toolkit:CameraView Will cause the program to automatically exit, iOS

[bbhxwl]

Will cause the program to automatically exit, iOS

[stephenquan]

You have to supply more information on the repro steps and the iOS device you're testing on.

[bbhxwl]

HomeBedCamera.zip

[bbhxwl]

You have to supply more information on the repro steps and the iOS device you're testing on.

Take 2 quick photos, and if you take 2 photos in 1 second, there will be an error.

[stephenquan]

I think both your description and your code highlights a reentrant problem of your code. A simple solution would be set IsEnabled = false whilst a capture is in progress to guard against a reentrant problem, e.g.

<Grid VerticalOptions="End" RowDefinitions="30">
    <Button x:Name="CaptureButton" Grid.Row="1" Clicked="Button_OnClicked" Height="100" Width="100" Text="拍照"></Button>
</Grid>

    private async void CameraView_OnMediaCaptured(object? sender, MediaCapturedEventArgs e)
    {
        var uuid=await Utils.GetAverageHash(e.Media);
        Console.WriteLine(uuid);
        CaptureButton.IsEnabled = true;
    }

    private void Button_OnClicked(object? sender, EventArgs e)
    {
        CaptureButton.IsEnabled = false;
        Camera.CaptureImage(new CancellationTokenSource().Token);
    }

[bbhxwl]

I think both your description and your code highlights a reentrant problem of your code. A simple solution would be set IsEnabled = false whilst a capture is in progress to guard against a reentrant problem, e.g.

<Grid VerticalOptions="End" RowDefinitions="30">
    <Button x:Name="CaptureButton" Grid.Row="1" Clicked="Button_OnClicked" Height="100" Width="100" Text="拍照"></Button>
</Grid>

    private async void CameraView_OnMediaCaptured(object? sender, MediaCapturedEventArgs e)
    {
        var uuid=await Utils.GetAverageHash(e.Media);
        Console.WriteLine(uuid);
        CaptureButton.IsEnabled = true;
    }

    private void Button_OnClicked(object? sender, EventArgs e)
    {
        CaptureButton.IsEnabled = false;
        Camera.CaptureImage(new CancellationTokenSource().Token);
    }

Cannot avoid exceptions, can we only avoid them this way?

[stephenquan]

Of course, there is more than one way to solve this problem. Do you understand the problem is because Camera.CaptureImage is slower (takes more time) than the rate in which the user clicks Button_OnClicked?

So there are several solutions:

1. Guard against reentrant code else you will have Camera.CaptureImage being initiated before the previous is completed
2. Use the CancellationToken to abort previous run of Camera.CaptureImage before commence of a new one
3. Increase the speed, or shorten the time of a Camera.CaptureImage (which can be achieved by lowering the capture resolution)

N.B. CameraView is part of the CommunityToolkit.Maui and this discussion should not be here, but over in https://github.com/CommunityToolkit/Maui/discussions