How to Implement Barcode Scanning and QR Code Reading in Flutter: A Complete Guide with Code

Introduction

Barcode scanning and QR code reading have become increasingly common in modern mobile applications. These features allow users to quickly and easily capture data from barcodes and QR codes, making it easier to store, share, and manage information. In this blog, we’ll explore how to integrate barcode scanning and QR code reading in a Flutter app.

Prerequisites

Before we dive into the implementation, there are a few prerequisites you should be aware of:

~ Basic understanding of Flutter and Dart programming

~ A development environment set up for Flutter development

Integrating the Barcode Scanner Package

To get started, we’ll need to add the barcode_scan package to our Flutter project. This package provides a simple and easy-to-use API for barcode scanning and QR code reading in Flutter.

To add the barcode_scan package to your project, add the following line to your pubspec.yaml file:

dependencies:
 barcode_scan: ^2.0.0

With the package installed, we can now import it into our Dart code by adding the following line to the top of the file:

import 'package:barcode_scan/barcode_scan.dart';

Implementing the Barcode Scanner

With the package installed, we can now start implementing the barcode scanner in our Flutter app. To do this, we’ll need to create an asynchronous method that triggers the barcode scanner and processes the results.

Here’s an example implementation of the barcode scanner in Dart:

Future _scanBarcode() async {
  try {
    String barcode =
     await BarcodeScanner.scan();
    setState(() {
      this._barcode =barcode;
    });
  } on PlatformException 
  catch (e) {
    if (e.code ==
        BarcodeScanner.CameraAccessDenied)
    {
      setState(() {
        this._barcode = 
        'The user did not grant the'
            ' camera permission!';
      });
    } else 
    {
      setState(() =>
      this._barcode = 'Unknown error: $e');
    }
  } on FormatException{
    setState(() => this._barcode = 
    'null '
        '(User returned using'
        ' the "back"-button'
        ' before scanning'
        ' anything. Result)');
  } catch (e) {
    setState(() => 
    this._barcode = 
    'Unknown error: $e');
  }
 }

In this implementation, we’re using the BarcodeScanner.scan method to initiate the barcode scanner. The results of the scan are returned as a string, which we store in the _barcode property.

We’ve also added error handling to this implementation. If the user denies camera access, the CameraAccessDenied error will be thrown. In this case, we’ll display an error message to the user indicating that camera access was denied. Additionally, we’ve added error handling for the FormatException and a generic catch-all for any other errors that may occur.

Triggering the Barcode Scanner

To trigger the barcode scanner, we’ll need to create a button in our Flutter app that calls the _scanBarcode method we implemented earlier.

Here’s an example implementation of the button in Flutter:

RaisedButton(
 child: Text('Scan Barcode'),
 onPressed: _scanBarcode,
 )

When the user taps this button, the _scanBarcode method will be called, triggering the barcode scanner. Once the user scans a barcode, the results will be processed and stored in the _barcode property.

Displaying the Results

With the barcode scanner implemented, we can now display the results to the user. To do this, we’ll create a text widget that displays the contents of the _barcode property.

Here’s an example implementation of the text widget:

Text(
 'Barcode: $_barcode',
 style: TextStyle(fontSize: 20),
 )

This text widget will display the contents of the _barcode property, allowing the user to see the results of the barcode scan.

Conclusion

In this blog, we’ve explored how to integrate barcode scanning and QR code reading in a Flutter app. We’ve covered the process of adding the barcode_scan package to our project, implementing the barcode scanner, triggering the scanner, and displaying the results to the user.

This is just the tip of the iceberg when it comes to barcode scanning and QR code reading in Flutter. There are many other features and customization options available in the barcode_scan package that you can explore on your own.

I hope you found this blog helpful and informative.

Happy coding!