SwiftUI macOS 앱 titlebar 샘플

import Cocoa
import SwiftUI

@NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {

    var window: NSWindow!


    func applicationDidFinishLaunching(_ aNotification: Notification) {
        // Create the SwiftUI view that provides the window contents.
        let contentView = ContentView()

        // Create the titlebar accessory
        let titlebarAccessoryView = TitlebarAccessory().padding([.top, .leading, .trailing], 16.0).padding(.bottom,0.0).edgesIgnoringSafeArea(.top)

        let accessoryHostingView = NSHostingView(rootView:titlebarAccessoryView)
        accessoryHostingView.frame.size = accessoryHostingView.fittingSize

        let titlebarAccessory = NSTitlebarAccessoryViewController()
        titlebarAccessory.view = accessoryHostingView

        // Create the window and set the content view.
        window = NSWindow(
            contentRect: NSRect(x: 0, y: 0, width: 480, height: 300),
            styleMask: [.titled, .closable, .miniaturizable, .resizable, .fullSizeContentView],
            backing: .buffered, defer: false)
        window.center()
        window.setFrameAutosaveName("Main Window")

        // Add the titlebar accessory
        window.addTitlebarAccessoryViewController(titlebarAccessory)

        window.contentView = NSHostingView(rootView: contentView)
        window.makeKeyAndOrderFront(nil)
    }

    func applicationWillTerminate(_ aNotification: Notification) {
        // Insert code here to tear down your application
    }


}

import SwiftUI

struct ContentView: View {
    var body: some View {
        Text("Hello, World!")
            .frame(maxWidth: .infinity, maxHeight: .infinity)
    }
}


struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}


struct TitlebarAccessory: View {
    var body: some View {
        Text("hoge")
    }
}