iOS Swift protocol & delegate - ios

Question

Why my delegation is not working?
With my sample the action button works when clicked, but for some reason it does not reach the didAction function in my second controller.
protocol HomeControllerDelegate: class {
func didAction()
}
class HomeController: UIViewController {
weak var delegate: HomeControllerDelegate?
private let actionButton: UIButton = {
let button = UIButton(type: .system)
button.setTitle("Action", for: .normal)
button.setTitleColor(.white, for: .normal)
button.backgroundColor = .black
button.setHeight(50)
button.setWidth(100)
button.addTarget(self, action: #selector(handleAction), for: .touchUpInside)
return button
}()
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .white
view.addSubview(actionButton)
actionButton.centerX(inView: view)
actionButton.centerY(inView: view)
}
#objc func handleAction() {
print("DEBUG: Handle Action Button delegate here....")
delegate?.didAction()
}
}
class SecondController: UIViewController {
let homeController = HomeController()
override func viewDidLoad() {
super.viewDidLoad()
homeController.delegate = self
}
}
extension SecondController: HomeControllerDelegate {
func didAction() {
print("DEBUG: In SecondController - didAction()")
}
}

Answer 1

Many thanks for the guidance, it has made me look at the fundamentals and also what to research.
I have created the below which solves my problem.
A container controller that Instantiates two ViewControlers and sets them as childVC's
Then created a protocol on FirstChildVC and SecondChildVC is the delegate
All is working now an I understand a lot better.
class ContainerController: UIViewController {
let secondChildVC = SecondChildVC()
let firstChildVC = FirstChildVC()
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .white
addFirstChildVC()
addSecondChildVC()
}
func addSecondChildVC(){
addChild(secondChildVC)
view.addSubview(secondChildVC.view)
secondChildVC.didMove(toParent: self)
setSecondChildVCConstraints()
}
func addFirstChildVC(){
addChild(firstChildVC)
view.addSubview(firstChildVC.view)
firstChildVC.delegateActionButton = secondChildVC
firstChildVC.didMove(toParent: self)
setFirstChildVCConstraints()
}
func setFirstChildVCConstraints() {
firstChildVC.view.translatesAutoresizingMaskIntoConstraints = false
firstChildVC.view.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 20).isActive = true
firstChildVC.view.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 20).isActive = true
firstChildVC.view.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -20).isActive = true
firstChildVC.view.heightAnchor.constraint(equalToConstant: 200).isActive = true
}
func setSecondChildVCConstraints() {
secondChildVC.view.translatesAutoresizingMaskIntoConstraints = false
secondChildVC.view.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor, constant: -20).isActive = true
secondChildVC.view.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 20).isActive = true
secondChildVC.view.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -20).isActive = true
secondChildVC.view.heightAnchor.constraint(equalToConstant: 200).isActive = true
}
}
protocol FirstChildVCDelegate: class {
func didAction(data: String)
}
class FirstChildVC: UIViewController {
weak var delegateActionButton: FirstChildVCDelegate!
private let actionButton: UIButton = {
let button = UIButton(type: .system)
let buttonHeight = 30
button.setTitle("Button", for: .normal)
button.setTitleColor(.white, for: .normal)
button.backgroundColor = .black
button.layer.cornerRadius = CGFloat(buttonHeight / 2)
button.translatesAutoresizingMaskIntoConstraints = false
button.heightAnchor.constraint(equalToConstant: CGFloat(buttonHeight)).isActive = true
button.translatesAutoresizingMaskIntoConstraints = false
button.widthAnchor.constraint(equalToConstant: 100).isActive = true
button.addTarget(self, action: #selector(handleAction), for: .touchUpInside)
return button
}()
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .systemPink
configureActionButtonView()
}
func configureActionButtonView() {
view.addSubview(actionButton)
actionButton.translatesAutoresizingMaskIntoConstraints = false
actionButton.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
actionButton.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
}
#objc func handleAction() {
delegateActionButton.didAction(data: "Button Pressed")
}
}
class SecondChildVC: UIViewController {
private let actionButtonLabel: UILabel = {
let label = UILabel()
label.text = "test"
label.font = .systemFont(ofSize: 18)
label.textColor = .white
label.isHidden = true
return label
}()
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .systemPurple
configureActionButtonLabel()
}
func configureActionButtonLabel() {
view.addSubview(actionButtonLabel)
actionButtonLabel.translatesAutoresizingMaskIntoConstraints = false
actionButtonLabel.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
actionButtonLabel.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
}
}
extension SecondChildVC: FirstChildVCDelegate {
func didAction(data: String) {
actionButtonLabel.isHidden.toggle()
actionButtonLabel.text = data
}
}
Initial State
State once Button pressed