获取listview当前滚动的高度

public int getScrollY() {

      View c = mListView.getChildAt(0);

      if  (c ==  null  ) {

          return  0;

      }

      int firstVisiblePosition = mListView.getFirstVisiblePosition();

      int top = c.getTop();

      return  -top + firstVisiblePosition * c.getHeight() ;

}