Hide Title Bar in SwiftUI App for macCatalyst

Question

How can I hide the Title Bar in the new SwiftUI App Protocol?

Since the AppDelegate.swift and SceneDelegate.swift protocols are gone, I cant follow this documentation anymore: https://developer.apple.com/documentation/uikit/mac_catalyst/removing_the_title_bar_in_your_mac_app_built_with_mac_catalyst

I can't implement this code:

class SceneDelegate: UIResponder, UIWindowSceneDelegate {
    var window: UIWindow?    
    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
        guard let windowScene = (scene as? UIWindowScene) else { return }
        #if targetEnvironment(macCatalyst)
        if let titlebar = windowScene.titlebar {
            titlebar.titleVisibility = .hidden
            titlebar.toolbar = nil
        }
        #endif
    }
}

Hope it's still possible with the new AppProtocol..

Thanks in advance

Answer 1

This is how to hide the titlebar:

struct ContentView: View {
    var body: some View {
        ZStack {
            Text("Example UI")
        }
        .withHostingWindow { window in
            #if targetEnvironment(macCatalyst)
            if let titlebar = window?.windowScene?.titlebar {
                titlebar.titleVisibility = .hidden
                titlebar.toolbar = nil
            }
            #endif
        }
    }
}

extension View {
    fileprivate func withHostingWindow(_ callback: @escaping (UIWindow?) -> Void) -> some View {
        self.background(HostingWindowFinder(callback: callback))
    }
}

fileprivate struct HostingWindowFinder: UIViewRepresentable {
    var callback: (UIWindow?) -> ()

    func makeUIView(context: Context) -> UIView {
        let view = UIView()
        DispatchQueue.main.async { [weak view] in
            self.callback(view?.window)
        }
        return view
    }

    func updateUIView(_ uiView: UIView, context: Context) {
    }
}

Answer 2

On your Scene, set .windowStyle(_:) to HiddenTitleBarWindowStyle().

@main
struct MyApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
        .windowStyle(HiddenTitleBarWindowStyle())
    }
}

EDIT: Ah crap. While this API is supposedly available for Mac Catalyst according to the online documentation, it looks like it’s not actually marked as such in frameworks so you can’t use it.