# init(_:) Creates a WatchKit extension delegate adaptor using an observable delegate. ``` @MainActor @preconcurrency init(_ delegateType: DelegateType.Type = DelegateType.self) ``` ## Parameters `delegateType` The type of extension delegate that you define in your app, which conforms to the and protocols. ## Discussion Call this initializer indirectly by creating a property with the [`WKExtensionDelegateAdaptor`](/documentation/SwiftUI/WKExtensionDelegateAdaptor) property wrapper from inside your [`App`](/documentation/SwiftUI/App) declaration: ``` @main struct MyApp: App { @WKExtensionDelegateAdaptor private var extensionDelegate: MyExtensionDelegate var body: some Scene { ... } } ``` SwiftUI initializes the delegate and manages its lifetime, calling it as needed to handle extension delegate callbacks. SwiftUI invokes this method when your app delegate conforms to the protocol. In this case, SwiftUI automatically places the delegate in the [`Environment`](/documentation/SwiftUI/Environment). You can access such a delegate from any scene or view in your app using the [`Environment`](/documentation/SwiftUI/Environment) property wrapper: ``` @Environment(MyAppDelegate.self) private var appDelegate ``` If your delegate isn’t observable, SwiftUI invokes the [`init(_:)`](/documentation/SwiftUI/WKExtensionDelegateAdaptor/init(_:)-2556) initializer rather than this one, and doesn’t put the delegate instance in the environment. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)