title: How to start specific screen when notification appear in flutter
body: <p>I am using <a href="https://pub.dev/packages/firebase_messaging" rel="nofollow noreferrer">firebase_messaging</a> for notification, everyting is work fine.
  I have a video calling screen I want to start this screen on notification when app in background.
  It's working fine when application in foreground.</p>
  
  <p>here is my firebase integration code: </p>
  
  <pre><code>final FirebaseMessaging _firebaseMessaging = FirebaseMessaging();
  _firebaseMessaging.configure(
        onMessage: (Map&lt;String, dynamic&gt; message) async {
          Map data = message["data"];
          if (data.isNotEmpty){
            Fcm.startRinging(data);
          } else {
            showNotification(title: "Message", body: "Telemedicine");
          }
        },
        onLaunch: (Map&lt;String, dynamic&gt; message) async {
          Map data = message["data"];
          print("OnLaunch::: $message");
          showNotification(title: "Message", body: "Telemedicine Call");
        },
        onBackgroundMessage: Fcm.myBackgroundMessageHandler,
        onResume: (Map&lt;String, dynamic&gt; message) async {
          Map data = message["data"];
          print("onResume::: $message");
  
        },
      );
  </code></pre>
  
  <p>Here I handle payload notification when application in background:</p>
  
  <pre><code>class Fcm{
    static Future&lt;dynamic&gt; myBackgroundMessageHandler(Map&lt;String, dynamic&gt; message) async {
      print("hello"+message.toString());
  
      if (message.containsKey('data')) {
        // Handle data message
        final dynamic data = message['data'];
        await startRinging(data);
        print(data);
      }
  
      if (message.containsKey('notification')) {
        // Handle notification message
        final dynamic notification = message['notification'];
        print(notification);
      }
  
      return Future&lt;void&gt;.value();
      // Or do other work.
    }
  
  
    static void startRinging(Map&lt;dynamic, dynamic&gt; data) async {
      print("start");
      String docName = data["DoctorName"];
      String docImage = data["DoctorImage"];
      String room = data["RoomName"];
      String token = data["PatientToken"];
      Route route = MaterialPageRoute(builder: (_)=&gt; CallResponse(
          docName: docName,
          docImage: docImage,
          token: token,
          roomName: room
      ));
      &lt;Here I am trying to start next route but i don't have BuildContext&gt;
  //    await Navigator.push(context, route);
    }
  }
  </code></pre>