当点击 FCM 推送通知时，如何在选项卡栏中打开特定的视图控制器？答案

【问题标题】：How do I open a particular view controller in a tab bar when a FCM push notification is tapped?当点击 FCM 推送通知时，如何在选项卡栏中打开特定的视图控制器？
【发布时间】：2021-04-11 19:18:41
【问题描述】：

每当我在应用关闭时点击推送通知，应用就会一直崩溃。如果它在后台或当我点击推送通知时打开，那么它加载就好了。

我已经尝试过这里的建议：Swift - How to open specific view controller when push notification received?

以下是应用委托中的相关功能。没有注册任何用于确定导致崩溃的确切位置的打印功能，因此我无法正确调试。我看到的唯一消息是：

来自调试器的消息：由于信号 9 而终止

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        
        // Navigation customization
        UIBarButtonItem.appearance().setTitleTextAttributes([NSAttributedString.Key.foregroundColor: UIColor(hex: Constants.Colors.primary)!, NSAttributedString.Key.font: UIFont(name: "NexaLight", size: 18)!], for: UIControl.State.normal)
        
        UIBarButtonItem.appearance().setTitleTextAttributes([NSAttributedString.Key.foregroundColor: UIColor(hex: Constants.Colors.primary)!, NSAttributedString.Key.font : UIFont(name: "NexaBold", size: 18)! ], for: .highlighted)
        
        UIBarButtonItem.appearance().setTitleTextAttributes([NSAttributedString.Key.foregroundColor: UIColor(hex: Constants.Colors.secondary)!, NSAttributedString.Key.font : UIFont(name: "NexaBold", size: 18)! ], for: .focused)
        
        ApplicationDelegate.shared.application( application, didFinishLaunchingWithOptions: launchOptions )
        
        if #available(iOS 10.0, *) {
          // For iOS 10 display notification (sent via APNS)
          UNUserNotificationCenter.current().delegate = self
        }
        
        // Firebase
        FirebaseApp.configure()
        
        // APN FCM
        Messaging.messaging().delegate = self
        
        // Stripe
        StripeAPI.defaultPublishableKey = "test"
        
        // Google sign-in
        GIDSignIn.sharedInstance()?.clientID = "test"

        return true
    }

func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {


    if let window = (UIApplication.shared.connectedScenes.first?.delegate as? SceneDelegate)?.window {
        guard let rootViewController = (UIApplication.shared.connectedScenes.first?.delegate as? SceneDelegate)?.window?.rootViewController else { return }
        if let tabBarController = rootViewController as? MainTabBarController {
            tabBarController.selectedIndex = 1
            window.rootViewController = tabBarController
            window.makeKeyAndVisible()
        } 
    }

completionHandler()
}

【问题讨论】：

您正在做的是，您正在从窗口中提取 rootViewController。但是当应用程序关闭时，没有与窗口关联的 rootViewController。所以你没有设置任何 rootViewController，但是 window 需要一个 rootView 来显示内容，这就是你的应用程序崩溃的原因。但是当应用程序处于后台或活动状态时，它正在工作，因为您从窗口获取 rootViewController，您明白我的意思吗？
我明白你在说什么。看起来我正在做与您在另一个线程中的回答中指出的相同的事情，除了我没有使用故事板。

标签： swift push-notification

【解决方案1】：

这是我解释的代码

func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {

    if let window = (UIApplication.shared.connectedScenes.first?.delegate as? SceneDelegate)?.window {
        if let rootViewController = (UIApplication.shared.connectedScenes.first?.delegate as? SceneDelegate)?.window?.rootViewController {
            if let tabBarController = rootViewController as? MainTabBarController {
                tabBarController.selectedIndex = 1
                window.rootViewController = tabBarController
                window.makeKeyAndVisible()
            }
        } else {
            let tabBarController = UIStoryboard(name: "main", bundle: .main).instantiateViewController(identifier: "MainTabBarController") as? MainTabBarController
            tabBarController.selectedIndex = 1
            window.rootViewController = tabBarController
            window.makeKeyAndVisible()
        }
    }
    completionHandler()
}

【讨论】：