How to Convert a Mobile App Demo Video to a React Native App with Expo using Replay AI

TL;DR: Convert a mobile app demo video into a functional React Native application with Expo using Replay's AI-powered behavior-driven reconstruction.

The promise of "screenshot-to-code" has always been tempting, but the reality often falls short. Static images simply lack the context needed to create truly functional applications. They can generate UI, but they don't understand user intent or application flow. What if you could use a video instead?

That's where Replay comes in. Replay analyzes video recordings of user interactions and leverages Gemini to reconstruct not just the UI, but the underlying logic and behavior. This allows you to rapidly prototype and iterate on mobile applications by simply recording a demo. Let's dive into how you can convert a mobile app demo video into a React Native app with Expo using Replay.

Understanding Behavior-Driven Reconstruction#

Traditional image-to-code tools focus on visual elements. Replay takes a different approach, focusing on behavior. It analyzes the video to understand:

• •User interactions (taps, swipes, text input)
• •Application state changes (navigation, data updates)
• •Underlying data flow

This "Behavior-Driven Reconstruction" allows Replay to generate code that's not just visually similar, but also functionally equivalent to the demoed application. This is crucial for creating usable and maintainable code.

Here's a comparison:

Converting Your Mobile App Demo to React Native#

Here's a step-by-step guide to converting your mobile app demo video into a React Native app using Expo and Replay.

Step 1: Record Your Demo Video#

The quality of your demo video directly impacts the accuracy of the reconstruction. Keep these tips in mind:

• •Clear and Steady: Use a stable recording setup.
• •Realistic Interactions: Perform typical user flows.
• •Complete Flows: Demonstrate entire user journeys, from start to finish.
• •Highlight Key Features: Focus on the most important aspects of your application.
• •Avoid Distractions: Minimize background noise and visual clutter.

💡 Pro Tip: Narrate your actions while recording. This provides additional context that Replay can use to improve accuracy.

Step 2: Upload and Process with Replay#

1. •Navigate to the Replay platform (https://replay.build).
2. •Create an account or log in.
3. •Upload your mobile app demo video.
4. •Specify that you want to generate a React Native application with Expo.
5. •Replay will process the video, analyze the behavior, and reconstruct the application. This process can take a few minutes, depending on the length and complexity of the video.

Step 3: Review and Refine the Generated Code#

Once Replay has finished processing, you'll be presented with a code preview. This is where you can review and refine the generated code:

• •Verify UI Elements: Check that all UI elements have been correctly identified and rendered.
• •Test Interactions: Ensure that all interactions (taps, swipes, text input) are working as expected.
• •Inspect State Management: Examine how application state is being managed and updated.
• •Adjust Styling: Fine-tune the styling to match your desired look and feel.

⚠️ Warning: The generated code may not be perfect. You may need to make manual adjustments to ensure that the application is fully functional and meets your specific requirements.

Step 4: Integrate with Expo#

Replay provides you with a downloadable Expo project. To run it:

1. •

   Install Expo CLI:

   bash
   npm install -g expo-cli

2. •

   Navigate to the project directory:

   bash
   cd your-project-directory

3. •

   Install dependencies:

   bash
   npm install
   # or
   yarn install

4. •

   Start the Expo development server:

   bash
   expo start

This will open the Expo DevTools in your browser. You can then use the Expo Go app on your mobile device to preview the application, or run it in an emulator.

Step 5: Enhance with Supabase (Optional)#

Replay offers seamless integration with Supabase. If your demo video includes data interactions, Replay can generate the necessary Supabase schema and API calls.

1. •Connect your Supabase project to Replay during the processing stage.
2. •Replay will analyze the video and generate the necessary Supabase schema based on the data interactions observed.
3. •The generated React Native code will include API calls to interact with your Supabase database.

Here's an example of a generated API call using

:

typescript
import { createClient } from '@supabase/supabase-js';

const supabaseUrl = 'YOUR_SUPABASE_URL';
const supabaseKey = 'YOUR_SUPABASE_ANON_KEY';
const supabase = createClient(supabaseUrl, supabaseKey);

const fetchData = async () => {
  const { data, error } = await supabase
    .from('your_table')
    .select('*');

  if (error) {
    console.error('Error fetching data:', error);
    return [];
  }

  return data;
};

📝 Note: You'll need to replace

text

YOUR_SUPABASE_URL

and

text

YOUR_SUPABASE_ANON_KEY

with your actual Supabase credentials.

Step 6: Customize and Extend#

The code generated by Replay is a starting point. You can customize and extend it to meet your specific needs.

• •Add New Features: Implement new features and functionalities.
• •Refactor Code: Improve the code's structure and maintainability.
• •Optimize Performance: Enhance the application's performance.
• •Integrate with Other Services: Connect to other APIs and services.

Benefits of Using Replay#

• •Rapid Prototyping: Quickly create functional prototypes from demo videos.
• •Reduced Development Time: Automate the initial code generation process.
• •Improved Accuracy: Leverage behavior-driven reconstruction for more accurate results.
• •Enhanced Collaboration: Share demo videos and generated code with your team.
• •Simplified Iteration: Easily iterate on your application based on user feedback.
• •Multi-Page Application Generation: Replay can analyze videos showcasing multiple pages and generate the corresponding code, handling navigation and state transitions automatically.
• •Product Flow Maps: Replay can generate visual flow maps of the user's journey through the app, providing valuable insights into user behavior.

Frequently Asked Questions#

Is Replay free to use?#

Replay offers a free tier with limited usage. Paid plans are available for more extensive use and advanced features. Check the pricing page on the Replay website for the most up-to-date information.

How is Replay different from v0.dev?#

v0.dev primarily generates UI components based on text prompts. Replay, on the other hand, analyzes video recordings to reconstruct entire applications, including UI, behavior, and data flow. Replay focuses on understanding user intent through video analysis, whereas v0.dev focuses on generating UI based on textual descriptions.

What types of mobile app demos work best with Replay?#

Demos that showcase complete user flows, clear interactions, and well-defined data interactions tend to produce the best results. Shorter, focused videos are often easier for Replay to process accurately.

What if the generated code isn't exactly what I need?#

The generated code is a starting point. You can customize and extend it to meet your specific requirements. Think of Replay as a powerful code generation tool that significantly accelerates the development process, not a replacement for skilled developers.

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Ready to try behavior-driven code generation? Get started with Replay - transform any video into working code in seconds.