How to use an IBAction in another View Swift

Question

I have an IBAction in my ViewControllerA that I am trying to use in ViewControllerB, how can I implement it? When I run the code and tap on the sign out button, the walkthrough screen does not display.

Here is the code for ViewControllerA

@objc protocol walkThroughViewControllerDelegate{
    @objc optional func walkThroughButtonTapped()
}

class walkThroughViewController: UIViewController, BWWalkthroughViewControllerDelegate {

    var delegate: walkThroughViewControllerDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }

    override func viewDidAppear(animated: Bool) {
        let userId = NSUserDefaults().stringForKey("userId")

        if(userId != nil){

            print ("user is signed in")

        } else{
             print ("user is nil show walkthrough")
            walkThroughButtonTapped()
        }
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    @IBAction func walkThroughButtonTapped() {
         delegate?.walkThroughButtonTapped!()
        let stb = UIStoryboard(name: "Main", bundle: nil)
        let walkthrough = stb.instantiateViewControllerWithIdentifier("walk0") as! BWWalkthroughViewController
        let page_one = stb.instantiateViewControllerWithIdentifier("walk1") as UIViewController
        let page_two = stb.instantiateViewControllerWithIdentifier("walk2") as UIViewController
        let page_three = stb.instantiateViewControllerWithIdentifier("walk3") as UIViewController

        // Attach the pages to the master
        walkthrough.delegate = self
        walkthrough.addViewController(page_one)
        walkthrough.addViewController(page_two)
        walkthrough.addViewController(page_three)

        self.presentViewController(walkthrough, animated: true, completion: nil)            
    }

    func walkthroughCloseButtonPressed() {
        print("closeButtonPrt")
        self.dismissViewControllerAnimated(true, completion: nil)
    }

And here is the code for ViewControllerB

class LeftSideViewController: UIViewController, UITableViewDataSource, UITableViewDelegate, walkThroughViewControllerDelegate {


     var menuItems: [String] = ["Main", "About", "Sign Out"]

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


    func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

        return menuItems.count
    }

    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

        var myCell = tableView.dequeueReusableCellWithIdentifier("myCell", forIndexPath: indexPath) as! UITableViewCell

        myCell.textLabel?.text = menuItems[indexPath.row]

        return myCell
    }


    func tableView(tableVIew: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath){


        switch(indexPath.row)
        {
        case 0:
            var mainPageViewController = self.storyboard?.instantiateViewControllerWithIdentifier("MainPageViewController") as! MainPageViewController
            var mainPageNav = UINavigationController(rootViewController:mainPageViewController)

            var appDelegate:AppDelegate = UIApplication.sharedApplication().delegate as! AppDelegate

            appDelegate.drawerContainer!.centerViewController = mainPageNav
            appDelegate.drawerContainer!.toggleDrawerSide(MMDrawerSide.Left, animated: true, completion: nil)

            break
        case 1:

            var aboutViewController = self.storyboard?.instantiateViewControllerWithIdentifier("AboutViewController") as! AboutViewController
            var aboutPageNav = UINavigationController(rootViewController:aboutViewController)

            var appDelegate:AppDelegate = UIApplication.sharedApplication().delegate as! AppDelegate

            appDelegate.drawerContainer!.centerViewController = aboutPageNav
            appDelegate.drawerContainer!.toggleDrawerSide(MMDrawerSide.Left, animated: true, completion: nil)

            break
        case 2:


            NSUserDefaults.standardUserDefaults().removeObjectForKey("userFirstName")
            NSUserDefaults.standardUserDefaults().removeObjectForKey("userLastName")
            NSUserDefaults.standardUserDefaults().removeObjectForKey("userId")
            NSUserDefaults.standardUserDefaults().synchronize()

            func walkThroughButtonTapped(){
                print("worked")
            }

        /*
            let signInPage = self.storyboard?.instantiateViewControllerWithIdentifier("ViewController") as! ViewController

            let signInNav = UINavigationController(rootVixewController: signInPage)

            let appDelegate = UIApplication.sharedApplication().delegate
            appDelegate?.window??.rootViewController = signInNav

            */

            break


        default:
            print("Not handled")
        }
    }

}

Answer 1

It looks to me like you never set view controller A's delegate. If it's nil then the line

delegate?.walkThroughButtonTapped!()

...won't do anything. (The ? means "If the optional 'delegate' is not nil, send it the following message. If it's nil, don't do anything.")