插入或更新对象时，NSFetchedResultsController未检测到更改类型

Question

我有一个collectionView。集合的第二部分由NSFetchedResultsController填充。单元格由“收件人”对象填充。在另一个viewController上，我将视频添加到核心数据。视频是与收件人对象的关系。这是一对多的关系。一个收件人可以有多个视频，但是每个视频只能有一个收件人。视频存储为NSOrderedSet。使用时

编辑：这是NSFetchedResultsController的声明

  lazy var fetchedRC: NSFetchedResultsController<Recipient> = {
    let fetchRequest:NSFetchRequest<Recipient> = Recipient.fetchRequest()

    let reversedDescriptor = dateSortDescriptor.reversedSortDescriptor as! NSSortDescriptor


    fetchRequest.sortDescriptors = [dateSortDescriptor]

    let appDelegate = UIApplication.shared.delegate as! AppDelegate

    let managedContext = appDelegate.persistentContainer.viewContext

    let fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext:managedContext , sectionNameKeyPath: nil, cacheName: nil)

   fetchedResultsController.delegate = self

    return fetchedResultsController
}()

编辑：打算发布此方法。

 func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?) {

    switch type {
    case .insert:
        print("I inserted")
        break;
    case .delete:
        print("I deleted")
        break;
    case . update:
        print("I updated")
        break;
    default:
        print("I don't know")
    }


}

即使检测到更改，它总是返回我不知道的东西。

  let selectedPerson = personsArray[cellSelected] as? Recipient

    guard let currentContext = selectedPerson?.managedObjectContext else {
        print("I AM NOT SET")
        return
    }

    let video = Videos(context: currentContext)
    video.thumbNail = savedImageData
    video.urlPath = url
    video.isVideo = true
    video.isVoiceMemo = false
    video.isWrittenMemo = false
    video.uuID = uuid
    video.creationDate = NSDate()


    if let videos = selectedPerson?.videos?.mutableCopy() as? NSMutableOrderedSet {
        videos.add(video)
        selectedPerson?.latestMemoDate = NSDate()
        selectedPerson?.videos = videos
    }
        do {

        try selectedPerson?.managedObjectContext?.save()
        try video.managedObjectContext?.save()
        self.tableView.reloadData()

    }
    catch let error as NSError {
        print("Could not save. \(error), \(error.userInfo)")
    }