NSLayout Constraint not working on Custom View - ios

Question

I am creating a custom UIView in swift, here is the code for the custom View,
class FormField: UIView {
#IBOutlet var viewLabel : UILabel!
#IBOutlet var textField: UITextField!
#IBOutlet var separator: UIView!
private var verticallyCenteredAnchor : NSLayoutConstraint!
private var topPositionedAnchor : NSLayoutConstraint!
private var isViewHighlighted = false
private var view: UIView?
let nibName = "FormField"
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
commonInit()
}
override init(frame: CGRect) {
super.init(frame: frame)
commonInit()
}
override class var requiresConstraintBasedLayout: Bool {
return true
}
func commonInit() {
guard let view = loadViewFromNib() else { return }
self.view = view
view.frame = self.bounds
self.addSubview(view)
verticallyCenteredAnchor = viewLabel.centerYAnchor.constraint(equalTo: self.view!.centerYAnchor)
verticallyCenteredAnchor.isActive = false
topPositionedAnchor = viewLabel.topAnchor.constraint(equalTo: self.view!.topAnchor,constant: 0)
topPositionedAnchor.isActive = true
let userNameTap = UITapGestureRecognizer(target: self, action: #selector(animateLabel))
userNameTap.numberOfTapsRequired = 1
view.addGestureRecognizer(userNameTap)
}
#objc func animateLabel() {
if(self.isViewHighlighted) {
verticallyCenteredAnchor.isActive = true
topPositionedAnchor.isActive = false
} else {
verticallyCenteredAnchor.isActive = false
topPositionedAnchor.isActive = true
}
self.isViewHighlighted = !self.isViewHighlighted
UIView.animate(withDuration: 0.5) {
self.view!.layoutIfNeeded()
}
}
func loadViewFromNib() -> UIView? {
let nib = UINib(nibName: nibName, bundle: nil)
return nib.instantiate(withOwner: self, options: nil).first as? UIView
}
}
I am using a xib file for the view and constraints are set in that. Now when someone taps on the view I am trying to change the constraints with animation. But that's not working, no layout change is happening when the user taps on the view. I can confirm that the animateLabel() method is called when the user taps.
Now if is add in the line,
self.view!.translatesAutoresizingMaskIntoConstraints = false
all constraints are messed up, it's not honouring the constraints I already set in the xib.
What's going wrong here?

Answer 1

I am using a xib file for the view and constraints are set in that.
You have conflicts in your constraints who are in xib + in code , you need to hook the constraints in xib as outlets and play with their .isActive property and completely remove the code constraints