Events triggers multiple times. - Continuation of Issue 50

It is a continuation of issue 50. URL - https://github.com/CrossGeeks/FirebasePushNotificationPlugin/issues/50

My code setup is same as explained in issue 50.

I have register notification events in App class constructor. These events trigger multiple times on successive notification clicks. As these events are register every time I click on notification, it calls App class constructor using LoadApplication method in MainActivity in Xamarin.Android. I have tried removing registered event and then register again but still event called multiple times. 😦

Below code I tried but did not work.

public App()
        {
            InitializeComponent();

            MainPage = new MainPage();

            try
            {
                CrossFirebasePushNotification.Current.OnTokenRefresh -= FCM_OnTokenRefresh;
                CrossFirebasePushNotification.Current.OnTokenRefresh += FCM_OnTokenRefresh;
                CrossFirebasePushNotification.Current.OnNotificationReceived -= FCM_OnNotificationReceived;
                CrossFirebasePushNotification.Current.OnNotificationReceived += FCM_OnNotificationReceived;
                CrossFirebasePushNotification.Current.OnNotificationOpened -= FCM_OnNotificationOpened;
                CrossFirebasePushNotification.Current.OnNotificationOpened += FCM_OnNotificationOpened;
            }
            catch (Exception ex)
            {
                var msg = ex.Message;
            }


        }

[abrari]

Same here on Android, using the latest version of the plugin and all of the above workarounds.

Steps to reproduce:

1. Open app (first open)
2. Press back button, app exited
3. Reopen the app (second open)
4. Send a notification
5. Open the notification, the OnNotificationOpened event will be fired twice

If I exited and reopened the app for the third time, the OnNotificationOpened event will be fired three times. The number of app reopen is the number of the event fired.

[collaorodrigo7]

@ravikanasagra1 I do not know if you noticed they reference this issue on issue 14 In case you have not seen it and to help you is not you taping multiple times 😃 , what happens is that everytime you tap the notification a new instance of App gets created handling the event again, and that will happen everytime you open a new one. If you notice the more notifications you open, the more times you will see your event reaching.
This is the solution:

1. Is better to handle the events overriding the OnStart() method on App.xaml.cs

   protected override void OnStart()
   {
            // Handle when your app starts
            CrossFirebasePushNotification.Current.OnTokenRefresh += (s, p) =>{ //handle here };

            CrossFirebasePushNotification.Current.OnNotificationReceived += (s, p) =>{//handle here};
            CrossFirebasePushNotification.Current.OnNotificationOpened += async (s, p) =>{//handle here};
  }

1. As claudiocleberson explains on issue 14 , you should Put the LaunchMode = LaunchMode.SingleTop in the MainActivity class. That should do the trick. That means modify the line on top your main activity class like this:

[Activity(LaunchMode = LaunchMode.SingleTop, Label = "MainAuthApp", Icon = "@drawable/icon", Theme = "@style/MainTheme", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)]
    public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity{...}

1. Add this to your MainActivity.cs

using Android.Content;

1. Just like claudiocleberson explains later on #14 , Override OnNewIntent method on MainActivity

/// Called when the app is in the background and a notification is clicked on (also called each time the app is minimized and the brought back up), a new Intent is created
        /// and sent out, since we use LaunchMode set to SingleTop this method is called instead of the app being restarted.
        ///
        /// The Intent that was set when the call was made. If started from a notification click, extra string values can be extracted.
        protected override void OnNewIntent(Intent intent)
        {
            base.OnNewIntent(intent);
            FirebasePushNotificationManager.ProcessIntent(intent);
        }

I was having the same issues than you and I was able to fix it by following those steps. Let me know if it fixes the your problem or if you need more help. If you had already figured it out, hope it helps someone else.