// <key>UIStatusBarHidden</key>
// <true/>
// <key>UIViewControllerBasedStatusBarAppearance</key>
// <false/>
// Specifies whether the view controller determines the status bar style.
// See UIViewControllerBasedStatusBarAppearance for details.

// Previously one could just do something like this:
override func viewDidAppear(_ animated: Bool) {

    super.viewDidAppear(animated)

    // set the status bar hidden at the application level
    // status bar will be hidden on all view controllers
    UIApplication.shared.isStatusBarHidden = true
}

// as of iOS 9.0, isStatusBarHidden is deprecated
// so, we have to override this method in our view controller:
override var prefersStatusBarHidden: Bool {
    return true
}