How to Rebuild a Flutter App with User Auth from UI from video Using Replay AI, tested in 2026

TL;DR: Rebuild a Flutter app with user authentication from a video of the UI using Replay AI, leveraging behavior-driven reconstruction for accurate and functional code generation.

Manually recreating user interfaces is tedious and error-prone, especially when trying to replicate complex user flows and interactions. Imagine having a video of your desired Flutter app's UI and user interactions, and being able to automatically generate the code to rebuild it, complete with user authentication. That's the power of Replay, a video-to-code engine that understands user behavior and reconstructs working UI.

The Problem: Manual UI Reconstruction is a Nightmare#

Rebuilding UIs from scratch, or even from static screenshots, is a common pain point for developers. This process is slow, requires deep domain knowledge, and often results in imperfect replicas. Consider these challenges:

• •Subjectivity: Interpreting UI elements from static images is subjective and prone to errors.
• •Dynamic Behavior: Screenshots capture a single state, missing crucial dynamic behaviors like animations, transitions, and user interactions.
• •Authentication Flows: Replicating complex authentication flows (sign-up, login, password reset) requires significant effort and understanding of the underlying logic.
• •Maintaining Consistency: Ensuring consistency across the entire application is difficult when manually rebuilding UI elements.

The Solution: Behavior-Driven Reconstruction with Replay#

Replay tackles these problems head-on by analyzing video recordings of UI interactions. It uses Gemini to understand user intent and reconstruct functional code, rather than just visual representations. This approach, known as "Behavior-Driven Reconstruction," ensures that the generated code accurately reflects the intended user experience.

Key Benefits of Replay:#

• •Video as Source of Truth: Replay uses video input, capturing dynamic behaviors and user interactions.
• •Behavior Analysis: It understands what users are trying to do, not just what they see.
• •Multi-Page Generation: Replay can generate code for entire applications, not just individual screens.
• •Supabase Integration: Seamlessly integrate with Supabase for backend functionality, including user authentication.
• •Style Injection: Customize the look and feel of your application with style injection.
• •Product Flow Maps: Visualize and understand the user flows within your application.

How Replay Differs from Other Tools#

Step-by-Step Guide: Rebuilding a Flutter App with User Auth from Video#

Let's walk through the process of rebuilding a Flutter app with user authentication from a video using Replay. This example assumes you have a video recording of a Flutter app demonstrating the sign-up, login, and profile management flows.

Step 1: Prepare Your Video#

Ensure your video recording is clear and demonstrates all the key user interactions you want to recreate. This includes:

• •Sign-up process (entering email, password, etc.)
• •Login process (entering credentials)
• •Navigation between pages
• •Profile management (updating information)
• •Logout process

💡 Pro Tip: Record multiple takes of each flow to ensure Replay has enough data to accurately reconstruct the code.

Step 2: Upload Your Video to Replay#

1. •Go to Replay and create an account.
2. •Upload your video recording to the platform.
3. •Replay will begin analyzing the video and identifying UI elements and user interactions. This process may take a few minutes depending on the length of the video.

Step 3: Configure Supabase Integration#

Replay can automatically integrate with Supabase to handle user authentication.

1. •Create a Supabase project if you don't already have one.
2. •Obtain your Supabase URL and API key.
3. •In Replay, navigate to the project settings and configure the Supabase integration by providing your URL and API key.

Step 4: Generate the Flutter Code#

Once Replay has finished analyzing the video and you've configured the Supabase integration, you can generate the Flutter code.

1. •Click the "Generate Code" button.
2. •Replay will generate a Flutter project with all the necessary UI elements, navigation logic, and authentication flows.

📝 Note: Replay uses the latest Flutter version available at the time of code generation.

Step 5: Review and Customize the Code#

After the code is generated, download the Flutter project and open it in your preferred IDE (e.g., VS Code, Android Studio).

1. •Review the generated code to ensure it meets your requirements.
2. •Customize the UI elements and styling as needed.
3. •Test the authentication flows to ensure they are working correctly.

Here's an example of the generated code for a simple login screen:

typescript
// lib/screens/login_screen.dart
import 'package:flutter/material.dart';
import 'package:supabase_flutter/supabase_flutter.dart';

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

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

class _LoginScreenState extends State<LoginScreen> {
  final _emailController = TextEditingController();
  final _passwordController = TextEditingController();
  bool _isLoading = false;

  Future<void> _signIn() async {
    setState(() {
      _isLoading = true;
    });

    try {
      final response = await Supabase.instance.client.auth.signInWithPassword(
        email: _emailController.text.trim(),
        password: _passwordController.text.trim(),
      );

      if (response.session != null) {
        // Navigate to home screen
        Navigator.pushReplacementNamed(context, '/home');
      } else {
        // Show error message
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Invalid credentials')),
        );
      }
    } catch (error) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Error: ${error.toString()}')),
      );
    } finally {
      setState(() {
        _isLoading = false;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Login')),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            TextFormField(
              controller: _emailController,
              decoration: const InputDecoration(labelText: 'Email'),
            ),
            TextFormField(
              controller: _passwordController,
              decoration: const InputDecoration(labelText: 'Password'),
              obscureText: true,
            ),
            const SizedBox(height: 20),
            ElevatedButton(
              onPressed: _isLoading ? null : _signIn,
              child: _isLoading
                  ? const CircularProgressIndicator()
                  : const Text('Login'),
            ),
          ],
        ),
      ),
    );
  }
}

This code demonstrates how Replay can generate a functional login screen with Supabase integration, including error handling and navigation.

Step 6: Run and Test Your App#

Connect your device or emulator and run the Flutter app. Test all the user flows to ensure they are working as expected.

⚠️ Warning: Always thoroughly test your application after generating code with Replay. While Replay aims for high accuracy, manual review and testing are essential to ensure the application functions correctly.

Advanced Features and Customization#

Replay offers several advanced features for further customization and control:

• •Style Injection: Inject custom CSS or Flutter themes to match your desired branding.
• •Product Flow Maps: Visualize the user flows within your application to identify areas for improvement.
• •Code Snippet Editing: Directly edit the generated code snippets within Replay to fine-tune the functionality.

Here's an example of how to add custom styling using style injection:

dart
// lib/themes/app_theme.dart
import 'package:flutter/material.dart';

class AppTheme {
  static ThemeData lightTheme = ThemeData(
    primaryColor: Colors.blue,
    accentColor: Colors.blueAccent,
    textTheme: const TextTheme(
      headline1: TextStyle(fontSize: 72.0, fontWeight: FontWeight.bold),
      headline6: TextStyle(fontSize: 36.0, fontStyle: FontStyle.italic),
      bodyText2: TextStyle(fontSize: 14.0, fontFamily: 'Hind'),
    ),
  );
}

You can then apply this theme to your app in the

file:

dart
// lib/main.dart
import 'package:flutter/material.dart';
import 'package:your_app/themes/app_theme.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Your App',
      theme: AppTheme.lightTheme,
      home: const LoginScreen(), // Assuming you have a LoginScreen
    );
  }
}

Benefits of Using Replay#

• •Faster Development: Rebuild UIs in minutes instead of days.
• •Reduced Errors: Eliminate manual errors and inconsistencies.
• •Improved Accuracy: Capture dynamic behaviors and user interactions.
• •Seamless Integration: Integrate with Supabase for backend functionality.
• •Enhanced Collaboration: Share video recordings and generated code with your team.

Frequently Asked Questions#

Is Replay free to use?#

Replay offers a free tier with limited features. Paid plans are available for more advanced features and higher usage limits. Check the Replay pricing page for details.

How is Replay different from v0.dev?#

While both tools aim to generate code from visual inputs, Replay focuses on video analysis and behavior-driven reconstruction. v0.dev primarily uses static screenshots and lacks the ability to understand user intent and dynamic behaviors. Replay captures the process of interaction, enabling more accurate and functional code generation, especially for complex flows like user authentication.

What types of applications can Replay rebuild?#

Replay can rebuild a wide range of applications, including mobile apps (Flutter, React Native), web apps (React, Angular, Vue.js), and desktop applications. The accuracy and completeness of the generated code depend on the clarity and completeness of the video recording.

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