React Native Camera with Expo | Tutorial

Learn how to create a camera app in React Native using Expo. You'll learn requesting permissions for the camera and media library, displaying the camera preview, and adding controls like flash toggle, camera flip, and taking pictures.

It's perfect for developers who want to integrate camera functionality in their Expo projects and learn how to handle permissions, camera types, and saving photos to the device.

What's inside

• Setting up the Expo project and installing dependencies
• Requesting camera and media library permissions asynchronously
• Managing camera type and flash mode with React state
• Using a camera reference to capture photos
• Displaying the camera preview with styling
• Creating reusable button components with icons
• Handling photo capture, preview, retake, and saving to the media library
• Switching between front and back cameras and toggling flash

Setting up the Expo project and installing dependencies

I start by initializing a new Expo project with the blank template using expo init. After opening the project in Visual Studio Code, the necessary dependencies are installed: expo-camera and expo-media-library. These packages provide access to the device camera and the ability to save photos to the user's media library.

The setup ensures the project is ready to handle camera functionality and media storage, which are essential for building a camera app.

Requesting camera and media library permissions asynchronously

Before accessing the camera or saving photos, the app must request permissions from the user. I demonstrate using React's useEffect hook to run an async function on component mount that requests permissions.

It calls MediaLibrary.requestPermissionsAsync() and Camera.requestCameraPermissionsAsync(). The camera permission status is stored in state and checked to confirm if access was granted. This approach ensures the app only proceeds if the user allows camera and media library access.

Managing camera type and flash mode with React state

The camera type (front or back) and flash mode (on, off, auto) are controlled using React state variables. I show initializing state with Camera.Constants.Type.back for the back camera and Camera.Constants.FlashMode.off for flash off.

These states are used as props on the Camera component to dynamically update the camera behavior. This setup allows toggling between front/back cameras and flash modes during runtime.

Using a camera reference to capture photos

To take pictures, I use React's useRef hook to create a reference to the Camera component. This reference is passed via the ref prop.

When the user taps the capture button, the app calls the takePictureAsync() method on the camera ref. This returns the photo data, which can then be saved or previewed. Using a ref is essential to access imperative camera methods.

Displaying the camera preview with styling

The Camera component is styled to fill the entire screen using flex: 1. I also adds a border radius to soften the edges.

Inside the camera view, UI elements like buttons and text can be nested. I show adding a simple "hello" text inside the camera to demonstrate this. Styling ensures the camera preview looks good and occupies the desired space.

Creating reusable button components with icons

To keep the UI clean and maintainable, I create a reusable Button component inside a components folder. This button uses TouchableOpacity and can display text or icons.

Expo's icon set (@expo/vector-icons) is used to add camera-related icons like flash and rotate. This modular approach makes it easy to add multiple buttons for camera controls.

Handling photo capture, preview, retake, and saving to the media library

After capturing a photo, the app shows a preview and offers options to retake or save the picture. I explain how to store the captured image URI in state and conditionally render the preview.

Saving the photo uses MediaLibrary.createAssetAsync() to add the image to the device's gallery. The app displays an alert confirming the save operation. This flow mimics a real camera app experience.

Switching between front and back cameras and toggling flash

I cover toggling the camera type between front and back by updating the state variable controlling the camera type. Similarly, the flash mode state is toggled between off and on.

These controls are wired to buttons inside the camera view, allowing the user to switch cameras and flash modes seamlessly while using the app.

Resources

CourseReact Native course

Fundamentals through shipping: the concepts behind the prompts, with lifetime access.

YouTubeReact Native Camera with Expo | Tutorial

Official video tutorial on building a camera app with Expo Camera and Media Library.