UIAlertController automatically closes fraction of time after it appears

Question

I have created a wrapper for creating AlertDialog to mimic how it is done in Android

import Foundation

protocol AlertDialogDelegate {
    func onAlertPositiveActionClicked(alertDialog: AlertDialog)
    func onAlertNegativeActionClicked(alertDialog: AlertDialog)
}

final class AlertDialog {

    private var controller: UIViewController?
    private var alert: UIAlertController?
    private var title: String = ""
    private var message: String = ""
    private var posAct: UIAlertAction?
    private var negAct: UIAlertAction?
    private var neuAct: UIAlertAction?
    private var cancelable: Bool?

    private var delegate: AlertDialogDelegate?

    private init() {

    }

    private func setController(controller: UIViewController) {
        self.controller = controller
    }

    private func setListener(listener: AlertDialogDelegate) {
        self.delegate = listener
    }

    private func callPositiveActionListener() {
        assert(self.delegate != nil)
        self.delegate!.onAlertPositiveActionClicked(alertDialog: self)
    }

    private func callNegativeActionListener() {
        assert(self.delegate != nil)
        self.delegate!.onAlertNegativeActionClicked(alertDialog: self)
    }

    private func setTitle(title: String) {
        self.title = title
    }

    private func setMessage(message: String) {
        self.message = message
    }

    private func setPosAct(action: UIAlertAction) {
        self.posAct = action
    }

    private func setNegAct(action: UIAlertAction) {
        self.negAct = action
    }

    private func setNeuAct(action: UIAlertAction) {
        self.neuAct = action
    }

    private func setCancelable(isCancelable: Bool) {
        self.cancelable = isCancelable
    }

    private func build() {
        alert = UIAlertController(title: self.title, message: self.message, preferredStyle: .alert)

        if (self.neuAct != nil) {
            alert!.addAction(self.neuAct!)
        }

        if (self.negAct != nil) {
            alert!.addAction(self.negAct!)
        }

        if (self.posAct != nil) {
            alert!.addAction(self.posAct!)
        }

        self.controller!.present(alert!, animated: true, completion: nil)
    }

    func dissmiss() {
        if (self.cancelable!) {
            self.alert!.dismiss(animated: true, completion: nil)
        }
    }


    final class Builder {

        private let alertDialog: AlertDialog

        init(controller: UIViewController) {
            self.alertDialog = AlertDialog()
            print("call coming")
            self.alertDialog.setController(controller: controller)
            self.alertDialog.setListener(listener: controller as! AlertDialogDelegate)
        }

        func setTitle(title: String) -> Builder {
            print("call coming1")
            self.alertDialog.setTitle(title: title)
            return self
        }

        func setMessage(message: String) -> Builder {
            print("call coming2")
            self.alertDialog.setMessage(message: message)
            return self
        }

        func setPositiveAction(title: String) -> Builder {
            print("call coming3")
            let action = UIAlertAction(title: title, style: .destructive, handler: { _ in
                print("call coming")
                self.alertDialog.callPositiveActionListener() })

            self.alertDialog.setPosAct(action: action)
            return self
        }

        func setNegativeAction(title: String) -> Builder {
            let action = UIAlertAction(title: title, style: .cancel, handler: { _ in self.alertDialog.callNegativeActionListener() })
            self.alertDialog.setNegAct(action: action)
            return self
        }

        func setNeutralAction(title: String) -> Builder {
            let action = UIAlertAction(title: title, style: .default, handler: { _ in self.alertDialog.dissmiss() })
            self.alertDialog.setNeuAct(action: action)
            return self
        }

        func setCancelable(isCancelable: Bool) -> Builder {
            self.alertDialog.setCancelable(isCancelable: isCancelable)
            return self
        }

        func show() {
            self.alertDialog.build()
        }

    }

}

As soon as this piece of code is loaded an alert comes to the screen but it disappears fraction of seconds after it comes. I had put several logs but it is confirm that no action handler is executed.

I am calling builder.show() when edge swipe callback comes.

override func viewDidLoad() {

        super.viewDidLoad()

        builder = AlertDialog.Builder(controller: self)
            .setTitle(title: "Caution")
            .setMessage(message: "To cancel this payment request, please go to.")
            .setCancelable(isCancelable: false)
            .setPositiveAction(title: "Ok")
            .setNegativeAction(title: "Cancel")
}

extension OPController : EdgeSwipeGesture {
    internal func handleEdgeSwipe(sender: UIScreenEdgePanGestureRecognizer) {
        // TODO: Handle back press kind of action in here
        if (!backAlertShown) {
            self.builder!.show()

            backAlertShown = true
        } else {

            assert(self.delegate != nil)

            self.finish()
        }

    }
}

Second one is the callback that comes when we edge swipe on screen.

Answer 1

You receive more than one message for UIScreenEdgePanGestureRecognizer - possible values are:

    case possible
    case began
    case changed
    case ended
    case cancelled
    case failed

So, you are showing the dialog on .began and then immediately dismissing it on the next message -- which, I believe, is .cancelled because you show the alert.

Inside your handleEdgeSwipe() func, do this:

    if sender.state == .recognized {
        print("Screen edge swiped!")
        builder.show()
    }

You shouldn't have to do anything else there, as you won't get an edge-swipe while the dialog is showing.

Note: .recognized is an internal var of UIScreenEdgePanGestureRecognizer that allows you to avoid checking the different states if you don't need them.

Answer 2

AlertDialog is released and whole view is disappearing, try to init AlertDialog somewhere else and then use that instance to display dialog