Why Zxing Maui barcode scanner crashes on IOS?

[ThomasCarltonInPerson]

Hi,

I'm using Zxing barcode scanner on an empty project as follows :

XAML : <?xml version="1.0" encoding="utf-8" ?> <ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" x:Class="CameraTest.MainPage" xmlns:zxing="clr-namespace:ZXing.Net.Maui.Controls;assembly=ZXing.Net.MAUI">

    <ScrollView>
        <VerticalStackLayout
            Spacing="25"
            Padding="30,0"
            VerticalOptions="Center">

            <zxing:CameraBarcodeReaderView x:Name="cameraBarcodeReaderView" />
        </VerticalStackLayout>
    </ScrollView>

</ContentPage>

C#

using ZXing.Net.Maui;

namespace CameraTest;

public partial class MainPage : ContentPage
{
    int count = 0;

    public MainPage()
    {
        InitializeComponent();

        cameraBarcodeReaderView.Options = new BarcodeReaderOptions
        {
            Formats = BarcodeFormats.OneDimensional,
            AutoRotate = true,
            Multiple = true
        };
    }
}

MauiProgram.cs

using ZXing.Net.Maui;
using Microsoft.Extensions.Logging;

namespace CameraTest;

public static class MauiProgram
{
    public static MauiApp CreateMauiApp()
    {
        var builder = MauiApp.CreateBuilder();
        builder
            .UseMauiApp<App>()
            .UseBarcodeReader()
            .ConfigureFonts(fonts =>
            {
                fonts.AddFont("OpenSans-Regular.ttf", "OpenSansRegular");
                fonts.AddFont("OpenSans-Semibold.ttf", "OpenSansSemibold");
            });

#if DEBUG
        builder.Logging.AddDebug();
#endif

        return builder.Build();
    }
}

Info.plist :

<key>NSCameraUsageDescription</key>
<string>This app uses barcode scanning to...</string>

But when running the app on IPhone 14 iOS 16.4 simulator, I'm getting the following error. By the way, I didn't write a single line of my own code.

Does anyway know whats wrong with the Zxing barcode please ?

Thanks.

{System.ArgumentNullException: Value cannot be null. (Parameter 'device')
   at ObjCRuntime.ThrowHelper.ThrowArgumentNullException(String argumentName)
   at ObjCRuntime.NativeObjectExtensions.GetNonNullHandle(INativeObject self, String argumentName)
   at AVFoundation.AVCaptureDeviceInput..ctor(AVCaptureDevice device, NSError& error)
   at ZXing.Net.Maui.CameraManager.UpdateCamera()
   at ZXing.Net.Maui.CameraManager.UpdateCameraLocation(CameraLocation cameraLocation)
   at ZXing.Net.Maui.CameraBarcodeReaderViewHandler.<>c.<.cctor>b__24_1(CameraBarcodeReaderViewHandler handler, ICameraBarcodeReaderView virtualView)
   at Microsoft.Maui.PropertyMapper`2.<>c__DisplayClass5_0[[ZXing.Net.Maui.ICameraBarcodeReaderView, ZXing.Net.Maui, Version=1.0.2.0, Culture=neutral, PublicKeyToken=null],[ZXing.Net.Maui.CameraBarcodeReaderViewHandler, ZXing.Net.Maui, Version=1.0.2.0, Culture=neutral, PublicKeyToken=null]].<Add>b__0(IElementHandler h, IElement v)
   at Microsoft.Maui.PropertyMapper.UpdatePropertyCore(String key, IElementHandler viewHandler, IElement virtualView)
   at Microsoft.Maui.PropertyMapper.UpdateProperties(IElementHandler viewHandler, IElement virtualView)
   at Microsoft.Maui.Handlers.ElementHandler.SetVirtualView(IElement view)
   at Microsoft.Maui.Handlers.ViewHandler`2[[ZXing.Net.Maui.ICameraBarcodeReaderView, ZXing.Net.Maui, Version=1.0.2.0, Culture=neutral, PublicKeyToken=null],[UIKit.UIView, Microsoft.iOS, Version=16.4.0.0, Culture=neutral, PublicKeyToken=84e04ff9cfb79065]].SetVirtualView(IView view)
   at Microsoft.Maui.Handlers.ViewHandler`2[[ZXing.Net.Maui.ICameraBarcodeReaderView, ZXing.Net.Maui, Version=1.0.2.0, Culture=neutral, PublicKeyToken=null],[UIKit.UIView, Microsoft.iOS, Version=16.4.0.0, Culture=neutral, PublicKeyToken=84e04ff9cfb79065]].SetVirtualView(IElement view)
   at Microsoft.Maui.Controls.Element.SetHandler(IElementHandler newHandler)
   at Microsoft.Maui.Controls.Element.set_Handler(IElementHandler value)
   at Microsoft.Maui.Controls.VisualElement.Microsoft.Maui.IElement.set_Handler(IElementHandler value)
   at Microsoft.Maui.Platform.ElementExtensions.ToHandler(IElement view, IMauiContext context)
   at Microsoft.Maui.Platform.ElementExtensions.ToPlatform(IElement view, IMauiContext context)
   at Microsoft.Maui.Handlers.LayoutHandler.SetVirtualView(IView view)
   at Microsoft.Maui.Handlers.ViewHandler`2[[Microsoft.Maui.ILayout, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Microsoft.Maui.Platform.LayoutView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].SetVirtualView(IElement view)
   at Microsoft.Maui.Controls.Element.SetHandler(IElementHandler newHandler)
   at Microsoft.Maui.Controls.Element.set_Handler(IElementHandler value)
   at Microsoft.Maui.Controls.VisualElement.Microsoft.Maui.IElement.set_Handler(IElementHandler value)
   at Microsoft.Maui.Platform.ElementExtensions.ToHandler(IElement view, IMauiContext context)
   at Microsoft.Maui.Platform.ElementExtensions.ToPlatform(IElement view, IMauiContext context)
   at Microsoft.Maui.Handlers.ScrollViewHandler.UpdateContentView(IScrollView scrollView, IScrollViewHandler handler)
   at Microsoft.Maui.Handlers.ScrollViewHandler.MapContent(IScrollViewHandler handler, IScrollView scrollView)
   at Microsoft.Maui.PropertyMapper`2.<>c__DisplayClass5_0[[Microsoft.Maui.IScrollView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Microsoft.Maui.Handlers.IScrollViewHandler, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].<Add>b__0(IElementHandler h, IElement v)
   at Microsoft.Maui.PropertyMapper.UpdatePropertyCore(String key, IElementHandler viewHandler, IElement virtualView)
   at Microsoft.Maui.PropertyMapper.UpdateProperties(IElementHandler viewHandler, IElement virtualView)
   at Microsoft.Maui.Handlers.ElementHandler.SetVirtualView(IElement view)
   at Microsoft.Maui.Handlers.ViewHandler`2[[Microsoft.Maui.IScrollView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[UIKit.UIScrollView, Microsoft.iOS, Version=16.4.0.0, Culture=neutral, PublicKeyToken=84e04ff9cfb79065]].SetVirtualView(IView view)
   at Microsoft.Maui.Handlers.ViewHandler`2[[Microsoft.Maui.IScrollView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[UIKit.UIScrollView, Microsoft.iOS, Version=16.4.0.0, Culture=neutral, PublicKeyToken=84e04ff9cfb79065]].SetVirtualView(IElement view)
   at Microsoft.Maui.Controls.Element.SetHandler(IElementHandler newHandler)
   at Microsoft.Maui.Controls.Element.set_Handler(IElementHandler value)
   at Microsoft.Maui.Controls.VisualElement.Microsoft.Maui.IElement.set_Handler(IElementHandler value)
   at Microsoft.Maui.Platform.ElementExtensions.ToHandler(IElement view, IMauiContext context)
   at Microsoft.Maui.Platform.ElementExtensions.ToPlatform(IElement view, IMauiContext context)
   at Microsoft.Maui.Handlers.ContentViewHandler.UpdateContent(IContentViewHandler handler)
   at Microsoft.Maui.Handlers.ContentViewHandler.MapContent(IContentViewHandler handler, IContentView page)
   at Microsoft.Maui.PropertyMapper`2.<>c__DisplayClass5_0[[Microsoft.Maui.IContentView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Microsoft.Maui.Handlers.IContentViewHandler, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].<Add>b__0(IElementHandler h, IElement v)
   at Microsoft.Maui.PropertyMapper.UpdatePropertyCore(String key, IElementHandler viewHandler, IElement virtualView)
   at Microsoft.Maui.PropertyMapper.UpdateProperties(IElementHandler viewHandler, IElement virtualView)
   at Microsoft.Maui.Handlers.ElementHandler.SetVirtualView(IElement view)
   at Microsoft.Maui.Handlers.ViewHandler`2[[Microsoft.Maui.IContentView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Microsoft.Maui.Platform.ContentView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].SetVirtualView(IView view)
   at Microsoft.Maui.Handlers.ContentViewHandler.SetVirtualView(IView view)
   at Microsoft.Maui.Handlers.ViewHandler`2[[Microsoft.Maui.IContentView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Microsoft.Maui.Platform.ContentView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].SetVirtualView(IElement view)
   at Microsoft.Maui.Controls.Element.SetHandler(IElementHandler newHandler)
   at Microsoft.Maui.Controls.Element.set_Handler(IElementHandler value)
   at Microsoft.Maui.Controls.VisualElement.Microsoft.Maui.IElement.set_Handler(IElementHandler value)
   at Microsoft.Maui.Platform.ElementExtensions.ToHandler(IElement view, IMauiContext context)
   at Microsoft.Maui.Platform.ViewExtensions.ToHandler(IView view, IMauiContext context)
   at Microsoft.Maui.Controls.Platform.Compatibility.ShellSectionRootRenderer.SetPageRenderer(Page page, ShellContent shellContent)
   at Microsoft.Maui.Controls.Platform.Compatibility.ShellSectionRootRenderer.LoadRenderers()
   at Microsoft.Maui.Controls.Platform.Compatibility.ShellSectionRootRenderer.ViewDidLoad()
   at UIKit.UIApplication.UIApplicationMain(Int32 argc, String[] argv, IntPtr principalClassName, IntPtr delegateClassName)
   at UIKit.UIApplication.Main(String[] args, Type principalClass, Type delegateClass)
   at CameraTest.Program.Main(String[] args) in D:\Maui\annex_apps\CameraTest\CameraTest\Platforms\iOS\Program.cs:line 13}

[tigreye007]

We are having the exact same issue. Latest prerelease version (0.3.0-preview.1)

Visual Studio Community v17.7.4 Xcode v14.3

[madmapper]

This is because you are using the simulator, which has no camera. You need to check device type before you flip on the bar code reader view.

[Redth]

115 should help here, but yeah, simulator isn't great for iOS for using camera