@Override
 public View getView(int position, View convertView, ViewGroup parent) {
   if (convertView != null && convertView.getTag() instanceof BaseHolder) {
     mHolder = (BaseHolder) convertView.getTag();
   } else {
     mHolder = getHolder(mContext); // 1
   }
   mHolder.setData(mDatas.get(position)); // 2
   return mHolder.getRootView();
 }