BarcodeScanner.XF

Powerful barcode scanning library for Xamarin Forms using Google MLKit API.

Works on iOS 11+ and Android (MonoAndroid10.0 and MonoAndroid11.0)

For user who are using Visual Studio for Windows, please make sure Hot-Restart is disabled to run the debug mode. https://docs.microsoft.com/en-us/xamarin/xamarin-forms/deploy-test/hot-restart

Please feel free to improve my source code.

Current Version

6.2.0.0-pre, Update iOS Firebase library, will need to create nuget source in localhost, please read iOS part for more details

6.1.1.2-pre, Add CameraFacing and default quality, bug fixing on Android crashing issue

5.0.0.9 for Xamarin Forms 5.0.0.2012

Release notes

https://github.com/JimmyPun610/BarcodeScanner.XF/tree/master/ReleaseNotes

App Center Build

Android

iOS

Installation

Install Nuget package to Forms, Android and iOS project

Install-Package BarcodeScanner.XF

Android setup

Manifest.xml

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

Init the library in MainActivity.cs

  base.OnCreate(savedInstanceState);
...
  GoogleVisionBarCodeScanner.Droid.RendererInitializer.Init();
...
  global::Xamarin.Forms.Forms.Init(this, savedInstanceState);
  LoadApplication(new App());

public override void OnRequestPermissionsResult(int requestCode, string[] permissions, [GeneratedEnum] Android.Content.PM.Permission[] grantResults)
{
    Xamarin.Essentials.Platform.OnRequestPermissionsResult(requestCode, permissions, grantResults);
    base.OnRequestPermissionsResult(requestCode, permissions, grantResults);
}

ProGuard configuration

-keep class com.google.mlkit.common.internal.MlKitInitProvider {*;}
-keep class androidx.camera.camera2.internal.Camera2CameraInfoImpl {*;}
-keep class android.media.Image {*;}
-keep class androidx.camera.core.** {*;}
-keep class com.google.mlkit.vision.barcode.internal.BarcodeScannerImpl {*;}

iOS Setup

Edit Info.plist, add camera rights

	<key>NSCameraUsageDescription</key>
	<string>Require to use camera</string>

Create an project in Google Firebase Console, download GoogleService-Info.plist https://console.firebase.google.com/
Put GoogleService-Info.plist into Resources folder of iOS project, set Build Action as BundleResource
Init project and firebase on AppDelegate.cs

            global::Xamarin.Forms.Forms.Init();
            LoadApplication(new App());
            ....
            GoogleVisionBarCodeScanner.iOS.Initializer.Init();
            // Temporary work around for bug on Firebase Library
	    // https://github.com/xamarin/GoogleApisForiOSComponents/issues/368
	    Firebase.Core.App.Configure();
            // This line is not needed in version 5.0.5
	    // _ = Firebase.RemoteConfig.RemoteConfig.SharedInstance;
            ....
            return base.FinishedLaunching(app, options);

Set Linker Behavior to Link SDK assemblies only
Download the Nuget file Xamarin.Firebase.iOS.Core.8.10.0, Xamarin.MLKit.iOS.Core.5.0.0 and Xamarin.MLKit.iOS.BarcodeScanning.1.6.0 to your localhost, set the 3rd party source to the directory in the visual studio.

Scan from Camera

1. Set support barcode format (Default is all), call it before you start to init CameraView

GoogleVisionBarCodeScanner.Methods.SetSupportBarcodeFormat(BarcodeFormats.QRCode);

2. It is all about the camera view, use it on the page.xaml. For now, it will spend your whole width of the screen and the height will be equal to width.

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:d="http://xamarin.com/schemas/2014/forms/design"
             xmlns:gv="clr-namespace:GoogleVisionBarCodeScanner;assembly=BarcodeScanner.XF"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             mc:Ignorable="d"
             x:Class="SampleApp.Page1">
   <ContentPage.Content>
     <ScrollView HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand">
	 <!--VirbationOnDetected: Indicate the device will vibrate or not when detected barcode, default is True
		 TorchOn: Indicate the torch will on or not when the view appear, default is False
		 IsScanning : Indicate whether the device will start scanning after it is opened, default is True
		 RequestedFPS: Affect Android only, leave it if you want a default value (https://developers.google.com/android/reference/com/google/android/gms/vision/CameraSource.Builder.html#public-camerasource.builder-setrequestedfps-float-fps)
		 ScanInterval: Scan interval for iOS, default is 500ms and the minimum is 100ms, please be reminded that double scanning may be occurred if it is too small
		 -->
             <gv:CameraView HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" OnDetected="CameraView_OnDetected" Grid.Row="1"
                            TorchOn="True" VibrationOnDetected="False" IsScanning="True" RequestedFPS="30" ScanInterval="500"/>
     </ScrollView>
   </ContentPage.Content>
</ContentPage>

3. Once barcode detected, "OnDetected" event will be triggered, do the stuff you want with the barcode, it will contains type and display value

   private async void CameraView_OnDetected(object sender, GoogleVisionBarCodeScanner.OnDetectedEventArg e)
        {
            List<GoogleVisionBarCodeScanner.BarcodeResult> obj = e.BarcodeResults;

            string result = string.Empty;
            for(int i = 0; i < obj.Count; i++)
            {
                result += $"{i + 1}. Type : {obj[i].BarcodeType}, Value : {obj[i].DisplayValue}{Environment.NewLine}";
            }
            Device.BeginInvokeOnMainThread(async() =>
            {
                await DisplayAlert("Result", result, "OK");
		//If you want to stop scanning, you can close the scanning page
                await Navigation.PopModalAsync();
		//if you want to keep scanning the next barcode, do not close the scanning page and call below function
		//GoogleVisionBarCodeScanner.Methods.SetIsScanning(true);
            });
            
        }

4. To use torch, please call

   GoogleVisionBarCodeScanner.Methods.ToggleFlashlight();

5. To ask for permission

bool allowed = await GoogleVisionBarCodeScanner.Methods.AskForRequiredPermission();

6. To check the condition of torch

   // CameraView is from the Name of gv:CameraView defined in XAML
   CameraView.TorchOn = true / false;

7. Restart scanning

// CameraView is from the Name of gv:CameraView defined in XAML
CameraView.IsScanning = true / false;

8. Use front/back camera

// CameraView is from the Name of gv:CameraView defined in XAML
// Default is CameraFacing.Back
CameraView.CameraFacing = CameraFacing.Back / CameraFacing.Front;

9. Modify caputre quality (to balance speed/precision)

// CameraView is from the Name of gv:CameraView defined in XAML
// Default is CaptureQuality.Medium
CameraView.CaptureQuality = CaptureQuality.Lowest / CaptureQuality.Low / CaptureQuality.Medium / CaptureQuality.High / CaptureQuality.Highest;

MVVM

Properties support MVVM:

OnDetectedCommand
IsScanning
TorchOn
VibrationOnDetected
ScanInterval
CameraFacing
CaptureQuality

Check out the MVVM from sample app for demo

            <gv:CameraView Grid.Row="1" Grid.Column="1"
                           OnDetectedCommand="{Binding OnDetectCommand}" 
                           IsScanning="{Binding IsScanning}" 
                           TorchOn="{Binding TorchOn}" VibrationOnDetected="{Binding VibrationOnDetected}" ScanInterval="{Binding ScanInterval}"
                           x:Name="Camera" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand"/>

Scan from Image

1. Get the image byte array by your method.

//Used MediaPlugin in sample for example
 var file = await CrossMedia.Current.PickPhotoAsync();
Stream stream = file.GetStream();
byte[] bytes = new byte[stream.Length];
stream.Read(bytes, 0, bytes.Length);
stream.Seek(0, SeekOrigin.Begin);

2. Analyze the image and wait for result

List<GoogleVisionBarCodeScanner.BarcodeResult> obj = await GoogleVisionBarCodeScanner.Methods.ScanFromImage(bytes);

luismts/BarcodeScanner.XF