Right-clicking the Exit icon yields an empty window. Can't Ctrl-drag a connection to any IB elements or corresponding source files. Docs give no love. Doesn't appear in nib files, only storyboards. My assumption is that it's a corollary to segues, but I don't see any new methods to back it up. Anyone?
There's a lot of information in the WWDC video "Session 407 - Adopting Storyboards in your App."
Say you have two view controllers linked by a segue. Implement the following exit action on the first view controller:
- (IBAction)done:(UIStoryboardSegue *)segue {
NSLog(@"Popping back to this view controller!");
// reset UI elements etc here
}
Then, on Storyboard scene for the second view controller, Ctrl-drag from a UI element, such as a button, to the exit icon at the bottom of this view controller. The done:
action you added to the code of the first controller will appear as an option. Now, activating the button you Ctrl-dragged to the exit icon will pop back to the first view controller and maintain its original state (ie UI elements such as text input supposedly still intact).
I had a hard time following the accepted answer so here is more detail.
Given the photo below on view controller C you can "exit" back to any view controller in the segue path.

ViewController A you can write:
- (IBAction)done:(UIStoryboardSegue *)segue {
// Optional place to read data from closing controller
}
ViewController B you can write:
- (IBAction)back:(UIStoryboardSegue *)segue {
// Optional place to read data from closing controller
}
ViewController C you control drag from "back" button to the green exit option and select back: ViewController C you control drag from "done" button to the green exit option and select done:

Note: Even though the methods are on other view controllers they show up for the ViewController C's exit. Control dragging and selecting a method defines which ViewController to unwind to.
来源:https://stackoverflow.com/questions/12569316/does-anyone-know-what-the-new-exit-icon-is-used-for-when-editing-storyboards-usi