Microsoft.Maui.Platform.HandlerNotFoundException: 'Handler not found for view BarcodeScanning.CameraView.'

[Makayla-Forsyth]

Sorry of this is the wrong place to get help but I have no idea where else to post.

I keep getting this error when trying to set up a simple scanner. It happens after the OnAppearing method has run. Investigating further down it seems the Handler == null.

Trying to run it on a Pixel 5 Android Emulator with API 34. Running on Maui version 8.0.92 targeting net8.0-ios and net8.0-android34.0 (Haven't bothered testing on iOS yet as it's not as important). Running version 1.5.8 of BarcodeScanning.Native.Maui.

using BarcodeScanning;
using CommunityToolkit.Maui.Alerts;

namespace App.Views;

public partial class ScanPage : ContentPage
{
    public ScanPage()
    {
        try
        {
            InitializeComponent();

        }
        catch (Exception e)
        {

            throw;
        }
    }

    protected override async void OnAppearing()
    {
        try
        {
            await Methods.AskForRequiredPermissionAsync();
            base.OnAppearing();
            scanner.CameraEnabled = true;
            var test = scanner;

        }
        catch (Exception e)
        {

            throw;
        }
    }
}

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage x:Class="App.Views.ScanPage"
             xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:scanner="clr-namespace:BarcodeScanning;assembly=BarcodeScanning.Native.Maui"
             x:Name="QRCodeContent"
             Title="Scan QR Code">
    <Grid HorizontalOptions="Fill">
        <Grid.RowDefinitions>
            <RowDefinition Height="*" />
        </Grid.RowDefinitions>
        <scanner:CameraView x:Name="scanner"
                            CameraFacing="Back"
                            CaptureQuality="High"
                            CameraEnabled="False"
                            BarcodeSymbologies="All"
                            OnDetectionFinished="CameraView_OnDetectionFinished"
                            TapToFocusEnabled="True" />
    </Grid>

</ContentPage>

[afriscic]

Hello.
To me it looks like a Handler issue. If your page doesn't get disposed (it handles like a Singleton) when you close or navigate from it then don't call DisposeHandler method as you'll get into the issue that you describe.
On the other hand if your page gets disposed (like a Transient) the it is best to call DisposeHandler to prevent memory lekas.