ios - 在特定的 viewController 中处理 PushNotifcations

Question

当我的应用程序处于前台时，我正在尝试处理 PushNotifcation。如果刚刚激活的 ViewController 是特定的，我想重新加载它的数据。如果它处于非事件状态，我希望我的应用实例化一个特定的 viewController

这是我在 appDelegate 中的代码:

    func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any], fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {

    if userInfo["matchInfo"] != nil {

        if application.applicationState == .active {

            if self.window!.rootViewController is chatUebersichtTVC{
                let uebersicht = self.window!.rootViewController as! chatUebersichtTVC
                uebersicht.refresh()
            }
            else{
            return
            }


        }
        else{
            print ("trying to activate")
            let mainStoryBoard:UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
            let chat:chatUebersichtTVC = mainStoryBoard.instantiateViewController(withIdentifier: "chatUebersichtTVC") as! chatUebersichtTVC
            let mainPageNav = UINavigationController(rootViewController: chat)
            let appDelegate:AppDelegate = UIApplication.shared.delegate as! AppDelegate
            appDelegate.window?.rootViewController = mainPageNav
        }



    }
      else{
               PFPush.handle(userInfo)

     }
             completionHandler(.newData)

 } 

我能够到达 self.window!.rootViewController is chatUebersichtTVC 行但它不会在之后执行。此外，当应用程序关闭时，它总是会打开最后打开的 Controller ，而不是特定的 chatUebersichTVC。

我做错了什么？

Answer 1

以下是使用NotificationCenter的示例代码:

首先，您必须声明通知名称。在 Swift 3 之前，我们使用字符串来实现此目的，现在它应该作为Notification.Name 的扩展来完成:

extension Notification.Name {
    static let pushNotificationReceived = Notification.Name("pushNotificationReceived")
}

现在您可以在您的方法中发布通知:

func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any], fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {    
    if userInfo["matchInfo"] != nil {
        if application.applicationState == .active {
            NotificationCenter.default.post(name: Notification.Name.pushNotificationReceived, object: nil)
        }
        else{
            //create a new view controller and add it to the hierarchy
        }
    }
    completionHandler(.newData)
}

现在任何对象都可以监听此通知并执行其需要的任何操作。您只需在需要时订阅和取消订阅即可。在您的情况下，明智的做法是在 viewWillAppear 和 viewDidDisappear 方法中执行此操作:

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    NotificationCenter.default.addObserver(self, selector: #selector(ViewController.refresh), name: Notification.Name.pushNotificationReceived, object: nil)
}

override func viewDidDisappear(_ animated: Bool) {
    super.viewDidDisappear(animated)
    NotificationCenter.default.removeObserver(self, name: Notification.Name.pushNotificationReceived, object: nil)
}

func refresh() {
    //do your stuff here
}