how to Make Notification Service in flutter and method channel(kotlin)

Question

i want to make a notification service without any click of a button,just like other apps such as whatsapp,messaging apps do,whenever message comes,it should show in android status bar.

Answer 1

I can tell the option if you want to get the message when app is open.Firebase messaging can be handled in 3 states in flutter

//onLaunch(completely closed - not in background)
_firebaseMessaging.getInitialMessage().then((RemoteMessage? message) {
  _sendFromNotificationClick(message);
});

//onMessage(app in open)
FirebaseMessaging.onMessage.listen((RemoteMessage? message) {
  _sendFromNotificationClick(message, isNavigate: false);
});

//onResume(app in background)
FirebaseMessaging.onMessageOpenedApp.listen((RemoteMessage? message) {
  _sendFromNotificationClick(message);
});

_sendFromNotification is a method to handle the state wise click event.You can use onMessage method if you want to show in appbar when the app is open.

    void _sendFromNotificationClick(RemoteMessage? message, {bool isNavigate = true}) {
    var data = message?.data;

    if(data != null) {
      var body = data['body'];
      var title = data['title'];
      var tradeCode = data['tradeCode'];
      var companyName = data['companyName'];
      var unreadCounterData = data['unreadCount'];

      if(unreadCounterData != null && unreadCounterData != "") {
        var unreadCounter = int.parse(unreadCounterData);

        SharedPref.read(keyJwtToken).then((jwt) {
          if(jwt != null) {
            if(unreadCounter > 0) {
              _notificationController.unreadCounter.value = unreadCounter;
            }

            if(isNavigate) {
              //do your operation on onClick
            } else if(title != null && body != null) { //your purpose,if you want to show message in appbar,set the message text as you want
              Get.snackbar(
                title,
                body,
                isDismissible: true,
                backgroundColor: fadeAshColor,
                snackPosition: SnackPosition.BOTTOM,
                icon: const Icon(
                  Icons.notifications,
                  color: colorPrimary,
                ),
              );
            }
          } else {
            EasyLoading.showError("Something went wrong!");
          }
        }).catchError((onError) {
          EasyLoading.showError(onError.toString());
        });
      }
    }
  }