将NSPredicate与Core Data NSFetchedResultsController配合使用

本文介绍了将NSPredicate与Core Data NSFetchedResultsController配合使用的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我有一个fetchedResultsController，返回了我的实体帐户的所有记录。

我想快速搜索所有帐户记录的属性lastName= = value，并给我返回Account对象，或至少在fetchedResultsController中的对象的indexPath。

除了遍历每个objectAtIndexPath之外，是否有更好的方法使用NSPredicate搜索fetchController？

mootymoots，只是用另一个谓词过滤抓取的对象...

NSPredicate * lastNameMatch = ... NSArray * matchingFetchedObjects = [fetchedResultsController.fetchedObjects filteredArrayUsingPredicate：lastNameMatch];

这会使您的 fetchedResultsController 结果，但是给你一个数组，其中包含了最后一个名字谓词的匹配。

I have a fetchedResultsController that has returned all records for my entity "Account".

I would like to quickly search all Account records for the attribute "lastName" == value, and give me back the Account object, or at least the indexPath of the object in the fetchedResultsController. There should only be 1 object returned.

Other than iterate through every objectAtIndexPath, is there a better way to search the fetchController using NSPredicate?

解决方案

mootymoots, just filter the fetched objects with another predicate...

NSPredicate *lastNameMatch = ... NSArray *matchingFetchedObjects = [fetchedResultsController.fetchedObjects filteredArrayUsingPredicate:lastNameMatch];

That leaves your fetchedResultsController results un-altered, but gives you an array with a match for the last name predicate.