[Android]Fix deadlock on modal navigation

[pictos]

Note

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It would be very helpful if you could test the resulting artifacts from this PR and let us know in a comment if this change resolves your issue. Thank you!

Description of Change

This PR adds the Navigated event inside DialogFragment. The issue happens because the Push/PopModal navigation returns too early and causes the hanging since it gets lost.

Also added TaskCreationOptions.RunContinuationsAsynchronously to both TaskCompletionSource in Pop and Push modal navigations. This will make the continuations run in the expected order.

I kept the AnimationEnded event because they fire in different moments, so I believe it's better to keep it for animated navigations.

Issues Fixed

This is a follow up of: #32853

Fixes #32310

[Copilot]

Pull request overview

This PR fixes an Android-specific deadlock issue where calling PopModalAsync immediately after PushModalAsync with only a Task.Yield() in between would cause the app to hang. The solution introduces a Navigated event in the ModalFragment that fires in OnResume() to ensure non-animated modal navigation completes properly, and applies TaskCreationOptions.RunContinuationsAsynchronously to both TaskCompletionSource instances to ensure continuations run in the expected order.

Key changes:

• Added Navigated event to ModalFragment class that fires in OnResume() lifecycle method
• Applied TaskCreationOptions.RunContinuationsAsynchronously to both modal Push and Pop TaskCompletionSource instances
• Added comprehensive UI test to verify the fix prevents the deadlock

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/Controls/src/Core/Platform/ModalNavigationManager/ModalNavigationManager.Android.cs	Core fix: Added Navigated event, OnResume() override, and TaskCreationOptions.RunContinuationsAsynchronously to prevent deadlock in modal navigation
src/Controls/tests/TestCases.HostApp/Issues/Issue32310.cs	Test reproduction page that demonstrates the deadlock scenario with PushModalAsync + Task.Yield() + PopModalAsync
src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue32310.cs	UI test that verifies modal navigation completes without hanging

Comments suppressed due to low confidence (1)

src/Controls/src/Core/Platform/ModalNavigationManager/ModalNavigationManager.Android.cs:207

• Consider using TrySetResult instead of SetResult for consistency with the Pop modal path (line 123, 137) and for better error handling. If OnResume() is called multiple times or if there's any other race condition, SetResult will throw an InvalidOperationException, while TrySetResult would gracefully handle the case where the result is already set.

void OnNavigated(object? sender, EventArgs e)
{
    dialogFragment.Navigated -= OnNavigated;
    animationCompletionSource.TrySetResult(true);
}

void OnAnimationEnded(object? sender, EventArgs e)
{
    dialogFragment!.AnimationEnded -= OnAnimationEnded;
    animationCompletionSource.TrySetResult(true);
}

			void OnNavigated(object? sender, EventArgs e)
			{
				dialogFragment.Navigated -= OnNavigated;
				animationCompletionSource.SetResult(true);
			}

			void OnAnimationEnded(object? sender, EventArgs e)
			{
				dialogFragment!.AnimationEnded -= OnAnimationEnded;
				animationCompletionSource.SetResult(true);

[PureWeen]

@pictos

What about this one?

#32479

[pictos]

@PureWeen didn't see that one, by bad. I added some comments on that PR and will close this one