尝试知道基于macOS Document的应用程序中的窗口何时关闭

Question

我试图知道何时关闭窗口，我实现了以下代码：

class ViewController: NSViewController, NSWindowDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()

        let window: NSWindow? = view.window
        window?.delegate = self
    }

    func windowWillClose(_ aNotification: Notification) {
        print("windowWillClose")
    }

}

不幸的是，什么都没有发生，我该怎么办？

文件：https
:
//developer.apple.com/documentation/appkit/nswindow/1419400-willclosenotification

Answer 1

问题在于window属性将始终在viewDidLoadMethod内部返回nil。您需要在viewWillAppear方法中设置委托：

class ViewController: NSViewController, NSWindowDelegate {
    override func viewWillAppear() {
        super.viewWillAppear()
        view.window?.delegate = self
    }
    func windowWillClose(_ aNotification: Notification) {
        print("windowWillClose")
    }
}