Flutter workmanager not work when app is terminated [2022] - flutter

Question

I'm trying in Android to show a local notification as a test, everything works fine if the app is foreground and background, but I need the notification to show when the app is terminated, which is this mode (when I terminate the app) workmanager doesn't work .
I have seen many questions and answers but I have not found anything clear, does anyone know how to make the notification appear when the application is finished? I don't want to use push notifications or Fcm, I know that, but I need to know how to do this locally.
my main.dart
I'm trying to show a local notification as a test, everything works fine if the app is foreground and background, but I need the notification to show when the app is terminated, which is this mode (when I terminate the app) workmanager doesn't work .
I have seen many questions and answers but I have not found anything clear, does anyone know how to make the notification appear when the application is finished? I don't want to use push notifications or Fmc, I know that, but I need to know how to do this locally.
my main.dart
import 'package:flutter/material.dart';
import 'package:workmanager/workmanager.dart';
import 'package:flutter_local_notifications/flutter_local_notifications.dart';
void callbackDispatcher() {
Workmanager.executeTask((task, inputData) async {
if (task == 'uniqueKey') {
///do the task in Backend for how and when to send notification
final FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
FlutterLocalNotificationsPlugin();
const AndroidNotificationDetails androidPlatformChannelSpecifics =
AndroidNotificationDetails('your channel id', 'your channel name',
'your channel description',
importance: Importance.max,
priority: Priority.high,
showWhen: false);
const NotificationDetails platformChannelSpecifics =
NotificationDetails(android: androidPlatformChannelSpecifics);
await flutterLocalNotificationsPlugin.show(
0,
'hello',
'1245',
platformChannelSpecifics,
payload: 'item x');
}
return Future.value(true);
});
}
Future<void> main() async {
WidgetsFlutterBinding.ensureInitialized();
Workmanager.initialize(
callbackDispatcher,
isInDebugMode:
true);
FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
FlutterLocalNotificationsPlugin();
const AndroidInitializationSettings initializationSettingsAndroid =
AndroidInitializationSettings(
'#mipmap/ic_launcher');
final IOSInitializationSettings initializationSettingsIOS =
IOSInitializationSettings();
final MacOSInitializationSettings initializationSettingsMacOS =
MacOSInitializationSettings();
final InitializationSettings initializationSettings = InitializationSettings(
android: initializationSettingsAndroid,
iOS: initializationSettingsIOS,
macOS: initializationSettingsMacOS);
await flutterLocalNotificationsPlugin.initialize(initializationSettings,
onSelectNotification: selectNotification);
runApp(const MyApp());
}
Future selectNotification(String payload) async {
if (payload != null) {
debugPrint('notification payload: $payload');
}
}
class MyApp extends StatelessWidget {
const MyApp({Key key}) : super(key: key);
#override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: const MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({Key key}) : super(key: key);
#override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
centerTitle: true,
title: const Text("Work manager Example"),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
ElevatedButton(
onPressed: () {
Workmanager.registerPeriodicTask(
"1",
"uniqueKey",
frequency: Duration(minutes: 15),
initialDelay: Duration(seconds:10),
);
print('START');
},
child: Text("Run Task")),
SizedBox(
height: 10,
),
ElevatedButton(
onPressed: () {
Workmanager.cancelByUniqueName("1");
print('cancel');
},
child: Text("Cancel Task"))
],
),
),
);
}
#override
void initState() {
// TODO: implement initState
super.initState();
}
}