base on A universal scanner for Flutter based on MLKit. Uses CameraX on Android and AVFoundation on iOS. # mobile_scanner [](https://pub.dev/packages/mobile_scanner) [](https://pub.dev/packages/lint) [](https://github.com/juliansteenbakker/mobile_scanner/actions/workflows/flutter.yml) [](https://github.com/sponsors/juliansteenbakker) A universal scanner for Flutter based on MLKit. Uses CameraX on Android and AVFoundation on iOS. ## Breaking Changes v5.0.0 Version 5.0.0 brings some breaking changes. However, some are reverted in version 5.1.0. Please see the list below for all breaking changes, and Changelog.md for a more detailed list. * ~~The `autoStart` attribute has been removed from the `MobileScannerController`. The controller should be manually started on-demand.~~ (Reverted in version 5.1.0) * ~~A controller is now required for the `MobileScanner` widget.~~ (Reverted in version 5.1.0) * ~~The `onDetect` method has been removed from the `MobileScanner` widget. Instead, listen to `MobileScannerController.barcodes` directly.~~ (Reverted in version 5.1.0) * The `width` and `height` of `BarcodeCapture` have been removed, in favor of `size`. * The `raw` attribute is now `Object?` instead of `dynamic`, so that it participates in type promotion. * The `MobileScannerArguments` class has been removed from the public API, as it is an internal type. * The `cameraFacingOverride` named argument for the `start()` method has been renamed to `cameraDirection`. * The `analyzeImage` function now correctly returns a `BarcodeCapture?` instead of a boolean. * The `formats` attribute of the `MobileScannerController` is now non-null. * The `MobileScannerState` enum has been renamed to `MobileScannerAuthorizationState`. * The various `ValueNotifier`s for the camera state have been removed. Use the `value` of the `MobileScannerController` instead. * The `hasTorch` getter has been removed. Instead, use the torch state of the controller's value. * The `TorchState` enum now provides a new value for unavailable flashlights. * The `onPermissionSet`, `onStart` and `onScannerStarted` methods have been removed from the `MobileScanner` widget. Instead, await `MobileScannerController.start()`. * The `startDelay` has been removed from the `MobileScanner` widget. Instead, use a delay between manual starts of one or more controllers. * The `overlay` widget of the `MobileScanner` has been replaced by a new property, `overlayBuilder`, which provides the constraints for the overlay. * The torch can no longer be toggled on the web, as this is only available for image tracks and not video tracks. As a result the torch state for the web will always be `TorchState.unavailable`. * The zoom scale can no longer be modified on the web, as this is only available for image tracks and not video tracks. As a result, the zoom scale will always be `1.0`. ## Features Supported See the example app for detailed implementation information. | Features | Android | iOS | macOS | Web | |------------------------|--------------------|--------------------|----------------------|-----| | analyzeImage (Gallery) | :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: | ## Platform Support | Android | iOS | macOS | Web | Linux | Windows | |---------|-----|-------|-----|-------|---------| | ✔ | ✔ | ✔ | ✔ | :x: | :x: | ## Platform specific setup ### 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 _iOS arm64 Simulators are currently not yet supported, until the migration to the Vision API is complete._ _See_ https://github.com/juliansteenbakker/mobile_scanner/issues/1225 **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)** 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 Import the package with `package:mobile_scanner/mobile_scanner.dart`. Create a new `MobileScannerController` controller, using the required options. Provide a `StreamSubscription` for the barcode events. ```dart final MobileScannerController controller = MobileScannerController( // required options for the scanner ); StreamSubscription<Object?>? _subscription; ``` Ensure that your `State` class mixes in `WidgetsBindingObserver`, to handle lifecyle changes: ```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(); } ``` To display the camera preview, pass the controller to a `MobileScanner` widget. 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.", 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"