ios - how to know if second controller is dismissed?

Question

is it possible to handle and trigger some func in first controller if second controller is dimissed?

this my code to open second controller from first controller

self.present(UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "LockScreen") as UIViewController, animated: true, completion: nil)

and this my code to dismiss controller from second controller to first controller

self.navigationController?.popViewController(animated: true)

self.dismiss(animated: true, completion: nil)

There are several ways to do that. E.g: `delegate`, completion inside `dismiss(animate: completion:)`... But why you popViewController then dimisss instead of dismissing the navigation right away? — son, May 25 '21 at 02:19
Does this answer your question? [Detect when a presented view controller is dismissed](https://stackoverflow.com/questions/32853212/detect-when-a-presented-view-controller-is-dismissed) — Coder-256, May 25 '21 at 02:20
@son ooh ok I just dismiss only. any example to handle that? — E-Place, May 25 '21 at 02:37

score 1 · Accepted Answer · answered May 25 '21 at 03:06

Inside your LockScreen controller, declare a closure to handle when dismissed:

class LockScreen: UIViewController {
    var onDismissHandler: (() -> ())?
    
    func dismissController() {
        self.dismiss(animated: true, completion: onDismissHandler)
    }
}

Then when you're presenting LockScreen:

func onPresent() {
    let controller = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(identifier: "LockScreen") as LockScreen
    controller.onDismissHandler = { [weak self] in
        // TODO: Do something when dismissed
    }
    self.present(controller, animated: true, completion: nil)
}

score 0 · Answer 2 · answered May 25 '21 at 12:47

When second viewController is dismissed, trigger some func on dismissing of the current viewController.

class ViewController: UIViewController {
override func viewDidLoad() {
    super.viewDidLoad()
}

@IBAction private func buttonClick(sender: UIButton) {
    let viewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "SecondViewController")
    onDismiss()
    self.present(viewController, animated: false, completion: nil)
}

Trigger some func on dismissing of the current view controller

func onDismiss() {
    self.dismiss(animated: false) {
        print("Dismissing current view controller")
    }
}

}

ios - how to know if second controller is dismissed?

2 Answers2