Add completion handler to presentViewControllerAsSheet(NSViewController)?

Question

I am attempting to present a sheet configuration view (AddSoundEffect) for my main window/view controller (I\'m using storyboards), and when the configuration view

Answer 1

The easiest way to detect sheet opening or closing is to use the Sheet Notifications:

class ViewController: NSViewController, NSWindowDelegate {

    override func viewDidLoad(){
        NSApplication.sharedApplication().windows.first?.delegate = self
    }
    func windowDidEndSheet(notification: NSNotification) {

    }
    func windowWillBeginSheet(notification: NSNotification) {

    }
}

Answer 2

Delegation pattern is the easiest way for you.

// Replace this with your tuple or whatever data represents your sound effect
struct SoundEffect {}

protocol AddSoundViewControllerDelegate: class {
  func soundViewController(controller: AddSoundViewController, didAddSoundEffect: SoundEffect)
}

//
// Let's say this controller is a modal view controller for adding new sound effects
//
class AddSoundViewController: UIViewController {
  weak var delegate: AddSoundViewControllerDelegate?

  func done(sender: AnyObject) {
    // Dummy sound effect info, replace it with your own data
    let soundEffect = SoundEffect()

    //
    // Call it whenever you would like to inform presenting view controller
    // about added sound effect (in case of Done, Add, ... button tapped, do not call it
    // when user taps on Cancel to just dismiss AddSoundViewController)
    //
    self.delegate?.soundViewController(self, didAddSoundEffect: soundEffect)

    // Dismiss self
    self.dismissViewControllerAnimated(true, completion: {})
  }
}

//
// Let's say this controller is main view controller, which contains list of all sound effects,
// with button to add new sound effect via AddSoundViewController
//
class SoundEffectsViewController: UIViewController, AddSoundViewControllerDelegate {
  func presentAddSoundEffectController(sender: AnyObject) {
    if let addSoundController = self.storyboard?.instantiateViewControllerWithIdentifier("AddSoundEffect") as? AddSoundViewController {
      addSoundController.delegate = self
      self.presentViewController(addSoundController, animated: true, completion: {})
    }
  }

  func soundViewController(controller: AddSoundViewController, didAddSoundEffect: SoundEffect) {
    // This method is called only when new sound effect is added
  }
}

Another way is to use closures:

// Replace this with your tuple or whatever data represents your sound effect
struct SoundEffect {}

//
// Let's say this controller is a modal view controller for adding new sound effects
//
class AddSoundViewController: UIViewController {
  var completionHandler: ((SoundEffect) -> ())?

  func done(sender: AnyObject) {
    // Dummy sound effect info, replace it with your own data
    let soundEffect = SoundEffect()

    //
    // Call it whenever you would like to inform presenting view controller
    // about added sound effect (in case of Done, Add, ... button tapped, do not call it
    // when user taps on Cancel to just dismiss AddSoundViewController)
    //
    self.completionHandler?(soundEffect)

    // Dismiss self
    self.dismissViewControllerAnimated(true, completion: {})
  }
}

//
// Let's say this controller is main view controller, which contains list of all sound effects,
// with button to add new sound effect via AddSoundViewController
//
class SoundEffectsViewController: UIViewController {
  func presentAddSoundEffectController(sender: AnyObject) {
    if let addSoundController = self.storyboard?.instantiateViewControllerWithIdentifier("AddSoundEffect") as? AddSoundViewController {
      addSoundController.completionHandler = { [weak self] (soundEffect) -> () in
        // Called when new sound effect is added
      }
      self.presentViewController(addSoundController, animated: true, completion: {})
    }
  }
}

Or many other ways like sending notification, ... Whatever suits your needs. But delegation pattern or closures is the best way to go in this specific case.

---

I missed that your question is about NSViewController. This example is for iOS, but same pattern can be used on OS X without any issues.