Flutter - How to remove iOS notification badge after opening app

Question

When I send a notification from Firebase Cloud Messaging, the notification badge shows up on the app icon, but there is no code to remove it.

The count of notifications do not matter so I don't have to have any notification counter or whatever, so all I need to do is clear the notification badge when the app is opened.

How can I accomplish this without rewriting my entire code for notifications (I barely got it working)?

This is the code:

_fcm.getToken().then((token) {
  print("The token is: " + token);
  setState(() {
    tokenSave = token;
  });
});

_fcm.requestPermission(
  sound: true,
  badge: true,
  alert: true,
  provisional: false,
);

FirebaseMessaging.onMessage.listen((RemoteMessage message) {
  RemoteNotification notification = message.notification;
  AndroidNotification android = message.notification?.android;
  if (notification != null && android != null) {
    flutterLocalNotificationsPlugin.show(
      notification.hashCode,
      notification.title,
      notification.body,
      NotificationDetails(
        android: AndroidNotificationDetails(
          channel.id,
          channel.name,
          channel.description,
          color: Colors.blue,
          playSound: true,
          icon: null,
        ),
      ),
    );
  }
});

FirebaseMessaging.onMessageOpenedApp.listen((RemoteMessage message) {
  print("onMessageOpenedApp event");
  RemoteNotification notification = message.notification;
  AndroidNotification android = message.notification?.android;
  if (notification != null && android != null) {
    showDialog(
        context: context,
        builder: (_) {
          return AlertDialog(
            title: Text(notification.title),
            content: SingleChildScrollView(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [Text(notification.body)],
              ),
            ),
          );
        });
  }
});

}

Answer 1

Add the following function to your AppDelegate.swift, under the application() function:

override func applicationDidBecomeActive(_ application: UIApplication) {
  application.applicationIconBadgeNumber = 0;
}