/** 目標(biāo)項(xiàng)是否在最后一個(gè)可見項(xiàng)之后*/
 private boolean mShouldScroll;
 /** 記錄目標(biāo)項(xiàng)位置*/
 private int mToPosition;

 /**
 * 滑動(dòng)到指定位置
 * @param mRecyclerView
 * @param position
 */
 private void smoothMoveToPosition(RecyclerView mRecyclerView, final int position) {
 // 第一個(gè)可見位置
 int firstItem = mRecyclerView.getChildLayoutPosition(mRecyclerView.getChildAt(0));
 // 最后一個(gè)可見位置
 int lastItem = mRecyclerView.getChildLayoutPosition(mRecyclerView.getChildAt(mRecyclerView.getChildCount() - 1));

 if (position < firstItem) {
 // 如果跳轉(zhuǎn)位置在第一個(gè)可見位置之前，就smoothScrollToPosition可以直接跳轉(zhuǎn)
 mRecyclerView.smoothScrollToPosition(position);
 } else if (position <= lastItem) {
 // 跳轉(zhuǎn)位置在第一個(gè)可見項(xiàng)之后，最后一個(gè)可見項(xiàng)之前
 // smoothScrollToPosition根本不會(huì)動(dòng)，此時(shí)調(diào)用smoothScrollBy來滑動(dòng)到指定位置
 int movePosition = position - firstItem;
 if (movePosition >= 0 && movePosition < mRecyclerView.getChildCount()) {
 int top = mRecyclerView.getChildAt(movePosition).getTop();
 mRecyclerView.smoothScrollBy(0, top);
 }
 }else {
 // 如果要跳轉(zhuǎn)的位置在最后可見項(xiàng)之后，則先調(diào)用smoothScrollToPosition將要跳轉(zhuǎn)的位置滾動(dòng)到可見位置
 // 再通過onScrollStateChanged控制再次調(diào)用smoothMoveToPosition，執(zhí)行上一個(gè)判斷中的方法
 mRecyclerView.smoothScrollToPosition(position);
 mToPosition = position;
 mShouldScroll = true;
 }
 }

 mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
 @Override
 public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
 super.onScrollStateChanged(recyclerView, newState);
 if (mShouldScroll){
  mShouldScroll = false;
  smoothMoveToPosition(mRecyclerView,mToPosition);
 }
 }
 });
 }