Customizing the UIApplicationDelegate on iOS

Uno Platform provides the ability to provide custom behavior for UIApplicationDelegate on iOS in case of both native- and Skia-based rendering.

Skia rendering

In Skia-based apps, the App type no longer derives from UIApplicationDelegate. Instead, Uno Platform provides Uno.UI.Runtime.Skia.AppleUIKit.UnoUIApplicationDelegate. If you decide to implement your own application lifecycle handling, create a new type that derives from it:

public class MyApplicationDelegate : Uno.UI.Runtime.Skia.AppleUIKit.UnoUIApplicationDelegate
{
    // Your own code or overrides
}

You then need to inform Uno Platform to use this custom class instead of the built-in delegate by adjusting the host creation in Main.iOS.cs:

using Uno.UI.Hosting;

var host = UnoPlatformHostBuilder.Create()
    .App(() => new SamplesApp.App())
    .UseAppleUIKit(builder => builder.UseUIApplicationDelegate<MyApplicationDelegate>())
    .Build();

host.Run();

Important

Make sure to call the base methods when you override key application lifecycle methods, so that the internals of Uno Platform are still properly executed.

Native rendering

Your App class already derives from UIApplicationDelegate. This means you can directly override the UIKit methods this class provides:

public App : Application
{
    // Existing code in App.xaml.cs

    public override bool FinishedLaunching(UIApplication application, NSDictionary launchOptions)
    {
        // Your custom handling

        return base.FinishedLaunching(application, launchOptions);
    }
}

Important

Make sure to call the base methods when you override key application lifecycle methods, so that the internals of Uno Platform are still properly executed.