Duncan Duncan - 4 months ago 10
Swift Question

How to pop back to a view in a different navigation controller?

I want to create the following user flow in my Swift application:


  1. User clicks a button

  2. A modal view pops over with a choice. The user selects a choice.

  3. A second view appears with another choice (using a "show" transition, so the user can press < Back to alter choice #1). The user selects the second choice.

  4. The second modal view segues back to the original view (which has the button).



To do this, I created the following structure:

--> NC1 --> VC1 --modal-> NC2 --> VC2 --show-> VC3 (NC = UINavigationController,
^ | VC = UIViewController)
| |
----Segue I'm trying to achieve-----


I've tried to pop all the way back to VC1 by passing a reference to VC1 all the way through to VC3, then calling the following code in VC3:

override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
// Perform Segue
print("Trying to segue")
rootController!.navigationController!.popToRootViewControllerAnimated(true)

tableView.deselectRowAtIndexPath(indexPath, animated: true)
}


where
rootController
is the reference to VC1. Unfortunately the segue doesn't occur; the second modal view stays on the screen, but I get the "Trying to segue" message printed.

Am I trying to implement this user flow the right way? If so, any suggestions why I can't pop to a root view in another navigation controller?

Answer

If you are using storyboards, you can do this using an unwind segue.

In VC1 implement an @IBAction method, which takes a UIStoryboardSegue as parameter:

@IBAction func unwindToVC1(sender: UIStoryboardSegue) {

}

Then from the Prototype cell of VC3 control-drag to the Exit icon of the view controller, select Selection Segue: unwindToVC1: and you are good to go.

enter image description here

You can achieve a similar result using code also.
Implement didSelectRowAtIndexPath in VC3 like this:

override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    navigationController!.dismissViewControllerAnimated(true, completion: nil)
}