Non-blocking UI Thread animation - multithreading

Question

I'm trying to execute an async animation, which is not blocking the main thread.
The scenario that I am trying to do:
a user clicks a button, and after some time the ViewModel property
changes its state.
in a MvxFragment view I subscribe to the OnPropertyChanged event, and if the desired property has changed, I perform an animation (show a notification to
a user for a few seconds).
I am stuck with the app is not responding when animation is in progress:
public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
var ignore = base.OnCreateView(inflater, container, savedInstanceState);
var view = this.BindingInflate(Resource.Layout.MyView, null);
ViewModel.WeakSubscribe(PropertyChanged);
return view;
}
private void PropertyChanged(object sender, PropertyChangedEventArgs e)
{
if (e.PropertyName == "IsSaved")
{
if (ViewModel.IsSaved)
{
ShowSavedPopup();
}
}
}
private void ShowSavedPopup()
{
var dispatcher = Mvx.Resolve<IMvxMainThreadDispatcher>();
dispatcher.RequestMainThreadAction(() =>
{
var popupView = View.FindViewById(Resource.Id.popup);
popupView.Alpha = 0.0f;
popupView.Animate()
.SetDuration(4000)
.Alpha(1f)));
});
}
I also tried different ways to run animation async, but none of them worked (await Task.Run, Activity.RunOnUiThread..).
How I can run my animation async?

Answer 1

I apologize for my poor English.
In question I removed the end lines of animation scenario for brewity, but the problem was hidden there.
In my case the problem was with usage of Thread.Sleep.
That freezed the main UI thread.
I should use the async Task instead. And use Task.Delay to show the popup for a needed period of time.
Working solution will be:
private async void ShowSavedPopup()
{
// check if animation is in progress
if (_isBusy) return;
_isBusy = true;
await Task.Factory.StartNew(() =>
{
_popupView.Post(() =>
{
_popupView.Visibility = ViewStates.Visible;
_popupView.Alpha = 0.0f;
_popupView.Animate()
.SetDuration(400)
.Alpha(1f)
.WithEndAction(new Runnable(async () =>
{
await Task.Delay(2000);
_popupView.Animate()
.SetDuration(400)
.Alpha(0.0f)
.WithEndAction(new Runnable(() => {
_popupView.Visibility = ViewStates.Gone;
isBusy = false;
}));
}));
});
});
}