android控件跟随手势滑动改变位置

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/wei11556/article/details/72818568

    private View.OnTouchListener shopCarSettleTouch = new View.OnTouchListener() {
        int lastX, lastY;

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            int ea = event.getAction();
            DisplayMetrics dm = getResources().getDisplayMetrics();
            int screenWidth = dm.widthPixels;
//            int screenHeight = dm.heightPixels - 100;//需要减掉图片的高度
            int screenHeight = dm.heightPixels;//需要减掉图片的高度
            switch (ea) {
                case MotionEvent.ACTION_DOWN:
                    lastX = (int) event.getRawX();//获取触摸事件触摸位置的原始X坐标
                    lastY = (int) event.getRawY();
                case MotionEvent.ACTION_MOVE:
                    //event.getRawX();获得移动的位置
                    int dx = (int) event.getRawX() - lastX;
                    int dy = (int) event.getRawY() - lastY;
                    int l = v.getLeft() + dx;
                    int b = v.getBottom() + dy;
                    int r = v.getRight() + dx;
                    int t = v.getTop() + dy;

                    //下面判断移动是否超出屏幕
                    if (l < 0) {
                        l = 0;
                        r = l + v.getWidth();
                    }
                    if (t < 0) {
                        t = 0;
                        b = t + v.getHeight();
                    }
                    if (r > screenWidth) {
                        r = screenWidth;
                        l = r - v.getWidth();
                    }
                    if (b > screenHeight) {
                        b = screenHeight;
                        t = b - v.getHeight();
                    }
                    v.layout(l, t, r, b);
                    Log.e(TAG, "onTouch: " +l+"=="+t+"=="+r+"=="+b);
                    lastX = (int) event.getRawX();
                    lastY = (int) event.getRawY();
                    v.postInvalidate();
                    break;
                case MotionEvent.ACTION_UP:
                    break;
            }
            return true;
        }

};

使用方法：

iv = (ImageView) findViewById(R.id.iv);
iv.setOnTouchListener(shopCarSettleTouch);