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Quickstart: Flutter

Intro​

This example provides the steps to build a simple user management app (from scratch!) using Supabase and Flutter. It includes:

  • Supabase Database: a Postgres database for storing your user data.
  • Supabase Auth: users can sign in with magic links (no passwords, only email).
  • Row Level Security: data is protected so that individuals can only access their own data.
  • Instant APIs: APIs will be automatically generated when you create your database tables.

By the end of this guide you'll have an app which allows users to login and update some basic profile details:

Supabase User Management example

GitHub​

Whenever you get stuck at any point, take a look at this repo.

Project set up​

Before we start building we're going to set up our Database and API. This is as simple as starting a new Project in Supabase and then creating a "schema" inside the database.

Create a project​

  1. Go to app.supabase.com.
  2. Click on "New Project".
  3. Enter your project details.
  4. Wait for the new database to launch.

Set up the database schema​

Now we are going to set up the database schema. We can use the "User Management Starter" quickstart in the SQL Editor, or you can just copy/paste the SQL from below and run it yourself.

  1. Go to the SQL Editor page in the Dashboard.
  2. Click User Management Starter.
  3. Click Run.

Get the API Keys​

Now that you've created some database tables, you are ready to insert data using the auto-generated API. We just need to get the URL and anon key from the API settings.

  1. Go to the Settings page in the Dashboard.
  2. Click API in the sidebar.
  3. Find your API URL, anon, and service_role keys on this page.

Building the App​

Let's start building the Flutter app from scratch.

Initialize a Flutter app​

We can use flutter create to initialize an app called supabase_quickstart:

flutter create supabase_quickstart

Then let's install the only additional dependency: supabase_flutter

Run the following command to get the newest version of supabase_flutter to your project.

flutter pub add supabase_flutter

Run flutter pub get to install the dependencies.

Now that we have the dependencies installed let's setup deep links so users who have logged in via magic link or OAuth can come back to the app.

1. Go to the "Authentication" section.
2. Click "Settings" in the sidebar.
3. Type `io.supabase.flutterquickstart://login-callback/` in the Additional Redirect URLs input field.
4. Hit save.

Supabase console deep link setting

That is it on Supabase's end and the rest are platform specific settings:

For Android, add an intent-filter to enable deep linking:

android/app/src/main/AndroidManifest.xml
<manifest ...>
  <!-- ... other tags -->
  <application ...>
    <activity ...>
      <!-- ... other tags -->

      <!-- Add this intent-filter for Deep Links -->
      <intent-filter>
        <action android:name="android.intent.action.VIEW" />
        <category android:name="android.intent.category.DEFAULT" />
        <category android:name="android.intent.category.BROWSABLE" />
        <!-- Accepts URIs that begin with YOUR_SCHEME://YOUR_HOST -->
        <data
          android:scheme="io.supabase.flutterquickstart"
          android:host="login-callback" />
      </intent-filter>

    </activity>
  </application>
</manifest>

For iOS add CFBundleURLTypes to enable deep linking:

ios/Runner/Info.plist
<!-- ... other tags -->
<plist>
<dict>
  <!-- ... other tags -->

  <!-- Add this array for Deep Links -->
  <key>CFBundleURLTypes</key>
  <array>
    <dict>
      <key>CFBundleTypeRole</key>
      <string>Editor</string>
      <key>CFBundleURLSchemes</key>
      <array>
        <string>io.supabase.flutterquickstart</string>
      </array>
    </dict>
  </array>
  <!-- ... other tags -->
</dict>
</plist>

For web:

There are no additional configurations.

Main function​

Now that we have deep links ready let's initialize the Supabase client inside our main function with the API credentials that you copied earlier. These variables will be exposed on the app, and that's completely fine since we have Row Level Security enabled on our Database.

lib/main.dart
Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();

  await Supabase.initialize(
    url: '[YOUR_SUPABASE_URL]',
    anonKey: '[YOUR_SUPABASE_ANON_KEY]',
  );
  runApp(MyApp());
}

Set up AuthState​

In order to handle deep links for Android and iOS, let's create a class that will do just that. supabase_flutter plugin comes with SupabaseAuthState class where we can inherit from to react to various deep link events.

lib/components/auth_state.dart
import 'package:flutter/material.dart';
import 'package:supabase/supabase.dart';
import 'package:supabase_flutter/supabase_flutter.dart';
import 'package:supabase_quickstart/utils/constants.dart';

class AuthState<T extends StatefulWidget> extends SupabaseAuthState<T> {
  @override
  void onUnauthenticated() {
    if (mounted) {
      Navigator.of(context).pushNamedAndRemoveUntil('/login', (route) => false);
    }
  }

  @override
  void onAuthenticated(Session session) {
    if (mounted) {
      Navigator.of(context)
          .pushNamedAndRemoveUntil('/account', (route) => false);
    }
  }

  @override
  void onPasswordRecovery(Session session) {}

  @override
  void onErrorAuthenticating(String message) {
    context.showErrorSnackBar(message: message);
  }
}

Set up AuthRequiredState​

We might want to show certain pages to the users only if they are signed in. For that we can create a handy AuthRequiredState class that we can inherit from for pages where the users need to be authenticated. AuthRequiredState will inherit SupabaseAuthRequiredState which is provided by supabase_flutter package.

lib/components/auth_required_state.dart
import 'package:flutter/material.dart';
import 'package:supabase_flutter/supabase_flutter.dart';

class AuthRequiredState<T extends StatefulWidget>
    extends SupabaseAuthRequiredState<T> {
  @override
  void onUnauthenticated() {
    /// Users will be sent back to the LoginPage if they sign out.
    if (mounted) {
      /// Users will be sent back to the LoginPage if they sign out.
      Navigator.of(context).pushNamedAndRemoveUntil('/login', (route) => false);
    }
  }
}

Let's also create a constant file to make it easier to use Supabase client. We will also include an extension method declaration to call showSnackBar with one line of code.

lib/utils/constants.dart
import 'package:flutter/material.dart';
import 'package:supabase_flutter/supabase_flutter.dart';

final supabase = Supabase.instance.client;

extension ShowSnackBar on BuildContext {
  void showSnackBar({
    required String message,
    Color backgroundColor = Colors.white,
  }) {
    ScaffoldMessenger.of(this).showSnackBar(SnackBar(
      content: Text(message),
      backgroundColor: backgroundColor,
    ));
  }

  void showErrorSnackBar({required String message}) {
    showSnackBar(message: message, backgroundColor: Colors.red);
  }
}

Set up Splash Screen​

Let's create a splash screen that will be shown to users right after they open the app. This splash screen inherits AuthState to redirect users to the appropriate pages depending on their authentication state.

lib/pages/splash_page.dart
import 'package:flutter/material.dart';
import 'package:supabase_quickstart/components/auth_state.dart';

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

  @override
  _SplashPageState createState() => _SplashPageState();
}

class _SplashPageState extends AuthState<SplashPage> {
  @override
  void initState() {
    recoverSupabaseSession();
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return const Scaffold(
      body: Center(child: CircularProgressIndicator()),
    );
  }
}

Set up a Login page​

Let's create a Flutter widget to manage logins and sign ups. We'll use Magic Links, so users can sign in with their email without using passwords. This page will also inherit AuthState as it will handle user login.

lib/pages/login_page.dart
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:supabase/supabase.dart';
import 'package:supabase_quickstart/components/auth_state.dart';
import 'package:supabase_quickstart/utils/constants.dart';

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

  @override
  _LoginPageState createState() => _LoginPageState();
}

class _LoginPageState extends AuthState<LoginPage> {
  bool _isLoading = false;
  late final TextEditingController _emailController;

  Future<void> _signIn() async {
    setState(() {
      _isLoading = true;
    });
    final response = await supabase.auth.signIn(
        email: _emailController.text,
        options: AuthOptions(
            redirectTo: kIsWeb
                ? null
                : 'io.supabase.flutterquickstart://login-callback/'));
    final error = response.error;
    if (error != null) {
      context.showErrorSnackBar(message: error.message);
    } else {
      context.showSnackBar(message: 'Check your email for login link!');
      _emailController.clear();
    }

    setState(() {
      _isLoading = false;
    });
  }

  @override
  void initState() {
    super.initState();
    _emailController = TextEditingController();
  }

  @override
  void dispose() {
    _emailController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Sign In')),
      body: ListView(
        padding: const EdgeInsets.symmetric(vertical: 18, horizontal: 12),
        children: [
          const Text('Sign in via the magic link with your email below'),
          const SizedBox(height: 18),
          TextFormField(
            controller: _emailController,
            decoration: const InputDecoration(labelText: 'Email'),
          ),
          const SizedBox(height: 18),
          ElevatedButton(
            onPressed: _isLoading ? null : _signIn,
            child: Text(_isLoading ? 'Loading' : 'Send Magic Link'),
          ),
        ],
      ),
    );
  }
}

Set up Account page​

After a user is signed in we can allow them to edit their profile details and manage their account. Let's create a new widget called account_page.dart for that. Note that this page will inherit AuthRequiredState as user needs to be authenticated to view this page.

lib/pages/account_page.dart
import 'package:flutter/material.dart';
import 'package:supabase/supabase.dart';
import 'package:supabase_quickstart/components/auth_required_state.dart';
import 'package:supabase_quickstart/utils/constants.dart';

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

  @override
  _AccountPageState createState() => _AccountPageState();
}

class _AccountPageState extends AuthRequiredState<AccountPage> {
  final _usernameController = TextEditingController();
  final _websiteController = TextEditingController();
  var _loading = false;

  /// Called once a user id is received within `onAuthenticated()`
  Future<void> _getProfile(String userId) async {
    setState(() {
      _loading = true;
    });
    final response = await supabase
        .from('profiles')
        .select()
        .eq('id', userId)
        .single()
        .execute();
    final error = response.error;
    if (error != null && response.status != 406) {
      context.showErrorSnackBar(message: error.message);
    }
    final data = response.data;
    if (data != null) {
      _usernameController.text = (data['username'] ?? '') as String;
      _websiteController.text = (data['website'] ?? '') as String;
    }
    setState(() {
      _loading = false;
    });
  }

  /// Called when user taps `Update` button
  Future<void> _updateProfile() async {
    setState(() {
      _loading = true;
    });
    final userName = _usernameController.text;
    final website = _websiteController.text;
    final user = supabase.auth.currentUser;
    final updates = {
      'id': user!.id,
      'username': userName,
      'website': website,
      'updated_at': DateTime.now().toIso8601String(),
    };
    final response = await supabase.from('profiles').upsert(updates).execute();
    final error = response.error;
    if (error != null) {
      context.showErrorSnackBar(message: error.message);
    } else {
      context.showSnackBar(message: 'Successfully updated profile!');
    }
    setState(() {
      _loading = false;
    });
  }

  Future<void> _signOut() async {
    final response = await supabase.auth.signOut();
    final error = response.error;
    if (error != null) {
      context.showErrorSnackBar(message: error.message);
    }
  }

  @override
  void onAuthenticated(Session session) {
    final user = session.user;
    if (user != null) {
      _getProfile(user.id);
    }
  }

  @override
  void dispose() {
    _usernameController.dispose();
    _websiteController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Profile')),
      body: ListView(
        padding: const EdgeInsets.symmetric(vertical: 18, horizontal: 12),
        children: [
          TextFormField(
            controller: _usernameController,
            decoration: const InputDecoration(labelText: 'User Name'),
          ),
          const SizedBox(height: 18),
          TextFormField(
            controller: _websiteController,
            decoration: const InputDecoration(labelText: 'Website'),
          ),
          const SizedBox(height: 18),
          ElevatedButton(
              onPressed: _updateProfile,
              child: Text(_loading ? 'Saving...' : 'Update')),
          const SizedBox(height: 18),
          ElevatedButton(onPressed: _signOut, child: const Text('Sign Out')),
        ],
      ),
    );
  }
}

Launch!​

Now that we have all the components in place, let's update lib/main.dart:

lib/main.dart
import 'package:flutter/material.dart';
import 'package:supabase_flutter/supabase_flutter.dart';
import 'package:supabase_quickstart/pages/account_page.dart';
import 'package:supabase_quickstart/pages/login_page.dart';
import 'package:supabase_quickstart/pages/splash_page.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();

  await Supabase.initialize(
    // TODO: Replace credentials with your own
    url: '[YOUR_SUPABASE_URL]',
    anonKey: '[YOUR_SUPABASE_ANNON_KEY]',
  );
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Supabase Flutter',
      theme: ThemeData.dark().copyWith(
        primaryColor: Colors.green,
        elevatedButtonTheme: ElevatedButtonThemeData(
          style: ElevatedButton.styleFrom(
            onPrimary: Colors.white,
            primary: Colors.green,
          ),
        ),
      ),
      initialRoute: '/',
      routes: <String, WidgetBuilder>{
        '/': (_) => const SplashPage(),
        '/login': (_) => const LoginPage(),
        '/account': (_) => const AccountPage(),
      },
    );
  }
}

Once that's done, run this in a terminal window to launch on Android or iOS:

flutter run

Or for web, run the following command to launch it on localhost:3000

flutter run -d web-server --web-hostname localhost --web-port 3000

And then open the browser to localhost:3000 and you should see the completed app.

Supabase User Management example

Bonus: Profile photos​

Every Supabase project is configured with Storage for managing large files like photos and videos.

Making sure we have a public bucket​

We will be storing the image as a publicly sharable image. Make sure your avatars bucket is set to public, and if it is not, change the publicity by clicking the dot menu that appears when you hover over the bucket name. You should see an orange Public badge next to your bucket name if your bucket is set to public.

Adding image uploading feature to Account page​

We will use image_picker plugin to select an image from the device.

Run the following command to install it.

flutter pub add image_picker

Using image_picker requires some additional preparation depending on the platform. Follow the instruction on README.md of image_picker on how to set it up for the platform you are using.

Once you are done with all of the above, it is time to dive into coding.

Create an upload widget​

Let's create an avatar for the user so that they can upload a profile photo. We can start by creating a new component:

lib/components/avatar.dart
import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';
import 'package:supabase_quickstart/utils/constants.dart';

class Avatar extends StatefulWidget {
  const Avatar({
    Key? key,
    required this.imageUrl,
    required this.onUpload,
  }) : super(key: key);

  final String? imageUrl;
  final void Function(String) onUpload;

  @override
  _AvatarState createState() => _AvatarState();
}

class _AvatarState extends State<Avatar> {
  bool _isLoading = false;

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        if (widget.imageUrl == null)
          Container(
            width: 150,
            height: 150,
            color: Colors.grey,
            child: const Center(
              child: Text('No Image'),
            ),
          )
        else
          Image.network(
            widget.imageUrl!,
            width: 150,
            height: 150,
            fit: BoxFit.cover,
          ),
        ElevatedButton(
          onPressed: _isLoading ? null : _upload,
          child: const Text('Upload'),
        ),
      ],
    );
  }

  Future<void> _upload() async {
    final _picker = ImagePicker();
    final imageFile = await _picker.pickImage(
      source: ImageSource.gallery,
      maxWidth: 300,
      maxHeight: 300,
    );
    if (imageFile == null) {
      return;
    }
    setState(() => _isLoading = true);

    final bytes = await imageFile.readAsBytes();
    final fileExt = imageFile.path.split('.').last;
    final fileName = '${DateTime.now().toIso8601String()}.$fileExt';
    final filePath = fileName;
    final response =
        await supabase.storage.from('avatars').uploadBinary(filePath, bytes);

    setState(() => _isLoading = false);

    final error = response.error;
    if (error != null) {
      context.showErrorSnackBar(message: error.message);
      return;
    }
    final imageUrlResponse =
        supabase.storage.from('avatars').getPublicUrl(filePath);
    widget.onUpload(imageUrlResponse.data!);
  }
}

Add the new widget​

And then we can add the widget to the Account page as well as some logic to update the avatar_url whenever the user uploads a new avatar.

lib/pages/account_page.dart
import 'package:flutter/material.dart';
import 'package:supabase/supabase.dart';
import 'package:supabase_quickstart/components/auth_required_state.dart';
import 'package:supabase_quickstart/components/avatar.dart';
import 'package:supabase_quickstart/utils/constants.dart';

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

  @override
  _AccountPageState createState() => _AccountPageState();
}

class _AccountPageState extends AuthRequiredState<AccountPage> {
  final _usernameController = TextEditingController();
  final _websiteController = TextEditingController();
  String? _userId;
  String? _avatarUrl;
  var _loading = false;

  /// Called once a user id is received within `onAuthenticated()`
  Future<void> _getProfile(String userId) async {
    setState(() {
      _loading = true;
    });
    final response = await supabase
        .from('profiles')
        .select()
        .eq('id', userId)
        .single()
        .execute();
    final error = response.error;
    if (error != null && response.status != 406) {
      context.showErrorSnackBar(message: error.message);
    }
    final data = response.data;
    if (data != null) {
      _usernameController.text = (data['username'] ?? '') as String;
      _websiteController.text = (data['website'] ?? '') as String;
      _avatarUrl = (data['avatar_url'] ?? '') as String;
    }
    setState(() {
      _loading = false;
    });
  }

  /// Called when user taps `Update` button
  Future<void> _updateProfile() async {
    setState(() {
      _loading = true;
    });
    final userName = _usernameController.text;
    final website = _websiteController.text;
    final user = supabase.auth.currentUser;
    final updates = {
      'id': user!.id,
      'username': userName,
      'website': website,
      'updated_at': DateTime.now().toIso8601String(),
    };
    final response = await supabase.from('profiles').upsert(updates).execute();
    final error = response.error;
    if (error != null) {
      context.showErrorSnackBar(message: error.message);
    } else {
      context.showSnackBar(message: 'Successfully updated profile!');
    }
    setState(() {
      _loading = false;
    });
  }

  Future<void> _signOut() async {
    final response = await supabase.auth.signOut();
    final error = response.error;
    if (error != null) {
      context.showErrorSnackBar(message: error.message);
    }
    Navigator.of(context).pushReplacementNamed('/login');
  }

  /// Called when image has been uploaded to Supabase storage from within Avatar widget
  Future<void> _onUpload(String imageUrl) async {
    final response = await supabase.from('profiles').upsert({
      'id': _userId,
      'avatar_url': imageUrl,
    }).execute();
    final error = response.error;
    if (error != null) {
      context.showErrorSnackBar(message: error.message);
    }
    setState(() {
      _avatarUrl = imageUrl;
    });
    context.showSnackBar(message: 'Updated your profile image!');
  }

  @override
  void onAuthenticated(Session session) {
    final user = session.user;
    if (user != null) {
      _userId = user.id;
      _getProfile(user.id);
    }
  }

  @override
  void onUnauthenticated() {
    Navigator.of(context).pushReplacementNamed('/login');
  }

  @override
  void dispose() {
    _usernameController.dispose();
    _websiteController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Profile')),
      body: ListView(
        padding: const EdgeInsets.symmetric(vertical: 18, horizontal: 12),
        children: [
          Avatar(
            imageUrl: _avatarUrl,
            onUpload: _onUpload,
          ),
          const SizedBox(height: 18),
          TextFormField(
            controller: _usernameController,
            decoration: const InputDecoration(labelText: 'User Name'),
          ),
          const SizedBox(height: 18),
          TextFormField(
            controller: _websiteController,
            decoration: const InputDecoration(labelText: 'Website'),
          ),
          const SizedBox(height: 18),
          ElevatedButton(
              onPressed: _updateProfile,
              child: Text(_loading ? 'Saving...' : 'Update')),
          const SizedBox(height: 18),
          ElevatedButton(onPressed: _signOut, child: const Text('Sign Out')),
        ],
      ),
    );
  }
}

Congratulations, that is it! You have now built a fully functional user management app using Flutter and Supabase!

Next steps​

At this stage you have a fully functional application!

Flutter and Supabase resources​