"Nice" way to exit app when Menu button is pressed?

Are you responding to pressesBegan/Changed/Ended? If you do, I think you can just pass that event to 'super' and it will exit the app.

[super pressesBegan:presses withEvent:event];

No, we're not using pressesBegan. If we could pass the Menu button event up to the presenting view controller, so the system could handle it at that level (and then exit the app), that would work – I'm not sure that can be done though.

You can use exit(0) but it doesn't look good due to the missing fade-out animation and most likely would be rejected at review.

Implement pressesBegan in the tab view controller. If user presses Menu at Signin then do as bsabiston says and super the press. Because in your use case, there is no screen higher up where the user can go if they are not signed in, so Menu at Signin means Back to Home.

It's likely that the tab view controller gets the press before the sign in controller depending on how you have things set up. You can add pressesBegan to both controllers and add logging to see which is being called, and in which order. You will need to super the first one in order for the system to handle Menu back to Home screen.

Implement pressesEnded in the Sign In screen like below. The app will exit gracefully with the exit chime.

override func pressesEnded(presses: Set<UIPress>, withEvent event: UIPressesEvent?) {     
     for press in presses {
          switch press.type {
          case .Menu:
               UIApplication.sharedApplication().pressesEnded(presses, withEvent: event)
...

I don't think calling pressesEnded on UIApplication directly is a good idea, you're better off just calling super here and letting it bubble-up to UIApplication normally.

Just a small point...but...

Apple's guidelines say you should avoid presenting a sign-on screen as your first screen.

Instead you should not ask the user to sign-in until absolutely necessary.

Give them all the free goodies first.

We're doing a similar thing for our app. We load the sign in screen as out rootviewcontroller when the user isn't logged in and then swap this out for the tabbarcontroller once the user has logged in.

Seems to work quite nicely and fixes the issue of menu going back. Alternatively, I have seen people using a global "App Nav Controller" and then changing the root view of the nav controller rather than the app.

Code Block 
open class MenuUIPress : UIPress {
  weak var view: UIView?
  init(view: UIView) {
    self.view = view
  }
  open override var timestamp: TimeInterval {
    Date().timeIntervalSince1970
  }
  open override var phase: UIPress.Phase {
    UIPress.Phase.began
  }
  open override var type: UIPress.PressType {
    UIPress.PressType.menu
  }
  open override var window: UIWindow? {
    view?.window
  }
  open override var responder: UIResponder? {
    view
  }
  open override var gestureRecognizers: [UIGestureRecognizer]? {
    return view?.gestureRecognizers
  }
}
class SignInViewController: UIViewController {
  func  viewDidLoad() {
      setUpTapGesture()
   }
   private func setUpTapGesture() {
    #if os(tvOS)
      let tap = UITapGestureRecognizer()
      tap.allowedPressTypes = [NSNumber(value: UIPress.PressType.menu.rawValue)]
      tap.addTarget(self, action: #selector(SignInViewController.sendEndMenuTap))
      view.addGestureRecognizer(tap)
    #endif
  }
  @objc func sendEndMenuTap(_ gestureRecognizer: UITapGestureRecognizer) {
    print("@@@@@ called on touch end 3 state=", gestureRecognizer.state.rawValue)
    UIApplication.shared.pressesEnded([MenuUIPress(view: view)], with: UIPressesEvent())
  }
}