摘要: 首先,我们需要知道何谓谓词,让我们看看官方的解释: The NSPredicate class is used to define logical conditions used to constrain a search either for a fetch or for in-memory fi 阅读全文
posted @ 2016-06-28 10:39 子非余安知余子非 阅读(237) 评论(0) 推荐(0)