IActivatableLifetime doesn't work on MacOS

[JamesSmith85]

Describe the bug

I have updated the Avalonia version in my application from an older nightly build to 11.4.1 (The issue can be reproduced from 11.1.0 to 11.2.1).

I had to update my code as IActivatableApplicationLifetime interface doesn't exist anymore, but I can use TryGetFeature<IActivatableLifetime>() instead.
The new code successfully finds the feature and subscribe to its event, but sadly the behavior changed.
Deactivated event never gets called, at least in the scenario where it was called before now it is not.

To Reproduce

1. Create a new Avalonia app.
2. Hide it from macOS's Dock.
3. Deactivated event is not called (Activated is called instead)

Simple repo:

 public MainViewModel()
    {
        if (Application.Current?.TryGetFeature<IActivatableLifetime>() is { } activatableLifetime)
        {
            activatableLifetime.Activated += OnActivated;
            activatableLifetime.Deactivated += OnDeactivated;
        }
        
    }

    private void OnActivated(object? sender, ActivatedEventArgs e)
    {
        Console.WriteLine("Activated");
    }
    
    private void OnDeactivated(object? sender, ActivatedEventArgs e)
    {
        Console.WriteLine("Deactivated");
    }

Expected behavior

No response

Avalonia version

11.1.0 - 11.2.1

OS

macOS

Additional context

No response

[maxkatz6]

Can you confirm, that subscribing earlier doesn't solve the problem?
For example, in OnFrameworkInitializationCompleted method.

[JamesSmith85]

Can you confirm, that subscribing earlier doesn't solve the problem? For example, in OnFrameworkInitializationCompleted method.

Doesn't solve it. The issue here is why the activated event gets invoked when the app is deactivated. With the current concept doesn't matter if the app gets activated or deactivated, always the Activated event gets fired.

[maxkatz6]

You are right. It should call OnDeactived from OnHide method:

Avalonia/src/Avalonia.Native/AvaloniaNativeApplicationPlatform.cs

Lines 89 to 103 in a7c3ad9

	void IAvnApplicationEvents.OnHide()
	{
	if (AvaloniaLocator.Current.GetService<IActivatableLifetime>() is ActivatableLifetimeBase lifetime)
	{
	lifetime.OnActivated(ActivationKind.Background);
	}
	}
	void IAvnApplicationEvents.OnUnhide()
	{
	if (AvaloniaLocator.Current.GetService<IActivatableLifetime>() is ActivatableLifetimeBase lifetime)
	{
	lifetime.OnActivated(ActivationKind.Background);
	}
	}

[maxkatz6]

If anybody wants to contribute, it should be a simple fix.

[JamesSmith85]

If anybody wants to contribute, it should be a simple fix.

Done #17573