android view画图笔记-1

1、一个简单的示例
 
Java代码 
public class View1 extends Activity { 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        setContentView(new SampleView(this)); 
    } 
     
    private static class SampleView extends View { 
        private Paint paint; 
        public SampleView(Context context) { 
            super(context); 
            //创建Paint 
            paint = new Paint(); 
            //设置抗锯齿效果 
            paint.setAntiAlias(true); 
            //设置画刷的颜色 
            paint.setColor(Color.BLUE); 
        } 
         
        @Override protected void onDraw(Canvas canvas) { 
//          canvas.drawColor(Color.WHITE); 
            paint.setStyle(Paint.Style.FILL); 
            canvas.drawRect(new RectF(10, 10, 100, 100), paint); 
            canvas.drawCircle(55, 145, 45, paint); 
             
            paint.setStyle(Paint.Style.STROKE); 
            canvas.drawRect(new RectF(110, 10, 200, 100), paint); 
            canvas.drawCircle(155, 145, 45, paint); 
             
            paint.setStyle(Paint.Style.FILL_AND_STROKE); 
            canvas.drawRect(new RectF(210, 10, 300, 100), paint); 
            canvas.drawCircle(255, 145, 45, paint); 
//          invalidate();