Flutter FCM is not showing popup in terminated state

I'm setting up push notifications via FCM and LocalPushNotifications, I was able to set it up in foreground state of app and in the background. But not In terminated state of the app. have set up every thing According to documentation but still face this issue
kindly do check my code if I'm doing anything wrong

@pragma('vm:entry-point')
Future<void> _firebaseMessagingBackgroundHandler(RemoteMessage message) async {
await Firebase.initializeApp(options: DefaultFirebaseOptions.currentPlatform);
await setupFlutterNotifications();
showFlutterNotification(message);
// If you're going to use other Firebase services in the background, such as Firestore,
// make sure you call `initializeApp` before using other Firebase services.
print('Handling a background message ${message.messageId}');
}
/// Create a [AndroidNotificationChannel] for heads up notifications
late AndroidNotificationChannel channel;
bool isFlutterLocalNotificationsInitialized = false;
Future<void> setupFlutterNotifications() async {
if (isFlutterLocalNotificationsInitialized) {
return;
}
channel = const AndroidNotificationChannel(
'high_importance_channel', // id
'High Importance Notifications', // title
description:
'This channel is used for important notifications.', // description
importance: Importance.high,
);
flutterLocalNotificationsPlugin = FlutterLocalNotificationsPlugin();
await flutterLocalNotificationsPlugin
.resolvePlatformSpecificImplementation<
AndroidFlutterLocalNotificationsPlugin>()
?.createNotificationChannel(channel);
await FirebaseMessaging.instance.setForegroundNotificationPresentationOptions(
alert: true,
badge: true,
sound: true,
);
isFlutterLocalNotificationsInitialized = true;
}
void showFlutterNotification(RemoteMessage message) {
RemoteNotification? notification = message.notification;
AndroidNotification? android = message.notification?.android;
if (notification != null && android != null && !kIsWeb) {
flutterLocalNotificationsPlugin.show(
notification.hashCode,
notification.title,
notification.body,
NotificationDetails(
android: AndroidNotificationDetails(
channel.id,
channel.name,
channelDescription: channel.description,
icon: 'ic_launcher',
),
),
);
}
}
/// Initialize the [FlutterLocalNotificationsPlugin] package.
late FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin;
Future<void> main() async {
WidgetsFlutterBinding.ensureInitialized();
await Firebase.initializeApp(options: DefaultFirebaseOptions.currentPlatform);
// Set the background messaging handler early on, as a named top-level function
FirebaseMessaging.onBackgroundMessage(_firebaseMessagingBackgroundHandler);
if (!kIsWeb) {
await setupFlutterNotifications();
}
// } catch (e) {}
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
home: const MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({super.key, required this.title});
// This widget is the home page of your application. It is stateful, meaning
// that it has a State object (defined below) that contains fields that affect
// how it looks.
// This class is the configuration for the state. It holds the values (in this
// case the title) provided by the parent (in this case the App widget) and
// used by the build method of the State. Fields in a Widget subclass are
// always marked "final".
final String title;
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
void sub() async {
var pref = await SharedPreferences.getInstance();
bool sb = pref.getBool('sub') ?? false;
if (!sb) {
await FirebaseMessaging.instance.subscribeToTopic('foosbar');
await pref.setBool('sub', true);
}
}
@override
void initState() {
super.initState();
sub();
FirebaseMessaging.instance.getInitialMessage();
FirebaseMessaging.onMessage.listen(showFlutterNotification);
FirebaseMessaging.onMessageOpenedApp.listen((RemoteMessage message) {
print('A new onMessageOpenedApp event was published!');
});
}
@override
Widget build(BuildContext context) {
// This method is rerun every time setState is called, for instance as done
// by the _incrementCounter method above.
//
// The Flutter framework has been optimized to make rerunning build methods
// fast, so that you can just rebuild anything that needs updating rather
// than having to individually change instances of widgets.
return Scaffold(
appBar: AppBar(
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text(widget.title),
),
body: Center(
// Center is a layout widget. It takes a single child and positions it
// in the middle of the parent.
child: Column(
// Column is also a layout widget. It takes a list of children and
// arranges them vertically. By default, it sizes itself to fit its
// children horizontally, and tries to be as tall as its parent.
//
// Invoke "debug painting" (press "p" in the console, choose the
// "Toggle Debug Paint" action from the Flutter Inspector in Android
// Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
// to see the wireframe for each widget.
//
// Column has various properties to control how it sizes itself and
// how it positions its children. Here we use mainAxisAlignment to
// center the children vertically; the main axis here is the vertical
// axis because Columns are vertical (the cross axis would be
// horizontal).
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
const Text(
'You have pushed the button this many times:',
),
Text(
'',
style: Theme.of(context).textTheme.headlineMedium,
),
],
),
),
// This trailing comma makes auto-formatting nicer for build methods.
);
}
}

onBackgroundMessage handles the messages when the app is terminated. If you're sending data-only payload, it will be ignored as it is considered low priority. You should set the priority to high in this case.

I almost spent more than 3 hours to debug this issue and the problem was:
Channel Id and name must be same as the channel Id which we get from firebase when we call onMessage or any other get message fuction.
so first we have to get the RemoteMessage from FirebaseMessaging.onMessage.

void getFirebaseNotification() {
FirebaseMessaging.onMessage.listen((message) {
showRemoteMessages(message);
});
}

Here's showRemoteMessages function and it is just showing the notification data.

void showRemoteMessages(RemoteMessage messages) {
settingAndoidNotifications(messages);
initializeNotifications();
notificationsPlugin.show(id, messages.notification!.title,
messages.notification!.body, notificationDetails(),
payload: "Timer Notification");
id++;
}

Here initializeNotifications() is just initializing the plugin and do not get confuse with "id" you can put any integer here.

AndroidNotificationDetails? androidNotificationDetails;
void settingAndoidNotifications(RemoteMessage message) {
AndroidNotificationChannel channel = AndroidNotificationChannel(
message.notification!.android!.channelId!.toString(),
message.notification!.android!.channelId.toString(),
importance: Importance.max);
androidNotificationDetails = AndroidNotificationDetails(
channel.id, channel.name,
importance: Importance.max, priority: Priority.max, showWhen: true,
ticker: 'ticker',
playSound: true, color: Colors.blue,
//  sound: UriAndroidNotificationSound()
);
}

This function is creating Android channel and assigning the Firebase's channel id to Android Notification channel.