Ios 在swift 4中显示Firebase通知弹出窗口

注意：解决方案在底部。

原版。 我按照firebase上的说明在iOS中设置推送通知。我确实成功地获得了手机通知，如果应用程序关闭，我会在手机顶部显示通知，但如果我在应用程序中，则不会显示通知。我在终端上看到了打印件，所以我知道它收到了通知

理想的功能是： 1） 如果当用户单击通知时，应用程序已关闭或处于后台，则会打开应用程序，然后会显示应用程序内弹出警报，通知中会显示“确定”按钮以单击

2） 如果应用程序位于前台，通知将显示为弹出警报，并单击“确定”按钮

下面是AppDelegate.swift代码，当我运行它并发送通知时，我会收到通知，但在尝试显示警报时也会出现以下错误警告：尝试在视图不在窗口层次结构中的Company.AuthorizationCheckViewController上显示UIAlertController

谢谢你能提供的任何帮助

import UIKit
import GoogleMaps
import Sentry

import UserNotifications

import Firebase

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate  {

    var window: UIWindow?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        let userDefaults = UserDefaults.standard

        FirebaseApp.configure()
        Messaging.messaging().delegate = self

        if #available(iOS 10.0, *) {
            UNUserNotificationCenter.current().delegate = self

            let authOptions: UNAuthorizationOptions = [.alert, .badge, .sound]
            UNUserNotificationCenter.current().requestAuthorization(
                options: authOptions,
                completionHandler: {_, _ in })
        } else {
            let settings: UIUserNotificationSettings =
                UIUserNotificationSettings(types: [.alert, .badge, .sound], categories: nil)
            application.registerUserNotificationSettings(settings)
        }

        application.registerForRemoteNotifications()

        return true
    }

    func applicationWillResignActive(_ application: UIApplication) {
    }

    func applicationDidEnterBackground(_ application: UIApplication) {
    }

    func applicationWillEnterForeground(_ application: UIApplication) {

        VersionCheck.shared.IsUpdateRequired()
    }

    func applicationDidBecomeActive(_ application: UIApplication) {
    }

    func applicationWillTerminate(_ application: UIApplication) {
    }

    func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable: Any]) {
        if let messageID = userInfo["gcm.message_id"] {
            print("Message ID: \(messageID)")
        }

        let message : [String : Any] = userInfo["aps"] as! [String : Any]
        let messageAlert : [String : Any] = message["alert"] as! [String : Any]
        let lBody : String = messageAlert["body"] as! String
        let lTitle : String = messageAlert["title"] as! String

        print("body 1 = \(lBody)") //this works!
        print("title = \(lTitle)") //this works!

        let alert = UIAlertController(title:  lTitle, message: lBody, preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil);
        self.window?.rootViewController?.present(alert, animated: true, completion: nil)
    }

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

        let message : [String : Any] = userInfo["aps"] as! [String : Any]
        let messageAlert : [String : Any] = message["alert"] as! [String : Any]
        let lBody : String = messageAlert["body"] as! String
        let lTitle : String = messageAlert["title"] as! String

        print("body 2 = \(lBody)")
        print("title = \(lTitle)")

      let alert = UIAlertController(title:  lTitle, message: lBody, preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil);
        self.window?.rootViewController?.present(alert, animated: true, completion: nil)

        completionHandler(UIBackgroundFetchResult.newData)
    }
    func application(_ application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: Error) {
        print("Unable to register for remote notifications: \(error.localizedDescription)")
    }


    func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
        print("APNs token retrieved: \(deviceToken)")
    }

}

@available(iOS 10, *)
extension AppDelegate : UNUserNotificationCenterDelegate {

    func userNotificationCenter(_ center: UNUserNotificationCenter,
                                willPresent notification: UNNotification,
                                withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        let userInfo = notification.request.content.userInfo

        let message : [String : Any] = userInfo["aps"] as! [String : Any]
        let messageAlert : [String : Any] = message["alert"] as! [String : Any]
        let lBody : String = messageAlert["body"] as! String
        let lTitle : String = messageAlert["title"] as! String

        print("body 3 = \(lBody)")
        print("title = \(lTitle)")

        let alert = UIAlertController(title:  lTitle, message: lBody, preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
        self.window?.rootViewController?.present(alert, animated: true, completion: nil)

        completionHandler([UNNotificationPresentationOptions.alert])
    }

    func userNotificationCenter(_ center: UNUserNotificationCenter,
                                didReceive response: UNNotificationResponse,
                                withCompletionHandler completionHandler: @escaping () -> Void) {
        let userInfo = response.notification.request.content.userInfo
        if let messageID = userInfo["gcm.message_id"] {
            print("Message ID: \(messageID)") //can use the id later to privent multiple popups of the same message
        }

        let message : [String : Any] = userInfo["aps"] as! [String : Any]
        let messageAlert : [String : Any] = message["alert"] as! [String : Any]
        let lBody : String = messageAlert["body"] as! String
        let lTitle : String = messageAlert["title"] as! String

        print("body 4 = \(lBody)")
        print("title = \(lTitle)")

        let alert = UIAlertController(title:  lTitle, message: lBody, preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil)
        self.window?.rootViewController?.present(alert, animated: true, completion: nil)

        completionHandler()
    }
}

extension AppDelegate : MessagingDelegate {
    func messaging(_ messaging: Messaging, didReceiveRegistrationToken fcmToken: String) {
        print("Firebase registration token: \(fcmToken)")

        let dataDict:[String: String] = ["token": fcmToken]
        NotificationCenter.default.post(name: Notification.Name("FCMToken"), object: nil, userInfo: dataDict)whenever a new token is generated.
    }
    func messaging(_ messaging: Messaging, didReceive remoteMessage: MessagingRemoteMessage) {
        print("Received data message: \(remoteMessage.appData)")
    }
}

解决方案：

我添加了PresentedViewController？并允许显示警报弹出窗口。 另外，通过将UIBackgroundFetchResults.newData添加到completionHandler，我能够在应用程序中显示通知

新代码如下所示

let alert = UIAlertController(title:  lTitle, message: lBody, preferredStyle: .alert)
    alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
    self.window?.rootViewController?.presentedViewController?.present(alert, animated: true, completion: nil)

    completionHandler(UIBackgroundFetchResult.newData)