mobile_scanner

A universal barcode and QR code scanner for Flutter based on MLKit. Uses CameraX on Android, AVFoundation on iOS and Apple Vision & AVFoundation on macOS.

Platform Support

Android	iOS	MacOS	Web	Linux	Windows
✔️	✔️	✔️	✔️

Android

SDK 21 and newer. Reason: CameraX requires at least SDK 21. Also, make sure you upgrade kotlin to the latest version in your project.

This packages uses the bundled version of MLKit Barcode-scanning for Android. This version is more accurate and immediately available to devices. However, this version will increas the size of the app with approximately 3 to 10 MB. The alternative for this is to use the unbundled version of MLKit Barcode-scanning for Android. This version is older than the bundled version however this only increases the size by around 600KB.

To use this version you must alter the mobile_scanner gradle file to replace com.google.mlkit:barcode-scanning:17.0.2 with com.google.android.gms:play-services-mlkit-barcode-scanning:18.0.0. Keep in mind that if you alter the gradle files directly in your project it can be overriden when you update your pubspec.yaml. I am still searching for a way to properly replace the module in gradle but have yet to find one.

iOS

iOS 11 and newer. Reason: MLKit for iOS requires at least iOS 10 and a 64bit device.

Add the following keys to your Info.plist file, located in /ios/Runner/Info.plist:

NSCameraUsageDescription – describe why your app needs access to the camera. This is called Privacy – Camera Usage Description in the visual editor.

If you want to use the local gallery feature from image_picker

NSPhotoLibraryUsageDescription – describe why your app needs permission for the photo library. This is called Privacy – Photo Library Usage Description in the visual editor.

macOS

macOS 10.13 or newer. Reason: Apple Vision library.

Web

Add this to web/index.html:

<script src="https://cdn.jsdelivr.net/npm/jsqr@1.4.0/dist/jsQR.min.js"></script>

Web only supports QR codes for now. Do you have experience with Flutter Web development? Help me with migrating from jsQR to qr-scanner for full barcode support!

Features Supported

Features	Android	iOS	macOS	Web
analyzeImage (Gallery)	✔️	✔️	❌	❌

Usage

Import package:mobile_scanner/mobile_scanner.dart, and use the widget with or without the controller.

If you don’t provide a controller, you can’t control functions like the torch(flash) or switching camera.

If you don’t set allowDuplicates to false, you can get multiple scans in a very short time, causing things like pop() to fire lots of times.

Example without controller:

import 'package:mobile_scanner/mobile_scanner.dart';

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Mobile Scanner')),
      body: MobileScanner(
          allowDuplicates: false,
          onDetect: (barcode, args) {
            if (barcode.rawValue == null) {
              debugPrint('Failed to scan Barcode');
            } else {
              final String code = barcode.rawValue!;
              debugPrint('Barcode found! $code');
            }
          }),
    );
  }

Example with controller and initial values:

import 'package:mobile_scanner/mobile_scanner.dart';

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Mobile Scanner')),
      body: MobileScanner(
          allowDuplicates: false,
          controller: MobileScannerController(
            facing: CameraFacing.front, torchEnabled: true),
          onDetect: (barcode, args) {
            if (barcode.rawValue == null) {
              debugPrint('Failed to scan Barcode');
            } else {
              final String code = barcode.rawValue!;
              debugPrint('Barcode found! $code');
            }
          }),
    );
  }

Example with controller and torch & camera controls:

import 'package:mobile_scanner/mobile_scanner.dart';

  MobileScannerController cameraController = MobileScannerController();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: const Text('Mobile Scanner'),
          actions: [
            IconButton(
              color: Colors.white,
              icon: ValueListenableBuilder(
                valueListenable: cameraController.torchState,
                builder: (context, state, child) {
                  switch (state as TorchState) {
                    case TorchState.off:
                      return const Icon(Icons.flash_off, color: Colors.grey);
                    case TorchState.on:
                      return const Icon(Icons.flash_on, color: Colors.yellow);
                  }
                },
              ),
              iconSize: 32.0,
              onPressed: () => cameraController.toggleTorch(),
            ),
            IconButton(
              color: Colors.white,
              icon: ValueListenableBuilder(
                valueListenable: cameraController.cameraFacingState,
                builder: (context, state, child) {
                  switch (state as CameraFacing) {
                    case CameraFacing.front:
                      return const Icon(Icons.camera_front);
                    case CameraFacing.back:
                      return const Icon(Icons.camera_rear);
                  }
                },
              ),
              iconSize: 32.0,
              onPressed: () => cameraController.switchCamera(),
            ),
          ],
        ),
        body: MobileScanner(
            allowDuplicates: false,
            controller: cameraController,
            onDetect: (barcode, args) {
              if (barcode.rawValue == null) {
                debugPrint('Failed to scan Barcode');
              } else {
                final String code = barcode.rawValue!;
                debugPrint('Barcode found! $code');
              }
            }));
  }

Example with controller and returning images

import 'package:mobile_scanner/mobile_scanner.dart';

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Mobile Scanner')),
      body: MobileScanner(
        controller: MobileScannerController(
          facing: CameraFacing.front,
          torchEnabled: true,
          returnImage: true,
        ),
        onDetect: (barcode, args) {
          if (barcode.rawValue == null) {
            debugPrint('Failed to scan Barcode');
          } else {
            final String code = barcode.rawValue!;
            debugPrint('Barcode found! $code');

            debugPrint(
                'Image returned! length: ${barcode.image!.lengthInBytes}b');
            showDialog(
              context: context,
              builder: (context) => Image(image: MemoryImage(barcode.image!)),
            );
            Future.delayed(const Duration(seconds: 2), () {
              Navigator.pop(context);
            });
          }
        },
      ),
    );
  }