Ошибка отображения локальных уведомлений во Flutter

Question

Я использую плагин flutter_local_notifications и стандартное приложение по умолчанию.

Это код, который я использую -

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

void main() async {
  FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
      FlutterLocalNotificationsPlugin();

// added boat.png in the drawables folder
  const AndroidInitializationSettings initializationSettingsAndroid =
      AndroidInitializationSettings('boat.png');

  final InitializationSettings initializationSettings = InitializationSettings(
    android: initializationSettingsAndroid,
    iOS: null,
    macOS: null,
  );
  await flutterLocalNotificationsPlugin.initialize(initializationSettings,
      onSelectNotification: selectNotification);

  void showNotification() async {
    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, 'plain title', 'plain body', platformChannelSpecifics,
        payload: 'item x');
  }

  showNotification();
  runApp(MyApp());
}

Future selectNotification(String payload) async {
  if (payload != null) {
    debugPrint('notification payload: $payload');
  }
  // Modified the example code - it navigated to a different screen. I am just printing the payload
  print(payload); 
}

Примечание. Я использую плагин исключительно для приложений Android. Итак, я не настраивал его для iOS или macOS.

Подозреваю, что неправильно использую плагин. Но я выполнил все инструкции на сайте плагина.

Я получил это сообщение об ошибке -

      E/flutter ( 5446): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: Null check operator used on a null value
E/flutter ( 5446): #0      MethodChannel.binaryMessenger (package:flutter/src/services/platform_channel.dart:142:86)
E/flutter ( 5446): #1      MethodChannel.setMethodCallHandler (package:flutter/src/services/platform_channel.dart:378:5)
E/flutter ( 5446): #2      AndroidFlutterLocalNotificationsPlugin.initialize (package:flutter_local_notifications/src/platform_flutter_local_notifications.dart:84:14)
E/flutter ( 5446): #3      FlutterLocalNotificationsPlugin.initialize (package:flutter_local_notifications/src/flutter_local_notifications_plugin.dart:120:13)
E/flutter ( 5446): #4      main (package:desktop_test/main.dart:16:41)
E/flutter ( 5446): #5      _runMainZoned.<anonymous closure>.<anonymous closure> (dart:ui/hooks.dart:146:25)
E/flutter ( 5446): #6      _rootRun (dart:async/zone.dart:1354:13)
E/flutter ( 5446): #7      _CustomZone.run (dart:async/zone.dart:1258:19)
E/flutter ( 5446): #8      _runZoned (dart:async/zone.dart:1789:10)
E/flutter ( 5446): #9      runZonedGuarded (dart:async/zone.dart:1777:12)
E/flutter ( 5446): #10     _runMainZoned.<anonymous closure> (dart:ui/hooks.dart:139:5)
E/flutter ( 5446): #11     _delayEntrypointInvocation.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:283:19)
E/flutter ( 5446): #12     _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:184:12)
E/flutter ( 5446):