layoutmanager.FindFirstCompletelyVisibleItemPosition總是返回-1

我在我的android項目中有一個recyclerview，它顯示了每個視圖中的媒體內容。我想要實現的是我可以在上下滾動時播放/暫停媒體。我需要獲取完全可見視圖的適配器位置。我正在做這樣的事情。layoutmanager.FindFirstCompletelyVisibleItemPosition總是返回-1

在我的活動片段我有這樣的：

 layoutmanager = new LinearLayoutManager(Activity); 

     adapter = new FeedAdapter(vid, userName, this.Context); 

     feeditem.SetLayoutManager(layoutmanager); 
     feeditem.SetAdapter(adapter); 

     var onScrollListener = new XamarinRecyclerViewOnScrollListener(Activity, layoutmanager, adapter);

滾動監聽事件是這樣的：

public override void OnScrollStateChanged(RecyclerView recyclerView, int newState) 
    { 
     base.OnScrollStateChanged(recyclerView, newState); 

     if (newState == (int)ScrollState.Idle) 
     { 
      layoutmanager = (LinearLayoutManager)recyclerView.GetLayoutManager(); 

      int firstVisiblePosition = layoutmanager.FindFirstCompletelyVisibleItemPosition(); 
      int visible = layoutmanager.FindFirstVisibleItemPosition(); 
      int last = layoutmanager.FindLastVisibleItemPosition(); 
      if (firstVisiblePosition >= 0) 
      { 
       if (oldFocusedLayout != null) 
       { 
        Toast.MakeText(ctx, "Stop Video", ToastLength.Long).Show(); 
       } 


      } 
      currentFocusedLayout = layoutmanager.FindViewByPosition(firstVisiblePosition); 

      Toast.MakeText(ctx, "Play video", ToastLength.Long).Show(); 

      oldFocusedLayout = currentFocusedLayout; 

     } 
    } 

     feeditem.AddOnScrollListener(onScrollListener);

的問題是LinearLayout中管理方法FindFirstCompletelyVisibleItemPosition總是返回-1，即使視圖完全可見。其他方法如FindFirstVisibleItemPosition和FindLastVisibleItemPosition給出了視圖的正確位置。

任何想法可能是這裏的問題？

來源

2016-05-21 Ahmed Mujtaba