Dismiss more than one view controller simultaneous

问题:

I'm making a game using SpriteKit. I have 3 viewControllers: selecting level vc, game vc, and win vc. After the game is over, I want to show the win vc, then if I press OK button on the win vc, I want to dismiss the win vc AND the game vc (pop two view controllers out of the stack). But I don't know how to do it because if I call

self.dismissViewControllerAnimated(true, completion: {})    

the win vc (top of the stack) is dismissed, so I don't know where to call it again to dismiss the game vc. Is there any way I can fix this without using navigation controller?

This is the 1st VC: (Please pay attention to my comments below starting with "//")

class SelectLevelViewController: UIViewController { // I implemented a UIButton on its storyboard, and its segue shows GameViewController
    override func viewDidLoad() {
        super.viewDidLoad()
    }
}

This is the 2nd VC:

class GameViewController: UIViewController, UIPopoverPresentationControllerDelegate {
    var scene: GameScene!
    var stage: Stage!

    var startTime = NSTimeInterval()
    var timer = NSTimer()
    var seconds: Double = 0
    var timeStopped = false

    var score = 0

    @IBOutlet weak var targetLabel: UILabel!
    @IBOutlet var displayTimeLabel: UILabel!
    @IBOutlet weak var scoreLabel: UILabel!
    @IBOutlet weak var gameOverPanel: UIImageView!
    @IBOutlet weak var shuffleButton: UIButton!
    @IBOutlet weak var msNum: UILabel!

    var mapNum = Int()
    var stageNum = Int()

    var tapGestureRecognizer: UITapGestureRecognizer!

    override func viewDidLoad() {
        super.viewDidLoad()

        let skView = view as! SKView
        skView.multipleTouchEnabled = false

        scene = GameScene(size: skView.bounds.size)
        scene.scaleMode = .AspectFill
        msNum.text = "\(mapNum) - \(stageNum)"

        stage = Stage(filename: "Map_0_Stage_1")
        scene.stage = stage
        scene.addTiles()
        scene.swipeHandler = handleSwipe

        gameOverPanel.hidden = true
        shuffleButton.hidden = true

        skView.presentScene(scene)

        Sound.backgroundMusic.play()

        beginGame()
    }

    func beginGame() {
        displayTimeLabel.text = String(format: "%ld", stage.maximumTime)
        score = 0
        updateLabels()

        stage.resetComboMultiplier()

        scene.animateBeginGame() {
            self.shuffleButton.hidden = false
        }

        shuffle()

        startTiming()
    }

    func showWin() {
        gameOverPanel.hidden = false
        scene.userInteractionEnabled = false
        shuffleButton.hidden = true

        scene.animateGameOver() {
            self.tapGestureRecognizer = UITapGestureRecognizer(target: self, action: "hideWin")
            self.view.addGestureRecognizer(self.tapGestureRecognizer)
        }
    }

    func hideWin() {
        view.removeGestureRecognizer(tapGestureRecognizer)
        tapGestureRecognizer = nil

        gameOverPanel.hidden = true
        scene.userInteractionEnabled = true

        self.performSegueWithIdentifier("win", sender: self) // this segue shows WinVC but idk where to dismiss this GameVC after WinVC gets dismissed...
    }

    func shuffle() {...}
    func startTiming() {...}
}

And this is the 3rd VC:

class WinVC: UIViewController {

    @IBOutlet weak var awardResult: UILabel!

    @IBAction func dismissVC(sender: UIButton) {
        self.dismissViewControllerAnimated(true, completion: {}) // dismissing WinVC here when this button is clicked
    }

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }

}

回答1:

@Ken Toh's comment was what worked for me in this situation -- call dismiss from the view controller that you want to show after everything else is dismissed.

If you have a "stack" of 3 presented view controllers A, B and C, where C is on top, then calling A.dismiss(animated: true, completion: nil) will dismiss B and C simultaneously.

If you don't have a reference to the root of the stack, you could chain a couple of accesses to presentingViewController to get to it. Something like this:

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

回答2:

You can dismiss WinVC's presenting controller (GameViewController) in the completion block:

let presentingViewController = self.presentingViewController
self.dismissViewControllerAnimated(false, completion: {
  presentingViewController?.dismissViewControllerAnimated(true, completion: {})
})

Alternatively, you could reach out to the root view controller and call dismissViewControllerAnimated, which will dismiss both modal viewcontrollers in a single animation:

self.presentingViewController?.presentingViewController?.dismissViewControllerAnimated(true, completion: {})

回答3:

You should be able to call:

self.presentingViewController.dismissViewControllerAnimated(true, completion: {});

(You may need to add ? or ! somewhere - I'm not a swift developer)

回答4:

There's special unwind segue intended to roll back view stack to certain view controller. Please see my answer here: how to dismiss 2 view controller in swift ios?

回答5:

I had some animation issues when trying the accepted answer in my application. The previously presented views would flash or try to animate on the screen. This was my solution:

     if let first = presentingViewController,
        let second = first.presentingViewController,
            let third = second.presentingViewController {
                second.view.isHidden = true
                first.view.isHidden = true
                    third.dismiss(animated: true)

     }