ScrollView的滚动监听setOnScrollChangeListener

当子控件移出可视范围后的处理及当子控件出现在可视范围的处理：

goodsScroll.setOnScrollChangeListener(new View.OnScrollChangeListener() {    @Override    public void onScrollChange(View view, int x, int y, int oldX, int oldY) {        Rect scrollRect = new Rect();        goodsScroll.getHitRect(scrollRect);        //子控件在可视范围内（至少有一个像素在可视范围内）        if (llNum.getLocalVisibleRect(scrollRect)) {            llNum.setVisibility(View.VISIBLE);            ll_numBottom.setVisibility(View.INVISIBLE);        } else {            ////子控件完全不在可视范围内            llNum.setVisibility(View.INVISIBLE);            ll_numBottom.setVisibility(View.VISIBLE);        }    }});