Beginning Android 2

417 Pages·2010·7.98 MB·English

by  Mark Murphy

Begin the journey toward your own

successful Android 2 applications

Beginning
Android 2

Mark L. Murphy

Beginning Android 2

■ ■ ■
Mark L. Murphy
Beginning Android 2
Copyright © 2010 by Mark L. Murphy
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Contents at a Glance
■Contents at a Glance.................................................................................................................................iv
■Contents.....................................................................................................................................................v
■About the Author.....................................................................................................................................xiii
■Acknowledgments...................................................................................................................................xiv
■Preface......................................................................................................................................................xv
■Chapter 1: The Big Picture.........................................................................................................................1
■Chapter 2: Projects and Targets................................................................................................................5
■Chapter 3: Creating a Skeleton Application.............................................................................................17
■Chapter 4: Using XML-Based Layouts......................................................................................................23
■Chapter 5: Employing Basic Widgets.......................................................................................................29
■Chapter 6: Working with Containers........................................................................................................39
■Chapter 7: Using Selection Widgets.........................................................................................................59
■Chapter 8: Getting Fancy with Lists.........................................................................................................75
■Chapter 9: Employing Fancy Widgets and Containers.............................................................................95
■Chapter 10: The Input Method Framework............................................................................................117
■Chapter 11: Applying Menus..................................................................................................................125
■Chapter 12: Fonts...................................................................................................................................137
■Chapter 13: Embedding the WebKit Browser.........................................................................................141
■Chapter 14: Showing Pop-Up Messages................................................................................................149
■Chapter 15: Dealing with Threads.........................................................................................................155
■Chapter 16: Handling Activity Life Cycle Events....................................................................................167
■Chapter 17: Creating Intent Filters........................................................................................................171
■Chapter 18: Launching Activities and Subactivities..............................................................................177
■Chapter 19: Handling Rotation...............................................................................................................185
■Chapter 20: Working with Resources....................................................................................................197
■Chapter 21: Using Preferences..............................................................................................................213
■Chapter 22: Managing and Accessing Local Databases........................................................................225
■Chapter 23: Accessing Files...................................................................................................................237
■Chapter 24: Leveraging Java Libraries..................................................................................................245
■Chapter 25: Communicating via the Internet.........................................................................................253
■Chapter 26: Using a Content Provider....................................................................................................259
■Chapter 27: Building a Content Provider...............................................................................................265
■Chapter 28: Requesting and Requiring Permissions.............................................................................275
■Chapter 29: Creating a Service..............................................................................................................279
■Chapter 30: Invoking a Service..............................................................................................................285
■Chapter 31: Alerting Users via Notifications..........................................................................................289
■Chapter 32: Accessing Location-Based Services...................................................................................295
■Chapter 33: Mapping with MapView and MapActivity...........................................................................301
■Chapter 34: Handling Telephone Calls...................................................................................................311
■Chapter 35: Development Tools.............................................................................................................315
■Chapter 36: Handling Multiple Screen Sizes..........................................................................................331
■Chapter 37: Dealing with Devices..........................................................................................................353
■Chapter 38: Handling Platform Changes................................................................................................359
■Chapter 39: Where Do We Go from Here?..............................................................................................367
■Index......................................................................................................................................................369
iv
Contents
■Contents at a Glance.......................................................................................iv
■Contents..........................................................................................................v
■About the Author..........................................................................................xiii
■Acknowledgments.........................................................................................xiv
■Preface...........................................................................................................xv

■Chapter 1: The Big Picture...............................................................................1
Challenges of Smartphone Programming...............................................................................................................1
What Androids Are Made Of....................................................................................................................................2
Stuff at Your Disposal.............................................................................................................................................3
■Chapter 2: Projects and Targets......................................................................5
Pieces and Parts.....................................................................................................................................................5
Creating a Project...................................................................................................................................................6
Project Structure.....................................................................................................................................................6
Root Contents....................................................................................................................................................6
The Sweat Off Your Brow...................................................................................................................................7
And Now, the Rest of the Story..........................................................................................................................7
What You Get Out of It........................................................................................................................................8
Inside the Manifest.................................................................................................................................................8
In the Beginning, There Was the Root, And It Was Good...................................................................................9
Permissions, Instrumentations, and Applications (Oh My!)...............................................................................9
Your Application Does Something, Right?.......................................................................................................10
Achieving the Minimum...................................................................................................................................11
Version=Control...............................................................................................................................................12
Emulators and Targets..........................................................................................................................................12
Virtually There..................................................................................................................................................12
Aiming at a Target...........................................................................................................................................14
v
■ CONTENTS
■Chapter 3: Creating a Skeleton Application...................................................17
Begin at the Beginning..........................................................................................................................................17
Dissecting the Activity..........................................................................................................................................18
Building and Running the Activity.........................................................................................................................20
■Chapter 4: Using XML-Based Layouts ...........................................................23
What Is an XML-Based Layout?............................................................................................................................23
Why Use XML-Based Layouts?.............................................................................................................................24
OK, So What Does It Look Like?............................................................................................................................24
What’s with the @ Signs?.....................................................................................................................................25
And How Do We Attach These to the Java?..........................................................................................................25
The Rest of the Story............................................................................................................................................26
■Chapter 5: Employing Basic Widgets.............................................................29
Assigning Labels...................................................................................................................................................29
Button, Button, Who’s Got the Button?.................................................................................................................30
Fleeting Images....................................................................................................................................................31
Fields of Green. Or Other Colors...........................................................................................................................32
Just Another Box to Check....................................................................................................................................33
Turn the Radio Up.................................................................................................................................................35
It’s Quite a View....................................................................................................................................................37
Useful Properties.............................................................................................................................................37
Useful Methods................................................................................................................................................38
Colors...............................................................................................................................................................38
■Chapter 6: Working with Containers.............................................................39
Thinking Linearly..................................................................................................................................................39
LinearLayout Concepts and Properties............................................................................................................40
LinearLayout Example......................................................................................................................................42
All Things Are Relative..........................................................................................................................................46
RelativeLayout Concepts and Properties.........................................................................................................47
RelativeLayout Example...................................................................................................................................49
Tabula Rasa..........................................................................................................................................................51
TableLayout Concepts and Properties.............................................................................................................52
TableLayout Example.......................................................................................................................................53
Scrollwork.............................................................................................................................................................54
■Chapter 7: Using Selection Widgets..............................................................59
Adapting to the Circumstances.............................................................................................................................59
Lists of Naughty and Nice.....................................................................................................................................60
Spin Control..........................................................................................................................................................63
Grid Your Lions (or Something Like That...)..........................................................................................................66
Fields: Now with 35% Less Typing!......................................................................................................................69
Galleries, Give or Take the Art..............................................................................................................................72
■Chapter 8: Getting Fancy with Lists..............................................................75
Getting to First Base.............................................................................................................................................75
A Dynamic Presentation........................................................................................................................................77
Better. Stronger. Faster........................................................................................................................................80
Using convertView...........................................................................................................................................80
Using the Holder Pattern..................................................................................................................................81
vi
■ CONTENTS
Making a List........................................................................................................................................................84
...And Checking It Twice.......................................................................................................................................89
Adapting Other Adapters.......................................................................................................................................94
■Chapter 9: Employing Fancy Widgets and Containers...................................95
Pick and Choose...................................................................................................................................................95
Time Keeps Flowing Like a River..........................................................................................................................99
Making Progress.................................................................................................................................................101
Seeking Resolution.............................................................................................................................................101
Put It on My Tab..................................................................................................................................................102
The Pieces.....................................................................................................................................................103
The Idiosyncrasies.........................................................................................................................................103
Wiring It Together..........................................................................................................................................104
Adding Them Up.............................................................................................................................................106
Intents and Views..........................................................................................................................................109
Flipping Them Off................................................................................................................................................109
Manual Flipping.............................................................................................................................................110
Adding Contents on the Fly............................................................................................................................112
Automatic Flipping.........................................................................................................................................113
Getting in Someone’s Drawer.............................................................................................................................114
Other Good Stuff.................................................................................................................................................116
■Chapter 10: The Input Method Framework..................................................117
Keyboards, Hard and Soft...................................................................................................................................117
Tailored to Your Needs........................................................................................................................................118
Tell Android Where It Can Go..............................................................................................................................121
Fitting In..............................................................................................................................................................123
Unleash Your Inner Dvorak.................................................................................................................................124
■Chapter 11: Applying Menus.......................................................................125
Menus of Options................................................................................................................................................125
Creating an Options Menu.............................................................................................................................125
Adding Menu Choices and Submenus...........................................................................................................126
Menus in Context................................................................................................................................................127
Taking a Peek.....................................................................................................................................................128
Yet More Inflation................................................................................................................................................133
Menu XML Structure......................................................................................................................................133
Menu Options and XML..................................................................................................................................134
Inflating the Menu..........................................................................................................................................135
■Chapter 12: Fonts........................................................................................137
Love the One You’re With....................................................................................................................................137
More Fonts..........................................................................................................................................................138
Here a Glyph, There a Glyph...............................................................................................................................140
■Chapter 13: Embedding the WebKit Browser..............................................141
A Browser, Writ Small.........................................................................................................................................141
Loading It Up.......................................................................................................................................................143
Navigating the Waters.........................................................................................................................................144
Entertaining the Client........................................................................................................................................145
Settings, Preferences, and Options (Oh My!)......................................................................................................147
vii
■ CONTENTS
■Chapter 14: Showing Pop-Up Messages......................................................149
Raising Toasts.....................................................................................................................................................149
Alert! Alert!..........................................................................................................................................................150
Checking Them Out.............................................................................................................................................151
■Chapter 15: Dealing with Threads...............................................................155
Getting Through the Handlers.............................................................................................................................155
Messages.......................................................................................................................................................156
Runnables......................................................................................................................................................158
Running in Place.................................................................................................................................................159
Where Oh Where Has My UI Thread Gone?.........................................................................................................159
Asyncing Feeling.................................................................................................................................................159
The Theory.....................................................................................................................................................159
AsyncTask, Generics, and Varargs.................................................................................................................160
The Stages of AsyncTask...............................................................................................................................160
A Sample Task...............................................................................................................................................161
And Now, the Caveats.........................................................................................................................................164
■Chapter 16: Handling Activity Life Cycle Events..........................................167
Schroedinger’s Activity.......................................................................................................................................167
Life, Death, and Your Activity..............................................................................................................................168
onCreate() and onDestroy()............................................................................................................................168
onStart(), onRestart(), and onStop()...............................................................................................................169
onPause() and onResume()............................................................................................................................169
The Grace of State..............................................................................................................................................169
■Chapter 17: Creating Intent Filters..............................................................171
What’s Your Intent?.............................................................................................................................................171
Pieces of Intents............................................................................................................................................172
Intent Routing................................................................................................................................................172
Stating Your Intent(ions).....................................................................................................................................173
Narrow Receivers...............................................................................................................................................174
The Pause Caveat...............................................................................................................................................175
■Chapter 18: Launching Activities and Subactivities....................................177
Peers and Subs...................................................................................................................................................177
Start ’Em Up........................................................................................................................................................178
Make an Intent...............................................................................................................................................178
Make the Call.................................................................................................................................................178
Tabbed Browsing, Sort Of...................................................................................................................................182
■Chapter 19: Handling Rotation....................................................................185
A Philosophy of Destruction................................................................................................................................185
It’s All the Same, Just Different..........................................................................................................................185
Now with More Savings!.....................................................................................................................................189
DIY Rotation........................................................................................................................................................191
Forcing the Issue................................................................................................................................................193
Making Sense of It All.........................................................................................................................................195
■Chapter 20: Working with Resources..........................................................197
The Resource Lineup..........................................................................................................................................197
String Theory......................................................................................................................................................198
viii