我有一个使用无声通知订阅的程序:letpredicate=NSPredicate(format:"recordID==%@",CKRecordID(recordName:"ListName"))letsilentNotification=CKNotificationInfo()silentNotification.shouldSendContentAvailable=truesilentNotification.desiredKeys=["Update"]letsubscription=CKSubscription(recordType:"Lists",predicate:predic