ViewController looses animated position after navigation - swift

Question

I want a view to appearing and disappear from the left (depending if it has some useful information for the user).
I want to view to be positioned using constraints, so I need it to be created from the storyboard.
In this code snippet, the view should be moved out of the way when to code appears.
But: When I segue to the next VC I can see that the view appears again at its original position and when going back from the VC to the initial VC it has, in fact, resumed the original position.
I played a little around with saving the "state" of the view in a variable, making it appear/disappear in the various lifecycles of the VC, but nothing really helped.
How is the best way to achieve this?
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var myView: UIView!
var boxIsVisible = false
override func viewDidLoad() {
super.viewDidLoad()
}
var originalX:CGFloat = 0.0
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
originalX = self.myView.frame.origin.x
if boxIsVisible == false {
self.myView.center.x -= 200
}
}
#IBAction func slideInAction(sender: AnyObject) {
UIView.animateWithDuration(3.0, animations: {
self.myView.center.x = self.originalX
self.boxIsVisible = true
})
}
#IBAction func slideOutAction(sender: AnyObject) {
UIView.animateWithDuration(3.0, animations: {
self.myView.center.x = -200
self.boxIsVisible = false
})
}
}

Answer 1

Update leading constraint instead of the view's position, because you use auto layout.
class ViewController: UIViewController {
#IBOutlet weak var myView: UIView!
var boxIsVisible = false
#IBOutlet weak var leadingConstraint: NSLayoutConstraint!
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
if boxIsVisible == false {
leadingConstraint.constant = -myView.frame.width
}
}
#IBAction func slideInAction(sender: AnyObject) {
UIView.animateWithDuration(3.0, animations: {
self.leadingConstraint.constant = -50
self.view.layoutIfNeeded()
self.boxIsVisible = true
})
}
#IBAction func slideOutAction(sender: AnyObject) {
UIView.animateWithDuration(3.0, animations: {
self.leadingConstraint.constant = -self.myView.frame.width
self.view.layoutIfNeeded()
self.boxIsVisible = false
})
}
}