iOS 6 and Xcode 4.5 has a new feature referred to as "Unwind Segue":
Unwind segues can allow transitioning to existing instances of scenes in a storyboard
In addition to this brief entry in Xcode 4.5's release notes, UIViewController now seem to have a couple of new methods:
- (BOOL)canPerformUnwindSegueAction:(SEL)action fromViewController:(UIViewController *)fromViewController withSender:(id)sender
- (UIViewController *)viewControllerForUnwindSegueAction:(SEL)action fromViewController:(UIViewController *)fromViewController withSender:(id)sender
- (UIStoryboardSegue *)segueForUnwindingToViewController:(UIViewController *)toViewController fromViewController:(UIViewController *)fromViewController identifier:(NSString *)identifier
How do unwind segues work and what they can be used for?
This question is related to
ios
ios6
uistoryboard
Swift iOS:
Step 1: define this method into your MASTER controller view. in which you want to go back:
//pragma mark - Unwind Seques
@IBAction func goToSideMenu(segue: UIStoryboardSegue) {
println("Called goToSideMenu: unwind action")
}
Step 2: (StoryBoard) Right click on you SLAVE/CHILD EXIT button and Select "goToSideMenu" As action to Connect you Button on which you will click to return back to you MASTER controller view:
step 3: Build and Run ...
As far as how to use unwind segues in StoryBoard...
Step 1)
Go to the code for the view controller that you wish to unwind to and add this:
Objective-C
- (IBAction)unwindToViewControllerNameHere:(UIStoryboardSegue *)segue {
//nothing goes here
}
Be sure to also declare this method in your .h file in Obj-C
Swift
@IBAction func unwindToViewControllerNameHere(segue: UIStoryboardSegue) {
//nothing goes here
}
Step 2)
In storyboard, go to the view that you want to unwind from and simply drag a segue from your button or whatever up to the little orange "EXIT" icon at the top right of your source view.
There should now be an option to connect to "- unwindToViewControllerNameHere"
That's it, your segue will unwind when your button is tapped.
For example if you navigate from viewControllerB to viewControllerA then in your viewControllerA below delegate will call and data will share.
@IBAction func unWindSeague (_ sender : UIStoryboardSegue) {
if sender.source is ViewControllerB {
if let _ = sender.source as? ViewControllerB {
self.textLabel.text = "Came from B = B->A , B exited"
}
}
}
Unwind segues are used to "go back" to some view controller from which, through a number of segues, you got to the "current" view controller.
Imagine you have something a MyNavController
with A
as its root view controller. Now you use a push segue to B
. Now the navigation controller has A and B in its viewControllers
array, and B is visible. Now you present C
modally.
With unwind segues, you could now unwind "back" from C
to B
(i.e. dismissing the modally presented view controller), basically "undoing" the modal segue. You could even unwind all the way back to the root view controller A
, undoing both the modal segue and the push segue.
Unwind segues make it easy to backtrack. For example, before iOS 6, the best practice for dismissing presented view controllers was to set the presenting view controller as the presented view controller’s delegate, then call your custom delegate method, which then dismisses the presentedViewController. Sound cumbersome and complicated? It was. That’s why unwind segues are nice.
Something that I didn't see mentioned in the other answers here is how you deal with unwinding when you don't know where the initial segue originated, which to me is an even more important use case. For example, say you have a help view controller (H) that you display modally from two different view controllers (A and B):
A ? H
B ? H
How do you set up the unwind segue so that you go back to the correct view controller? The answer is that you declare an unwind action in A and B with the same name, e.g.:
// put in AViewController.swift and BViewController.swift
@IBAction func unwindFromHelp(sender: UIStoryboardSegue) {
// empty
}
This way, the unwind will find whichever view controller (A or B) initiated the segue and go back to it.
In other words, think of the unwind action as describing where the segue is coming from, rather than where it is going to.
Source: Stackoverflow.com