@Override
 public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
   int itemViewType = getItemViewType(position);
   switch (itemViewType) {
     case TYPE_TITLE:
       TitleViewHolder titleViewHolder = (TitleViewHolder) holder;
       if (position == 0) {
         titleViewHolder.bind("Top");
       } else {
         titleViewHolder.bind("Bottom");
       }
       break;
     case TYPE_ITEM:
       ItemViewHolder itemViewHolder = (ItemViewHolder) holder;
       if (position < topGridData.size() + 1) {
         itemViewHolder.bind(topGridData.get(position - 1));
       } else {
         itemViewHolder.bind(bottomGridData.get(position - topGridData.size() - 2));
       }
       break;
   }
 }