Swift, Get action Bar Button Action from Container - swift

Question

I have ParentViewController.swift and ChildContainer.swift.
In ParentViewController, I have bar button item action like below :
#IBAction func onClickBarItemRefresh(_ sender: UIBarButtonItem) {
print("Refresh")
}
I want to know, how to call/get this action from ChildContainer?
I can change the title with parent?.navigationItem.title = "YourName", but I cannot find related question about to get the action.
Addition Info:
I have like 4 or 5 container in 1 ParentViewController, so all logic is on their container. So I need call the action on 4 or 5 child container with different login inside the action

Answer 1

First declare a callback function in the ContainerViewController.
var refreshButtonTapped: (() -> Void)?
In ParentViewController where you initialise ContainerViewController give action of the callback function.
In your case create a separate method i.e. refreshContent() and call it from onClickBarItemRefresh() method and also in refreshButtonTapped function where you initialise ContainerViewController.
class ParentViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .white
self.navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .refresh, target: self, action: #selector(onClickBarItemRefresh(_:)))
showContainerVC()
}
#objc func onClickBarItemRefresh(_ sender: UIBarButtonItem) {
refreshContent()
}
private func refreshContent() {
print("Refresh Content")
}
func showContainerVC() {
let vc = ContainerViewController()
// call refreshContent() inside the callback function
vc.refreshButtonTapped = { [weak self] in
self?.refreshContent()
}
let nav = UINavigationController(rootViewController: vc)
self.addChild(nav)
nav.view.frame = CGRect(x: 20, y: 100, width: 320, height: 200)
self.view.addSubview(nav.view)
nav.didMove(toParent: self)
}
}
In ContainerViewController where you want to perform the action of refreshContent() just call the callback function refreshButtonTapped like below. For example i call it from viewDidAppear() method. It will perform the action of refreshing in ParentViewController.
class ContainerViewController: UIViewController {
var refreshButtonTapped: (() -> Void)?
override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .yellow
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
print(#function)
// call this where you want to perform refreshing of ParentViewController
refreshButtonTapped?()
}
}