Programmatically create NSWindow

Xcode 11 • Swift 5.1

import Cocoa@NSApplicationMainclass AppDelegate: NSObject, NSApplicationDelegate {    @IBOutlet weak var window: NSWindow!    let newWindow = NSWindow(contentRect: .init(origin: .zero,                                                size: .init(width: NSScreen.main!.frame.midX,                                                            height: NSScreen.main!.frame.midY)),                             styleMask: [.closable],                             backing: .buffered,                             defer: false)    func createNewWindow() {        newWindow.title = "New Window"        newWindow.isOpaque = false        newWindow.center()        newWindow.isMovableByWindowBackground = true        newWindow.backgroundColor = NSColor(calibratedHue: 0, saturation: 1.0, brightness: 0, alpha: 0.7)        newWindow.makeKeyAndOrderFront(nil)    }    func applicationDidFinishLaunching(_ aNotification: Notification) {        createNewWindow()    }    func applicationWillTerminate(_ aNotification: Notification) {        // Insert code here to tear down your application    }}

Window Style Mask

Sample project

Here's a working example without any bells & whistles, updated to Swift 4.2.

It creates a bare window, with & without a nib depending on which function you call.

In IB, uncheck "initial controller" everywhere. For the nib version to work, you must give the IB-supplied window controller a storyboard ID of "WindowController."

    import Cocoa    @NSApplicationMain    class AppDelegate: NSObject, NSApplicationDelegate, DebugHelper {        var myName: String = "AppDelegate"        var windowController: NSWindowController!        var window: NSWindow!        func applicationDidFinishLaunching(_ aNotification: Notification) {            //nib()            diy()        }        func nib() {            let storyboard = NSStoryboard(name: NSStoryboard.Name("Main"), bundle: nil)            guard let wc = storyboard.instantiateController(withIdentifier: "WindowController") as? NSWindowController else { return }            windowController = wc            wc.showWindow(self)        }        func diy() {            window = NSWindow()            window.styleMask = NSWindow.StyleMask(rawValue: 0xf)            window.backingType = .buffered            window.contentViewController = ViewController()            window.setFrame(NSRect(x: 700, y: 200, width: 500, height: 500), display: false)            windowController = NSWindowController()            windowController.contentViewController = window.contentViewController            windowController.window = window            windowController.showWindow(self)        }        func applicationWillTerminate(_ aNotification: Notification) {            // Insert code here to tear down your application        }    }    import Cocoa    class ViewController: NSViewController, DebugHelper {        var myName: String = "ViewController"        override func loadView() {            view = NSView()        }    }