[Android] Modal Animation Repeats When Returning from Background - Fix

[kubaflo]

Issues Fixed

Fixes #28492

Before	After
Screen.Recording.2025-03-19.at.20.33.12.mov	Screen.Recording.2025-03-19.at.20.32.14.mov

Window!.Page!.Navigation.PushModalAsync(new ContentPage()
{
	Content = new Label() { Text = "Hello from Modal Page!" }
}, true);

What do you think @pictos?

[dotnet-policy-service]

Hey there @kubaflo! Thank you so much for your PR! Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[pictos]

LGTM,

but thinking loud here... isn't a way to say if the animation happened? If already happened we don't want to trigger it again, I think it will be more robust and possibly cover more scenarios, what do you think?

[kubaflo]

LGTM,

but thinking loud here... isn't a way to say if the animation happened? If already happened we don't want to trigger it again, I think it will be more robust and possibly cover more scenarios, what do you think?

Yea, initially I thought the same, but I wasn't sure if the animation should trigger only once for an instance of a fragment, or maybe there were some cases where it should trigger again

@PureWeen what do you think?

[bhavanesh2001]

I can't think of any scenario where the animation should restart after the initial OnStart() call. We can use _pendingAnimation instead of overriding OnStop() and introducing a new flag.

if (IsAnimated && _pendingAnimation)

I also think that starting the animation from OnStart() is a poor choice to begin with, as it has led us to introduce flags to handle everything properly.