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

[bhavanesh2001]

Description of Change

This PR provides a fix for #28492 and is an alternative to #28522. It ensures that modal animations only play once when the modal is first displayed and do not replay when the app returns from the background.

Rather than starting the animation in OnStart(),this fix attaches a GlobalLayoutListener to the view inside OnCreateView(). When the view's layout is complete for the first time, the listener invokes the animation and then removes itself to prevent any further invocations. Additionally, the OnAnimationEnded method has been moved out of the lambda for improved readability.

After Fix:

fix.mov

Issues Fixed

Fixes #28492

Related PR #28522

[dotnet-policy-service]

Hey there @bhavanesh2001! Thank you so much for your PR! Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[jsuarezruiz]

Could include an UITest like
https://github.com/user-attachments/assets/bf28a45f-dcde-4b26-bdb3-1342dc9d4a3c
?

In the test, can use:

App.BackgroundApp();
App.ForegroundApp();

To move the App to background etc.

[bhavanesh2001]

@jsuarezruiz Would it be possible to include a UI test for this? Since the issue is that the modal animation replays when returning from the background, how can we verify in an automated test that the animation has not been triggered again?

[pictos]

is it fine to not dispose this GenericGlobalLayoutListener? would be good to add double check with a memory leak test, if the existing ones don't test for that

[bhavanesh2001]

@pictos I added a commit to explicitly dispose the listener once it's no longer needed. Does this look like the correct approach for cleanup?

[bhavanesh2001]

On the other hand, I don't think it's a good idea to call Dispose() manually, so I reverted the commit. Since we are already removing it from ViewTreeObserver, it should be cleaned up automatically.

[PureWeen]

GenericGlobalLayoutListener has an Invalidate method you can call which won't dispose of it but still cleans it up

I think we should use that vs the calling Remove on line 329

[bhavanesh2001]

@PureWeen Thanks for the suggestion

[kubaflo]

I think GenericGlobalLayoutListener will cause memory leaks

[kubaflo]

IMO the animation should start in the OnStart() method like @pictos initially implemented.

GlobalLayoutListener is typically used to detect changes in the view's layout. Using it solely to start an animation adds unnecessary complexity.

[bhavanesh2001]

@kubaflo I get that GlobalLayoutListener might not seem like the perfect fit, but using OnStart() for this isn’t a good alternative either. Relying on flags isn't a clean solution as it introduces unnecessary state tracking instead of addressing the root cause directly, which is why I explored a different approach in this PR.

[bhavanesh2001]

I think GenericGlobalLayoutListener will cause memory leaks

@kubaflo I’ve added a memory leak test for when a modal is opened with animation, and it passes with the GenericGlobalLayoutListener implementation.

device_test.mov

@jsuarezruiz could you run pipelines on this?

[jsuarezruiz]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

[jsuarezruiz]

The test Issue31366PushingAndPoppingModallyCausesArgumentOutOfRangeException is failing with a crash:

The app was expected to be running still, investigate as possible crash

Could you review if is related with the changes?

[bhavanesh2001]

@jsuarezruiz fixed failing tests.