如何判断滚动是向上还是向下？

Question

如果gridview滚动顶部或底部，我想删除所有数据并重新加载其他数据，但我不知道如何获取向上或向下滚动状态？我尝试使用

 @Override    
public boolean onTouchEvent(MotionEvent event) 

获取状态，但 onTouchEvent 未运行。

mygridview.setOnScrollListener(new OnScrollListener()
{         
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) 
{
}          

public void onScrollStateChanged(AbsListView view, int scrollState) 
{           
    switch (scrollState)
    {  
    case OnScrollListener.SCROLL_STATE_TOUCH_SCROLL:

       if (photolist_scroll_flag == 0)   //scroll up
       {
         if (has_loaded_item - page_item_num > 0)
         {
             LoadRemainingItems(); 
        }
      }
      else if (photolist_scroll_flag == 1)  //scroll down
      { 
        if (lastItem == view.getCount()) 
        {  
            if (has_loaded_item < listtotalitem)
            {    
                  LoadRemainingItems();  
            }    
         }  
     }
     break;  

     case OnScrollListener.SCROLL_STATE_FLING: 
        break;  

    case OnScrollListener.SCROLL_STATE_IDLE:
        break;  
    }
}      
});