Activatable Lifetime v11.1

The IActivatableLifetime service defines a set of methods and events related to the activation and deactivation lifecycle of an application. IActivatableLifetime is a global app-level service that can be accessed from the Application instance using the TryGetService method: Application.Current.TryGetService<IActivatableLifetime>().

Events

Activated

An event that is raised when the application is Activated for various reasons as described by the ActivationKind enumeration.

Deactivated

An event that is raised when the application is Deactivated for various reasons as described by the ActivationKind enumeration.

Methods

TryLeaveBackground

Tells the application that it should attempt to leave its background state. Returns true if it was possible and the platform supports this. False otherwise.

примечание

For example on macOS this would be [NSApp unhide].

TryEnterBackground

Tells the application that it should attempt to enter its background state.

Returns true if it was possible and the platform supports this. False otherwise.

примечание

For example on macOS this would be [NSApp hide].

Examples

Handling app entering and exiting background state

In some applications, you might want to pause or stop some code processing, while application is in background. It might be pausing multimedia playback, or disabling recurrent HTTP requests.

if (Application.Current.TryGetFeature<IActivatableLifetime>() is { } activatableLifetime)
{
    activatableLifetime.Activated += (sender, args) =>
    {
        if (args.Kind == ActivationKind.Background)
        {
            Console.WriteLine($"App exited background");
        }
    };
    activatableLifetime.Deactivated += (sender, args) =>
    {
        if (args.Kind == ActivationKind.Background)
        {
            Console.WriteLine($"App entered background");
        }
    };
}

Handling URI activation

Some apps might need to supports Protocol Activation, or as it's often called - deep linking. Link schemas (protocols) that are registered in the system and associated with the app. Once registered, OS will always redirect these links to the app.

App can handle these links in different ways. But typical use cases would be either enabling navigation to the specific page, or using it as a redirect URL in OAuth operations.

if (Application.Current.TryGetFeature<IActivatableLifetime>() is { } activatableLifetime)
{
    activatableLifetime.Activated += (s, a) =>
   {
        if (a is ProtocolActivatedEventArgs protocolArgs && protocolArgs.Kind == ActivationKind.OpenUri)
        {
            Console.WriteLine($"App activated via Uri: {protocolArgs.Uri}");
        }
   };
}

примечание

In order to enable protocol handling for your app, you need to follow platform specific instructions on updating manifest. On macOS and iOS, you need to add CFBundleURLTypes with CFBundleURLSchemes segment to your Info.plist. See https://rderik.com/blog/creating-app-custom-url-scheme/ (skip Swift part, as it's handled by IActivatableLifetime). On Android, you need to add intent-filter with specific android:scheme to your AndroidManifest.xml. See https://developer.android.com/training/app-links/deep-linking for details (skip Kotlin/Java parts, as it's handled by IActivatableLifetime).

Platform compatibility:

Feature	Windows	macOS	Linux	Browser	Android	iOS	Tizen
ActivationKind.Background	✖	✔	✖	✔	✔	✔	✖
ActivationKind.File	✖	✔	✖	✖	✔	✔	✖
ActivationKind.OpenUri	✖	✔	✖	✖	✔	✔	✖
ActivationKind.Reopen	✖	✔	✖	✖	✖	✖	✖
TryLeaveBackground	✖	✔	✖	✖	✖	✖	✖
TryEnterBackground	✖	✔	✖	✖	✔	✖	✖

See https://github.com/AvaloniaUI/Avalonia/issues/15316 for more information on currently supported and unsupported platforms.