[BUG][iOS] MediaElement crashes at startup when used in ContentPage as App.MainPage

[TimLariviere]

Is there an existing issue for this?

• [X] I have searched the existing issues

Did you read the "Reporting a bug" section on Contributing file?

• [X] I have read the "Reporting a bug" section on Contributing file: https://github.com/CommunityToolkit/Maui/blob/main/CONTRIBUTING.md#reporting-a-bug

Current Behavior

When adding a MediaElement to a ContentPage used as the MainPage of Application (no Shell), the app crashes on iOS at startup because of an InvalidOperationException. Android seems fine.

System.InvalidOperationException: ViewController can't be null.
   at CommunityToolkit.Maui.Core.Views.MauiMediaElement..ctor(AVPlayerViewController playerViewController)
   at CommunityToolkit.Maui.Core.Handlers.MediaElementHandler.CreatePlatformView()

I tracked it down to WindowStateManager.Default.GetCurrentUIViewController() returning null. https://github.com/CommunityToolkit/Maui/blob/e6f9e9180e8d6141c73752caaf19597b32c91492/src/CommunityToolkit.Maui.MediaElement/Views/MauiMediaElement.macios.cs#L24

This is not the case when using Shell, so I believe the creation of the MediaElement is somehow delayed when using Shell, giving time for WindowStateManager to be initialized, but not when using ContentPage directly.

Expected Behavior

The app should run fine on iOS, just like it works already on Android.

Steps To Reproduce

1. Create a new Maui project (from the official template)
2. Add .UseMauiCommunityToolkitMediaElement() to the MauiApp builder
3. Replace the default App with this code

public class App : Application
{
    public App()
    {
        MainPage = new ContentPage
        {
            Content = new MediaElement
            {
                Source = MediaSource.FromUri("https://commondatastorage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4"),
                HeightRequest = 300,
                WidthRequest = 400,
                ShouldAutoPlay = true
            }
        };
    }
}

4. Run the application on iOS

A workaround is available in the project below

Link to public reproduction project repository

https://github.com/TimLariviere/CommunityToolkit-Maui-MediaElement-Crash

Environment

- CommunityToolkit.Maui.MediaElement: 1.0.1
- OS: macOS Ventura 13.1 (22C65)
- .NET MAUI: 7.0.59

Anything else?

No response

[derekpapworth]

@TimLariviere - I was just about to post the same issue! :) It appears to be, as you say, iOS only related and I took the standard template project (with shell) and added MediaElement to MainPage and all works fine but I then replace the line in app "MainPage = new AppShell()" with "MainPage = new MainPage()" (or with NavigationPage) the expection occurs.

[derekpapworth]

p.s. Not sure that workaround works if the MediaElement is in XAML?

[bijington]

I wonder if we need to implement something similar to #934 where we check whether IsPlatformEnabled before trying to take action.

[derekpapworth]

This seems to be actually a bigger problem than first thought as having tried numerous scenarios it appears you can't use the MediaElement outside of a Shell based app (iOS at least) as trying to use it anywhere in a NavigationPage based app you get exceptions either on PushAsync to a page with a MediaElement or when PopAsync which cause issues with the page popped to. I suspect that there's an internal reliance or reference to Shell somewhere (perhaps main window?) and that it's just not possible to use it in a non-Shell app .. does anyone know if this is the case?

[jfversluis]

Closing this in favor of #985