processes Are Created ............................................................ 263
◦ BACK, HOME, and Your Process ...................................................... 264
◦ Termination ........................................................................................ 265
◦ Foreground Means “I Love You” ....................................................... 265
◦ You and Your Heap ........................................................................... 266
• Activities and Their Lifecycles
◦ Creating Your Second (and Third and…) Activity .......................... 268
◦ Warning! Contains Explicit Intents! ................................................. 273
◦ Using Implicit Intents ....................................................................... 275
◦ Extra! Extra! ....................................................................................... 280
◦ Asynchronicity and Results .............................................................. 282
◦ Schroedinger’s Activity ........................................................... 282
◦ Life, Death, and Your Activity ........................................................... 283
◦ When Activities Die .......................................................................... 285
◦ Walking Through the Lifecycle ....................................................... 286
◦ Recycling Activities ........................................................................... 289
• Tutorial #8 - Setting Up An Activity
◦ Step #1: Creating the Stub Activity Class ......................................... 291
◦ Step #2: Adding the Activity to the Manifest .................................. 293
◦ Step #3: Launching Our Activity ...................................................... 295
◦ In Our Next Episode… ...................................................................... 296
• The Tactics of Fragments
◦ The Six Questions .............................................................................. 297
◦ Your First Fragment .......................................................................... 299
◦ The Fragment Lifecycle Methods ..................................................... 304
◦ Your First Dynamic Fragment ........................................................... 305
◦ Fragments and the Action Bar .......................................................... 309
◦ Fragments Within Fragments: Just Say No ...................................... 310
◦ Fragments and Multiple Activities ................................................... 310
• Tutorial #9 - Starting Our Fragments
◦ Step #1: Copy In WebViewFragment ................................................. 313
◦ Step #2: Examining WebViewFragment ............................................ 317
◦ Step #3: Creating AbstractContentFragment ................................... 317
◦ Step #4: Examining AbstractContentFragment ............................... 319
◦ In Our Next Episode… ....................................................................... 319
• Swiping with ViewPager
◦ Swiping Design Patterns .................................................................... 321
◦ Paging Fragments .............................................................................. 322
◦ Paging Other Stuff ............................................................................. 327
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◦ Indicators ........................................................................................... 327
◦ Fragment-Free Paging ........................................................................ 331
• Tutorial #10 - Rigging Up a ViewPager
◦ Step #1: Add a ViewPager to the Layout ........................................... 333
◦ Step #2: Obtaining Our ViewPager .................................................. 334
◦ Step #3: Creating a ContentsAdapter ............................................... 335
◦ Step #4: Setting Up the ViewPager ................................................... 336
◦ In Our Next Episode… ....................................................................... 337
• Resource Sets and Configurations
◦ What’s a Configuration? And How Do They Change? .................... 339
◦ Configurations and Resource Sets .................................................... 340
◦ Coping with Complexity ................................................................... 341
◦ Default Change Behavior .................................................................. 343
◦ Your Options for Configuration Changes ............................... 345
◦ Blocking Rotations ............................................................................ 357
• Dealing with Threads
◦ The Main Application Thread .......................................................... 359
◦ Getting to the Background ................................................................ 360
◦ Asyncing Feeling ................................................................................ 361
◦ Alternatives to AsyncTask ................................................................. 369
◦ And Now, The Caveats ....................................................................... 370
• Requesting Permissions
◦ Mother, May I? ................................................................................... 372
◦ New Permissions in Old Applications .............................................. 373
◦ Permissions: Up Front Or Not At All ............................................... 374
◦ Signature Permissions ....................................................................... 375
◦ Requiring Permissions ....................................................................... 375
• Assets, Files, and Data Parsing
◦ Packaging Files with Your App ......................................................... 377
◦ Files and Android .............................................................................. 379
◦ Working with Internal Storage ......................................................... 380
◦ Working with External Storage ......................................................... 382
◦ Linux Filesystems: You Sync, You Win ............................................. 386
◦ StrictMode: Avoiding Janky Code ..................................................... 387
◦ XML Parsing Options ........................................................................ 394
◦ JSON Parsing Options ....................................................................... 395
• Tutorial #11 - Adding Simple Content
◦ Step #1: Adding Some Content ......................................................... 397
◦ Step #2: Create a SimpleContentFragment ...................................... 398
◦ Step #3: Examining SimpleContentFragment ................................. 399
◦ Step #4: Using SimpleContentFragment .......................................... 399
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◦ Step #5: Launching Our Activities, For Real This Time ................. 400
◦ In Our Next Episode… ....................................................................... 403
• Tutorial #12 - Displaying the Book
◦ Step #1: Adding a Book ...................................................................... 405
◦ Step #2: Defining Our Model ........................................................... 406
◦ Step #3: Examining Our Model ....................................................... 408
◦ Step #4: Creating a ModelFragment ................................................ 408
◦ Step #5: Examining the ModelFragment ........................................... 411
◦ Step #6: Supplying the Content ........................................................ 412
◦ Step #7: Adapting the Content .......................................................... 413
◦ Step #8: Going Home, Again ............................................................ 415
◦ In Our Next Episode… ....................................................................... 416
• Using Preferences
◦ Getting What You Want .................................................................... 417
◦ Stating Your Preference ..................................................................... 418
◦ Introducing PreferenceActivity ........................................................ 419
◦ Types of Preferences .......................................................................... 431
◦ Intents for Headers or Preferences ................................................... 434
• Tutorial #13 - Using Some Preferences
◦ Step #1: Adding a StockPreferenceFragment ................................... 438
◦ Step #2: Defining the Preference XML Files .................................... 439
◦ Step #3: Creating Our PreferenceActivity ........................................ 441
◦ Step #4: Adding To Our Action Bar .................................................. 442
◦ Step #5: Launching the PreferenceActivity ..................................... 444
◦ Step #6: Loading Our Preferences .................................................... 447
◦ Step #7: Saving the Last-Read Position ........................................... 449
◦ Step #8: Restoring the Last-Read Position ....................................... 450
◦ Step #9: Keeping the Screen On ....................................................... 450
◦ In Our Next Episode… ....................................................................... 451
• SQLite Databases
◦ Introducting SQLite .......................................................................... 453
◦ Thinking About Schemas .................................................................. 454
◦ Start with a Helper ............................................................................ 454
◦ Getting Data Out .............................................................................. 460
◦ The Rest of the CRUD ....................................................................... 465
◦ Hey, What About Hibernate? ........................................................... 470
◦ Visit the Trails! ................................................................................... 470
• Tutorial #14 - Saving Notes
◦ Step #1: Adding a DatabaseHelper ................................................... 471
◦ Step #2: Examining DatabaseHelper ................................................ 473
◦ Step #3: Creating a NoteFragment ................................................... 474
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