Ios NSNotification未从调度异步内部激发

我有以下代码：

在会话completionHandler中，我有一个dispatch_async，其中包含对NSNotificationCenter post通知方法的调用。但是通知从来没有被激发过任何想法

NSURLSession *session = [NSURLSession sharedSession];

[[session dataTaskWithURL:[NSURL URLWithString:url] completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {

    // populating appDelegate.statusItems variable ///// 

   ....... 

    dispatch_async(dispatch_get_main_queue()
                   , ^{

                       [[NSNotificationCenter defaultCenter] postNotificationName:@"DataReceived" object:nil userInfo:@{@"StatusItems":appDelegate.statusItems}];

                        [self performSegueWithIdentifier:@"DashboardSegue" sender:nil];
                   });



}]resume];

在LoginViewController（代码在上面）中，我还为侦听器注册了通知，但从未调用它们：

    -(void) setupNotifications
    {
        ViewController *viewController = [self.storyboard instantiateViewControllerWithIdentifier:@"ViewController"];

        [viewController registerNotifications];

    }


-(void) registerNotifications
{
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(populateList:) name:@"DataReceived" object:nil];
}

- (void)viewDidLoad
{
    [super viewDidLoad];
}

-(void) populateList:(NSNotification *) notification
{
    NSDictionary *dict = notification.userInfo;

    _statusItems =  [dict valueForKey:@"StatusItems"];

    dispatch_async(dispatch_get_main_queue(), ^{
        [self.tableView reloadData];
    });

}

---

是否调用registerNotifications方法？您是否必须使用[self registerNotifications]而不是[viewController registerNotifications]仪表板Segue类接收通知。可能会在创建此视图之前发送通知。