小编You*_*uer的帖子

我尝试Timer在接到电话后 12 秒添加超时，CallKit但是Appdelegate当应用程序处于后台时它不会被触发。我的代码：

self.callBackgroundHandlerIdentifier = UIApplication.shared.beginBackgroundTask(expirationHandler: { 
            UIApplication.shared.endBackgroundTask(self.callBackgroundHandlerIdentifier!)
            self.callBackgroundHandlerIdentifier = UIBackgroundTaskInvalid
        })
        DispatchQueue.global(qos: .userInitiated).async {
            AppDelegate.callAnswerTimer = Timer.scheduledTimer(timeInterval: 12, target: self, selector: #selector(AppDelegate.hangUpOnCallTimeOut), userInfo: nil, repeats: false)

            self.callBackgroundHandlerIdentifier = UIBackgroundTaskInvalid
        }

func hangUpOnCallTimeOut(){
        AppDelegate.timeOutTimer?.invalidate()
        AppDelegate.timeOutTimer = nil
        if #available(iOS 10.0, *) {
            ProviderDelegate.sharedInstance.endCall(uuids: ApplicationDelegate.activeCalls!) { (uuid) in }
        }
        if self.callBackgroundHandlerIdentifier != UIBackgroundTaskInvalid {
            UIApplication.shared.endBackgroundTask(self.callBackgroundHandlerIdentifier!)
        }
    }

任何想法我做错了什么？