Activity Indicator not appears center on custom UIAlertView when search view controller push ups VC - ios

Question

I want to show the activity indicator on UIAlertViewController which contain the table view, So its working perfectly, but second case is when search controller appears on the Parent of UIAlertViewController then activity indicator not appears in center on UIAlertViewController.
Attaching image before attaching searchVC on Parent
And when searchVC added on Parent then
Following is code of activity indicator
var actInd: UIActivityIndicatorView = UIActivityIndicatorView()
func startActivityIndicator() {
self.view.isUserInteractionEnabled = false
let loadingView: UIView = UIView()
loadingView.frame = CGRect(x: 0, y: 0, width: 80.0, height: 80.0)
loadingView.center = self.view.center
loadingView.backgroundColor = UIColor(red: 44/255, green: 44/255, blue: 44/255, alpha: 0.7)
loadingView.clipsToBounds = true
loadingView.layer.cornerRadius = 10
actInd.frame = CGRect(x: 0, y: 0, width: 40.0, height: 40.0)
actInd.style = .whiteLarge
actInd.center = CGPoint(x: loadingView.frame.size.width / 2, y: loadingView.frame.size.height / 2)
loadingView.addSubview(actInd)
self.view.addSubview(loadingView)
actInd.startAnimating()
}
func stopActivityIndicator() {
self.view.isUserInteractionEnabled = true
actInd.stopAnimating()
let view = actInd.superview
view?.removeFromSuperview()
}
above code I have added in extension on UIViewController

Answer 1

Finally solved it by setting constraints by following way
func startActivityIndicator() {
self.view.isUserInteractionEnabled = false
let loadingView: UIView = UIView()
loadingView.translatesAutoresizingMaskIntoConstraints = false
actInd.translatesAutoresizingMaskIntoConstraints = false
self.view.addSubview(loadingView)
loadingView.addSubview(actInd)
loadingView.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive = true
loadingView.centerYAnchor.constraint(equalTo: self.view.centerYAnchor).isActive = true
loadingView.widthAnchor.constraint(equalToConstant: 80.0).isActive = true
loadingView.heightAnchor.constraint(equalToConstant: 80.0).isActive = true
loadingView.center = self.view.center
loadingView.backgroundColor = UIColor(red: 44/255, green: 44/255, blue: 44/255, alpha: 0.7)
loadingView.clipsToBounds = true
loadingView.layer.cornerRadius = 10
actInd.leadingAnchor.constraint(equalTo: loadingView.leadingAnchor).isActive = true
actInd.trailingAnchor.constraint(equalTo: loadingView.trailingAnchor).isActive = true
actInd.topAnchor.constraint(equalTo: loadingView.topAnchor).isActive = true
actInd.bottomAnchor.constraint(equalTo: loadingView.bottomAnchor).isActive = true
actInd.style = .whiteLarge
actInd.center = CGPoint(x: loadingView.frame.size.width / 2, y: loadingView.frame.size.height / 2)
actInd.startAnimating()
}