Popwindow在7.0系统上显示全屏

重写popwindow方法

    @Override
    public void showAsDropDown(View anchor) {
        if(Build.VERSION.SDK_INT == 24) {
            Rect rect = new Rect();
            anchor.getGlobalVisibleRect(rect);
            int h = anchor.getResources().getDisplayMetrics().heightPixels - rect.bottom;
            setHeight(h);
        }
        super.showAsDropDown(anchor);
    }