This module provides a React Native component for scanning QR codes, specifically designed for use with Expo. It offers a customizable QR code scanning experience, allowing users to specify various parameters and styles.
To use this module in your Expo project, install it via npm or yarn:
npm install expo-qrcode-scanner
# or
yarn add expo-qrcode-scanner
First, import the QRCodeScanner
into your React Native component:
import QRCodeScanner from 'expo-qrcode-scanner';
Then, you can use the QRCodeScanner
in your component's render method:
import React from 'react';
import { View } from 'react-native';
import QRCodeScanner from 'expo-qrcode-scanner';
const YourComponent = () => {
const handleScanSuccess = (scanData) => {
// Handle successful scan
console.log('QR Code Scanned:', scanData);
};
const handleScanFail = () => {
// Handle scan failure
console.log('Failed to scan QR Code.');
};
return (
<View style={{ flex: 1 }}>
<QRCodeScanner
onScanSuccess={handleScanSuccess}
onScanFail={handleScanFail}
// Additional props
/>
</View>
);
};
export default YourComponent;
Before scanning QR codes, your app must ask the user for permission to access the camera. You can do this using Expo's Permissions
API:
import { useState, useEffect } from 'react';
import { Text, View } from 'react-native';
import QRCodeScanner from 'expo-qrcode-scanner';
import {BarCodeScanner} from 'expo-barcode-scanner';
const CameraScreen = () => {
const [hasPermission, setHasPermission] = useState(null);
useEffect(() => {
(async () => {
const { status } = await BarCodeScanner.requestPermissionsAsync();
setHasPermission(status === 'granted');
})();
}, []);
if (hasPermission === null) {
return <View />;
}
if (hasPermission === false) {
return <Text>No access to camera</Text>;
}
return (
<View style={{ flex: 1 }}>
<QRCodeScanner
onScanSuccess={(scanData) => console.log(scanData)}
onScanFail={() => console.log('Failed to scan')}
// Additional props
/>
</View>
);
};
The QRCodeScannerComponent
accepts the following props:
Prop | Type | Default | Required | Description |
---|---|---|---|---|
style |
Object | - | No | A custom style object to apply to the scanner component. |
onScanSuccess |
Function | - | No | A callback function invoked when a QR code is successfully scanned. |
onScanFail |
Function | - | No | A callback function invoked when a scan attempt fails. |
toleranceFactor |
Number | 0.5 | No | A number representing the tolerance factor for QR code centering. |
minSize |
Number | 140 | Yes | The minimum size for a QR code to be considered valid. |
maxSize |
Number | 220 | Yes | The maximum size for a QR code to be considered valid. |
scanningInfinitely |
boolean | false | Yes | Scan QR code continously |
Contributions to this module are welcome. Please ensure that your code adheres to the existing style and functionality.
This module is licensed under the MIT License.