NSView无法观察NSWINDOW的变化-KVO和Swift

Question

我很难让我的 NSView观察其父 NSWindow的变化。我在一个测试项目上尝试了这一点，只不过是一个包含NSView的MyView子类的NSWindow，只是为了看看我是否缺少某些东西。

class MyView: NSView {
    //add observer on awake from nib
    //works fine
    override func awakeFromNib() {
        if let win = self.window {
            win.addObserver(self, forKeyPath: Notification.Name.NSWindowDidBecomeKey.rawValue, options: .new, context: nil)
        }
    }
    //remove observer on dealloc
    //allso works fine
    deinit {
        if let win = self.window {
            win.removeObserver(self, forKeyPath: Notification.Name.NSWindowDidBecomeKey.rawValue)
        }
    }
    //never gets called
    override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
        Swift.print(keyPath ?? "")
        Swift.print("worked!")
    }
    override func draw(_ dirtyRect: NSRect) {
        NSColor.blue.set()
        NSBezierPath.fill(dirtyRect)
    }
} 

我也在这里尝试了建议，但没有运气。我还检查了其他答案，找不到答案。大多数封面使您自己的KVO符合KVO。我想观察一个nswindow对象。我想念什么？

Answer 1

，因此看来NSWindowDidBecomeKey是Notification需要发布到默认的NotificationCenter，而不是窗口本身。这是有效的正确代码

class MyView: NSView {
    //add observer on awake from nib
    //works fine
    override func awakeFromNib() {
        if let win = self.window {
            NotificationCenter.default.addObserver(self, selector: #selector(self.windowIsKey(_:)), name: .NSWindowDidBecomeKey, object: win)
        }
    }
    //remove observer on dealloc
    //allso works fine
    deinit {
        if let win = self.window {
            NotificationCenter.default.removeObserver(self, name: .NSWindowDidBecomeKey, object: win)
        }
    }
    //now this method is called and works fine
    func windowIsKey(_ notification: Notification) {
        Swift.print("worked!")
    }
}