Android触屏事件处理—2

  /**
     * Called when the activity is first created
     */
    @Override
    protected void onCreate(Bundle instance)
    {
        super.onCreate(instance);
        setContentView(new TouchMotionView(this));
    }
   
    /**
     * 思路：先加载类,继承view
     *       定义半径，x、y轴 ， Paint绘画工具对象、action_value  Motion Action值
     *       构造对象，初始化x、y轴 ，action_value
     *       初始化画布
     *       定义onTouchEvent事件处理
     *
     * 触屏控制显示画布  在画布上绘制小球
     *
     * @author  mickey
     * @version  1.0, 2012-8-2
     * @since  NLP V100R001C01
     */
    private class TouchMotionView extends View
    {
       
        private int RADIUS = 10;
       
        private Paint myPaint = new Paint();
       
        private int action_value;
       
        private float x_value, y_value;
       
        /**
         * constructor
         *
         * @param
         * @throws
         * @since NLP V100R001C01
         */
        public TouchMotionView(Context context)
        {
            super(context);
           
            action_value = MotionEvent.ACTION_UP;
           
            x_value = 0;
            y_value = 0;
        }
       
        /**
         * 获取坐标点  在画布上绘制小球
         * @param canvas
         */
        @Override
        protected void onDraw(Canvas canvas)
        {
            Paint paint = myPaint;
           
            canvas.drawColor(R.color.red);
           
            if (MotionEvent.ACTION_MOVE == action_value) // 移动动作
            {
                paint.setColor(Color.RED);
            }
            else if (MotionEvent.ACTION_UP == action_value)  // 抬起动作
            {
                paint.setColor(Color.WHITE);
            }
            else if (MotionEvent.ACTION_DOWN == action_value)  // 按下动作
            {
                paint.setColor(Color.GREEN);
            }
           
            canvas.drawCircle(x_value, y_value, RADIUS, paint); //半径长度
            setTitle("Action = " + action_value + " ["+ x_value +","+ y_value +"]");
        }
       
        @Override
        public boolean onTouchEvent(MotionEvent event)
        {
            action_value = event.getAction();  // 获得动作
           
            x_value = event.getX();   // 获得坐标
            y_value = event.getY();
           
            invalidate();  // 重新绘制
            return true;
        }
    }