expo-use-camera

A React Hook for simplifying basic usage of expo-camera

This hook receives a boolean crop and returns an object and an component.

The object has five properties:

• a reference ref;

• a boolean state active;

• an asynchronous method activate, that asks for permission to access the camera, sets the aforementioned state to true if it is granted, and throws an error otherwise;

• a synchronous method deactivate, that sets the aforementioned state to false.

• an asynchronous method take that takes a picture and returns it.

If crop is true, the picture is cropped to a square area.

The component is a modified version of expo-camera, but without two props: ref, because it is already available in the object, and crop, because it is already defined by the hook argument.

Peer dependencies

{
    "@hashiprobr/expo-camera": "1.0.9",
    "@hashiprobr/react-use-mount-and-update": "1.0.5",
    "expo": "45.0.0",
    "expo-image-manipulator": "10.3.1",
    "hoist-non-react-statics": "3.3.2",
    "react": "17.0.2",
    "react-native": "0.68.2"
}

Install

With npm:

npm install @hashiprobr/expo-use-camera

With yarn:

yarn add @hashiprobr/expo-use-camera

With expo:

expo install @hashiprobr/expo-use-camera

If using Expo, add the module to webpack.config.js:

const createExpoWebpackConfigAsync = require('@expo/webpack-config');

module.exports = async function (env, argv) {
    const config = await createExpoWebpackConfigAsync({
        ...env,
        babel: {
            dangerouslyAddModulePathsToTranspile: [
                '@hashiprobr/expo-use-camera',
            ],
        },
    }, argv);
    return config;
};

If webpack.config.js does not exist, create it with:

expo customize:web

Example

import React, { useState } from 'react';

import { View, Image, Button } from 'react-native';

import useCamera from '@hashiprobr/expo-use-camera';

export default function MyComponent() {
    const [uri, setUri] = useState();

    const [camera, Preview] = useCamera(true);

    async function onPressOpen() {
        try {
            await camera.activate();
        } catch (error) {
            console.error(error);
        }
    }

    async function onPressTake() {
        let source;
        try {
            source = await camera.take();
        } catch (error) {
            console.error(error);
        }
        if (source) {
            camera.deactivate();
            setUri(source.uri);
        }
    }

    function onPressClose() {
        camera.deactivate();
    }

    return (
        <View
            style={{
                flexGrow: 1,
                justifyContent: 'center',
                alignItems: 'center',
            }}
        >
            {camera.active ? (
                <Preview
                    style={{
                        flexGrow: 1,
                        alignSelf: 'stretch',
                        justifyContent: 'flex-end',
                    }}
                >
                    <View
                        style={{
                            flexDirection: 'row',
                            justifyContent: 'space-around',
                        }}
                    >
                        <Button title="take" onPress={onPressTake} />
                        <Button title="close" onPress={onPressClose} />
                    </View>
                </Preview>
            ) : (
                <>
                    {uri && (
                        <Image style={{ width: 250, height: 250 }} source={{ uri }} />
                    )}
                    <Button title="open" onPress={onPressOpen} />
                </>
            )}
        </View>
    );
}