[swift] How to display an activity indicator with text on iOS 8 with Swift?

import UIKit

class ViewControllerUtils {

    let containerView: UIView = {

        let view = UIView()
        view.translatesAutoresizingMaskIntoConstraints = false
        view.backgroundColor = UIColor(white: 0, alpha: 0.3)
        return view
    }()

    let loadingView: UIView = {

        let view = UIView()
        view.translatesAutoresizingMaskIntoConstraints = false
        view.backgroundColor = UIColor(white: 0, alpha: 0.7)
        view.clipsToBounds = true
        view.layer.cornerRadius = 10
        return view
    }()

    let activityIndicatorView: UIActivityIndicatorView = {

        let aiv = UIActivityIndicatorView()
        aiv.translatesAutoresizingMaskIntoConstraints = false
        aiv.style = UIActivityIndicatorView.Style.whiteLarge
        return aiv
    }()

    let loadingLabel: UILabel = {

        let label = UILabel()
        label.translatesAutoresizingMaskIntoConstraints = false
        label.text = "Loading..."
        label.textAlignment = .center
        label.textColor = .white
        label.font = .systemFont(ofSize: 15, weight: UIFont.Weight.medium)
        return label
    }()

    func showLoader() {

        guard let window = UIApplication.shared.keyWindow else { return }

        window.addSubview(containerView)
        containerView.addSubview(loadingView)
        loadingView.addSubview(activityIndicatorView)
        loadingView.addSubview(loadingLabel)

        containerView.leftAnchor.constraint(equalTo: window.leftAnchor).isActive = true
        containerView.rightAnchor.constraint(equalTo: window.rightAnchor).isActive = true
        containerView.topAnchor.constraint(equalTo: window.topAnchor).isActive = true
        containerView.bottomAnchor.constraint(equalTo: window.bottomAnchor).isActive = true

        loadingView.centerXAnchor.constraint(equalTo: window.centerXAnchor).isActive = true
        loadingView.centerYAnchor.constraint(equalTo: window.centerYAnchor).isActive = true
        loadingView.widthAnchor.constraint(equalToConstant: 120).isActive = true
        loadingView.heightAnchor.constraint(equalToConstant: 120).isActive = true

        activityIndicatorView.centerXAnchor.constraint(equalTo: window.centerXAnchor).isActive = true
        activityIndicatorView.centerYAnchor.constraint(equalTo: window.centerYAnchor).isActive = true
        activityIndicatorView.widthAnchor.constraint(equalToConstant: 60).isActive = true
        activityIndicatorView.heightAnchor.constraint(equalToConstant: 60).isActive = true

        loadingLabel.leftAnchor.constraint(equalTo: loadingView.leftAnchor).isActive = true
        loadingLabel.rightAnchor.constraint(equalTo: loadingView.rightAnchor).isActive = true
        loadingLabel.bottomAnchor.constraint(equalTo: loadingView.bottomAnchor).isActive = true
        loadingLabel.heightAnchor.constraint(equalToConstant: 40).isActive = true

        DispatchQueue.main.async {

            self.activityIndicatorView.startAnimating()
        }
    }

    func hideLoader() {

        DispatchQueue.main.async {

            self.activityIndicatorView.stopAnimating()
            self.activityIndicatorView.removeFromSuperview()
            self.loadingLabel.removeFromSuperview()
            self.loadingView.removeFromSuperview()
            self.containerView.removeFromSuperview()
        }
    }
}

//// In order to show the activity indicator, call the function from your view controller
// let viewControllerUtils = ViewControllerUtils()
// viewControllerUtils.showLoader()

//// In order to hide the activity indicator, call the function from your view controller
// viewControllerUtils.hideLoader()

class ViewControllerUtils2 {

    var container: UIView = UIView()
    var loadingView: UIView = UIView()
    var activityIndicator: UIActivityIndicatorView = UIActivityIndicatorView()
    let loadingLabel = UILabel()

    func showLoader(_ uiView: UIView) {

        container.frame = uiView.frame
        container.center = uiView.center
        container.backgroundColor = UIColor(white: 0, alpha: 0.3)

        loadingView.frame = CGRect(x: 0, y: 0, width: 120, height: 120)
        loadingView.center = uiView.center
        loadingView.backgroundColor = UIColor(white: 0, alpha: 0.7)
        loadingView.clipsToBounds = true
        loadingView.layer.cornerRadius = 10

        activityIndicator.frame = CGRect(x: 0, y: 0, width: 60, height: 60)
        activityIndicator.style = UIActivityIndicatorView.Style.whiteLarge
        activityIndicator.center = CGPoint(x: loadingView.frame.size.width / 2, y: loadingView.frame.size.height / 2)

        loadingLabel.frame = CGRect(x: 0, y: 80, width: 120, height: 40)
        loadingLabel.text = "Loading..."
        loadingLabel.textAlignment = .center
        loadingLabel.textColor = .white
        loadingLabel.font = .systemFont(ofSize: 15, weight: UIFont.Weight.medium)

        uiView.addSubview(container)
        container.addSubview(loadingView)
        loadingView.addSubview(activityIndicator)
        loadingView.addSubview(loadingLabel)

        DispatchQueue.main.async {

            self.activityIndicator.startAnimating()
        }
    }

    func hideLoader() {

        DispatchQueue.main.async {

            self.activityIndicator.stopAnimating()
            self.activityIndicator.removeFromSuperview()
            self.loadingLabel.removeFromSuperview()
            self.loadingView.removeFromSuperview()
            self.container.removeFromSuperview()
        }
    }
}