在后台线程上下文中更新的可转换属性在合并到主线程上下文中时没有保存

Question

我有一个NSManagedObject，它包含一个日期列和一个可转换列(NSDictionary)。日期列和可转换列都是在后台线程自己的上下文中更新的，然后合并到主线程的上下文中。虽然日期列正在被正确更新和保存，但Transformable列却没有。可转换列以以下方式更新:

NSNotificationCenter *nc = [NSNotificationCenter defaultCenter]; 
[nc addObserver:self selector:@selector(mergeChanges:) name:NSManagedObjectContextDidSaveNotification object:managedObjectContext];
NSMutableDictionary *newUserDataDictionary = [NSMutableDictionary dictionaryWithDictionary:object.userDataDictionary];            
//Updated newUserDataDictionary here 
object.date = calendarDay.date;
object.userDataDictionary = newUserDataDictionary;
if (![managedObjectContext save:&error]) {
  NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
    abort();
}

在mergeChanges中:我有以下内容:

- (void)mergeChanges:(NSNotification *)notification
{    
AppDelegate *delegate = (AppDelegate*)[[UIApplication sharedApplication] delegate];
// Merge changes into the main context on the main thread
[delegate.managedObjectContext performSelectorOnMainThread:@selector(mergeChangesFromContextDidSaveNotification:)
                              withObject:notification
                           waitUntilDone:YES];  
}

请帮。

Answer 1

问题一定在mergeChangesFromContextDidSaveNotification方法中。检查是否正在调用此方法。