Android触控拖动事件处理

触控拖动屏幕事件一般情况下是重载onTouchEvent函数 实现方法如下

 

    /**mainView的坐标*/
    private float x, y;
    /**触屏事件处理*/
    public boolean onTouchEvent(MotionEvent event) {
        float x = event.getX();
        float y = event.getY();
        switch(event.getAction())
        {
        case MotionEvent.ACTION_DOWN:
            this.x = x;
            this.y = y;
        case MotionEvent.ACTION_MOVE:
            mainView.layout((int)(x - this.x), (int)(y - this.y), (int)(x + mainView.getWidth()
                    - this.x), (int)(y - this.y + mainView.getHeight()));

            break;
        case MotionEvent.ACTION_UP:
            if((Math.abs(this.y - y) < 10))
            {
                if(x - this.x > 30)
                {
                    MessageBox("向右移动");
                }else if(x - this.x < -30)
                {
                    MessageBox("向左移动");
                }
            }
            break;
        }
        mainView.postInvalidate();
        return super.onTouchEvent(event);
    }

处理控件拖动事件跟上边类似 可添加一个OnTouchListener到控件上

下边展示一个对Button按钮的拖动

 

        final Button btn = (Button) findViewById(R.id.btn_hello);

        btn.setOnTouchListener(new OnTouchListener() {
            int[] temp = new int[] { 0, 0 };

            public boolean onTouch(View v, MotionEvent event) {

                int eventaction = event.getAction();
                Log.i("&&&", "onTouchEvent:" + eventaction);

                int x = (int) event.getRawX();
                int y = (int) event.getRawY();

                switch (eventaction) {

                case MotionEvent.ACTION_DOWN: // touch down so check if the
                    temp[0] = (int) event.getX();
                    temp[1] = y - v.getTop();
                    break;

                case MotionEvent.ACTION_MOVE: // touch drag with the ball
                    v.layout(x - temp[0], y - temp[1], x + v.getWidth()
                            - temp[0], y - temp[1] + v.getHeight());

                    v.postInvalidate();
                    break;

                case MotionEvent.ACTION_UP:
                    break;
                }

                return false;
            }

        });

 

拖动事件主要就是在touch事件的envent中处理按下 移动 和 松开