How to keep window always on the top with Swift? [duplicate]

Question

• Xcode Version 7.3 (7D175)
• Swift Version 2.2
• Mac OS version OS X El Capitan 10.11.4

I want to make a desktop app for Mac OS and I had set the window level but it's not work.

Answer 1

Making your app always on top of the other applications in Swift 5 is so simple.

override func viewDidAppear() {
    view.window?.level = .floating
}

Answer 2

You need check window != nil before any custom code

class ViewController: NSViewController {
    var addedObserver = false

    override func viewDidLoad() {
        super.viewDidLoad()

        if let window = self.view.window {
            // custom window here
            window.level = Int(CGWindowLevelForKey(.FloatingWindowLevelKey))
        } else {
            addedObserver = true
            self.addObserver(self, forKeyPath: "view.window", options: [.New, .Initial], context: nil)
        }
    }

    override func observeValueForKeyPath(keyPath: String?, ofObject object: AnyObject?, change: [String : AnyObject]?, context: UnsafeMutablePointer<Void>) {
        if let window = self.view.window {
            // custom window here
            window.level = Int(CGWindowLevelForKey(.FloatingWindowLevelKey))
        }
    }

    deinit {
        if addedObserver {
            self.removeObserver(self, forKeyPath: "view.window")
        }
    }
}

Answer 3

Still testing it, but this is Larva's answer in Swift 4 and it seems to be working.

var observingFloat = false

 override func viewDidLoad() {
        super.viewDidLoad()
        self.view.wantsLayer = true

        if self.view.window != nil {
            NSApplication.shared.windows.first?.level = NSWindow.Level(rawValue: 1)
        } else {
            observingFloat = true
            self.addObserver(self, forKeyPath: "view.window", options: [.new, .initial], context: nil)
        }
    }

    override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {

        if self.view.window != nil {
            NSApplication.shared.windows.first?.level = NSWindow.Level(rawValue: 1)
        }
    }