android 图片拖动

代码如下：

private ImageView mShowImage = (ImageView) findViewById(R.id.mShowImage);

mShowImage.setOnTouchListener(new View.OnTouchListener() {
            int startX = 0,startY = 0;//触摸屏幕时候得相对于ImageView的X,Y坐标
            int mX = 0, mY=0;//ImageView对于屏幕的左边距和右边距
            @Override
            public boolean onTouch(View v, MotionEvent e) {
                switch (e.getAction())
                {
                    case MotionEvent.ACTION_DOWN:
                        startX = (int) e.getX();
                        startY = (int) e.getY();
                        break;
                    case MotionEvent.ACTION_MOVE:
                        mX = (int) (e.getRawX() - startX);//当前触摸关于屏幕的X坐标减去关于ImageView的X坐标就是ImageView的左边距
                        mY = (int) (e.getRawY() - startY - getStatusBarHeight());//跟左边距原理相同，不过需要减去通知栏的高度，若全屏，则不需要减去通知栏高度
                        v.layout(mX,mY,mX+v.getWidth(),mY+v.getHeight());
                        break;
                }
                return true;
            }
        });


//获取通知栏高度
private int getStatusBarHeight(){
        Rect rect = new Rect();
        getWindow().getDecorView().getWindowVisibleDisplayFrame(rect);
        return rect.top;
    }