final someNotifier = ChangeNotifierProvider((ref) => _SomeState());

class _SomeState extends ChangeNotifier {
  late Box box; // <- you can even use hive here

  _SomeState() {
    box = Hive.box('someBox');
  }

  void someMethod() {
    // some code...

    notifyListeners(); // <- this wil ensure all observers will be notified of value change
  }
}

class SomePage extends ConsumerWidget {
  SomePage({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final stateProvider = ref.watch(someNotifier); // <- and now you have access to the provider

    return ... // whatever;
  }
}

class SomeStateFulPage extends ConsumerStatefulWidget {
  const SomeStateFulPage({super.key});

  @override
  _SomeStatefulPageState createState() => _SomeStatefulPageState();
}

class _SomeStatefulPageState extends ConsumerState<SomeStateFulPage> {
	_SomeStatefulPageState();

	@override
	Widget build(BuildContext context) {
		final stateProvider = ref.watch(someNotifier); // <- same thing, you have access to the provider

		return ... // whatever
	}
}

  runApp(const ProviderScope(
    child: MyApp(),
  ));

import 'package:hive/hive.dart';

part 'SomeHiveClass.g.dart'; // <- this file will be generated by command

@HiveType(typeId: 1)
class SomeHiveClass {
  SomeHiveClass({
    required this.name,
    required this.url,
    this.maxZoom = 18,
    this.minZoom = 4,
  });

  @HiveField(0)
  late String name;

  @HiveField(1)
  late String url;

  @HiveField(2, defaultValue: 18)
  late double maxZoom;

  @HiveField(3, defaultValue: 4)
  late double minZoom;
}

Future main() async {
  await Hive.initFlutter();

  Hive.registerAdapter(HivePlotAdapter()); // <- that generated .g.dart file

  await Hive.openBox('currentPlotBox'); // <- name of the box that stores data

  runApp(const ProviderScope( // <- this is from riverpod
    child: MyApp(),
  ));
}

import 'dart:developer';

import 'package:flutter_local_notifications/flutter_local_notifications.dart';

class NotificationService {
  static final NotificationService _singleton =
      new NotificationService._internal();

  var initializationSettingsAndroid = const AndroidInitializationSettings(
    '@mipmap/ic_launcher',
  );

  late InitializationSettings initializationSettings;
  var flutterLocalNotificationsPlugin = FlutterLocalNotificationsPlugin();

  factory NotificationService() {
    return _singleton;
  }

  NotificationService._internal() {
    initializationSettings = InitializationSettings(
      android: initializationSettingsAndroid,
    );

    flutterLocalNotificationsPlugin.initialize(
      initializationSettings,
      onDidReceiveBackgroundNotificationResponse: inspect,
      onDidReceiveNotificationResponse: inspect,
    );
  }

  Future showNotification() async {
    var androidPlatformChannelSpecifics = const AndroidNotificationDetails(
        'Channel id', 'ChannelName',
        importance: Importance.defaultImportance,
        priority: Priority.defaultPriority);

    var platformChannelSpecifics = NotificationDetails(
      android: androidPlatformChannelSpecifics,
    );

    await flutterLocalNotificationsPlugin.show(
      0,
      'Notification Alert 🔔',
      'Message - There is a new notification on your account, kindly check it out',
      platformChannelSpecifics,
      payload:
          'Message - There is a new notification on your account, kindly check it out',
    );
  }
}