Swift: Unable to addConstraint to ImageView - ios

Question

I am adding an UberLogo on my app's menu bar using ImageView. However, the logo is paned towards the upper left corner of the cell. I tried to re-center it to its containing cell using an online video. The addConstraintWithFormat is working but not the add Constraint. Can anyone help? Thank you!
class MenuCell: BaseCell {
let imageView: UIImageView = {
let iv = UIImageView()
iv.image = UIImage(named: "UberLogo")
return iv
}()
override func setupViews() {
super.setupViews()
addSubview(imageView)
imageView.translatesAutoresizingMaskIntoConstraints = false
addConstraintsWithFormat("H:|[v0(28)]|", views: imageView)
addConstraintsWithFormat("V:|[v0(28)]|", views: imageView)
addConstraint(NSLayoutConstraint(item: imageView, attribute: .centerX, relatedBy: .equal, toItem: self, attribute: .centerX, multiplier: 1, constant: 0))
addConstraint(NSLayoutConstraint(item: imageView, attribute: .centerY, relatedBy: .equal, toItem: self, attribute: .centerY, multiplier: 1, constant: 0))
}
}

Answer 1

As per the addConstraint documentation:
When developing for iOS 8.0 or later, set the constraint’s isActive property to true instead of calling the addConstraint(_:) method directly. The isActive property automatically adds and removes the constraint from the correct view.
Additionally, NSLayoutConstraint has the following function:
class func activate(_ constraints: [NSLayoutConstraint])
Try activating your constraints like this and see if it helps:
addSubview(imageView)
imageView.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
imageView.heightAnchor.constraint(equalToConstant: 28),
imageView.widthAnchor.constraint(equalToConstant: 28),
imageView.centerXAnchor.constraint(equalTo: self.centerXAnchor),
imageView.centerYAnchor.constraint(equalTo: self.centerYAnchor)
])