firebase-messaging - Fatal: failed to find callback

Question

I\'m trying to use FCM messaging and keep getting this error.

E/FlutterFcmService( 3684): Fatal: failed to find callback

Below is the code I\'ve

Answer 1

You should declare a backgroundMessageHandler function that is outside a class or as a static function, in order to be reached from outside, and then you pass this function to fbm.configure:

Future myBackgroundMessageHandler(Map message) {
  print('on background $message');
}

fbm.configure(
      onMessage: (msg) {
        print(msg);
        return;
      },
      onLaunch: (msg) {
        print(msg);
        return;
      },
      onResume: (msg) {
        print(msg);
        return;
      },
      onBackgroundMessage: myBackgroundMessageHandler
);

Also open your_project_folder/android/app/source/AndroidManifest.xml and paste this XML code after existing intent-filter code of your main Activity:

The result will be similar to the following code: