Local Notification Code

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter_local_notifications/flutter_local_notifications.dart';

void main() {
  runApp(
    new MaterialApp(home: MyApp()),
  );
}

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  late FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin;

  @override
  initState() {
    super.initState();
    // initialise the plugin. app_icon needs to be a added as a drawable resource to the Android head project
    // If you have skipped STEP 3 then change app_icon to @mipmap/ic_launcher
    var initializationSettingsAndroid =
        const AndroidInitializationSettings('icon');
    var initializationSettingsIOS = IOSInitializationSettings();
    var initializationSettings = InitializationSettings(
        android: initializationSettingsAndroid, iOS: initializationSettingsIOS);
    flutterLocalNotificationsPlugin = FlutterLocalNotificationsPlugin();
    //flutterLocalNotificationsPlugin.initialize(initializationSettings, onSelectNotification);
    flutterLocalNotificationsPlugin.initialize(initializationSettings,
        onSelectNotification: onSelectNotification);
  }

  Future _showNotificationWithoutSound() async {
    var androidPlatformChannelSpecifics = const AndroidNotificationDetails(
        'channel id', 'channel name',
        playSound: false, importance: Importance.max, priority: Priority.high);
    var iOSPlatformChannelSpecifics =
        IOSNotificationDetails(presentSound: false);
    var platformChannelSpecifics = NotificationDetails(
        android: androidPlatformChannelSpecifics,
        iOS: iOSPlatformChannelSpecifics);
    await flutterLocalNotificationsPlugin.show(
      0,
      'Title',
      'Content',
      platformChannelSpecifics,
      payload: 'No_Sound',
    );
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Plugin example app'),
        ),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            mainAxisSize: MainAxisSize.max,
            children: <Widget>[
              RaisedButton(
                onPressed: _showNotificationWithoutSound,
                child: Text('Show Notification Without Sound'),
              ),
            ],
          ),
        ),
      ),
    );
  }

  void onSelectNotification(String? payload) async { // when pressed the notification
    showDialog(
      context: context,
      builder: (_) {
        return new AlertDialog(
          title: Text("PayLoad"),
          content: Text("Payload : $payload"),
        );
      },
    );
  }
}