我正在尝试设置静默推送通知，以使用CloudKit在设备之间传播本地通知，而我无法为每次收到远程通知时我的应用程序崩溃的原因而费解。

一切正常，直到我尝试处理收到的通知为止。尝试访问didReceiveRemoteNotification中CKQueryNotification对象的recordID时发生崩溃。

我正在注册应用程序didFinishlaunchingWithOptions内部的远程通知。这是其余的代码：

在didRegisterForRemoteNotification中，我正在为记录类型CD_Task创建CKSubscription。

   func application(_ application: UIApplication,didRegisterForRemoteNotificationsWithdevicetoken devicetoken: Data) {

        let subscription = CKQuerySubscription(recordType: "CD_Task",predicate: NSPredicate(format: "TRUEPREDICATE"),options: .firesOnRecordCreation)

        let info = CKSubscription.NotificationInfo()            
        subscription.notificationInfo = info

        CKContainer.default().privatecloudDatabase.save(subscription,completionHandler: { subscription,error in
            if error == nil {
                // Subscription saved successfully
            } else {
                // Error occurred,handle it
            }
        })
    }

在DidReceiveRemoteNotification中，我将CKQueryNotification对象传递给处理从iCloud接收的远程通知的函数：

   func application(_ application: UIApplication,didReceiveRemoteNotification userInfo: [AnyHashable : Any],fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
        if let ckqn = CKQueryNotification(fromRemoteNotificationDictionary: userInfo as! [String:NSObject]) {
            self.iCloudHandleNotification(ckqn)
        }
    }

最后，这是iCloudHandleNotification函数代码：

        func iCloudHandleNotification(_ ckqn: CKQueryNotification) {
                    switch ckqn.queryNotificationReason {
                    case .recordCreated:
                        // This is where it crashes.. when I try to access ckqn.recordID
                        CKContainer.default().privatecloudDatabase.fetch(withRecordID: ckqn.recordID!) { (record,error) in
                            if let record = record {
                                // Handle creating local notif for record
                            } else if let error = error {
                                print("Unable to retrieve record: \(error)")
                            }
                        }
                    default:
                        break
                 }
        }

编辑：

调查之后，好像我得到的是CKDatabaseNotification而不是CKQueryNotification －我应该如何指定我想要CKQueryNotification？