ios - NSFetchedResultsController 调用 didChangeObject 删除而不是更新

Question

这是代码，我通过 Magical Record 保存模型:

MagicalRecord.saveWithBlock({ (localContext) -> Void in
                    var localNotification = CDNotification.MR_findFirstByAttribute("notificationID", withValue: notification.notificationID, inContext: localContext) as CDNotification
                    localNotification.readNumber = NSNumber(bool: true)
                })

在调用上面的代码后调用删除而不是更新:

func controller(controller: NSFetchedResultsController, didChangeObject object: AnyObject, atIndexPath indexPath: NSIndexPath, forChangeType type: NSFetchedResultsChangeType, newIndexPath: NSIndexPath) {
    switch type {
    case NSFetchedResultsChangeType.Insert:
        self.tableView.insertRowsAtIndexPaths([newIndexPath], withRowAnimation: .Fade)
    case NSFetchedResultsChangeType.Update:
        if let cell = self.tableView.cellForRowAtIndexPath(indexPath){
            self.configureCell(cell as TableViewCell, atIndexPath: indexPath, withNotification: object as CDNotification)
        }
        self.tableView.reloadRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
    case NSFetchedResultsChangeType.Move:
        self.tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
        self.tableView.insertRowsAtIndexPaths([newIndexPath], withRowAnimation: .Fade)
    case NSFetchedResultsChangeType.Delete:
        self.tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
    default:
        return
    }
}

这只有在我为获取请求设置谓词时才会发生，例如:

fetchRequest.predicate = NSPredicate(format:"user == john")

Answer 1

这里发生的是，您得到的不是您期望的 NSFetchedResultsChangeUpdate 更改事件，而是一个 NSFetchedResultsChangeDelete 后跟 NSFetchedResultsChangeInsert。您还可能会看到 NSFetchedResultsChangeMove 具有与源和目标相同的 indexPath。这是 several beta versions of iOS 9 中的一个已知问题22380191和其他人。