stream-chat-flutter/example/lib/main.dart

import 'dart:io';

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter_apns/apns.dart';
import 'package:flutter_local_notifications/flutter_local_notifications.dart'
    hide Message;
import 'package:stream_chat_flutter/stream_chat_flutter.dart';

void showLocalNotification(Message message, ChannelModel channel) async {
  FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
      FlutterLocalNotificationsPlugin();
  final initializationSettingsAndroid =
      AndroidInitializationSettings('launch_background');
  final initializationSettingsIOS = IOSInitializationSettings();
  final initializationSettings = InitializationSettings(
    initializationSettingsAndroid,
    initializationSettingsIOS,
  );
  await flutterLocalNotificationsPlugin.initialize(initializationSettings);
  await flutterLocalNotificationsPlugin.show(
    message.id.hashCode,
    '${message.user.name} @ ${channel.name}',
    message.text,
    NotificationDetails(
      AndroidNotificationDetails(
        'message channel',
        'Message channel',
        'Channel used for showing messages',
        priority: Priority.High,
        importance: Importance.High,
      ),
      IOSNotificationDetails(),
    ),
  );
}

Future backgroundHandler(Map<String, dynamic> notification) async {
  final messageId = notification['data']['message_id'];

  final notificationData =
      await NotificationService.getAndStoreMessage(messageId);

  showLocalNotification(
    notificationData.message,
    notificationData.channel,
  );
}

void _initNotifications(Client client) {
  final connector = createPushConnector();
  connector.configure(
    onBackgroundMessage: backgroundHandler,
  );

  connector.requestNotificationPermissions();
  connector.token.addListener(() {
    if (connector.token.value != null) {
      client.addDevice(
        connector.token.value,
        Platform.isAndroid ? 'firebase' : 'apn',
      );
    }
  });
}

void main() async {
  final client = Client(
    's2dxdhpxd94g',
    logLevel: Level.FINEST,
    showLocalNotification: Platform.isAndroid ? showLocalNotification : null,
    persistenceEnabled: true,
  );

  await client.setUser(
    User(id: 'super-band-9'),
    'eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJ1c2VyX2lkIjoic3VwZXItYmFuZC05In0.0L6lGoeLwkz0aZRUcpZKsvaXtNEDHBcezVTZ0oPq40A',
  );

  _initNotifications(client);

  runApp(MyApp(client));
}

class MyApp extends StatelessWidget {
  final Client client;

  MyApp(this.client);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
//      debugShowMaterialGrid: true,
//      debugShowCheckedModeBanner: false,
      theme: ThemeData.light(),
      darkTheme: ThemeData.dark(),
      themeMode: ThemeMode.system,
      builder: (context, widget) {
        return StreamChat(
          child: widget,
          client: client,
        );
      },
      home: ChannelListPage(),
    );
  }
}

class ChannelListPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: ChannelsBloc(
        child: ChannelListView(
          filter: {
            'members': {
              '\$in': [StreamChat.of(context).user.id],
            }
          },
          options: {
            'presence': true,
          },
          sort: [SortOption('last_message_at')],
          pagination: PaginationParams(
            limit: 20,
          ),
          channelWidget: ChannelPage(),
        ),
      ),
    );
  }
}

class ChannelPage extends StatelessWidget {
  const ChannelPage({
    Key key,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: ChannelHeader(),
      body: Column(
        children: <Widget>[
          Expanded(
            child: Stack(
              children: <Widget>[
                MessageListView(
                  threadBuilder: (_, parentMessage) {
                    return ThreadPage(
                      parent: parentMessage,
                    );
                  },
                ),
                Positioned.fill(
                  child: Padding(
                    padding: const EdgeInsets.symmetric(
                      horizontal: 8.0,
                      vertical: 4,
                    ),
                    child: TypingIndicator(
                      alignment: Alignment.bottomRight,
                    ),
                  ),
                ),
              ],
            ),
          ),
          MessageInput(),
        ],
      ),
    );
  }
}

class ThreadPage extends StatelessWidget {
  final Message parent;

  ThreadPage({
    Key key,
    this.parent,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: ThreadHeader(
        parent: parent,
      ),
      body: Column(
        children: <Widget>[
          Expanded(
            child: MessageListView(
              parentMessage: parent,
            ),
          ),
          if (parent.type != 'deleted')
            MessageInput(
              parentMessage: parent,
            ),
        ],
      ),
    );
  }
}