swift - NSApplicationDelegate not working without Storyboard

Question

I'm attempting to create a macOS application without a storyboard in Xcode 8 (stable) on macOS Sierra. However, my AppDelegate is not even being initiated. Here's the code I have:

import Cocoa

@NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {
    var window: NSWindow!

    override init() {
        super.init()
        print("Init")
    }

    func applicationDidFinishLaunching(_ aNotification: Notification) {
        print("Finished launching")

        // Create a window
        window = NSWindow()

        // Add the view controller
        let viewController = ViewController()
        window.contentView?.addSubview(viewController.view)

        // Show the window
        window.makeKeyAndOrderFront(nil)
    }
}

Neither init or applicationDidFinishLaunching(_ aNotification: Notification) is being called. Any help would be much appreciated.

Answer 1

You need to do a few things here

1. Delete NSMainStoryboardFile key/value from the plist
2. Create a NSApplication subclass and assign it to the Principal Class (NSPrincipalClass) key.

The name must be fully qualified with your module name.

3. Manually instantiate your delegate in your NSApplication subclass and assign it to the delegate property.

Make sure you keep a strong reference to your delegate object. Ive just used a let here.

class GrookApplication: NSApplication {

    let strongDelegate = AppDelegate()

    override init() {
        super.init()
        self.delegate = strongDelegate
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

}

e.g a simple delegate.

@NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {

    override init() {
        super.init()
        print("wassup")
        //conceptual proof of life init override
        //wait until applicationDidFinishLaunching , specially for UI
    }

    var window: NSWindow!
    func applicationDidFinishLaunching(_ aNotification: Notification) {
        print("yo! I'm alive")
        window = NSWindow(contentRect: NSRect(x: 0, y: 0, width: 200, height: 200), styleMask: .titled, backing: .buffered, defer: false)
        window.makeKeyAndOrderFront(nil)
    }

}

EDIT 2018 Verified High Sierra

Do NOT try and do window or view controller initialisation inside init this leads to double app initialisation issues and crashing. The app has not finished launching at this stage. Wait until applicationDidFinishLaunching to fire any significant operations.