present view controller in UIContentView

Question

I'm having pageViewController(ABC) at rootViewController and pageViewController contains ViewController(PQR) Which contains ContentView. I want to Present ViewController but it is saying

Warning: Attempt to present XYZ: 0x17ee0730 on ABC: 0x17e67dc0 whose view is not in the window hierarchy!

On which controller I suppose to present View controller

Answer 1

Glad that your problem is solved. Incase if you want to display alert, from any UIView other than a view controller, this would help.

This method gets the top view controller, so that you can present your alert from it:

func currentTopViewController() -> UIViewController{

    var topVC: UIViewController? = UIApplication.shared.delegate?.window??.rootViewController

    while ((topVC?.presentedViewController) != nil) {

        topVC = topVC?.presentedViewController

    }

    return topVC!

}

func showAlert() { // This presents your alert from the received view controller object

    let alertController: UIAlertController = UIAlertController.init(title: "title", message: "message", preferredStyle: .alert)

    let alertAction = UIAlertAction.init(title: "OK", style: .default) { (UIAlertAction) in
            //Your action    
    }

    alertController.addAction(alertAction)

    currentTopViewController().present(alertController, animated: true, completion: nil)

}