base on A universal Flutter barcode and QR code scanner using CameraX/ML Kit for Android, AVFoundation/Apple Vision for iOS & macOS, and ZXing for web. # mobile_scanner [](https://pub.dev/packages/mobile_scanner) [](https://pub.dev/packages/mobile_scanner) [](https://github.com/juliansteenbakker/mobile_scanner/actions/workflows/code-coverage.yml) [](https://pub.dev/packages/very_good_analysis) [](https://codecov.io/gh/juliansteenbakker/mobile_scanner) [](https://github.com/sponsors/juliansteenbakker) A fast and lightweight Flutter plugin for scanning barcodes and QR codes using the device’s camera. It supports multiple barcode formats, real-time detection, and customization options for an optimized scanning experience on multiple platforms. ## Features - Fast barcode and QR code scanning - Supports multiple barcode formats - Real-time detection - Customizable camera and scanner behavior See the [examples](example/README.md) for runnable examples of various usages, such as the basic usage, applying a scan window, or retrieving images from the barcodes. ## Platform Support | Android | iOS | macOS | Web | Linux | Windows | |---------|-----|-------|-----|-------|---------| | ✔ | ✔ | ✔ | ✔ | :x: | :x: | ### Features Supported See the example app for detailed implementation information. | Features | Android | iOS | macOS | Web | |--------------|--------------------|--------------------|--------------------|-----| | analyzeImage | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: | :x: | | returnImage | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: | :x: | | scanWindow | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: | :x: | | autoZoom | :heavy_check_mark: | :x: | :x: | :x: | | lensType | :heavy_check_mark: | :heavy_check_mark: | :x: | :x: | ## Installation Add the dependency in your `pubspec.yaml` file: ``` dependencies: mobile_scanner: ^<latest_version> ``` Then run: `flutter pub get` ## Configuration ### Android This package uses by default the **bundled version** of MLKit Barcode-scanning for Android. This version is immediately available to the device. But it will increase the size of the app by approximately 3 to 10 MB. The alternative is to use the **unbundled version** of MLKit Barcode-scanning for Android. This version is downloaded on first use via Google Play Services. It increases the app size by around 600KB. [You can read more about the difference between the two versions here.](https://developers.google.com/ml-kit/vision/barcode-scanning/android) To use the **unbundled version** of the MLKit Barcode-scanning, add the following line to your `/android/gradle.properties` file: ``` dev.steenbakker.mobile_scanner.useUnbundled=true ``` ### iOS Since the scanner needs to use the camera, add the following keys to your Info.plist file. (located in <project root>/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](https://pub.dev/packages/image_picker), you also need to add the following key. NSPhotoLibraryUsageDescription - describe why your app needs permission for the photo library. This is called Privacy - Photo Library Usage Description in the visual editor. Example, ``` <key>NSCameraUsageDescription</key> <string>This app needs camera access to scan QR codes</string> <key>NSPhotoLibraryUsageDescription</key> <string>This app needs photos access to get QR code from photo library</string> ``` ### macOS Ensure that you granted camera permission in XCode -> Signing & Capabilities: <img width="696" alt="Screenshot of XCode where Camera is checked" src="https://user-images.githubusercontent.com/24459435/193464115-d76f81d0-6355-4cb2-8bee-538e413a3ad0.png"> ### Web As of version 5.0.0 adding the barcode scanning library script to the `index.html` is no longer required, as the script is automatically loaded on first use. #### Providing a mirror for the barcode scanning library If a different mirror is needed to load the barcode scanning library, the source URL can be set beforehand. ```dart import 'package:flutter/foundation.dart'; import 'package:mobile_scanner/mobile_scanner.dart'; final String scriptUrl = // ... if (kIsWeb) { MobileScannerPlatform.instance.setBarcodeLibraryScriptUrl(scriptUrl); } ``` ## Usage ### Simple Import the package with `package:mobile_scanner/mobile_scanner.dart`. The only required parameter is `onDetect`, which returns the scanned barcode or qr code. ```dart MobileScanner( onDetect: (result) { print(result.barcodes.first.rawValue); }, ), ``` ### Advanced If you want more control over the scanner, you need to create a new `MobileScannerController` controller. The controller contains multiple parameters to adjust the scanner. ```dart final MobileScannerController controller = MobileScannerController( cameraResolution: size, detectionSpeed: detectionSpeed, detectionTimeoutMs: detectionTimeout, formats: selectedFormats, returnImage: returnImage, torchEnabled: true, invertImage: invertImage, autoZoom: autoZoom, ); ``` ```dart MobileScanner( controller: controller, onDetect: (result) { print(result.barcodes.first.rawValue); }, ); ``` #### Switching lens types On devices with multiple cameras (normal, wide, zoom), you can switch between lens types: ```dart // Toggle through available lens types (normal -> wide -> zoom -> normal) await controller.switchCamera(const ToggleLensType()); // Or select a specific lens type await controller.switchCamera( const SelectCamera(lensType: CameraLensType.wide), ); // Get supported lens types for the current camera final Set<CameraLensType> supportedLenses = await controller.getSupportedLenses(); ``` #### Lifecycle changes If you want to pause the scanner when the app is inactive, you need to use `WidgetsBindingObserver`. First, provide a `StreamSubscription` for the barcode events. Also, make sure to create a `MobileScannerController` with `autoStart` set to false, since we will be handling the lifecycle ourself. ```dart final MobileScannerController controller = MobileScannerController( autoStart: false, ); StreamSubscription<Object?>? _subscription; ``` Then, ensure that your `State` class mixes in `WidgetsBindingObserver`, to handle lifecyle changes, and add the required logic to the `didChangeAppLifecycleState` function: ```dart class MyState extends State<MyStatefulWidget> with WidgetsBindingObserver { // ... @override void didChangeAppLifecycleState(AppLifecycleState state) { // If the controller is not ready, do not try to start or stop it. // Permission dialogs can trigger lifecycle changes before the controller is ready. if (!controller.value.hasCameraPermission) { return; } switch (state) { case AppLifecycleState.detached: case AppLifecycleState.hidden: case AppLifecycleState.paused: return; case AppLifecycleState.resumed: // Restart the scanner when the app is resumed. // Don't forget to resume listening to the barcode events. _subscription = controller.barcodes.listen(_handleBarcode); unawaited(controller.start()); case AppLifecycleState.inactive: // Stop the scanner when the app is paused. // Also stop the barcode events subscription. unawaited(_subscription?.cancel()); _subscription = null; unawaited(controller.stop()); } } // ... } ``` Then, start the scanner in `void initState()`: ```dart @override void initState() { super.initState(); // Start listening to lifecycle changes. WidgetsBinding.instance.addObserver(this); // Start listening to the barcode events. _subscription = controller.barcodes.listen(_handleBarcode); // Finally, start the scanner itself. unawaited(controller.start()); } ``` Finally, dispose of the the `MobileScannerController` when you are done with it. ```dart @override Future<void> dispose() async { // Stop listening to lifecycle changes. WidgetsBinding.instance.removeObserver(this); // Stop listening to the barcode events. unawaited(_subscription?.cancel()); _subscription = null; // Dispose the widget itself. super.dispose(); // Finally, dispose of the controller. await controller.dispose(); } ``` ", Assign "at most 3 tags" to the expected json: {"id":"9466","tags":[]} "only from the tags list I provide: [{"id":77,"name":"3d"},{"id":89,"name":"agent"},{"id":17,"name":"ai"},{"id":54,"name":"algorithm"},{"id":24,"name":"api"},{"id":44,"name":"authentication"},{"id":3,"name":"aws"},{"id":27,"name":"backend"},{"id":60,"name":"benchmark"},{"id":72,"name":"best-practices"},{"id":39,"name":"bitcoin"},{"id":37,"name":"blockchain"},{"id":1,"name":"blog"},{"id":45,"name":"bundler"},{"id":58,"name":"cache"},{"id":21,"name":"chat"},{"id":49,"name":"cicd"},{"id":4,"name":"cli"},{"id":64,"name":"cloud-native"},{"id":48,"name":"cms"},{"id":61,"name":"compiler"},{"id":68,"name":"containerization"},{"id":92,"name":"crm"},{"id":34,"name":"data"},{"id":47,"name":"database"},{"id":8,"name":"declarative-gui "},{"id":9,"name":"deploy-tool"},{"id":53,"name":"desktop-app"},{"id":6,"name":"dev-exp-lib"},{"id":59,"name":"dev-tool"},{"id":13,"name":"ecommerce"},{"id":26,"name":"editor"},{"id":66,"name":"emulator"},{"id":62,"name":"filesystem"},{"id":80,"name":"finance"},{"id":15,"name":"firmware"},{"id":73,"name":"for-fun"},{"id":2,"name":"framework"},{"id":11,"name":"frontend"},{"id":22,"name":"game"},{"id":81,"name":"game-engine "},{"id":23,"name":"graphql"},{"id":84,"name":"gui"},{"id":91,"name":"http"},{"id":5,"name":"http-client"},{"id":51,"name":"iac"},{"id":30,"name":"ide"},{"id":78,"name":"iot"},{"id":40,"name":"json"},{"id":83,"name":"julian"},{"id":38,"name":"k8s"},{"id":31,"name":"language"},{"id":10,"name":"learning-resource"},{"id":33,"name":"lib"},{"id":41,"name":"linter"},{"id":28,"name":"lms"},{"id":16,"name":"logging"},{"id":76,"name":"low-code"},{"id":90,"name":"message-queue"},{"id":42,"name":"mobile-app"},{"id":18,"name":"monitoring"},{"id":36,"name":"networking"},{"id":7,"name":"node-version"},{"id":55,"name":"nosql"},{"id":57,"name":"observability"},{"id":46,"name":"orm"},{"id":52,"name":"os"},{"id":14,"name":"parser"},{"id":74,"name":"react"},{"id":82,"name":"real-time"},{"id":56,"name":"robot"},{"id":65,"name":"runtime"},{"id":32,"name":"sdk"},{"id":71,"name":"search"},{"id":63,"name":"secrets"},{"id":25,"name":"security"},{"id":85,"name":"server"},{"id":86,"name":"serverless"},{"id":70,"name":"storage"},{"id":75,"name":"system-design"},{"id":79,"name":"terminal"},{"id":29,"name":"testing"},{"id":12,"name":"ui"},{"id":50,"name":"ux"},{"id":88,"name":"video"},{"id":20,"name":"web-app"},{"id":35,"name":"web-server"},{"id":43,"name":"webassembly"},{"id":69,"name":"workflow"},{"id":87,"name":"yaml"}]" returns me the "expected json"