README.md

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.

You can read more about the difference between the two versions here.

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/[email protected]/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');
              }
            }));
  }