How can I get notified about window get loaded in macOS Cocoa? - swift

Question

So there is a modifier in SwiftUI called .onAppear which allow us to know the view get appeared, I am looking to same functionality in Cocoa macOS, so there is method in AppDelegate in Cocoa called applicationDidFinishLaunching so I am looking for something like that for Windows, let say I am looking something like windowDidFinishLaunching, so I just want window notify me when window did launch or shown, in my question I am lunching a window called about, so how can i know that about window get fully lunched and shown in screen? So the goal is to get notified when about window did lunch or fully shown in screen.
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
}
}
By the way I am using a main file for lunching my application like this:
import Cocoa
// **** Main **** //
let nsApplication = NSApplication.shared
let appDelegate = AppDelegate()
nsApplication.delegate = appDelegate
nsApplication.run()