BarcodeScanning.Native.Maui 1.5.2

BarcodeScanning.Native.Maui

Barcode scanning library based on native platform APIs for barcode detection:

1. Google ML Kit
2. Apple Vision framework

This library was inspired by existing MAUI barcode scanning libraries: BarcodeScanner.Mobile & Zxing.Net.MAUI, but comes with many code improvements and uses native ML APIs on both Android and iOS/macOS.

Key features

1. Uses native APIs for maximal performance and barcode readability,
2. Optimized for continuous scanning,
3. Ability to scan multiple barcodes in one frame,
4. Ability to pool multiple scans for better scanning consistency,
5. Transformed barcode bounding box for on-screen positioning,
6. From version 1.2.0 implemented ViewfinderMode - detect only barcodes present in camera preview on screen and AimMode - detect only the barcode that is overlapped with the red dot centred in camera preview,
7. From version 1.4.1 ability to control camera zoom and camera selection on supported multi-camera setups on iOS and Android,
8. From version 1.5.0 ability to save images from the camera feed.
9. Code-behind and MVVM compatibility,
10. Android only - Ability to invert source image to scan natively unsupported inverted barcodes, but at a performance cost.

Usage

1. Install Nuget package,

2. Initialize the plugin in your MauiProgram.cs:

   public static MauiApp CreateMauiApp()
   {
       var builder = MauiApp.CreateBuilder();
       builder
           ...
           .UseBarcodeScanning();
           ...
   
       return builder.Build();
   }
   

3. Add required permissions:

   Android

   Edit AndroidManifest.xml file (under the Platforms\Android folder) and add the following permissions inside of the manifest node:

   <uses-permission android:name="android.permission.CAMERA" />
   

   iOS/macOS

   Edit info.plist file (under the Platforms\iOS or Platforms\MacCatalyst folder) and add the following permissions inside of the dict node:

   <key>NSCameraUsageDescription</key>
   <string>Enable camera for barcode scanning.</string>
   

   And ask for permission from user in your code:

   await Methods.AskForRequiredPermissionAsync();
   

4. In XAML, add correct namespace, for example:

   xmlns:scanner="clr-namespace:BarcodeScanning;assembly=BarcodeScanning.Native.Maui"
   

5. Set the CameraEnabled property to true in XAML, code behind or ViewModel to start the camera. As a best practice set it in OnAppearing() method override in your ContentPage.

6. Listen to OnDetectionFinished event in Code-behind:

   <scanner:CameraView ...
                       OnDetectionFinished="CameraView_OnDetectionFinished"
                       .../>
   

   private void CameraView_OnDetectionFinished(object sender, OnDetectionFinishedEventArg e)
   {
       if (e.Length > 0)
           ...
   }
   

   or bind OnDetectionFinishedCommand property to a Command in your ViewModel:

   <scanner:CameraView ...
                       OnDetectionFinishedCommand="{Binding DetectionFinishedCommand}"
                       .../>
   

   public ICommand DetectionFinishedCommand { get; set; }
   ...
   DetectionFinishedCommand = new Command<BarcodeResult[]>(BarcodeResult[] result) =>
   {
       if (result.Length > 0)
           ...
   }
   

7. As a best practice set the CameraEnabled property to false in OnDisappearing() method override in your ContentPage.

8. From version 1.2.2 automatic disposing of CameraView is disabled! If a page gets regullary disposed, to prevent memory leaks add a listener to Unloaded event on your ContentPage.

   This mainly applies to a page registered as "details page" using Routing.RegisterRoute() method! Do not do this for pages registered in AppShell.xaml <ShellContent .../>, Shell Tabs or Flyout, or you will get a error when navigating back to the page!

   For example:

   <ContentPage ...
                Unloaded="ContentPage_Unloaded"
                ...>
   
       <scanner:CameraView x:Name="BarcodeView"
                           .../>
   

   private void ContentPage_Unloaded(object sender, EventArgs e)
   {
       BarcodeView.Handler?.DisconnectHandler();
   }
   

9. From wersion 1.5.0 set the CaptureNextFrame property to true to capture next frame from the camera feed as a PlatformImage. Listen to OnImageCaptured event or bind to OnImageCapturedCommand property to get the caputured image. Image is captured from the original camera feed and can be different from the on-screen preview. After the image is captured CaptureNextFrame property is automaticly set to false to prevent memory leaks. Example can be found in ScanTab.xaml.cs.

Supported barcode symbologies

Android

1D: Codabar, Code 39, Code 93, Code 128, EAN-8, EAN-13, ITF, UPC-A, UPC-E; 2D: Aztec, Data Matrix, PDF417, QR Code

iOS/macOS

1D: Codabar, Code 39, Code 93, Code 128, EAN-8, EAN-13, GS1 DataBar, ITF, UPC-A, UPC-E; 2D: Aztec, Data Matrix, MicroPDF417, MicroQR, PDF417, QR Code

Bindable properties

A list of bindable properties with descriptions can be found in CameraView.cs source file.

TODO Windows support

Windows is currently unsupported, but support can be added in the future through Zxing.Net project.