/**
  * 评论列表
  *
  * @param catalog 1新闻 2帖子 3动弹 4动态
  * @param id 某条新闻,帖子,动弹的id 或者某条留言的friendid
  * @param pageIndex
  * @return
  * @throws AppException
  */
 public CommentList getCommentList(int catalog, int id, int pageIndex, boolean isRefresh)
     throws AppException {
   CommentList list = null;
   String key = "commentlist_" + catalog + "_" + id + "_" + pageIndex + "_" + PAGE_SIZE;
   if (isNetworkConnected() && (!isReadDataCache(key) || isRefresh)) {
     try {
       list = ApiClient.getCommentList(this, catalog, id, pageIndex, PAGE_SIZE);
       if (list != null && pageIndex == 0) {
         Notice notice = list.getNotice();
         list.setNotice(null);
         list.setCacheKey(key);
         saveObject(list, key);
         list.setNotice(notice);
       }
     } catch (AppException e) {
       list = (CommentList) readObject(key);
       if (list == null) throw e;
     }
   } else {
     list = (CommentList) readObject(key);
     if (list == null) list = new CommentList();
   }
   return list;
 }