Android ContentProvider 使用limit

String limit = item_favorites.Columns.MODIFIED + " desc limit 20 offset 0";

private void queryItemFavoriteList() {
		String limit = item_favorites.Columns.MODIFIED + " desc limit 20 offset 0"; 
		contentProviderHandler.startQuery(
				TOKEN_QUERY_ITEMFAVORITE,//Handler的msgWhat
				null,
				item_favorites.CONTENT_URI, //uri
				item_favorites.PROJECTION, //需要查询的字段
				null,
				null, 
//				item_favorites.Columns.MODIFIED.getName() + " DESC");//按最近的收藏时间排序
				limit);
	}