@Override
  public void onResume() {
    super.onResume();
    GroupSqlManager.registerGroupObserver(mGroupAdapter);
    mGroupAdapter.notifyChange();

    if (!sync) {
      GroupService.syncGroup(this);
      sync = true;
    }
  }
 @Override
 public void onSyncGroup() {
   mGroupAdapter.notifyChange();
   isRefresh = true;
 }