Creating a TikTok-like app in React Native involves several key steps, including setting up your development environment, designing the app's UI, integrating video playback and recording functionalities, and implementing features like user authentication, social sharing, and possibly an algorithm for video recommendation. Here's a simplified roadmap to get you started:

1. Environment Setup

• Install Node.js and npm: Ensure you have Node.js and npm installed on your computer as they are essential for React Native development.

• React Native CLI: Install the React Native CLI by running npm install -g react-native-cli in your terminal.

• Initialize Your Project: Create a new React Native project by running npx react-native init TikTokClone.

2. UI Design

• Navigation: Install React Navigation (npm install @react-navigation/native) and its dependencies to handle navigating between different screens.

• Layout and Components: Design your app's layout using React Native's built-in components like View, Text, ScrollView, and TouchableOpacity. You might also want to use third-party UI libraries like NativeBase or React Native Elements for more complex components.

3. Video Playback and Recording

• Video Playback: Use a library such as react-native-video for video playback. Install it using npm install react-native-video.

• Video Recording: For video recording, you can use react-native-camera. Install it using npm install react-native-camera.

4. User Authentication

• Firebase Authentication: A common choice for handling user authentication is Firebase. To use Firebase with React Native, install the @react-native-firebase/app package along with @react-native-firebase/auth.

• Implement Authentication Flow: Implement the signup, login, and logout functionality using Firebase authentication methods.

5. Backend and Database

• Firebase Firestore: For storing user data and video metadata, you can use Firestore. Install it by npm install @react-native-firebase/firestore.

• Serverless Functions: Consider using Firebase Functions for backend logic that can't be securely executed on the client side.

6. Social Sharing and Interaction

• Comments and Likes: Implement functionality for users to like and comment on videos. This will involve updating your database schema to support these features.

• Follow System: Implement a follow system to allow users to follow others and see their videos in a feed.

7. Video Feed and Recommendation Algorithm

• Video Feed: Implement a video feed that shows videos from users the current user follows or popular videos.

• Recommendation Algorithm: Developing a sophisticated recommendation algorithm can be complex. As a start, you might use simple criteria like showing popular videos or videos from related categories.

8. Testing and Deployment

• Testing: Thoroughly test your app on multiple devices and fix any bugs.

• Deployment: Follow the React Native deployment guides to deploy your app to the iOS App Store and Google Play Store.

Tools and Libraries You Might Need

• React Navigation (@react-navigation/native)

• React Native Video (react-native-video)

• React Native Camera (react-native-camera)

• Firebase (@react-native-firebase/app, @react-native-firebase/auth, @react-native-firebase/firestore)

• UI Libraries (NativeBase, React Native Elements)

Example Code Snippet

Here's a very basic example of using react-native-video to play a video:

import React from 'react';
import Video from 'react-native-video';

const App = () => {
  return (
    <Video source={{uri: "path/to/your/video.mp4"}}   // Can be a URL or a local file.
           ref={(ref) => {
             this.player = ref
           }}                                      
           onBuffer={this.onBuffer}                
           onError={this.videoError}               
           style={styles.backgroundVideo} />
  );
};

const styles = StyleSheet.create({
  backgroundVideo: {
    position: 'absolute',
    top: 0,
    left: 0,
    bottom: 0,
    right: 0,
  },
});

export default App;

This roadmap and example provide a foundational structure for creating a TikTok-like app in React Native. Remember, building an app as feature-rich and polished as TikTok requires a significant amount of time, effort, and possibly a team of developers, especially for backend development, UI/UX design, and testing.