unable to send messages From SendPort to ReceivePort in flutter - flutter

Question

I'm trying to send a message via the IsolateNameServer in flutter.
However, I am unable to receive messages. I've tried checking if the receiver port is listening by calling port.listen() twice, and it says that it is already listening.
Where am I going wrong? [ I am closely following this documentation ]
Here is my main.dart, based on the above doc:
import 'dart:isolate';
import 'dart:math';
import 'dart:ui';
import 'package:android_alarm_manager/android_alarm_manager.dart';
import 'package:flutter/material.dart';
final ReceivePort port = ReceivePort();
const String isolateName = 'isolate';
main() async {
WidgetsFlutterBinding.ensureInitialized();
IsolateNameServer.registerPortWithName(
port.sendPort,
isolateName,
);
runApp(MyApp());
}
class MyApp extends StatelessWidget {
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
accentColor: Colors.pink,
floatingActionButtonTheme:
FloatingActionButtonThemeData(backgroundColor: Colors.pink)),
home: AlarmManagerExample());
}
}
class AlarmManagerExample extends StatefulWidget {
#override
_AlarmManagerExampleState createState() => _AlarmManagerExampleState();
}
class _AlarmManagerExampleState extends State<AlarmManagerExample> {
#override
void initState() {
super.initState();
AndroidAlarmManager.initialize();
port.listen((_) async => await workForMe());
}
workForMe() async {
print("Secondary Function Triggered!");
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(),
body: Container(
child: RaisedButton(
onPressed: () async {
await AndroidAlarmManager.oneShot(const Duration(seconds: 5),
Random().nextInt(pow(2, 21)), callback);
},
child: Text(
"Alarm Manager",
),
),
),
);
}
static SendPort uiSendPort;
static callback() {
print("Callbacks Triggered!");
// This will be null if we're running in the background.
uiSendPort ??= IsolateNameServer.lookupPortByName(isolateName);
uiSendPort?.send(null);
}
}
The output I am getting is :
Callbacks Triggered!
However, the expected output is:
Callbacks Triggered!
Secondary Function Triggered!

Answer 1

I do believe that error is caused because the workForMe() function isn't static. Moreover, I don't know if callBacks support Future or async.
With that said, try this, as there is no need to make it async.
static void workForMe() {
print("Secondary Function Triggered!");
}