Bdtjtk

I am trying to use a if statement when the uses touches the imageview it changes the constraints. Right now my code changes from small to big but it does not change from big to small. So the if statement only works one time but does not work again.

 var counter = 0



    override func viewDidAppear(_ animated: Bool) {

        super.viewDidAppear(animated)



        let tap = UITapGestureRecognizer(target: self, action: #selector(ViewController.handleRegisterC))

        FIRE.addGestureRecognizer(tap)

        FIRE.isUserInteractionEnabled = true

        print(counter)



    }

override func viewDidLoad() {

    super.viewDidLoad()

    // Do any additional setup after loading the view, typically from a nib.



        view.addSubview(FIRE)

    FIRE.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true

    FIRE.topAnchor.constraint(equalTo: view.topAnchor, constant: 0).isActive = true







    FIRE.widthAnchor.constraint(equalToConstant: 400).isActive = true

    FIRE.heightAnchor.constraint(equalToConstant: 700).isActive = true

     FIRE.translatesAutoresizingMaskIntoConstraints = false







    @objc func handleRegisterC(sender: UIButton){



        counter += 1





        if counter % 2 == 0 {





            FIRE.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true

            FIRE.topAnchor.constraint(equalTo: view.topAnchor, constant: 0).isActive = true





            FIRE.widthAnchor.constraint(equalToConstant: 400).isActive = true

            FIRE.heightAnchor.constraint(equalToConstant: 700).isActive = true

            FIRE.translatesAutoresizingMaskIntoConstraints = false



        }

        if counter % 2 == 1 {

            FIRE.topAnchor.constraint(equalTo: view.topAnchor, constant: 0).isActive = true

            FIRE.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 0).isActive = true

            FIRE.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 0).isActive = true

            FIRE.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: 0).isActive = true

            FIRE.translatesAutoresizingMaskIntoConstraints = false





        }





    }







}

I don't think the if statement is working only once (you can put a print statement in each block to confirm). I think the problem is that you have two sets of constraints that are active at the same time. What you probably want to do is to alternate between these two sets; setting one of them to be active while the other one to be inactive. Try something like this

enum Size {

    case big

    case small

}

var counter = 0



override func viewDidLoad() {

    super.viewDidLoad()

    view.addSubview(FIRE)

    changeSizeTo(.small)

}



override func viewDidAppear(_ animated: Bool) {

    super.viewDidAppear(animated)

    let tap = UITapGestureRecognizer(target: self, action: #selector(ViewController.handleRegisterC))

    FIRE.addGestureRecognizer(tap)

    FIRE.isUserInteractionEnabled = true

}



private func changeSizeTo(_ size: Size) {

    FIRE.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = size == .small

    FIRE.topAnchor.constraint(equalTo: view.topAnchor, constant: 0).isActive = size == .small

    FIRE.widthAnchor.constraint(equalToConstant: 400).isActive = size == .small

    FIRE.heightAnchor.constraint(equalToConstant: 700).isActive = size == .small

    FIRE.topAnchor.constraint(equalTo: view.topAnchor, constant: 0).isActive = size == .big

    FIRE.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 0).isActive = size == .big

    FIRE.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 0).isActive = size == .big

    FIRE.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: 0).isActive = size == .big

    FIRE.translatesAutoresizingMaskIntoConstraints = false

}



@objc func handleRegisterC(sender: UIButton){

    counter += 1

    changeSizeTo(counter % 2 == 0 ? .small : .big)

}