Objective c NSFetchRequestController在iOS5上工作，在iOS4.3上崩溃

我一直在尝试在一个至少需要iOS 4.3的项目中实现核心数据。我让代码在iOS 5上正常工作，但在iOS 4.3上尝试时，代码崩溃的原因如下：

Unresolved error Error Domain=NSCocoaErrorDomain Code=134060 "The operation couldn’t be completed. (Cocoa error 134060.)" UserInfo=0x4fb59b0 {reason=The fetched object at index 4 has an out of order section name 'Å. Objects must be sorted by section name'}, {
reason = "The fetched object at index 4 has an out of order section name '\U00c5. Objects must be sorted by section name'";

这是我的密码：

- (NSFetchedResultsController *)fetchedResultsController
{
if (__fetchedResultsController != nil) {
    return __fetchedResultsController;
}

// Set up the fetched results controller.
// Create the fetch request for the entity.
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
// Edit the entity name as appropriate.

fetchRequest.entity = [NSEntityDescription entityForName:@"Exhibitor" 
                                  inManagedObjectContext:self.managedObjectContext];

// Edit the sort key as appropriate.
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name" 
                                                               ascending:YES 
                                                                selector:@selector(caseInsensitiveCompare:)];

fetchRequest.sortDescriptors = [NSArray arrayWithObject:sortDescriptor];

// Edit the section name key path and cache name if appropriate.
// nil for section name key path means "no sections".
NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] 
                                                         initWithFetchRequest:fetchRequest
                                                         managedObjectContext:self.managedObjectContext 
                                                         sectionNameKeyPath:@"firstLetter" 
                                                         cacheName:nil];
aFetchedResultsController.delegate = self;
self.fetchedResultsController = aFetchedResultsController;

NSError *error = nil;
if (![self.fetchedResultsController performFetch:&error]) {
    /*
     Replace this implementation with code to handle the error appropriately.

     abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. 
     */
    NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
    abort();
}

  return __fetchedResultsController;
}   

如果我在sortDesctriptor中选择使用caseInsensitivecompare:而不是localizedCaseInsensitiveCompare:它不会崩溃，但顺序是错误的（因为我需要ÄÖ在底部，而不是在A和O之后）

建议

更新：

---

似乎当我在多任务栏中关闭我的应用程序，然后重新启动它时，带有ÄÄÖ的顺序是正确的（使用caseInsensitiveCompare）。但只有在第一次重新启动之后。第一次发布时仍然是错误的…

您使用的是章节索引标题吗？这似乎就是这个错误所指的

只需添加：

-(NSString *)controller:(NSFetchedResultsController *)controller
             sectionIndexTitleForSectionName:(NSString *)sectionName {
   return sectionName;
}

---

到您的表视图控制器。

是否使用节索引标题？这似乎就是这个错误所指的

只需添加：

-(NSString *)controller:(NSFetchedResultsController *)controller
             sectionIndexTitleForSectionName:(NSString *)sectionName {
   return sectionName;
}

---

这实际上并没有解决localizedCaseInsensitiveCompare的问题，但它确实解决了caseInsensitiveCompare的错误顺序。所以这是一场胜利！因为我的应用程序只在瑞典语中本地化，所以它似乎可以自行解决问题。谢谢。这实际上并没有解决本地化caseInsensitiveCompare的问题，但它确实解决了caseInsensitiveCompare的错误顺序。所以这是一场胜利！因为我的应用程序只在瑞典语中本地化，所以它似乎可以自行解决问题。谢谢