iOS create overlay with UIWindow

RecordViewController.swift

import UIKit

class RecordViewController: UIViewController {
    @IBAction func closeOverlay(_ sender: Any) {
        self.view.window?.resignKey()
        self.view.window?.isHidden = true
    }
}

ViewController.swift

import UIKit

class ViewController: UIViewController {
    var window: UIWindow?

    override func viewDidLoad() {
        super.viewDidLoad()

        window = UIWindow(frame: self.view.bounds)
        window?.backgroundColor = UIColor(colorLiteralRed: 0, green: 0, blue: 0, alpha: 0.3)
        window?.rootViewController = storyboard!.instantiateViewController(withIdentifier: "RecordOverlay")
    }

    @IBAction func openOverlay(_ sender: Any) {
        window?.makeKeyAndVisible()
    }
}