expo-camera

What is expo-camera?

The expo-camera package is a part of the Expo ecosystem and provides a comprehensive API for accessing and using the device's camera in React Native applications. It allows developers to capture photos, record videos, and access various camera settings and features.

What are expo-camera's main functionalities?

Capture Photos

This feature allows you to capture photos using the device's camera. The code sample demonstrates how to set up the Camera component and take a picture when a button is pressed.

```javascript
import React, { useRef } from 'react';
import { View, Button } from 'react-native';
import { Camera } from 'expo-camera';

export default function App() {
  const cameraRef = useRef(null);

  const takePicture = async () => {
    if (cameraRef.current) {
      const photo = await cameraRef.current.takePictureAsync();
      console.log(photo);
    }
  };

  return (
    <View style={{ flex: 1 }}>
      <Camera style={{ flex: 1 }} ref={cameraRef} />
      <Button title="Take Picture" onPress={takePicture} />
    </View>
  );
}
```

Record Videos

This feature allows you to record videos using the device's camera. The code sample demonstrates how to set up the Camera component and start/stop video recording when a button is pressed.

```javascript
import React, { useRef, useState } from 'react';
import { View, Button } from 'react-native';
import { Camera } from 'expo-camera';

export default function App() {
  const cameraRef = useRef(null);
  const [isRecording, setIsRecording] = useState(false);

  const recordVideo = async () => {
    if (cameraRef.current) {
      if (isRecording) {
        cameraRef.current.stopRecording();
      } else {
        setIsRecording(true);
        const video = await cameraRef.current.recordAsync();
        console.log(video);
        setIsRecording(false);
      }
    }
  };

  return (
    <View style={{ flex: 1 }}>
      <Camera style={{ flex: 1 }} ref={cameraRef} />
      <Button title={isRecording ? "Stop Recording" : "Record Video"} onPress={recordVideo} />
    </View>
  );
}
```

Access Camera Settings

This feature allows you to access and modify camera settings such as switching between the front and back cameras. The code sample demonstrates how to request camera permissions and toggle the camera type.

```javascript
import React, { useState, useEffect } from 'react';
import { View, Text } from 'react-native';
import { Camera } from 'expo-camera';

export default function App() {
  const [hasPermission, setHasPermission] = useState(null);
  const [cameraType, setCameraType] = useState(Camera.Constants.Type.back);

  useEffect(() => {
    (async () => {
      const { status } = await Camera.requestPermissionsAsync();
      setHasPermission(status === 'granted');
    })();
  }, []);

  if (hasPermission === null) {
    return <View />;
  }
  if (hasPermission === false) {
    return <Text>No access to camera</Text>;
  }

  return (
    <View style={{ flex: 1 }}>
      <Camera style={{ flex: 1 }} type={cameraType} />
      <Button
        title="Flip Camera"
        onPress={() => {
          setCameraType(
            cameraType === Camera.Constants.Type.back
              ? Camera.Constants.Type.front
              : Camera.Constants.Type.back
          );
        }}
      />
    </View>
  );
}
```

Other packages similar to expo-camera

react-native-camera

The react-native-camera package is a popular alternative to expo-camera. It provides similar functionalities such as capturing photos, recording videos, and accessing camera settings. However, it requires linking and additional setup compared to the more streamlined experience of expo-camera within the Expo ecosystem.

react-native-vision-camera

The react-native-vision-camera package offers advanced camera functionalities, including frame processing and integration with machine learning models. It is more feature-rich compared to expo-camera but also requires more complex setup and configuration.

README

A React component that renders a preview for the device's either front or back camera. Camera's parameters like zoom, auto focus, white balance and flash mode are adjustable. With expo-camera, one can also take photos and record videos that are saved to the app's cache. Morever, the component is also capable of detecting faces and bar codes appearing on the preview.

API documentation

• Documentation for the latest stable release
• Documentation for the main branch

Installation in managed Expo projects

For managed Expo projects, please follow the installation instructions in the API documentation for the latest stable release.

Installation in bare React Native projects

For bare React Native projects, you must ensure that you have installed and configured the expo package before continuing.

Add the package to your npm dependencies

npx expo install expo-camera

Configure for Android

This package automatically adds the CAMERA permission to your app. If you want to record videos with audio, you have to include the RECORD_AUDIO.

<!-- Added permissions -->
<uses-permission android:name="android.permission.CAMERA" />

<!-- Optional permissions -->
<uses-permission android:name="android.permission.RECORD_AUDIO" />

Adjust the android/build.gradle to add a new maven block after all other repositories as described below:

allprojects {
    repositories {

        // * Your other repositories here *

        // * Add a new maven block after other repositories / blocks *
        maven {
            // expo-camera bundles a custom com.google.android:cameraview
            url "$rootDir/../node_modules/expo-camera/android/maven"
        }
    }
}

The sourcecode for cameraview can be found at expo/cameraview.

Configure for iOS

Add NSCameraUsageDescription and NSMicrophoneUsageDescription keys to your Info.plist:

<key>NSCameraUsageDescription</key>
<string>Allow $(PRODUCT_NAME) to use the camera</string>
<key>NSMicrophoneUsageDescription</key>
<string>Allow $(PRODUCT_NAME) to use the microphone</string>

Run npx pod-install after installing the npm package.

Contributing

Contributions are very welcome! Please refer to guidelines described in the contributing guide.