Creating a QR Code Scanner in React Native

Creating a QR code scanner for React Native is a straightforward process. With the right tools, it can be done in a few simple steps. In this article, we will cover the prerequisites, accessing the device's camera, scanning QR codes, and handling the data from the scanned QR codes.

Prerequisites

In order to create a QR code scanner for React Native, you will need the following:

• React Native
• Node.js
• Expo

Accessing the Device's Camera in React Native

The first step to creating a QR code scanner is accessing the device's camera. We can do this by creating a component that will render the camera view on the screen.

First, import the Camera component from expo-camera:

import { Camera } from 'expo-camera';

Then, create a variable cameraRef and set it to null:

let cameraRef = null;

Next, create a <Camera> component and set the ref attribute to cameraRef:

<Camera 
  ref={ref => {
    cameraRef = ref;
  }}
  style={{ flex: 1 }}
/>

The Camera component will render the device's camera view on the screen.

Scanning QR Codes in React Native

Now that we have access to the device's camera, we can start scanning for QR codes. To do this, we need to import the expo-barcode-scanner package:

import { BarCodeScanner } from 'expo-barcode-scanner';

Then, create a variable scannerRef and set it to null:

let scannerRef = null;

Next, create a <BarCodeScanner> component and set the ref attribute to scannerRef:

<BarCodeScanner
  ref={ref => {
    scannerRef = ref;
  }}
  onBarCodeScanned={handleBarCodeScanned}
/>

The BarCodeScanner component will scan for QR codes, and the handleBarCodeScanned function will be called when a QR code is detected.

Handling Scanned QR Code Data

Once a QR code is detected, the handleBarCodeScanned function will be called. This function will receive the data from the scanned QR code as an argument. We can then use this data to do whatever we want.

For example, we can log the data to the console:

const handleBarCodeScanned = ({ type, data }) => {
  console.log(`Bar code with type ${type} and data ${data} has been scanned!`);
};

Or, we can use the data to make an API call:

const handleBarCodeScanned = ({ type, data }) => {
  fetch(`https://example.com/api/v1/qr-code?type=${type}&data=${data}`)
    .then(response => response.json())
    .then(data => {
      // do something with the response data
    });
};

Conclusion

Creating a QR code scanner for React Native is a straightforward process. By following the steps outlined in this article, you can easily create a QR code scanner in React Native.