ios – 如何忽略NSManagedObjectContextWillSaveNotification中mergeChangesFromContextDidSaveNotification中的更改

我正在使用私有托管对象上下文在持久性存储中创建一些新对象,然后在保存私有MOC之后,使用mergeChangesFromContextDidSaveNotification将它们合并到主MOC中.这工作正常,并根据需要更新UI,并且此处不为mainMOC调用NsmanagedObjectContextWillSaveNotification.

然后我使用UI对mainMOC进行一些更改,并监听NsmanagedObjectContextWillSaveNotification.通知已发布,但它不仅包含我所做的编辑,还包含使用mergeChangesFromContextDidSaveNotification从PrivateMOC合并的对象.

有没有办法在后续的contextDidChange通知中忽略从另一个上下文合并到mainContext中的更改？

这是设置：

- (void) loadData {
   privateContext = [[NsmanagedObjectContext alloc] initWithConcurrencyType: NSPrivateQueueConcurrencyType];

   privateContext.persistentStoreCoordinator = self.mainContext.persistentStoreCoordinator;

   [[NsnotificationCenter defaultCenter] addObserver:self
                                         SELEctor:@SELEctor(contextWillSave:)
                                             name:NsmanagedObjectContextWillSaveNotification
                                           object: self.mainContext];

   NsmanagedObject *object = [NSEntityDescription insertNewObjectForEntityForName:record.recordType inManagedObjectContext: self.privateContext];

   // fill in object

   if ([self.privateContext hasChanges]) {
       [self savePrivateContextAndMergeWithMainContext: self.privateContext];
   }
}

- (void) savePrivateContextAndMergeWithMainContext: (NsmanagedObjectContext *) privateContext {
    [[NsnotificationCenter defaultCenter] addObserver:self SELEctor:@SELEctor(privateContextDidChange:) name:NsmanagedObjectContextDidSaveNotification object:privateContext];
    __block NSError *error = nil;
    [privateContext performBlockAndWait:^{
        NSLog(@"PrivateContext saved");
        [privateContext save:&error];
    }];


    [[NsnotificationCenter defaultCenter] removeObserver:self name:NsmanagedObjectContextDidSaveNotification object:privateContext];

    if (error) {
        NSLog(@"error = %@",error);
    }
}

- (void) privateContextDidChange: (Nsnotification *) notification{

    [self.mainContext performBlockAndWait:^{
        NSLog(@"merged into mainContext");
        [self.mainContext mergeChangesFromContextDidSaveNotification:notification];
    }];
}

这样可以正常工作并保存私有上下文并且合并到mainContext中不会触发contextWillSave通知.但是,在从UI(在主MOC上)编辑数据时,会触发通知并包含先前使用私有MOC保存的数据.

希望很清楚.如果我应该包含其他任何内容,请告诉我.

– 更新 –

似乎问题是专门从私有上下文中删除对象.从私有上下文中删除,并在主MOC上@L_455_0@mergeChangesFromContextDidSaveNotification后,mainMoc的deletedObjects集仍然@L_450_10@已删除的对象.私有上下文中的插入或更新不会发生这种情况.这在任何地方记录？可能的@L_262_12@是什么？

- (void) privateContextDidChange: (Nsnotification *) notification{
    if (notification.object == PrivateMOC) {
        [self.mainContext performBlockAndWait:^{
            NSLog(@"merged into mainContext");
            [self.mainContext mergeChangesFromContextDidSaveNotification:notification];
        }];
    }
}