Building a Real-Time Chat Application with Flutter and Supabase

In this tutorial, we will explore how to develop a real-time chat application using Flutter and Supabase. Supabase is an open-source platform that provides user authentication, real-time database, and API capabilities. We will leverage Flutter’s UI toolkit and Supabase’s real-time features to create an interactive and dynamic chat application.

1. Project Setup: a. Flutter Installation: Install the Flutter SDK and set up your development environment.

b. Supabase Setup: Create a Supabase account and set up a new project. Obtain the client key and database URL required for your Supabase project.

c. Project Setup: Create a new Flutter project and add the supabase_flutter and websocket packages to your pubspec.yaml file.

dependencies:
  flutter:
    sdk: flutter
  supabase_flutter: ^0.5.0
  websocket: ^2.0.0

Establishing the Supabase Connection in the Project:

import 'package:supabase_flutter/supabase_flutter.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  final supabaseClient = Supabase.instance.client;

  @override
  Widget build(BuildContext context) {
    return SupabaseProvider(
      child: MaterialApp(
        title: 'Supabase Chat App',
        theme: ThemeData(
          primarySwatch: Colors.blue,
        ),
        home: ChatScreen(),
      ),
      client: supabaseClient,
    );
  }
}

User Registration and Login:

void signUp(String email, String password) async {
  final response = await supabaseClient.auth.signUp(email, password);
  if (response.error == null) {
    // User registration successful.
  } else {
    // An error occurred during registration.
  }
}

void signIn(String email, String password) async {
  final response = await supabaseClient.auth.signIn(email, password);
  if (response.error == null) {
    // User login successful.
  } else {
    // An error occurred during login.
  }
}

Real-Time Chat Operations:

void createChatRoom(String roomName) async {
  final response = await supabaseClient
      .from('chat_rooms')
      .insert({'room_name': roomName}).execute();
  if (response.error == null) {
    // Chat room created successfully.
  } else {
    // An error occurred while creating the chat room.
  }
}

void sendMessage(String roomId, String message) async {
  final response = await supabaseClient
      .from('messages')
      .insert({'room_id': roomId, 'message': message}).execute();
  if (response.error == null) {
    // Message sent successfully.
  } else {
    // An error occurred while sending the message.
  }
}

void listenToMessages(String roomId) {
  supabaseClient
      .from('messages')
      .on(SupabaseEventTypes.insert, (payload) {
    // New message added, listen for updates and display them in the user interface.
  })
      .subscribe();
}

User Interface Design:

class ChatScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final supabaseClient = Supabase.instance.client;
    final authState = supabaseClient.auth.authState;

    return Scaffold(
      appBar: AppBar(
        title: Text('Supabase Chat'),
      ),
      body: Center(
        child: authState.when(
          data: (user) {
            if (user != null) {
              // User is logged in, show the chat interface.
              return ChatRoomList();
            } else {
              // User is not logged in, show the login interface.
              return LoginScreen();
            }
          },
          loading: () => CircularProgressIndicator(),
          error: (error, stackTrace) => Text('An error occurred: $error'),
        ),
      ),
    );
  }
}

class LoginScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      // Implement the login screen design here.
    );
  }
}

class ChatRoomList extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      // Implement the chat room list design here.
    );
  }
}

In this tutorial, we have covered the process of building a real-time chat application using Flutter and Supabase. By combining the power of Flutter’s UI toolkit and Supabase’s real-time database, we can create interactive chat experiences. Remember to refer to the official documentation of Flutter and Supabase for further information and explore additional features to enhance your chat application.

Resources:

• Supabase Official Website: https://supabase.io
• Flutter Official Website: https://flutter.dev
• supabase_flutter Package: https://pub.dev/packages/supabase_flutter
• websocket Package: https://pub.dev/packages/websocket