Android简明开发教程十六：Button 画刷示例

将RadioButton 换成Button ，类似的在res/layout 中新建brush.xml： 

<?xml version=”1.0″ encoding=”utf-8″?>
<LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android”
    android:orientation=”vertical”
    android:background=”@drawable/white”
 android:layout_width=”fill_parent”
 android:layout_height=”fill_parent”>
    <com.pstreets.graphics2d.GuidebeeGraphics2DView
     android:id=”@+id/graphics2dview”
     android:layout_weight=”1″
     android:layout_width=”fill_parent”
     android:layout_height=”wrap_content”/>
 <LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android”
  android:layout_width=”wrap_content” android:layout_height=”wrap_content”
  android:orientation=”horizontal”
  
  >
  
   <Button android:text=”Pattern”
       android:id=”@+id/btnPattern”
    android:layout_width=”wrap_content”
    android:textColor=”@color/black”
    android:checked=”true”
    android:layout_height=”wrap_content”>
   </Button>
   <Button android:text=”Gradients”
        android:id=”@+id/btnGradients”
    android:layout_width=”wrap_content”
    android:textColor=”@color/black”
    android:layout_height=”wrap_content”>
   </Button>
 
 </LinearLayout> 

</LinearLayout> 

修改Brushes.java ,完整代码如下： 

public class Brushes extends Graphics2DActivity
   implements OnClickListener {

 private Button btnPattern;
 private Button btnGradients;

 public void onCreate(Bundle savedInstanceState) {
  super .onCreate(savedInstanceState);
  setContentView(R.layout.brush);
  graphic2dView = (GuidebeeGraphics2DView)
      findViewById(R.id.graphics2dview);
  btnPattern = (Button) findViewById(R.id.btnPattern);
  btnGradients = (Button) findViewById(R.id.btnGradients);
  btnPattern.setOnClickListener( this );
  btnGradients.setOnClickListener( this );
 }

 @Override
 protected void drawImage() {
  drawPatterns();

 }

 @Override
 public void onClick(View view) {
  if (view == btnPattern) {
   drawPatterns();
  } else {
   drawGradient();
  }
  graphic2dView.refreshCanvas();

 }

 private void drawPatterns() {
  TextureBrush brush1;
  TextureBrush brush2;
  TextureBrush brush3;

  AffineTransform matrix1 = new AffineTransform();
  AffineTransform matrix2 = new AffineTransform();
  Bitmap bitmap
    = BitmapFactory.decodeResource(getResources(),
    R.drawable.brick);
  int [] rgbData = new int [bitmap.getHeight()
                          * bitmap.getWidth()];
  bitmap.getPixels(rgbData, 0 , bitmap.getWidth(), 0 , 0 ,
    bitmap.getWidth(), bitmap.getHeight());
  brush1 = new TextureBrush(rgbData, bitmap.getWidth(),
    bitmap.getHeight());

  bitmap = BitmapFactory.decodeResource(getResources(),
    R.drawable.bird);
  rgbData = new int [bitmap.getHeight() * bitmap.getWidth()];
  bitmap.getPixels(rgbData, 0 , bitmap.getWidth(), 0 , 0 ,
    bitmap.getWidth(), bitmap.getHeight());
  brush2 = new TextureBrush(rgbData, bitmap.getWidth(),
    bitmap.getHeight());
  brush3 = new TextureBrush(rgbData, bitmap.getWidth(),
    bitmap.getHeight(), 127 );
  matrix2.translate( 50 , 50 );
  // Clear the canvas with white color.
  graphics2D.clear(Color.WHITE);
  graphics2D.setAffineTransform(matrix1);
  graphics2D.fillRectangle(brush1,
     new Rectangle( 20 , 50 , 100 , 100 ));
  graphics2D.fillOval(brush2, 10 , 10 , 80 , 80 );
  graphics2D.setAffineTransform(matrix2);
  graphics2D.fillOval(brush3, 10 , 10 , 80 , 80 );

 }

 private void drawGradient() {
  /* The linear gradient color */
  LinearGradientBrush brush1;
  /* The radial gradient color */
  RadialGradientBrush brush2;
  /* The second radial gradient color */
  RadialGradientBrush brush3;

  char [] engText = "Brush" .toCharArray();

  FontEx font = FontEx.getSystemFont();

  int fontSize = 44 ;
  int X = 15 ;
  int Y = 50 ;
  int [] fractions = new int [] { 13 , 242 };
  Color[] colors = new Color[] { new Color( 0xffff6600 ),
    new Color( 0xffffff66 ) };
  brush1 = new LinearGradientBrush( 50 , 50 , 150 , 125 ,
    fractions, colors,
    Brush.NO_CYCLE);

  fractions = new int [] { 13 , 128 , 255 };
  colors = new Color[] { new Color( 0xffff6600 ),
    new Color( 0xffffff66 ),
    new Color( 0xffff6600 ) };
  brush2 = new RadialGradientBrush( 90 , 100 , 50 ,
    fractions, colors);

  fractions = new int [] { 0 , 255 };
  colors = new Color[] { new Color( 0xFFFFFF00 ),
    new Color( 0xFF000000 ) };
  brush3 = new RadialGradientBrush( 50 , 50 , 100 ,
    fractions, colors);
  // Clear the canvas with white color.
  graphics2D.clear(Color.white);
  graphics2D.fillRectangle(brush1,
    new Rectangle( 10 , 75 , 120 , 80 ));

  Pen pen = new Pen(brush2, 8 );
  graphics2D.drawOval(pen, 20 , 60 , 100 , 50 );
  graphics2D.setDefaultBrush(brush3);
  pen = new Pen(brush2, 2 );
  graphics2D.setDefaultPen(pen);
  graphics2D.drawChars(font, fontSize, engText, 0 ,
    engText.length, X, Y);
 }

}

 

介绍了RadioButton和Button 后，这时应该对使用Android提供的控件的用法有了基本的认识。 控件提供了onClick(),onLongClick(),onFocusChange(),onKey(),onTouch(),onCreateContextMenu()等多种事件以相应用户。用多种方法来处理用户事件。一种是示例代码同过Activity实现OnClickListener接口，再有是采用如下代码为Button支持事件处理方法：

// Create an anonymous implementation of OnClickListenerprivate
OnClickListener mCorkyListener = new OnClickListener() {
   public void onClick(View v) {
   // do something when the button is clicked
   }
};

protected void onCreate(Bundle savedValues) {
   ...
   // Capture our button from layout
   Button button = (Button)findViewById(R.id.corky);
   // Register the onClick listener with the implementation above
   button.setOnClickListener(mCorkyListener);
   ...
 }

在创建自定义控件时，也可以重载onKeyDown(int, KeyEvent),onKeyUp(int, KeyEvent) ,onTouchEvent(MotionEvent)等来处理用户事件。