IOS Presenting PageViewController

Question

I have a simple application in which I'd like to display a PageViewController when a user first logs into the app. Once they have viewed the tutorial, on the next load the PageViewController doesn't display.

However I'm receiving the following message.

2017-01-24 00:20:32.620321 Infinity Toolkit[591:83298] Warning: Attempt to present <Infinity_Toolkit.PageViewController: 0x10e026000> on <Infinity_Toolkit.ViewController: 0x10dd0b030> whose view is not in the window hierarchy!    

UIViewController - Default controller

 override func viewWillAppear(_ animated: Bool) {
    displayWalkthroughs()
}

Display Workthrough Function

func displayWalkthroughs()
{
    // check if walkthroughs have been shown
    let userDefaults = UserDefaults.standard
    let displayedWalkthrough = userDefaults.bool(forKey: "DisplayedWalkthrough")

    // if we haven't shown the walkthroughs, let's show them
    if !displayedWalkthrough {
        let storyboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
        // instantiate neew PageVC via storyboard
        if let pageViewController = storyboard.instantiateViewController(withIdentifier: "PageViewController") as? PageViewController {
            self.present(pageViewController, animated: true, completion: nil)
         print("tried")

        }
    }
}

I think there is enough code to investigate there. However happy to upload more should you need it.

Answer 1

I don't think viewWillAppear is sufficient. I think you can only display UI after viewDidAppear has been called. Try placing your call there.