private void moveToPosition(int n) {
    //先從RecyclerView的LayoutManager中獲取第一項(xiàng)和最后一項(xiàng)的Position
    int firstItem = mLinearLayoutManager.findFirstVisibleItemPosition();
    int lastItem = mLinearLayoutManager.findLastVisibleItemPosition();
    //然后區(qū)分情況
    if (n <= firstItem ){
    //當(dāng)要置頂?shù)捻?xiàng)在當(dāng)前顯示的第一個(gè)項(xiàng)的前面時(shí)
      mRecyclerView.scrollToPosition(n);
    }else if ( n <= lastItem ){
    //當(dāng)要置頂?shù)捻?xiàng)已經(jīng)在屏幕上顯示時(shí)
      int top = mRecyclerView.getChildAt(n - firstItem).getTop();
      mRecyclerView.scrollBy(0, top);
    }else{
    //當(dāng)要置頂?shù)捻?xiàng)在當(dāng)前顯示的最后一項(xiàng)的后面時(shí)
      mRecyclerView.scrollToPosition(n);
      //這里這個(gè)變量是用在RecyclerView滾動(dòng)監(jiān)聽里面的
      move = true;
    }

  }

class RecyclerViewListener extends RecyclerView.OnScrollListener{
    @Override
    public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
      super.onScrolled(recyclerView, dx, dy);
      //在這里進(jìn)行第二次滾動(dòng)（最后的100米?。?
      if (move ){
        move = false;
        //獲取要置頂?shù)捻?xiàng)在當(dāng)前屏幕的位置，mIndex是記錄的要置頂項(xiàng)在RecyclerView中的位置
        int n = mIndex - mLinearLayoutManager.findFirstVisibleItemPosition();
        if ( 0 <= n && n < mRecyclerView.getChildCount()){
          //獲取要置頂?shù)捻?xiàng)頂部離RecyclerView頂部的距離
          int top = mRecyclerView.getChildAt(n).getTop();
          //最后的移動(dòng)
          mRecyclerView.scrollBy(0, top);
        }
      }
    }
  }