Delegates and protocols with VC not connected - swift

Question

I have a parent view controller i.e. HomeViewController which has a navigation bar button via which a user can trigger an alert and enter a string. This string needs to be passed to the child view controller.
Here is the relevant code in the parent view controller:
protocol NewSectionDelegate {
func sendSectionName(name : String)
}
class HomeViewController: UIViewController {
var sectionNameDelegate : NewSectionDelegate?
func addCardAsChild() { // add the child VC to the parent VC
if cardViewController == nil {
cardViewController = CardViewController()
addViewController(newViewController: cardViewController!)
} else {
addViewController(newViewController: cardViewController!)
}
}
func triggerAlert() {
let alertController = UIAlertController(title: "New section", message: "Name the section with a words or a sentence", preferredStyle: .alert)
alertController.addTextField(configurationHandler:
{(_ textField: UITextField) -> Void in //txtview customization
})
let addAction = UIAlertAction(title: "Add", style: .default) { _ in
guard let sectionName = alertController.textFields?.first?.text else { return }
self.sectionNameDelegate?.sendSectionName(name: sectionName) // Sending string; verified that the string is not nil
}
alertController.addAction(addAction)
self.present(alertController, animated: true, completion: nil)
}
And here is the child view controller:
class CardViewController: UIViewController, NewSectionDelegate {
override func viewDidLoad() {
super.viewDidLoad()
let homeViewController = HomeViewController()
homeViewController.sectionNameDelegate = self
}
func sendSectionName(name: String) {
print("received name:\(name)") // This line of code is never called
}
The data is not getting passed and I have no idea why.

Answer 1

Is this what you are looking for?
protocol NewSectionDelegate {
func sendSectionName(name : String)
}
class HomeViewController: UIViewController {
var sectionNameDelegate : NewSectionDelegate?
var cardViewController = CardViewController()
func addCardAsChild() { // add the child VC to the parent VC
self.addChild(self.cardViewController)
}
func triggerAlert() {
let alertController = UIAlertController(title: "New section", message: "Name the section with a words or a sentence", preferredStyle: .alert)
alertController.addTextField(configurationHandler:
{(_ textField: UITextField) -> Void in //txtview customization
})
let addAction = UIAlertAction(title: "Add", style: .default) { _ in
guard let sectionName = alertController.textFields?.first?.text else { return }
self.sectionNameDelegate?.sendSectionName(name: sectionName) // Sending string; verified that the string is not nil
}
alertController.addAction(addAction)
self.present(alertController, animated: true, completion: nil)
}
}
class CardViewController: UIViewController, NewSectionDelegate {
override func viewDidLoad() {
super.viewDidLoad()
guard let homeViewController = self.parent as? HomeViewController else { return }
homeViewController.sectionNameDelegate = self
}
func sendSectionName(name: String) {
print("received name:\(name)") // This line of code is never called
}
}

Answer 2

I think the delegate method is getting called but for the internal HomeViewController you're making in the ChildViewController viewDidLoad method. It looks like you're expecting the method to get called on a different object. I would remove that code from viewDidLoad and set the sectionNameDelegate in HomeViewController