macOS Cocoa中如何监听窗口加载完成并接收通知？

SwiftUI 中的 .onAppear 修饰器可以让我们知晓视图何时出现，我希望在 macOS Cocoa 中实现相同的监听逻辑。虽然 AppDelegate 提供了 applicationDidFinishLaunching 方法，但我需要窗口级别的对应方法（类似 windowDidFinishLaunching），目标是在名为 About 的窗口完全加载并显示到屏幕上时收到通知。

以下是我的现有代码：

import Cocoa
import SwiftUI

class AppDelegate: NSObject, NSApplicationDelegate {
    
    private var window: NSWindow!
    
    func applicationDidFinishLaunching(_ aNotification: Notification) {
 
        buildMainMenu()
        
        buildWindow()
        
    }
    
    func buildWindow() {
        window = NSWindow(
            contentRect: NSRect(x: 0, y: 0, width: 100.0, height: 100.0),
            styleMask: [.titled, .closable, .miniaturizable, .resizable, .fullSizeContentView],
            backing: .buffered, defer: false)
        
        window.setFrameAutosaveName("Main Window")
        window.title = "No Storyboard Window"
        window.makeKeyAndOrderFront(window)
        window.center()
    }
   
    func buildMainMenu() {
        
        let appMainMenu: NSMenu = NSMenu()
        
        let mainMenu: NSMenuItem = NSMenuItem()
        mainMenu.submenu = NSMenu(title: "MainMenu")
        
        let mainMenuItem0 = NSMenuItem(title: "About", action: #selector(NSApplication.about), keyEquivalent: "a")
        mainMenuItem0.keyEquivalentModifierMask = .command
        
        let mainMenuItem1 = NSMenuItem(title: "Close", action: #selector(NSWindow.performClose(_:)), keyEquivalent: "w")
        mainMenuItem1.keyEquivalentModifierMask = .command
        
        let mainMenuItem2 = NSMenuItem(title: "Quit", action: #selector(NSApplication.shared.terminate(_:)), keyEquivalent: "q")
        mainMenuItem2.keyEquivalentModifierMask = .command
        
        mainMenu.submenu?.items = [mainMenuItem0, mainMenuItem1, mainMenuItem2]
        appMainMenu.items = [mainMenu]
        
        NSApp.mainMenu = appMainMenu
        
    }
}


extension NSApplication {
    @objc func about() {
        AboutView().openInWindow(title: "About My App", sender: self)
    }
}

struct AboutView: View {
    var body: some View {
        Color.green
    }
}


extension View {
    
    @discardableResult
    func openInWindow(title: String, sender: Any?) -> NSWindow {

        let window = NSWindow(
            contentRect: NSRect(x: 0, y: 0, width: 100.0, height: 100.0),
            styleMask: [.titled, .closable, .miniaturizable, .resizable, .fullSizeContentView],
            backing: .buffered, defer: false)
        
        window.makeKeyAndOrderFront(window)
        window.center()
        window.setFrameAutosaveName("Main Window")
        window.title = "No Storyboard Window"
        window.contentView = NSHostingView(rootView: self)
 
        return window
    }
}

应用的主启动文件代码如下：

import Cocoa

// **** Main **** //
let nsApplication = NSApplication.shared
let appDelegate = AppDelegate()
nsApplication.delegate = appDelegate
nsApplication.run()

内容的提问来源于stack exchange，提问作者swiftPunk