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https://github.com/juliansteenbakker/mobile_scanner

A universal scanner for Flutter based on MLKit. Uses CameraX on Android and AVFoundation on iOS.
https://github.com/juliansteenbakker/mobile_scanner

android dart flutter hacktoberfest ios

Last synced: 5 days ago
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A universal scanner for Flutter based on MLKit. Uses CameraX on Android and AVFoundation on iOS.

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README

        

# mobile_scanner

[![pub package](https://img.shields.io/pub/v/mobile_scanner.svg)](https://pub.dev/packages/mobile_scanner)
[![style: lint](https://img.shields.io/badge/style-lint-4BC0F5.svg)](https://pub.dev/packages/lint)
[![mobile_scanner](https://github.com/juliansteenbakker/mobile_scanner/actions/workflows/flutter.yml/badge.svg)](https://github.com/juliansteenbakker/mobile_scanner/actions/workflows/flutter.yml)
[![GitHub Sponsors](https://img.shields.io/github/sponsors/juliansteenbakker?label=like%20my%20work?%20sponsor%20me!)](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 /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,
```
NSCameraUsageDescription
This app needs camera access to scan QR codes

NSPhotoLibraryUsageDescription
This app needs photos access to get QR code from photo library
```

### macOS
Ensure that you granted camera permission in XCode -> Signing & Capabilities:

Screenshot of XCode where Camera is checked

## 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? _subscription;
```

Ensure that your `State` class mixes in `WidgetsBindingObserver`, to handle lifecyle changes:

```dart
class MyState extends State 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 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.