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Build a User Management App with Flutter

还没翻译译自英文（supabase.com）本页 67 段都还没译

This tutorial demonstrates how to build a basic user management app. The app authenticates and identifies the user, stores their profile information in the database, and allows the user to log in, update their profile details, and upload a profile photo. The app uses:

Supabase User Management example

Note

If you get stuck while working through this guide, refer to the full example on GitHub.

Project setup

Before you start building you need to set up the Database and API. You can do this by starting a new Project in Supabase and then creating a "schema" inside the database.

Create a project

  1. Create a new project in the Supabase Dashboard.
  2. Enter your project details.
  3. Wait for the new database to launch.

Set up the database schema

Now set up the database schema. You can use the "User Management Starter" quickstart in the SQL Editor, or you can copy/paste the SQL from below and run it.

  1. Go to the SQL Editor page in the Dashboard.
  2. Click User Management Starter under the Reference > Examples tab.
  3. Click Run.

Note

You can pull the database schema down to your local project by running the db pull command. Read the local development docs for detailed instructions.

supabase link --project-ref <project-id>
# You can get <project-id> from your project's dashboard URL: https://supabase.com/dashboard/project/<project-id>
supabase db pull

Note

When working locally you can run the following command to create a new migration file:

supabase migration new user_management_starter
-- Create a table for public profiles
create table profiles (
  id uuid references auth.users not null primary key,
  updated_at timestamp with time zone,
  username text unique,
  full_name text,
  avatar_url text,
  website text,

  constraint username_length check (char_length(username) >= 3)
);

-- Grant the privileges roles need
GRANT SELECT ON public.profiles TO anon;
GRANT SELECT, INSERT, UPDATE ON public.profiles TO authenticated;

-- Set up Row Level Security (RLS)
-- See https://supabase.com/docs/guides/database/postgres/row-level-security for more details.
alter table profiles
  enable row level security;

create policy "Public profiles are viewable by everyone." on profiles
  for select using (true);

create policy "Users can insert their own profile." on profiles
  for insert with check ((select auth.uid()) = id);

create policy "Users can update own profile." on profiles
  for update using ((select auth.uid()) = id);

-- This trigger automatically creates a profile entry when a new user signs up via Supabase Auth.
-- See https://supabase.com/docs/guides/auth/managing-user-data#using-triggers for more details.
create function public.handle_new_user()
returns trigger
set search_path = ''
as $$
begin
  insert into public.profiles (id, full_name, avatar_url)
  values (new.id, new.raw_user_meta_data->>'full_name', new.raw_user_meta_data->>'avatar_url');
  return new;
end;
$$ language plpgsql security definer;
create trigger on_auth_user_created
  after insert on auth.users
  for each row execute procedure public.handle_new_user();

-- Set up Storage!
insert into storage.buckets (id, name)
  values ('avatars', 'avatars');

-- Set up access controls for storage. Allows downloading object with public key
-- See https://supabase.com/docs/guides/storage/security/access-control#policy-examples for more details.
create policy "Avatar images are publicly accessible." on storage.objects
  for select using (bucket_id = 'avatars' and storage.allow_any_operation(array['object.get_authenticated_info', 'object.get_authenticated']));

create policy "Anyone can upload an avatar." on storage.objects
  for insert with check (bucket_id = 'avatars');

create policy "Anyone can update their own avatar." on storage.objects
  for update using ((select auth.uid()) = owner) with check (bucket_id = 'avatars');

Get API details

To interact with data in database tables, you use the client libraries that wrap the auto-generated Data API endpoints, authenticating using the Project URL and key from the project Connect dialog.

Project URL: https://<project-ref>.supabase.co (find yours in the dashboard)

Publishable key: sb_publishable_... (find yours in the dashboard)

Note

See API keys for a full explanation of all key types, their uses, and where to find them.

Building the app

Build 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 install the only additional dependency: supabase_flutter

Copy and paste the following line in your pubspec.yaml to install the package:

supabase_flutter: ^2.0.0

Run flutter pub get to install the dependencies.

Setup deep links

With dependencies installed, set up deep links. Setting up deep links is required to bring back the user to the app when they click on the magic link to sign in. We can setup deep links with a minor tweak on our Flutter application.

We have to use io.supabase.flutterquickstart as the scheme. In this example, we will use login-callback as the host for our deep link, but you can change it to whatever you would like.

First, add io.supabase.flutterquickstart://login-callback/ as a new redirect URL in the Dashboard.

Supabase console deep link setting

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

Edit the ios/Runner/Info.plist file.

Add CFBundleURLTypes to enable deep linking:

<!-- ... 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>

Edit the android/app/src/main/AndroidManifest.xml file.

Add an intent-filter to enable deep linking:

<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>

Supabase redirects do not work with Flutter's default URL strategy. We can switch to the path URL strategy as follows:

import 'package:flutter_web_plugins/url_strategy.dart';

void main() {
  usePathUrlStrategy();
  runApp(ExampleApp());
}

Main function

With deep links configured, initialize the Supabase client inside the 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.

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

Future<void> main() async {
  await Supabase.initialize(
    url: 'YOUR_SUPABASE_URL',
    publishableKey: 'YOUR_SUPABASE_PUBLISHABLE_KEY',
  );
  runApp(const MyApp());
}

final supabase = Supabase.instance.client;

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(title: 'Supabase Flutter');
  }
}

extension ContextExtension on BuildContext {
  void showSnackBar(String message, {bool isError = false}) {
    ScaffoldMessenger.of(this).showSnackBar(
      SnackBar(
        content: Text(message),
        backgroundColor: isError
            ? Theme.of(this).colorScheme.error
            : Theme.of(this).snackBarTheme.backgroundColor,
      ),
    );
  }
}

Notice that we have a showSnackBar extension method that we will use to show snack bars in the app. You could define this method in a separate file and import it where needed, but for simplicity, we will define it here.

Set up a sign-in page

Create a Flutter widget to manage sign-ins and sign-ups. We will use Magic Links, so users can sign in with their email without using passwords.

Notice that this page sets up a listener on the user's auth state using onAuthStateChange. A new event will fire when the user comes back to the app by clicking their magic link, which this page can catch and redirect the user accordingly.

import 'dart:async';

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:supabase_flutter/supabase_flutter.dart';
import 'package:supabase_quickstart/main.dart';
import 'package:supabase_quickstart/pages/account_page.dart';

class LoginPage extends StatefulWidget {
  const LoginPage({super.key});

  @override
  State<LoginPage> createState() => _LoginPageState();
}

class _LoginPageState extends State<LoginPage> {
  bool _isLoading = false;
  bool _redirecting = false;
  late final TextEditingController _emailController = TextEditingController();
  late final StreamSubscription<AuthState> _authStateSubscription;

  Future<void> _signIn() async {
    try {
      setState(() {
        _isLoading = true;
      });
      await supabase.auth.signInWithOtp(
        email: _emailController.text.trim(),
        emailRedirectTo:
            kIsWeb ? null : 'io.supabase.flutterquickstart://login-callback/',
      );
      if (mounted) {
        context.showSnackBar('Check your email for a login link!');

        _emailController.clear();
      }
    } on AuthException catch (error) {
      if (mounted) context.showSnackBar(error.message, isError: true);
    } catch (error) {
      if (mounted) {
        context.showSnackBar('Unexpected error occurred', isError: true);
      }
    } finally {
      if (mounted) {
        setState(() {
          _isLoading = false;
        });
      }
    }
  }

  @override
  void initState() {
    _authStateSubscription = supabase.auth.onAuthStateChange.listen(
      (data) {
        if (_redirecting) return;
        final session = data.session;
        if (session != null) {
          _redirecting = true;
          Navigator.of(context).pushReplacement(
            MaterialPageRoute(builder: (context) => const AccountPage()),
          );
        }
      },
      onError: (error) {
        if (error is AuthException) {
          context.showSnackBar(error.message, isError: true);
        } else {
          context.showSnackBar('Unexpected error occurred', isError: true);
        }
      },
    );
    super.initState();
  }

  @override
  void dispose() {
    _emailController.dispose();
    _authStateSubscription.cancel();
    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 ? 'Sending...' : '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. Create a new widget called account_page.dart.

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

class AccountPage extends StatefulWidget {
  const AccountPage({super.key});

  @override
  State<AccountPage> createState() => _AccountPageState();
}

class _AccountPageState extends State<AccountPage> {
  final _usernameController = TextEditingController();
  final _websiteController = TextEditingController();

  String? _avatarUrl;
  var _loading = true;

  /// Called once a user id is received within `onAuthenticated()`
  Future<void> _getProfile() async {
    setState(() {
      _loading = true;
    });

    try {
      final userId = supabase.auth.currentSession!.user.id;
      final data =
          await supabase.from('profiles').select().eq('id', userId).single();
      _usernameController.text = (data['username'] ?? '') as String;
      _websiteController.text = (data['website'] ?? '') as String;
      _avatarUrl = (data['avatar_url'] ?? '') as String;
    } on PostgrestException catch (error) {
      if (mounted) context.showSnackBar(error.message, isError: true);
    } catch (error) {
      if (mounted) {
        context.showSnackBar('Unexpected error occurred', isError: true);
      }
    } finally {
      if (mounted) {
        setState(() {
          _loading = false;
        });
      }
    }
  }

  /// Called when user taps `Update` button
  Future<void> _updateProfile() async {
    setState(() {
      _loading = true;
    });
    final userName = _usernameController.text.trim();
    final website = _websiteController.text.trim();
    final user = supabase.auth.currentUser;
    final updates = {
      'id': user!.id,
      'username': userName,
      'website': website,
      'updated_at': DateTime.now().toIso8601String(),
    };
    try {
      await supabase.from('profiles').upsert(updates);
      if (mounted) context.showSnackBar('Successfully updated profile!');
    } on PostgrestException catch (error) {
      if (mounted) context.showSnackBar(error.message, isError: true);
    } catch (error) {
      if (mounted) {
        context.showSnackBar('Unexpected error occurred', isError: true);
      }
    } finally {
      if (mounted) {
        setState(() {
          _loading = false;
        });
      }
    }
  }

  Future<void> _signOut() async {
    try {
      await supabase.auth.signOut();
    } on AuthException catch (error) {
      if (mounted) context.showSnackBar(error.message, isError: true);
    } catch (error) {
      if (mounted) {
        context.showSnackBar('Unexpected error occurred', isError: true);
      }
    } finally {
      if (mounted) {
        Navigator.of(context).pushReplacement(
          MaterialPageRoute(builder: (_) => const LoginPage()),
        );
      }
    }
  }

  @override
  void initState() {
    super.initState();
    _getProfile();
  }

  @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: _loading ? null : _updateProfile,
            child: Text(_loading ? 'Saving...' : 'Update'),
          ),
          const SizedBox(height: 18),
          TextButton(onPressed: _signOut, child: const Text('Sign Out')),
        ],
      ),
    );
  }
}

Launch!

With all components in place, update lib/main.dart. The home of the MaterialApp, meaning the initial page shown to the user, will be the LoginPage if the user is not authenticated, and the AccountPage if the user is authenticated. We also included some theming to make the app look a bit nicer.

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';

Future<void> main() async {
  await Supabase.initialize(
    url: 'YOUR_SUPABASE_URL',
    publishableKey: 'YOUR_SUPABASE_PUBLISHABLE_KEY',
  );
  runApp(const MyApp());
}

final supabase = Supabase.instance.client;

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Supabase Flutter',
      theme: ThemeData.dark().copyWith(
        primaryColor: Colors.green,
        textButtonTheme: TextButtonThemeData(
          style: TextButton.styleFrom(
            foregroundColor: Colors.green,
          ),
        ),
        elevatedButtonTheme: ElevatedButtonThemeData(
          style: ElevatedButton.styleFrom(
            foregroundColor: Colors.white,
            backgroundColor: Colors.green,
          ),
        ),
      ),
      home: supabase.auth.currentSession == null
          ? const LoginPage()
          : const AccountPage(),
    );
  }
}

extension ContextExtension on BuildContext {
  void showSnackBar(String message, {bool isError = false}) {
    ScaffoldMessenger.of(this).showSnackBar(
      SnackBar(
        content: Text(message),
        backgroundColor: isError
            ? Theme.of(this).colorScheme.error
            : Theme.of(this).snackBarTheme.backgroundColor,
      ),
    );
  }
}

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.

Add the following line in your pubspec.yaml file to install image_picker:

image_picker: ^1.0.5

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

Create an avatar so the user can upload a profile photo. We can start by creating a new component:

import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';
import 'package:supabase_flutter/supabase_flutter.dart';
import 'package:supabase_quickstart/main.dart';

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

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

  @override
  State<Avatar> createState() => _AvatarState();
}

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

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        if (widget.imageUrl == null || widget.imageUrl!.isEmpty)
          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);

    try {
      final bytes = await imageFile.readAsBytes();
      final fileExt = imageFile.path.split('.').last;
      final fileName = '${DateTime.now().toIso8601String()}.$fileExt';
      final filePath = fileName;
      await supabase.storage.from('avatars').uploadBinary(
            filePath,
            bytes,
            fileOptions: FileOptions(contentType: imageFile.mimeType),
          );
      final imageUrlResponse = await supabase.storage
          .from('avatars')
          .createSignedUrl(filePath, 60 * 60 * 24 * 365 * 10);
      widget.onUpload(imageUrlResponse);
    } on StorageException catch (error) {
      if (mounted) {
        context.showSnackBar(error.message, isError: true);
      }
    } catch (error) {
      if (mounted) {
        context.showSnackBar('Unexpected error occurred', isError: true);
      }
    }

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

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.

import 'package:flutter/material.dart';
import 'package:supabase_flutter/supabase_flutter.dart';
import 'package:supabase_quickstart/components/avatar.dart';
import 'package:supabase_quickstart/main.dart';
import 'package:supabase_quickstart/pages/login_page.dart';

class AccountPage extends StatefulWidget {
  const AccountPage({super.key});

  @override
  State<AccountPage> createState() => _AccountPageState();
}

class _AccountPageState extends State<AccountPage> {
  final _usernameController = TextEditingController();
  final _websiteController = TextEditingController();

  String? _avatarUrl;
  var _loading = true;

  /// Called once a user id is received within `onAuthenticated()`
  Future<void> _getProfile() async {
    setState(() {
      _loading = true;
    });

    try {
      final userId = supabase.auth.currentSession!.user.id;
      final data =
          await supabase.from('profiles').select().eq('id', userId).single();
      _usernameController.text = (data['username'] ?? '') as String;
      _websiteController.text = (data['website'] ?? '') as String;
      _avatarUrl = (data['avatar_url'] ?? '') as String;
    } on PostgrestException catch (error) {
      if (mounted) context.showSnackBar(error.message, isError: true);
    } catch (error) {
      if (mounted) {
        context.showSnackBar('Unexpected error occurred', isError: true);
      }
    } finally {
      if (mounted) {
        setState(() {
          _loading = false;
        });
      }
    }
  }

  /// Called when user taps `Update` button
  Future<void> _updateProfile() async {
    setState(() {
      _loading = true;
    });
    final userName = _usernameController.text.trim();
    final website = _websiteController.text.trim();
    final user = supabase.auth.currentUser;
    final updates = {
      'id': user!.id,
      'username': userName,
      'website': website,
      'updated_at': DateTime.now().toIso8601String(),
    };
    try {
      await supabase.from('profiles').upsert(updates);
      if (mounted) context.showSnackBar('Successfully updated profile!');
    } on PostgrestException catch (error) {
      if (mounted) context.showSnackBar(error.message, isError: true);
    } catch (error) {
      if (mounted) {
        context.showSnackBar('Unexpected error occurred', isError: true);
      }
    } finally {
      if (mounted) {
        setState(() {
          _loading = false;
        });
      }
    }
  }

  Future<void> _signOut() async {
    try {
      await supabase.auth.signOut();
    } on AuthException catch (error) {
      if (mounted) context.showSnackBar(error.message, isError: true);
    } catch (error) {
      if (mounted) {
        context.showSnackBar('Unexpected error occurred', isError: true);
      }
    } finally {
      if (mounted) {
        Navigator.of(context).pushReplacement(
          MaterialPageRoute(builder: (_) => const LoginPage()),
        );
      }
    }
  }

  /// Called when image has been uploaded to Supabase storage from within Avatar widget
  Future<void> _onUpload(String imageUrl) async {
    try {
      final userId = supabase.auth.currentUser!.id;
      await supabase.from('profiles').upsert({
        'id': userId,
        'avatar_url': imageUrl,
      });
      if (mounted) {
        const SnackBar(
          content: Text('Updated your profile image!'),
        );
      }
    } on PostgrestException catch (error) {
      if (mounted) context.showSnackBar(error.message, isError: true);
    } catch (error) {
      if (mounted) {
        context.showSnackBar('Unexpected error occurred', isError: true);
      }
    }
    if (!mounted) {
      return;
    }

    setState(() {
      _avatarUrl = imageUrl;
    });
  }

  @override
  void initState() {
    super.initState();
    _getProfile();
  }

  @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: _loading ? null : _updateProfile,
            child: Text(_loading ? 'Saving...' : 'Update'),
          ),
          const SizedBox(height: 18),
          TextButton(onPressed: _signOut, child: const Text('Sign Out')),
        ],
      ),
    );
  }
}

Congratulations, you've built a fully functional user management app using Flutter and Supabase!

See also

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