Calling method in another view controller from modal view controller using a delegate

问题

I am using a modal segue to create a view controller that I want to dismiss and then call a method in the origin view controller. I have used a protocol/delegate pattern but for some reason the method is never called. The code is below: Please note that I removed a lot of non-relevant code to keep it clean here

Thanks!!

VC1:

final class WorkoutViewController: UIViewController, StartWorkoutButtonDelegate {

weak var dataSource: WorkoutViewControllerDataSource!
private var workout: Workout!
private var workoutDataViewController: WorkoutDataViewController?
private var workoutFinishViewController: WorkoutFinishViewController?
private let workoutFinishViewControllerSegueIdentifier = "Workout Finish View Controller Segue"

@IBOutlet private var primaryActionButton: UIButton!
@IBOutlet private var pageControl: UIPageControl!

// MARK: - Handling View Lifecycle

override func viewDidLoad() {
    super .viewDidLoad()
    let workoutType = dataSource.workoutType(for: self)
    workout = Workout(workoutType: workoutType, managedObjectContext: persistentContainer.viewContext)
    setPrimaryActionButtonLabel()
}

// MARK: - Handling Storyboard Segues

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    super.prepare(for: segue, sender: sender)

    if let destinationWorkoutFinishViewController = segue.destination as? WorkoutFinishViewController {
        workoutFinishViewController = destinationWorkoutFinishViewController
    }
}

// MARK: - Managing Start and Pause 

@IBAction func startOrPauseWorkout() {
    if workout.isPaused {
        startWorkout()
    } else {
        pauseWorkout()
    }
}

}

VC 2:

protocol StartWorkoutButtonDelegate: AnyObject {
func startOrPauseWorkout()
 }

class WorkoutFinishViewController: UIViewController {

weak var delegate: StartWorkoutButtonDelegate?

@IBAction func startWorkout() {
    self.delegate?.startOrPauseWorkout()
    self.dismiss(animated: true, completion: nil)
}

@IBAction func finishWorkout() {
}

override func viewDidLoad() {
    super.viewDidLoad()

}
}

回答1:

Here set the delegate

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
   super.prepare(for: segue, sender: sender)
   if let destinationWorkoutFinishViewController = segue.destination as? WorkoutFinishViewController {
     destinationWorkoutFinishViewController.delegate = self
   }
}

来源：https://stackoverflow.com/questions/51809686/calling-method-in-another-view-controller-from-modal-view-controller-using-a-del