Pushing a Popup on startup leads to an NullReferenceException

[JonasSuchy]

Issue:

Pushing a Popup shortly after starting the App, leads to a NullReferenceException, and the Popup does not get pushed.
On Android the App crashes sometimes in this situation , but only in release mode.

Expected Behavior:

The Popup should be opened after the everything necessary was initialized.

Environment:

Platform: Windows, Android, iOS
.NET Version: 8.0.0
Mopups Version: 1.3.1
Maui Version: 8.0.20

Steps to Reproduce:

1. Clone SampleProject.
2. Add "MopupService.Instance.PushAsync(new LoginPage());" to MainPage.OnAppearing (Or click on one of the buttons (very!) quickly).
3. Popup does not open on App startup (and might crash).

Workaround:

Awaiting this method before calling PushAsync fixes the issue:

    private async Task WaitForPopupNavigationInitialization(PopupPage popupPage)
    {
        bool CheckPopupNavigationIsSet()
        {
#if WINDOWS
                return Application.Current?.MainPage?.Handler?.MauiContext?.Services?.GetService<Microsoft.UI.Xaml.Window>()?.Content?.XamlRoot is not null;
#elif ANDROID
                return (MauiApplication.Current?.Application?.Windows?.FirstOrDefault()?.Content as Element)?.Handler?.MauiContext is not null;
#elif IOS
                return popupPage?.Handler is not null || Application.Current?.MainPage?.Handler?.MauiContext is not null;
#else
                return false;
#endif
        }
        while (!CheckPopupNavigationIsSet())
        {
            await Task.Delay(100);
        }
    }

Probably not the cleanest way to prevent the issue, but maybe something similar could be integrated into Mopups.

[sheharyarshahid]

I've had this issue after updating to MAUI 8.0.20 on iOS only. Android and Windows seems to work fine as of now.

[JonasSuchy]

The is issue is reproducible on all three platforms for me.

[sheharyarshahid]

Do you know any temporary workaround? I tried the above one but didn't work. Still NullReferenceException is throwing

[JonasSuchy]

In your own project, or is the problem reproducible in the sample project?
Does the stack trace say where the exception occurs?

[sheharyarshahid]

Okay, so It had something to do with using ListView ItemSource binding inside Popup. Removing item source binding from XAML and assigning it in code behind resolves the issue for me.