Android自定义View之--理解视图层

直接看代码吧！

public class MyButton extends Button {public MyButton(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);}public MyButton(Context context, AttributeSet attrs) {super(context, attrs);}public MyButton(Context context) {super(context);}@Overrideprotected void onDraw(Canvas canvas) {//文本之下Paint paint = new Paint();paint.setTextSize(55);paint.setColor(Color.BLUE);canvas.drawText("下面", canvas.getWidth()/2, canvas.getHeight()/2, paint);super.onDraw(canvas);//文本之上paint.setColor(Color.RED);canvas.drawText("上面", canvas.getWidth()/2-100, canvas.getHeight()/2, paint);}}

图解：