How to trigger a button action only when it is pressed for multiple times?

Question

I am new to Swift 3. Currently, I have a UIBarButtonItem. How to make this button action to be triggered only when it is pressed for multiple times? For example, a ViewController will only appear when user pressed this button twice.

Answer 1

Create custom view for UIBarButtonItem and add UITapGestureRecognizer for the custom view and set the numberOfTapsRequired property value as 2

Sample code :

 class viewController: UIViewController {

        var doubleTapGesture: UITapGestureRecognizer!
        var barButton: UIBarButtonItem!
        var button: UIButton!

        override func viewDidLoad() {
            super.viewDidLoad()

            button = UIButton(type: .custom)
            button.setTitle("title", for: .normal)
            button.frame = CGRect(x: 0, y: 0, width: 64, height: 30)

            doubleTapGesture = UITapGestureRecognizer(target: self, action: #selector(viewController.buttonClicked))
            doubleTapGesture.numberOfTapsRequired = 2

            button.addGestureRecognizer(doubleTapGesture)

            barButton = UIBarButtonItem(customView: button);
            navigationItem.rightBarButtonItem = barButton
        }

        func buttonClicked() {
            // Method for UITapGestureRecognizer
        }
    }

Answer 2

Use UIButton instead of UIBarButtonItem and define its "Touch Down Repeat" event instead of "Touch Up Inside". Touch Down Repeat triggers when you double tap on button.

Check Below image for reference

Answer 3

Just add UITapGestureRecognizer to your UIBarButtonItem like below.

func addBarButton() -> UIBarButtonItem
{
        let btnImage    = UIImage(named: "imageName")!
        let imageButton : UIButton = UIButton(frame: CGRect(x: 0, y: 0, width: 25, height: 25))
        imageButton.setBackgroundImage(btnImage, for: UIControlState())

        let doubleTap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(self.buttonAction(_:)))
        doubleTap.numberOfTapsRequired = 2
        imageButton.addGestureRecognizer(doubleTap)

        return UIBarButtonItem(customView: imageButton)
}

call bellow line from your viewDidLoad function.

navigationItem.rightBarButtonItems  = [addBarButton()]