Code

Dependencies

• device_info_plus
• firebase_messaging
• flutter_local_notifications
• http

Code triển khai

fcm_services.dart

import 'dart:io';

import 'package:device_info_plus/device_info_plus.dart';
import 'package:firebase_messaging/firebase_messaging.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter_local_notifications/flutter_local_notifications.dart';

import 'local_notitfication_helper.dart';
import 'package:http/http.dart' as http;

class FCMService {
  FCMService._();

  static FCMService? _instance;

  static FCMService get instance {
    return _instance ??= FCMService._();
  }

  final FirebaseMessaging _messaging = FirebaseMessaging.instance;

  /// FCM Token
  Future<String> _getFCMToken() async {
    return await _messaging.getToken() ?? '';
  }

  /// APN Token IOS -> dùng khi muốn gửi noti trực tiếp qua APNs mà không dùng FCM
  Future<String> _getAPNToken() async {
    await FirebaseMessaging.instance.requestPermission();
    return await _messaging.getAPNSToken() ?? '';
  }

  Future<String> getFCMRegistrationToken() async {
    final token = await _getFCMToken();
    if (kDebugMode) {
      print('FCM RegistrationToken: $token');
    }
    return token;
  }

  /// Call in main.dart to init FCM
  Future<void> init() async {
    LocalNotificationHelper.instance.init();
    _listenMessageOnForeground();
    _listenMessageOnBackground();
  }

  void _listenMessageOnForeground() {
    FirebaseMessaging.onMessage.listen((RemoteMessage message) {
      final RemoteNotification? notification = message.notification;

      if (notification != null) {
        showLocalNotification(notification);
      }
    });
  }

  void showLocalNotification(RemoteNotification notification) async {
    // Đặt id cho thông báo (nếu có)
    final notificationId = LocalNotificationHelper.generalNotificationId;
    final notificationTitle = notification.title;
    final notificationBody = notification.body;
    final notificationImageUrl =
        notification.android?.imageUrl ?? notification.apple?.imageUrl;

    BigPictureStyleInformation? bigPictureStyleInformation;

    if (notificationImageUrl != null) {
      final Uint8List? bitmap = await _getBytesFromUrl(notificationImageUrl);
      if (bitmap != null) {
        final bigPicture = ByteArrayAndroidBitmap(bitmap);
        bigPictureStyleInformation = BigPictureStyleInformation(
          bigPicture,
        );
      }
    }

    final androidNotificationDetails = AndroidNotificationDetails(
      LocalNotificationHelper.generalNotificationChannelId,
      LocalNotificationHelper.generalNotificationChannelName,
      importance: Importance.defaultImportance,
      priority: Priority.high,
      styleInformation: bigPictureStyleInformation,
    );
    final generalNotificationDetails = NotificationDetails(
      android: androidNotificationDetails,
    );

    LocalNotificationHelper.instance.showNotification(
      notificationId,
      notificationTitle,
      notificationBody,
      notificationDetails: generalNotificationDetails,
    );
  }

  void _listenMessageOnBackground() {
    FirebaseMessaging.onBackgroundMessage(onBackgroundMessage);
  }

  static Future<void> onBackgroundMessage(RemoteMessage message) async {
    final notification = message.notification;

    if (notification != null) {
      // Todo: Tuỳ chỉnh nếu cần
      // FCMService.instance.showLocalNotification(notification);
    }
  }

  Future<Uint8List?> _getBytesFromUrl(String url) async {
    final uri = Uri.tryParse(url);
    if (uri == null) {
      return null;
    }
    final response = await http.get(uri);
    return response.bodyBytes;
  }

  /// Device Id
  Future<String?> getDeviceId() async {
    final deviceInfoPlugin = DeviceInfoPlugin();
    if (Platform.isAndroid) {
      final AndroidDeviceInfo androidInfo = await deviceInfoPlugin.androidInfo;
      return androidInfo.id;
    } else if (Platform.isIOS) {
      final IosDeviceInfo iosInfo = await deviceInfoPlugin.iosInfo;
      return iosInfo.identifierForVendor;
    }

    return null;
  }
}

local_notification_helper.dart

import 'package:flutter_local_notifications/flutter_local_notifications.dart';

/// [LocalNotificationHelper] handle show local notification
/// 
class LocalNotificationHelper {
  LocalNotificationHelper._();

  static LocalNotificationHelper? _instance;

  static LocalNotificationHelper get instance {
    return _instance ??= LocalNotificationHelper._();
  }

  static const String generalNotificationChannelId = 'id-general-notifications';
  static const String generalNotificationChannelName = 'General notifications';
  static const int generalNotificationId = 321;

  final FlutterLocalNotificationsPlugin _notificationsPlugin =
  FlutterLocalNotificationsPlugin();

  @pragma('vm:entry-point')
  static Function(NotificationResponse notificationResponse)?
  onDidReceiveBackgroundNotificationResponse;

  void init({
    Function(NotificationResponse notificationResponse)?
    onDidReceiveNotificationResponse,
  }) async {
    final AndroidInitializationSettings initializationSettingsAndroid =
    AndroidInitializationSettings('@mipmap/ic_launcher');
    final DarwinInitializationSettings initializationSettingsDarwin =
    DarwinInitializationSettings();

    final InitializationSettings initializationSettings =
    InitializationSettings(
      android: initializationSettingsAndroid,
      iOS: initializationSettingsDarwin,
    );

    await _notificationsPlugin.initialize(
      initializationSettings,
      onDidReceiveNotificationResponse: onDidReceiveNotificationResponse,
      onDidReceiveBackgroundNotificationResponse:
      onDidReceiveBackgroundNotificationResponse,
    );
  }

  Future<void> showNotification(int id,
      String? title,
      String? body, {
        NotificationDetails? notificationDetails,
        String? payload,
      }) async {
    final AndroidNotificationDetails androidNotificationDetails =
    AndroidNotificationDetails(
      generalNotificationChannelId,
      generalNotificationChannelName,
      importance: Importance.defaultImportance,
      priority: Priority.high,
    );
    final generalNotificationDetails = NotificationDetails(
      android: androidNotificationDetails,
    );

    await _notificationsPlugin.show(
      id,
      title,
      body,
      notificationDetails ?? generalNotificationDetails,
    );
  }
}

Sử dụng

• Gọi FCMService.instance.init() trong main.dart

main.dart

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp(
    options: DefaultFirebaseOptions.currentPlatform,
  );

  await FCMService.instance.init();

  runApp(const MyApp());
}