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

    if (!sync) {
      GroupService.syncGroup(this);
      sync = true;
    }
  }
 @Override
 protected void notifyChange() {
   Cursor cursor = GroupSqlManager.getGroupCursor(true);
   setCursor(cursor);
   super.notifyDataSetChanged();
 }
 @Override
 public void onPause() {
   super.onPause();
   GroupSqlManager.unregisterGroupObserver(mGroupAdapter);
 }