【Flutter】プッシュ通知機能の実装のメモ

import 'package:firebase_messaging/firebase_messaging.dart';

FirebaseMessaging messaging = FirebaseMessaging.instance;
String? token = await FirebaseMessaging.instance.getToken();

import 'package:flutter/material.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:firebase_messaging/firebase_messaging.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter_local_notifications/flutter_local_notifications.dart';

import '../screens/screen.dart';

final FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
    FlutterLocalNotificationsPlugin();

AndroidNotificationChannel channel = const AndroidNotificationChannel(
  'high_importance_channel', // id
  'High Importance Notifications', // title
  description:'This channel is used for important notifications.', // description
  importance: Importance.high,
);

Future<void> saveTokenToDatabase(String token) async {
  // Assume user is logged in for this example
  String? userId = FirebaseAuth.instance.currentUser?.uid;

  try {
    await FirebaseFirestore.instance.collection('users').doc(userId).update({
      'tokens': FieldValue.arrayUnion([token]),
    });
  } catch (e) {
    await FirebaseFirestore.instance.collection('users').doc(userId).set({
      'tokens': FieldValue.arrayUnion([token]),
    });
  }
}

class Application extends StatefulWidget {
  const Application({Key? key}) : super(key: key);

  @override
  State<StatefulWidget> createState() => _Application();
}

class _Application extends State<Application> {

  Future<void> setupInteractedMessage() async {
    FirebaseMessaging messaging = FirebaseMessaging.instance;
    await messaging.requestPermission(
      alert: true,
      announcement: false,
      badge: true,
      carPlay: false,
      criticalAlert: false,
      provisional: false,
      sound: true,
    );
    String? token = await FirebaseMessaging.instance.getToken();
    await saveTokenToDatabase(token!);

    RemoteMessage? initialMessage =
        await FirebaseMessaging.instance.getInitialMessage();


    if (initialMessage != null) {
      _handleMessage(initialMessage);
    }

    FirebaseMessaging.onMessageOpenedApp.listen(_handleMessage);
  }

  void _handleMessage(RemoteMessage message) {
    if (message.data['type'] == 'chat') {
      // ここでページの遷移設定をする
      // Navigator.pushNamed(context, '/chat',
      //   arguments: ChatArguments(message),
      // );
    }
  }

  @override
  void initState() {
    super.initState();
    setupInteractedMessage();
    
    FirebaseMessaging.onMessage.listen((RemoteMessage message) {
      print("フォアグラウンドでメッセージを受け取りました");
      RemoteNotification? notification = message.notification;
      AndroidNotification? android = message.notification?.android;

      if (notification != null && android != null) {
        flutterLocalNotificationsPlugin.show(
            notification.hashCode,
            notification.title,
            notification.body,
            NotificationDetails(
              android: AndroidNotificationDetails(
                channel.id,
                channel.name,
                channelDescription:channel.description,
                icon: 'launch_background',
              ),
            ));
      }

    });
  }

  @override
  Widget build(BuildContext context) {
    return const Main();
  }
}