macos – self.window总是零

NSWindow子类

import Cocoa
import CoreLocation

class Tweetwindow: NSWindow {

var locationManager: CLLocationManager!
var geoCoder: CLGeocoder!

@IBAction func tweetButtonpressed(sender:NSButton) {

}

func initialize() {
    self.titleVisibility = NSWindowTitleVisibility.Hidden;
    self.locationManager = CLLocationManager();
    self.locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation;
    self.locationManager.distanceFilter = 10;

    self.geoCoder = CLGeocoder();
}

func windowWillShow() {
    if !self.visible {
        let systemAppearanceName = (NSUserDefaults.standardUserDefaults().stringForKey("AppleInterfaceStyle") ?? "Light").lowercaseString;
        let systemAppearance = systemAppearanceName == "dark" ? NSAppearance(named: NSAppearanceNameVibrantDark) : NSAppearance(named: NSAppearanceNameVibrantLight);
        self.appearance = systemAppearance;

        self.locationManager.startUpdatingLocation();
    }
}

func windowWillClose() {
    self.locationManager.stopUpdatingLocation();
}
}

NSWindowController子类：

import Cocoa

class TweetwindowController: NSWindowController {

var tweetwindow: Tweetwindow { return self.window as! Tweetwindow; }

override func windowDidLoad() {
    super.windowDidLoad()
    self.tweetwindow.initialize()
    // Implement this method to handle any initialization after your window controller's window has been loaded from its nib file.
}

override func showWindow(sender: AnyObject?) {
    self.tweetwindow.windowWillShow()
    super.showWindow(sender)
}
}

当然,我也有一个包含我窗口的.xib文件.它被称为“Tweetwindow.xib”.
现在,到目前为止,这应该没问题.

在我的AppDelegate.swift中,我执行以下操作：

@NSApplicationMain
class AppDelegate: NSObject,NSApplicationDelegate {

var tweetwindowController:TweetwindowController!;

func applicationDidFinishLaunching(aNotification: NSNotification) {
    // Insert code here to initialize your application
    tweetwindowController = TweetwindowController(windowNibName: "Tweetwindow");
}

func applicationWillTerminate(aNotification: NSNotification) {
    // Insert code here to tear down your application
}

func showTweetwindowInternal() {
    NSApp.activateIgnoringOtherApps(true);
    tweetwindowController.showWindow(nil);
}

@IBAction func showTweetwindow(sender: AnyObject) {
    showTweetwindowInternal();
}

@IBAction func quitApp(sender: AnyObject) {
    NSApplication.sharedApplication().terminate(self);
}
}

我的问题如下：
当我尝试单击与IBAction相关联的按钮以显示窗口时,会抛出异常：
var tweetwindow：Tweetwindow {return self.window as！ Tweetwindow; }

它说致命错误：在展开Optional值时意外发现nil,因此窗口为零.

为什么那里的窗户没有？我试图过早地获取价值还是什么？

这是一些照片：

谢谢.