How to use a if else statement on constraints in swift - swift

Question

The code below has a uicolor box when pressed, the box becomes a smaller uicolor box. The problem is that the color box can only be pressed one time. So the box can go from large to small but it cant go from small to big. How can the code be written so when the box is clicked the box goes from big to small or small to big every time.
import UIKit
class ViewController: UIViewController {
let colorview = UIView()
var initialc = [NSLayoutConstraint]()
override func viewDidLoad() {
super.viewDidLoad()
let tapGestureRecognizer = UITapGestureRecognizer(target:self, action:#selector(ViewController.myFunction(_:)))
colorview.userInteractionEnabled = true
colorview.addGestureRecognizer(tapGestureRecognizer)
colorview.translatesAutoresizingMaskIntoConstraints = false
colorview.backgroundColor = UIColor.blueColor()
self.view.addSubview((colorview))
let leadingc = colorview.leadingAnchor.constraintEqualToAnchor(self.view.leadingAnchor)
let trailingC = colorview.trailingAnchor.constraintEqualToAnchor(self.view.trailingAnchor)
let topc = colorview.topAnchor.constraintEqualToAnchor(self.view.topAnchor)
let bottomc = colorview.bottomAnchor.constraintEqualToAnchor(self.view.bottomAnchor, constant: -50)
initialc.appendContentsOf([leadingc,trailingC,topc,bottomc])
NSLayoutConstraint.activateConstraints(initialc)
}
func myFunction(sender: AnyObject) {
NSLayoutConstraint.deactivateConstraints(initialc)
let widthc = colorview.widthAnchor.constraintEqualToConstant(100)
let heightc = colorview.heightAnchor.constraintEqualToConstant(100)
let centerxc = colorview.centerXAnchor.constraintEqualToAnchor(self.view.centerXAnchor)
let centeryc = colorview.centerYAnchor.constraintEqualToAnchor(self.view.centerYAnchor)
NSLayoutConstraint.activateConstraints([widthc,heightc,centerxc,centeryc])
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}

Answer 1

You are resizing the view in an awkward way. Instead of using constraints, don't place them. Tell the view where to go with its frame. If you need the view to animate the change between frames then use UIView.animateViewWithDuration() and inside the function do the frame changes you desire. This keeps transitions smooth and full control in your hands. Constraints are not as easy to implement properly during run time as frames.