ios - CloudKit 中的 CKNotification 和 CKQueryNotification 有什么区别？

Question

有时，当我在第一台设备上执行更改(例如添加 40 条记录)时，我会在第二台设备上收到 40 CKQueryNotifications。

尽管我可以将 CKQueryNotifications 标记为已读，但我无法将 CKNotifications 标记为已读。为什么？每次启动后，他们总是回到我的设备。为什么？

如何获取待处理的通知？

var serverChangeToken: CKServerChangeToken? {
    return UserDefaults(suiteName: SharedGroupName)?.object(forKey: "a") as? CKServerChangeToken
}

func fetchPendingNotifications(notifications: [CKNotification] = [], completion: ErrorHandler? = nil) {

    var queryNotifications = notifications

    let operation = CKFetchNotificationChangesOperation(previousServerChangeToken: serverChangeToken)
    let operationQueue = OperationQueue()

    operation.notificationChangedBlock = { notification in

        print("+++++ \(notification)")
        queryNotifications.append(notification)
    }

    operation.fetchNotificationChangesCompletionBlock = { token, error in

        if let token = token {

            UserDefaults(suiteName: SharedGroupName)?.set(NSKeyedArchiver.archivedData(withRootObject: token), forKey: "a")
            UserDefaults(suiteName: SharedGroupName)?.synchronize()
        }

        if error == nil && operation.moreComing {
            self.fetchPendingNotifications(notifications: queryNotifications, completion: completion)
        } else {
            self.perform(queryNotifications: queryNotifications, completion: completion)
        }
    }

    operationQueue.addOperation(operation)
}

如何将通知标记为已读？

func perform(queryNotifications: [CKNotification], completion: ErrorHandler? = nil) {

    var currentQueryNotifications = queryNotifications

    if let queryNotification = currentQueryNotifications.first {

        currentQueryNotifications.removeFirst()

        let operation = CKMarkNotificationsReadOperation(notificationIDsToMarkRead: [queryNotification.notificationID!])
        operation.markNotificationsReadCompletionBlock = { _, _ in

            print("marked as read")
            self.perform(queryNotifications: currentQueryNotifications, completion: completion)
        }

        OperationQueue().addOperation(operation)

    } else {

        completion?(nil)
    }
}

控制台上的输出是什么？

+++++ , containerIdentifier=iCloud.pl.blueworld.fieldservice, badge=0>+++++ , containerIdentifier=iCloud.pl.blueworld.fieldservice, badge=0>+++++ , containerIdentifier=iCloud.pl.blueworld.fieldservice, badge=0>+++++ , containerIdentifier=iCloud.pl.blueworld.fieldservice, badge=0>+++++ , containerIdentifier=iCloud.pl.blueworld.fieldservice, badge=0>+++++ , containerIdentifier=iCloud.pl.blueworld.fieldservice, badge=0>+++++ , containerIdentifier=iCloud.pl.blueworld.fieldservice, badge=0>+++++ , containerIdentifier=iCloud.pl.blueworld.fieldservice, badge=0>+++++ , containerIdentifier=iCloud.pl.blueworld.fieldservice, badge=0>+++++ , containerIdentifier=iCloud.pl.blueworld.fieldservice, badge=0>+++++ , containerIdentifier=iCloud.pl.blueworld.fieldservice, badge=0>+++++ , containerIdentifier=iCloud.pl.blueworld.fieldservice, badge=0>+++++ , containerIdentifier=iCloud.pl.blueworld.fieldservice, badge=0>+++++ , containerIdentifier=iCloud.pl.blueworld.fieldservice, badge=0>marked as readmarked as readmarked as readmarked as readmarked as readmarked as readmarked as readmarked as readmarked as readmarked as readmarked as readmarked as readmarked as readmarked as read

Answer 1

关于为什么一直出现已读通知，文档直接与WWDC视频相矛盾。 Apple Docs清楚地说(强调):

If you mark one or more notifications as read using a CKMarkNotificationsReadOperation object, those notifications are not returned, even if you specify nil for previousServerChangeToken.

然而，WWDC 2014 视频 231 (Advanced Cloudkit) 清楚地表明，阅读通知不会被删除并且总是返回，因此用户的其他设备仍然可以看到它们.演示者甚至举了一个例子，引用了一个在所有设备上突出显示大笔交易的应用程序，一旦任何设备将通知标记为已读，任何其他设备都应该看到该“已读”通知并禁用突出显示。为此，他们必须能够仔细阅读标记为“已读”的通知。

因此，我们必须考虑通知的两个独立属性:

• 已读/未读状态:告诉我们用户的任何设备是否看到了此通知。
• 服务器更改 token :告诉我们在每个特定设备上查看了哪些通知。

将您收到的更改 token 保存在提取的完成 block 中，并将其传递给后续的提取。这是确保设备只看到"new"通知的唯一方法。使用已读/未读状态了解用户是否已在另一台设备上对事件进行操作。