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我试图设置一个基本的NSFetchedResultsController
,它从我们下面的错误抛出一个“空”的错误。由于错误和它的userInfo都是null,我不知道我甚至可以开始做什么来解决发生了什么问题。这是“让你的头撞到砖墙上,不被告知为什么”节目的时刻之一。这里是造成崩溃的部分,这是在viewDidLoad
:从错误返回的NULL错误NSFetchedResultsController
NSError *error;
if (![_fetchedResultsController performFetch: &error]) {
NSLog(@"Error! %@, %@", error, [error userInfo]);
abort();
}
而这里的那台控制器最多的方法:
- (NSFetchedResultsController *) fetchedResultsController
{
if (_fetchedResultsController != nil) {
return _fetchedResultsController;
}
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName: @"Quote" inManagedObjectContext: [self managedObjectContext]];
[fetchRequest setEntity:entity];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:nil ascending: YES];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
[fetchRequest setFetchBatchSize: 50];
NSFetchedResultsController *theFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest: fetchRequest managedObjectContext: [self managedObjectContext] sectionNameKeyPath: nil cacheName: @"Root"];
self.fetchedResultsController = theFetchedResultsController;
_fetchedResultsController.delegate = self;
return _fetchedResultsController;
}
我在做什么错?
似乎就是这样,谢谢。我得到一个对象不能是零阵列现在错误.. – Luke 2013-02-25 12:42:23
我得到它在这一行上︰NSFetchedResultsController theFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:[self managedObjectContext] sectionNameKeyPath:nil cacheName: @ “”]; ' – Luke 2013-02-25 12:44:09
@lukech当你分配视图控制器时,你保留了managedObjectContext吗? B.t.w,最好是提出一个新问题,而不是继续回答下面的评论。 :) – Kjuly 2013-02-25 12:47:19