stream_beginner.dart

import 'package:flutter/material.dart';
import 'package:stream_chat_flutter/stream_chat_flutter.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  final client = StreamChatClient(
    'YOUR_API_KEY',
    logLevel: Level.INFO,
  );

  await client.connectUser(
    User(id: 'YOUR_USER_ID'),
    '''YOUR_USER_TOKEN''',
  );

  final channel = client.channel('messaging', id: 'YOUR_CHANNEL_ID');

  await channel.watch();

  runApp(
    MyApp(
      client: client,
      channel: channel,
    ),
  );
}

class MyApp extends StatelessWidget {

  const MyApp({
    Key? key,
    required this.client,
    required this.channel,
  }) : super(key: key);

  final StreamChatClient client;

  /// Instance of the Channel
  final Channel channel;

  @override
  Widget build(BuildContext context) => MaterialApp(
        theme: ThemeData.light(),
        darkTheme: ThemeData.dark(),
        builder: (context, widget) => StreamChat(
          client: client,
          child: widget,
        ),
        home: StreamChannel(
          channel: channel,
          child: const ChannelPage(),
        ),
      );
}

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

  @override
  State<ChannelPage> createState() => _ChannelPageState();
}

class _ChannelPageState extends State<ChannelPage> {
  
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: const ChannelHeader(),
        body: Column(
          children: <Widget>[
            const Expanded(
              child: MessageListView(),
            ),
            MessageInput(
              attachmentLimit: 3,
            ),
          ],
        ),
      );
  }
}