Present a view controller, dismiss it and present a different one in Swift

Question

I have a root view controller that has a button that when the user pushes it, another view controller is presented.

This second controller has a dismiss option that just comes back to the root view controller and a button that when the user touches it dismisses the current view controller so it goes back to the root view controller for a second and presents another one.

Going to the first controller I use:

let vc = FirstController()
self.present(vc, animated: true, completion: nil)

And when in the other view controller I select the button that only dismisses I do this.

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

So for the second controller that needs to dismiss and present another one I have tried the following:

self.dismiss(animated: true, completion: {
    let vc = SecondController()
    self.present(vc, animated: true, completion: nil)
})

But I get an error:

Warning: Attempt to present <UINavigationController: 0xa40c790> on <IIViewDeckController: 0xa843000> whose view is not in the window hierarchy!

score 97 · Accepted Answer · edited May 23 '17 at 12:02

97

The error occurs because you are trying to present SecondController from FirstController after you have dismissed FirstController. This doesn't work:

self.dismiss(animated: true, completion: {
    let vc = SecondController()

    // 'self' refers to FirstController, but you have just dismissed
    //  FirstController! It's no longer in the view hierarchy!
    self.present(vc, animated: true, completion: nil)
})

This problem is very similar to a question I answered yesterday.

Modified for your scenario, I would suggest this:

weak var pvc = self.presentingViewController

self.dismiss(animated: true, completion: {
    let vc = SecondController()
    pvc?.present(vc, animated: true, completion: nil)
})

edited May 23 '17 at 12:02

Community

1
1

answered Apr 23 '17 at 01:38

Mike Taverne

9,156
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Hey Mike, I get a red flag with "loadMissing argument for parameter 'coder' in call" next to SecondController() I don't know what its expecting. – Victor Dec 17 '18 at 18:20
2

How we can push new controller without getting a flicker / blink in the UI, how can we make the transition smooth? – Aman Gangurde Apr 24 '20 at 09:29
Is this code producing flicker / blink? If so, can you post a new question? Thanks. – Mike Taverne Apr 30 '20 at 01:19
This solution doesn't seem to work in my case. I've to use protocol. – Raymond Mar 06 '21 at 18:58
@AmanGangurde Did you post a question for eliminating the flicker? – ThomasW Apr 21 '21 at 07:26
Dude, you just made my day with this code! Thank you!! – marika.daboja Apr 27 '21 at 12:04
Simple and magnificent... – Wahab Khan Jadon Dec 13 '21 at 14:54

Roman Aliyev · Answer 2 · 2021-06-21T23:38:10.570

Only the presenting view controller (Root) can dismiss its presented view controller (First or Second). So you need to call dismiss(animated:completion:) inside the Root view controller's class, not inside any other one:

class RootViewController: UIViewController {
  func buttonTapped() {
    let vc = FirstViewController()
    vc.delegate = self
    present(vc, animated: true)
  }
}

extension RootViewController: FirstViewControllerDelegate {
  func firstDidComplete() {
    dismiss(animated: true) {
      let vc = SecondViewController()
      vc.delegate = self
      present(vc, animated: true)
    }
  }
}

extension RootViewController: SecondViewControllerDelegate {
  func secondDidComplete() {
    dismiss(animated: true) {
      let vc = ThirdViewController()
      present(vc, animated: true)
    }
  }
}

// and so on

If FirstViewController presents other view controller and you want its dismissal animation, implement FirstViewController as follows:

extension FirstViewController: OtherViewControllerDelegate {
  func otherDidComplete() {
    dismiss(animated: true) {
      self.delegate?.firstDidComplete()
    }
  }
}

Present a view controller, dismiss it and present a different one in Swift

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