A (175)

xii Contents

Instantiate an Intent Object: An App’s Context  226

Explaining Context: The Android Context Class  227

Creating Your Second Activity: The EditGalaxy Class  228

Starting an Activity: Using the startActivity( ) Method  231

Coding the onCreate( ) Method: Using setContentView( )  232

Creating an EditGalaxy UI: Using a RelativeLayout  233

Using Editable Text Fields: The EditText Widget  234

Using Buttons in UI Designs: The Button Widget 235

Aligning Widgets Using RelativeLayout Parameters  235

Using the Eclipse Graphical Layout Editor (GLE)  237

Giving an EditText Field a Hint for Your Users  238

Aligning Several UI Elements Using RelativeLayout Parameters  240

Adding EditGalaxy to Your App: Editing Your AndroidManifest  243

Finishing Up the RelativeLayout UI Design  244

Using Baseline Alignment: The layout_alignBaseline Parameter  247

Adding a Graphics Asset to the RelativeLayout Container  249

Event Handling: Using Event Listeners  251

Creating an Event Listener: onClickListener( )  251

Creating an Event Listener: onClickListener( )  252

Making the Galaxy Object Accessible: Using The static Keyword  254

Transferring EditText Data to the Galaxy Object Using parse( ) Methods  255

Summary  257

■ Chapter 8: Android UI Design: Using Advanced ViewGroup Layout Containers ������������� 259

Using the Android GridLayout UI Container  260

GridLayout Class: Grid-Based UI Layout Designs  260

Using the rowSpec and columnSpec Parameters  261

GridLayout Location, Flexibility, and Gravity  262

The GridLayoutLayoutParams Nested Class: Parameters  263

The GridLayoutAlignment Nested Class: Alignment Constants  265

Converting a RelativeLayout UI to a GridLayout  268

Upgrading Your HelloUniverse App to Android 4 0  269

GridLayout Parent Parameters: Let’s Experiment!  272