Unable to Activate Constraints

Question

I am receiving the error..

Terminating app due to uncaught exception 'NSGenericException', reason: 'Unable to activate constraint with anchors because they have no common ancestor. Does the constraint or its anchors reference items in different view hierarchies? That's illegal.'

I referenced other answers and the solution consistently had been to add the subview in viewDidLoad prior to activating constraints programmatically.

I am still receiving however the same crash and do not understand what is causing it. Any guidance would be appreciated. Below is relevant code:

@IBOutlet weak var activityIndicatorView: UIView!
@IBOutlet weak var refreshActivityIndicatorView: UIView!

let activityIndicator = AnimationView(name: "name")
let refreshActivityIndicator = AnimationView(name: "name")

override func viewDidLoad() {
    super.viewDidLoad()
    activityIndicatorView.addSubview(activityIndicator)
    activityIndicator.translatesAutoresizingMaskIntoConstraints = false
    refreshActivityIndicatorView.addSubview(activityIndicator)
    refreshActivityIndicator.translatesAutoresizingMaskIntoConstraints = false

    NSLayoutConstraint.activate([
        activityIndicator.centerXAnchor.constraint(equalTo: activityIndicatorView.centerXAnchor),
        activityIndicator.centerYAnchor.constraint(equalTo: activityIndicatorView.centerYAnchor),
        activityIndicator.widthAnchor.constraint(equalToConstant: activityIndicatorView.frame.width),
        activityIndicator.heightAnchor.constraint(equalToConstant: activityIndicatorView.frame.height),
        refreshActivityIndicator.centerXAnchor.constraint(equalTo: refreshActivityIndicatorView.centerXAnchor),
        refreshActivityIndicator.centerYAnchor.constraint(equalTo: refreshActivityIndicatorView.centerYAnchor),

    refreshActivityIndicator.widthAnchor.constraint(equalToConstant: refreshActivityIndicatorView.frame.width),

    refreshActivityIndicator.heightAnchor.constraint(equalToConstant: refreshActivityIndicatorView.frame.height)
    ])
}

Answer 1

Replace

refreshActivityIndicatorView.addSubview(activityIndicator)

with

refreshActivityIndicatorView.addSubview(refreshActivityIndicator)

as those why the crash

refreshActivityIndicator.centerXAnchor.constraint(equalTo: refreshActivityIndicatorView.centerXAnchor),
refreshActivityIndicator.centerYAnchor.constraint(equalTo: refreshActivityIndicatorView.centerYAnchor), 
refreshActivityIndicator.widthAnchor.constraint(equalToConstant: refreshActivityIndicatorView.frame.width), 
refreshActivityIndicator.heightAnchor.constraint(equalToConstant: refreshActivityIndicatorView.frame.height)

You set constraints between refreshActivityIndicatorView and refreshActivityIndicator while refreshActivityIndicator isn't added as a subview