Android可移动控件

可移动控件：

效果图：

获取屏幕的宽高：

        DisplayMetrics dm = getResources().getDisplayMetrics();
        screenWidth = dm.widthPixels;
        screenHeight = dm.heightPixels - 50;
        ImageView imageView = (ImageView)findViewById(R.id.spirit_img);
        imageView.setOnTouchListener(this);

onTouch设定： 

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        int action = event.getAction();
        switch (action){
            case MotionEvent.ACTION_DOWN:
                lastX = (int) event.getRawX();
                lastY = (int) event.getRawY();
                break;
            case MotionEvent.ACTION_MOVE:
                int dx =(int)event.getRawX() - lastX;
                int dy =(int)event.getRawY() - lastY;
                int left = v.getLeft() + dx;
                int top = v.getTop() + dy;
                int right = v.getRight() + dx;
                int bottom = v.getBottom() + dy;
                if(left < 0){
                    left = 0;
                    right = left + v.getWidth();
                }
                if(right > screenWidth){
                    right = screenWidth;
                    left = right - v.getWidth();
                }
                if(top < 0){
                    top = 0;
                    bottom = top + v.getHeight();
                }
                if(bottom > screenHeight){
                    bottom = screenHeight;
                    top = bottom - v.getHeight();
                }
                v.layout(left, top, right, bottom);
                lastX = (int) event.getRawX();
                lastY = (int) event.getRawY();
                break;
        }
        return false;
    }

layout的办法有一个问题，viewgroup里面的其他东西刷新，imageview就会归位。