macOS/SwiftUI onDisappear 窗口关闭时不会调用

Question

当用户关闭应用程序的首选项时，我试图简单地调用 AppDelegate 中的函数，如下所示ContentView。

onDisappear由于某种原因，断点永远不会命中。我希望得到一些帮助来理解为什么会这样。

struct ContentView: View {
    
    @EnvironmentObject var state: AppState
    
    var body: some View {
        Text("Hi there")
           .onDisappear {
                // Never gets in here, breakpoint never hits
                let appDelegate = NSApplication.shared.delegate as! AppDelegate
                appDelegate.hideIcon()
           }

    }

在我的 AppDelegate 中：

func hideIcon() {
    NSApp.setActivationPolicy(.accessory)
}

如何启动内容视图：

    @objc func preferences() {

        let contentView = ContentView().environmentObject(state)

        // Create the window and set the content view.
        window = NSWindow(
            contentRect: NSRect(x: 0, y: 0, width: 480, height: 300),
            styleMask: [.titled, .closable],
            backing: .buffered, defer: false)
        window.isReleasedWhenClosed = false
        window.center()
        window.setFrameAutosaveName("Arch OS System Preferences")
        window.contentView = NSHostingView(rootView: contentView)
        window.makeKeyAndOrderFront(nil)
    
        NSApp.setActivationPolicy(.regular)
        
        NSRunningApplication.current.activate(options: [.activateIgnoringOtherApps, .activateAllWindows])
    }

谢谢！