UIViewController container

UIViewController+ContainerExtensions.swift

import UIKit

extension UIViewController {
    func nxv_addChildViewController(_ childVC: UIViewController, containerView: UIView) {
        addChild(childVC)
        containerView.addSubview(childVC.view)
        containerView.translatesAutoresizingMaskIntoConstraints = false
        childVC.view.translatesAutoresizingMaskIntoConstraints = false
        
        NSLayoutConstraint.activate([
            childVC.view.topAnchor.constraint(equalTo: containerView.topAnchor),
            childVC.view.bottomAnchor.constraint(equalTo: containerView.bottomAnchor),
            childVC.view.leftAnchor.constraint(equalTo: containerView.leftAnchor),
            childVC.view.rightAnchor.constraint(equalTo: containerView.rightAnchor)
        ])
        
        childVC.didMove(toParent: self)
    }
    
    func nxv_removeFromParentViewController() {
        willMove(toParent: nil)
        view.removeFromSuperview()
        removeFromParent()
    }
    
    func nxv_exchangeViewControllerA(_ viewControllerA: UIViewController,
                                     with viewControllerB: UIViewController,
                                     containerView: UIView,
                                     rootViewController: UIViewController) {
        viewControllerA.nxv_removeFromParentViewController()
        rootViewController.nxv_addChildViewController(viewControllerB, containerView: containerView)
    }
}