# Flutter 好用package - flutter_local_notifications 介紹

## flutter_local_notifications
顯示通知訊息，通常搭配 firebase 做使用，在安著手機雖然收得到通知但當你正在使用 APP 時通知是不會顯示； IOS 手機上則是會依據設定正常顯示，為處理此狀況故安裝此套件做使用，此情況在[官網](https://firebase.flutter.dev/docs/messaging/notifications/#foreground-notifications)有進行描述並推薦此套件進行使用。

flutter pub add flutter_local_notifications

[官網](https://pub.dev/packages/flutter_local_notifications)

### 程式範例

import 'package:flutter_local_notifications/flutter_local_notifications.dart';

class NotificationService {
  static final NotificationService _notificationService =
      NotificationService._internal();
  factory NotificationService() {
    return _notificationService;
  }

  NotificationService._internal();

  static const channelId = '1';

  final FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
      FlutterLocalNotificationsPlugin();

  static const AndroidNotificationDetails _androidNotificationDetails =
      AndroidNotificationDetails(
    channelId,
    "推播通知",
    playSound: true,
    priority: Priority.high,
    importance: Importance.high,
  );
  static const DarwinNotificationDetails _iOSNotificationDetails =
      DarwinNotificationDetails();

  final NotificationDetails notificationDetails = const NotificationDetails(
    android: _androidNotificationDetails,
    iOS: _iOSNotificationDetails,
  );

  Future<void> init() async {
    const AndroidInitializationSettings androidInitializationSettings =
        AndroidInitializationSettings('@mipmap/launcher_icon');

    const DarwinInitializationSettings iOSInitializationSettings =
        DarwinInitializationSettings(
      defaultPresentAlert: false,
      defaultPresentBadge: false,
      defaultPresentSound: false,
    );

    const InitializationSettings initializationSettings =
        InitializationSettings(
      android: androidInitializationSettings,
      iOS: iOSInitializationSettings,
    );

    await flutterLocalNotificationsPlugin.initialize(
      initializationSettings,
    );
  }

  Future<void> requestIOSPermissions() async {
    await flutterLocalNotificationsPlugin
        .resolvePlatformSpecificImplementation<
            IOSFlutterLocalNotificationsPlugin>()
        ?.requestPermissions(
          alert: true,
          badge: true,
          sound: true,
        );
  }

  Future<void> showNotification(int id, String title, String body) async {
    await flutterLocalNotificationsPlugin.show(
      id,
      title,
      body,
      notificationDetails,
    );
  }

  Future<void> cancelNotification(int id) async {
    await flutterLocalNotificationsPlugin.cancel(id);
  }

  Future<void> cancelAllNotifications() async {
    await flutterLocalNotificationsPlugin.cancelAll();
  }
}

###### tags: `flutter` `firebase`