CrossFirebasePushNotification.Current.OnNotificationReceived 事件只执行一次

Question

我在 Xamarin Forms 应用程序中使用带有 FCM 的推送通知，因此除了一个特定情况外，一切看起来都正常。

使用过的包：Plugin.FirebasePushNotification

事件CrossFirebasePushNotification.Current.OnNotificationReceived +=仅在应用打开和应用启动时被调用一次。

如果我从服务器发送 2 个或更多通知，则仅在第一个通知时调用它，之后停止工作。然而，无论如何都会显示通知弹出窗口，即使在前台、后台、已终止时也是如此。

我希望在应用打开时调用它，因为我需要根据通知数据执行操作。

我正在 iOS 15.3.1

中进行测试

说明：https://github.com/CrossGeeks/FirebasePushNotificationPlugin/blob/master/docs/GettingStarted.md

版本：

"Plugin.FirebasePushNotification" Version="3.4.1"
"Xamarin.Forms" Version="5.0.0.2337"

提前致谢。

我的整个AppDelegate.cs代码：

[Register("AppDelegate")]
    public partial class AppDelegate : global::Xamarin.Forms.Platform.iOS.FormsApplicationDelegate
    {
        NSObject _onKeyboardShowObserver;
        NSObject _onKeyboardHideObserver;
       
        //
        // This method is invoked when the application has loaded and is ready to run. In this 
        // method you should instantiate the window, load the UI into it and then make the window
        // visible.
        //
        // You have 17 seconds to return from this method, or iOS will terminate your application.
        //
        public override bool FinishedLaunching(UIApplication app, NSDictionary options)
        {
            Rg.Plugins.Popup.Popup.Init();
            Xamarin.FormsMaps.Init();

            Firebase.Core.App.Configure();

            global::Xamarin.Forms.Forms.Init();
            LoadApplication(new App());
            RegisterKeyBoardObserver();
            FirebasePushNotificationManager.Initialize(options, true);
            return base.FinishedLaunching(app, options);
        }
        public override void RegisteredForRemoteNotifications(UIApplication application, NSData deviceToken)
        {
            FirebasePushNotificationManager.DidRegisterRemoteNotifications(deviceToken);
        }

        public override void FailedToRegisterForRemoteNotifications(UIApplication application, NSError error)
        {
            FirebasePushNotificationManager.RemoteNotificationRegistrationFailed(error);

        }

        // To receive notifications in foreground on iOS 9 and below.
        // To receive notifications in background in any iOS version
        //[Export("application:didReceiveRemoteNotification")]
        [Export("messaging:didReceiveRemoteNotification:withCompletionHandler:")]
        public override void DidReceiveRemoteNotification(UIApplication application, NSDictionary userInfo, Action<UIBackgroundFetchResult> completionHandler)
        {
            // If you are receiving a notification message while your app is in the background,
            // this callback will not be fired 'till the user taps on the notification launching the application.

            // If you disable method swizzling, you'll need to call this method. 
            // This lets FCM track message delivery and analytics, which is performed
            // automatically with method swizzling enabled.
            FirebasePushNotificationManager.DidReceiveMessage(userInfo);
            // Do your magic to handle the notification data
            System.Console.WriteLine(userInfo);
            
            completionHandler(UIBackgroundFetchResult.NewData);            
        }

        void RegisterKeyBoardObserver()
        {
            if (_onKeyboardShowObserver == null)
                _onKeyboardShowObserver = UIKeyboard.Notifications.ObserveWillShow((object sender, UIKeyboardEventArgs args) =>
                {
                    NSValue result = (NSValue)args.Notification.UserInfo.ObjectForKey(new NSString(UIKeyboard.FrameEndUserInfoKey));
                    CGSize keyboardSize = result.RectangleFValue.Size;
                    MessagingCenter.Send<object, KeyboardAppearEventArgs>(this, Constants.iOSKeyboardAppears, new KeyboardAppearEventArgs { KeyboardSize = (float)keyboardSize.Height });
                });
            if (_onKeyboardHideObserver == null)
                _onKeyboardHideObserver = UIKeyboard.Notifications.ObserveWillHide((object sender, UIKeyboardEventArgs args) =>
                    MessagingCenter.Send<object, string>(this, Constants.iOSKeyboardDisappears, Constants.iOSKeyboardDisappears));
        }
        
        public override void WillTerminate(UIApplication application)
        {
            if (_onKeyboardShowObserver == null)
            {
                _onKeyboardShowObserver.Dispose();
                _onKeyboardShowObserver = null;
            }

            if (_onKeyboardHideObserver == null)
            {
                _onKeyboardHideObserver.Dispose();
                _onKeyboardHideObserver = null;
            }
        }
    }

Answer 1

一些故障排除建议。

1. 如Almis 所述，将代码放入App.cs 的OnStart。

2. 确保初始化正确，检查iOS Initialization。

如果问题仍然存在，请考虑在 github 上提出问题。

Answer 2

经过不同的测试，我可以找到导致问题的原因，但我不知道为什么。 我在OnNotificationReceived 事件中所做的一件事是通过调用NotificationCenter.Current.Show 方法显示本地推送通知，这就是导致问题的原因。当我注释调用 await NotificationCenter.Current.Show(notification) 的代码行时开始正常工作。

一旦NotificationCenter.Current.Show 被执行，CrossFirebasePushNotification 插件就会开始工作，就像我的应用程序在后台或前台一样。