iOS 8 kills Unwind Segues [duplicate] - ios

I have an app, that works fine under iOS 7, but when built for iOS 8 the unwind segues are not working.
I created a new project and added a modal (navigationcontroller with tableviewcontroller)and tried to use an unwind modal. Unfortunately it doesn't work either. The methods that are being unwind to, are in the desination view controller. The unwind segue is created through the storyboard (a Navigationbar button in the tableviewcontroller) When I tap the button, nothing happens. There is no log output and the modal does not disappear. It also only seems to affect modal segues. push/popover are unwound normally.
Has anyone had a similar problem and has an Idea how I could solve it?

Apple has FIXED this bug in iOS 8.1
Temporary solutions for iOS 8.0
The unwind segue will not work only in next situation:
View structure: UITabBarController -> UINagivationController -> UIViewController1 -> UIViewController2
Normally (in iOS 7, 8.1), When unwind from UIViewController2 to UIViewController1, it will call viewControllerForUnwindSegueAction in UIViewController1.
However in iOS 8.0 and 8.0.x, it will call viewControllerForUnwindSegueAction in UITabBarController instead of UIViewController1, that is why unwind segue no longer working.
Solution: override viewControllerForUnwindSegueAction in UITabBarController by create a custom UITabBarController and use the custom one.
For Swift
CustomTabBarController.swift
import UIKit
class CustomTabBarController: UITabBarController {
override func viewControllerForUnwindSegueAction(action: Selector, fromViewController: UIViewController, withSender sender: AnyObject?) -> UIViewController? {
var resultVC = self.selectedViewController?.viewControllerForUnwindSegueAction(action, fromViewController: fromViewController, withSender: sender)
return resultVC
}
}
For old school Objective-C
CustomTabBarController.h
#import <UIKit/UIKit.h>
#interface CustomTabBarController : UITabBarController
#end
CustomTabBarController.m
#import "CustomTabBarController.h"
#interface CustomTabBarController ()
#end
#implementation CustomTabBarController
-(UIViewController *)viewControllerForUnwindSegueAction:(SEL)action fromViewController:(UIViewController *)fromViewController withSender:(id)sender
{
return [self.selectedViewController viewControllerForUnwindSegueAction:action fromViewController:fromViewController withSender:sender];
}
#end
==============================================================================
DO NOT USE ANY SOLUTIONS BELOW THIS POINT (they are out of date and just for reference)
Latest update on Sep 23
My new solution is pushing to a view that embedded in a navigation controller, and config that navigation controller to hide bottom bar on push(a tick box in IB). Then you will have a view looks like a modal view, the only different is the animate of pushing and popping. You can custom if you want
Updated: The solution below actually present the modal view under the tab bar, which will cause further view layout problems.
Change the segue type to Present As Popover will work only on iOS8 for iPhones, on iOS7 your app will crash.
Same here, to fix this, I set segue's presentation to current context(my app is for iphone only).
Default and full screen will not work.

[UPDATE: Bug fixed on iOS 8.1 beta but you'll need it for 8.0 and 8.0.2 support]
The only way I could make my unwind segue work was by mixing Aditya's and viirus' answers.
My setup going in:
[View Controller 1] > custom modal segue > [Navigation Controller] > root > [View Controller 2]
Unwind:
[View Controller 2] > custom unwind segue > [View Controller 1]
Fix:
Subclass the [Navigation Controller], add a property called sourceViewController and pass "self" to that property when prepare for segue is called when going from [View Controller 1] to [Navigation Controller]
In the [Navigation Controller] subclass .m override/add this two methods:
- (UIViewController *)viewControllerForUnwindSegueAction:(SEL)action fromViewController:(UIViewController *)fromViewController withSender:(id)sender
{
if ([self.sourceViewController canPerformUnwindSegueAction:action fromViewController:fromViewController withSender:sender]) {
return self.sourceViewController;
}
return [super viewControllerForUnwindSegueAction:action fromViewController:fromViewController withSender:sender];
}
Then I override this in that [Navigation Controller] subclass only because I have a custom unwind segue:
- (UIStoryboardSegue *)segueForUnwindingToViewController:(UIViewController *)toViewController fromViewController:(UIViewController *)fromViewController identifier:(NSString *)identifier {
return [fromViewController segueForUnwindingToViewController:toViewController
fromViewController:fromViewController
identifier:identifier];
}

This is a problem with iOS 8.0, 8.0.1, and 8.0.2. It was resolved in 8.1; unwind segues are calling the appropriate method now.
Note that on iOS 8, modally presented view controllers may not be automatically dismissed when performing an unwind segue, unlike iOS 7. To ensure it's always dismissed, you may detect if it's being dismissed and if not then manually dismiss it. These inconsistencies are resolved in iOS 9.0.
With iOS 8.4 running on iPhone, all of the modally presented segues with all presentation styles do dismiss upon unwind, except Over Full Screen and Over Current Context. That's also the case for iPad, with the addition of Form Sheet and Page Sheet also not auto-dismissing. With iOS 9, all presentation styles auto dismiss on both iPhone and iPad.

Yep it kinda happen to me too, I think for your case you have to subclass the UINavigationController and override the following:
- (UIViewController *)viewControllerForUnwindSegueAction:(SEL)action fromViewController:(UIViewController *)fromViewController withSender:(id)sender
{
for(UIViewController *vc in self.viewControllers){
// Always use -canPerformUnwindSegueAction:fromViewController:withSender:
// to determine if a view controller wants to handle an unwind action.
if ([vc canPerformUnwindSegueAction:action fromViewController:fromViewController withSender:sender])
return vc;
}
return [super viewControllerForUnwindSegueAction:action fromViewController:fromViewController withSender:sender];
}

Same problem here. Unwind method is not called. Only happens when
using modal segue
Presentation is anything but "current context"
NavigationController is not extended (using default from storyboard)
Also happens in IOS8 GM Seed, therefore I think we need to find a workaround.
Sounds like a bug to me...
Extending UINavigationController and implementing viewControllerForUnwindSegueAction didn't help, as it is not fired. The only thing which gets fired is canPerformUnwindSegueAction() within the extended UINavigationController. Strange.

Woah there! I'm still getting user reports of getting stuck on a modal view in iOS 8.1.1 (on an iPad 3).
I'm jettisoning all this unwind from a modal view stuff. Just a good old-fashioned...
[self dismissViewControllerAnimated:NO completion:nil];
...works fine on all those various iOS 8.x.x versions.

It seems that both iOS 7.1 and iOS 8.1/8.2 create unwind segue from navigation controller however unwind segue is registered on a child controller inside of navigation controller.
So manually creating an unwind segue from the controller where it's registered in storyboard solves the problem.
#implementation RootNavigationController
- (UIStoryboardSegue*)segueForUnwindingToViewController:(UIViewController *)toViewController fromViewController:(UIViewController *)fromViewController identifier:(NSString *)identifier {
return [toViewController segueForUnwindingToViewController:toViewController fromViewController:fromViewController identifier:identifier];
}
#end

I encountered the same problem when unwinding to a source view controller from a destination view controller. The destination was presented through a "show" segue from the source.
I was using iPhone simulator that shows iPhone 6, iOS8.3.
XCode 6.3.2
The solution of subclassing NavigationViewController worked for me. Here is the swift code which is essentially swift translation of Raul's answer. I am puzzled that if Apple has fixed it in iOS8.1 per Raul, how am I getting hit by it in 8.3.
var sourceViewController: UIViewController?
override func viewControllerForUnwindSegueAction(action: Selector, fromViewController: UIViewController, withSender sender: AnyObject?) -> UIViewController? {
if(self.sourceViewController! .canPerformUnwindSegueAction(action, fromViewController: fromViewController, withSender: sender!)){
return self.sourceViewController
}
return super.viewControllerForUnwindSegueAction(action, fromViewController: fromViewController, withSender: sender)
}

I just ran into this problem, and after some digging discovered that with modal segues (at least ones with the default and fullscreen presentation modes), you can't rely on the normal unwind mechanism, but rather you have to call the presented UIViewController's dismissViewControllerAnimated method.

Steps to be followed:
Link the unwind segue to the button in Storyboard.
Create IBAction for the button and add the below code in it:
[self dismissViewControllerAnimated:NO completion:nil];
This should work for all versions.

Related

UIPopoverPresentationControllerDelegate calls on iPhone

I'm attempting a project using the Xcode (version 9.1 9B55) Master-Detail template, using one Storyboard for both iPhone and iPad.
I want to use the built in popover segue, which ideally will show a popover when the size class is appropriate, or a modal view controller when the size class is compact (iPhone in portrait).
What I am finding is that it works just fine for iPad, but when I run it on an iPhone, you can't touch outside the popover to dismiss as I would expect.
When on iPad, popoverPresentationControllerDidDismissPopover is called and all is well.
When on iPhone, the popoverPresentationControllerDidDismissPopover never gets called and you cannot dismiss the popover.
To reproduce, I did this:
Create new Master-Detail App
New - File. Cocoa Touch Class, called MyPopoverViewController
In Storyboard:
Create new view controller, change class to MyPopoverViewController.
On MasterViewController, add bar button item "Popover". Control-drag from this to MyPopoverViewController. Set segue Kind to "Present As Popover". Set Identifier to "thePopover".
In MasterViewController.h, add UIPopoverPresentationControllerDelegate:
#interface MasterViewController : UITableViewController <UIPopoverPresentationControllerDelegate>
In MasterViewController.m:
#import "MyPopoverViewController.h"
In viewDidLoad, comment out two lines which create the "Add Button".
In prepareForSegue:
} else if ([[segue identifier] isEqualToString:#"thePopover"]) {
NSLog(#"MVC prepareForSegue thePopover");
MyPopoverViewController *myPopoverController = segue.destinationViewController;
myPopoverController.popoverPresentationController.delegate = self;
}
Add three UIPopoverPresentationControllerDelegate delegate methods:
- (void) prepareForPopoverPresentation:(UIPopoverPresentationController *)popoverPresentationController {
NSLog(#"MVC prepareForPopoverPresentation");
}
- (void) popoverPresentationControllerDidDismissPopover:(UIPopoverPresentationController *)popoverPresentationController {
NSLog(#"MVC popoverPresentationControllerDidDismissPopover");
}
- (BOOL) popoverPresentationControllerShouldDismissPopover:(UIPopoverPresentationController *)popoverPresentationController {
NSLog(#"MVC popoverPresentationControllerShouldDismissPopover");
return TRUE;
}
I tried this also, but all it does is force popover in portrait mode (which I don't want); doesn't change the lack of popover delegate calls and doesn't allow us to dismiss popover:
-(UIModalPresentationStyle)adaptivePresentationStyleForPresentationController:(UIPresentationController *)controller {
return UIModalPresentationNone;
}
I'm hoping there is something simple I'm missing here. I have uploaded a sample project here, which is exactly what I've described above:
https://github.com/johnstewart/MasterDetailPopoverTestProject
How do I allow iPhone to also dismiss popovers by touching outside the popover?
If I understand your question correctly your problem appears on iPhone 8 Plus in landscape mode.
In this situation, the presented popover actually is not a popover but a normal presented view. Visually it looks like a sheet that appears from the botton of the screen. In order to close such a view, you have to add your own button to do this.
If you want to show a real popover, you must implement:
adaptivePresentationStyleForPresentationController:traitCollection:
to return UIModalPresentationNone. Note the additional parameter traitcollection:. UIAdaptivePresentationControllerDelegate contains two similar methods. In your project you already implemented the method:
adaptivePresentationStyleForPresentationController:
Change this to the former method and everything should work.

Delegate / Unwind Segue at NavigationController Back Button

i have an app with three views:
FirstView
SecondView
ThirdView
When i am on the ThirdView and i click on the back button from navigation controller, i want to pass data from ThridView to SecondView.
But i don't know how to do this.
I don't want to add an extra button on my view.
The same when i'm on the SecondView and i want to go back to the FirstView.
I can't use the method "ViewWillDisappear" because if a set a "PerformSegueWithIdentifier" on this method to pass data from SecondView to FirstView, i can't switch to ThirdView because the "ViewWillDisappear" method will be executed.
Can you please help me?
PS: I use the language swift 2
In your viewWillDisappear or viewDidDisappear method you can check if back button is pressed by checking whether or not your view controller is moving from parent view controller.
override func viewWillDisappear(animated: Bool) {
if(self.isMovingFromParentViewController())
{
//Send data to previous view controller
print("Going back: Back button pressed");
}else{
print("Controller is hidden due to some other reason e.g Pushing another view controller");
}
}
I make subclass of UINavigationController because I cannot find Unwind Segue signature in UIViewController since Xcode 11.
#implementation CLUnwindNavigationController
- (BOOL)canPerformUnwindSegueAction:(SEL)action fromViewController:(UIViewController *)fromViewController withSender:(id)sender {
return NO;
}
- (IBAction)unwindForSegue:(UIStoryboardSegue *)unwindSegue towardsViewController:(UIViewController *)subsequentVC {
}
#end
You can find UnwindSegue signature.
You can connect to your desired action.

Custom Unwind Segue for iOS 8 and iOS 9

My question is, how do I get the following custom unwind segue to work on a device with a version prior to iOS 9 as well as on a device running iOS 9?
I have a Custom Segue showing a view controller, and then have a corresponding Custom Unwind Segue. This code has worked fine in iOS 8, and is implemented by creating subclasses of UIStoryboardSegue and implementing the perform method. Then I override the following method in my custom Navigation Controller:
- (UIStoryboardSegue *) segueForUnwindingToViewController: (UIViewController *)toViewController fromViewController:(UIViewController *)fromViewController identifier:(NSString *)identifier
{
UIStoryboardSegue *segue;
if([fromViewController isKindOfClass:[MyViewController class]]){
segue = [[CustomSegue alloc] initWithIdentifier:identifier source:fromViewController destination:toViewController]; //Custom Unwind Segue
}
else{
UIStoryboardSegue *unwindSegue = [super segueForUnwindingToViewController:toViewController fromViewController:fromViewController identifier:identifier]; //Normal Unwind Segue
segue = unwindSegue;
}
return segue;
}
In iOS 9, segueForUnwindingToViewController is deprecated. It still works for the MyViewController CustomSegue; however, the default unwind segue no longer works for any other unwind segue. Although calling the method on super returns an unwind segue, the segue never occurs, the view controller is never popped, and the user can never go back to the previous screen. So just to be clear, if I use a regular show segue, the corresponding unwind segue calls the deprecated method, which calls the method on super, and does not work.
I watched the WWDC talk on storyboards, and I was able to fix this issue in iOS 9 by a) no longer overriding this method in my custom Navigation Controller, and b) going into the storyboard, clicking on the custom segue, and entering in CustomSegue as the Segue Class. Unfortunately, since I am targeting iOS 7, I get the warning "Only Custom segues support class names prior to iOS 9", and the custom unwind segue now does not work for iOS 7 or iOS 8!
After a lot of trial and error, I found a workaround. I noticed that when you override segueForUnwindingToViewController, unwindForSegue:towardsViewController is no longer called, which is the problem. FYI, Apple's note in UIViewController for segueForUnwindingToViewController says:
Deprecated. Returns a segue that will unwind from the source to destination view controller via the unwindForSegue:towardViewController: method. When performing an unwind segue defined in a storyboard, if any view controller along the unwind path has overridden this method and returns non-nil, the runtime will use that segue object instead of constructing an instance of the class specified in Interface Builder.
The portion of the statement in bold does not seem to be implemented, i.e. if you override this method but return nil, unwindForSegue:towardViewController is still not called and the segue does not occur.
In order to get around this problem, I was able to edit the segueForUnwindingToViewController in my custom Navigation Controller:
- (UIStoryboardSegue *)segueForUnwindingToViewController:(UIViewController *)toViewController fromViewController:(UIViewController *)fromViewController identifier:(NSString *)identifier
{
UIStoryboardSegue *segue;
if([fromViewController isKindOfClass:[MyViewController class]]){
segue = [[CustomSegue alloc] initWithIdentifier:identifier source:fromViewController destination:toViewController]; //Custom Unwind Segue
}
else{
if([[UIDevice currentDevice].systemVersion floatValue] < 9.0){
return [super segueForUnwindingToViewController:toViewController fromViewController:fromViewController identifier:identifier]; //Normal Unwind Segue
}
else{
[super unwindForSegue:segue towardsViewController:toViewController];
return nil;
}
}
return segue;
}
UPDATE: Calling [super segueForUnwindingToViewController:toViewController fromViewController:fromViewController identifier:identifier]; seems to still work for modal unwind segues. The issue I described seems to happen for show segues. Consequently, if your device runs on a version < 9.0 or if the segue is modal, you should still call the old method. If you call [super unwindForSegue:segue towardsViewController:toViewController]; when the segue is modal, the segue will not work/occur.
I slightly modified your code.
I don't have to consider whether push or modal.
It seems to work fine.
- (UIStoryboardSegue *)segueForUnwindingToViewController:(UIViewController *)toViewController fromViewController:(UIViewController *)fromViewController identifier:(NSString *)identifier
{
UIStoryboardSegue *segue;
if ([fromViewController isKindOfClass:[MyViewController class]]) {
segue = [[CustomSegue alloc] initWithIdentifier:identifier source:fromViewController destination:toViewController]; //Custom Unwind Segue
}
else {
if ([super respondsToSelector:#selector(unwindForSegue:towardsViewController:)]) {
[super unwindForSegue:segue towardsViewController:toViewController];
}
segue = [super segueForUnwindingToViewController:toViewController fromViewController:fromViewController identifier:identifier];
}
return segue;
}

Unwind segue doesn't dismiss adaptive popover presentation when not modal

Update for iOS 9 beta: Apple may have fixed this for iOS 9. If you work(ed) around this issue for iOS 8, make sure it also works correctly on iOS 9.
In storyboard, I've created a popover presentation segue to present a navigation and view controller from a button, as well as creating an unwind segue.
In portrait orientation, the modal (fullscreen) presentation is unwound/dismissed, as expected.
In landscape orientation, the unwind segue also gets called, however the popover presentation is not automatically dismissed.
Did I miss hooking something up? Do I have to dismiss the popover presentation myself?
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)__unused sender
{
if ([[segue identifier] isEqualToString:#"showSelectBookChapter"])
{
UINavigationController *navigationController = segue.destinationViewController;
if ([navigationController.topViewController isKindOfClass:[BIBLESelectViewController class]])
{
BIBLESelectViewController *selectViewController = (BIBLESelectViewController *)navigationController.topViewController;
selectViewController.initialBookChapterVerse = self.bookChapterVerse;
}
}
}
- (IBAction)unwindToBIBLEChapterViewController:(UIStoryboardSegue *)segue
{
if ([segue.identifier isEqualToString:#"unwindToBIBLEChapterViewController"]) {
if ([segue.sourceViewController isKindOfClass:[BIBLESelectViewController class]])
{
BIBLESelectViewController *sourceViewController = (BIBLESelectViewController *)segue.sourceViewController;
self.bookChapterVerse = sourceViewController.selectedBookChapterVerse;
[self.tableView reloadData];
}
}
}
Update:
After looking at gabbler's sample code, I've narrowed the problem down to popover dismissing fine in a Single View Application, but not in a Master-Detail Application.
Update 2:
Here's what the hierarchy looks like (omitting navigation controllers for simplicity's sake), in answer to the question Luis asked:
Split view controller
Master view controller
Detail view controller
Chapter view controller (modal page sheet)
Select view controller (the problematic popover that unwinds to chapter view controller, but doesn't dismiss)
As I mentioned in the previous update, I created an new master/detail template, and simply presented a popover directly from (a button in) the detail view. It won't dismiss.
I ran into this problem too. I present a View Controller modally (as a form sheet), from the Master View Controller (UISplitViewController). The problem only occurred on the iPad (probably the iPhone 6+ in landscape mode too, but I didn't check it). I ended up doing the following in my unwind action method (using Swift), and it works good.
if !segue.sourceViewController.isBeingDismissed() {
segue.sourceViewController.dismissViewControllerAnimated(true, completion: nil)
}
If you segue as a popover from a view controller embedded in a navigation controller, the corresponding unwind fails to dismiss the popover.
It's a bug in -[UINavigationController segueForUnwindingToViewController:fromViewController:identifier]. The embedding navigation controller is supposed to supply a segue that will dismiss the popover but it doesn't. The fix then is to override this and supply a working segue, which we can get from the embedded view controller.
Here's a partial solution that will only handle unwinding to the top view controller of the navigation stack:
#implementation MyNavigationController
- (UIStoryboardSegue *)segueForUnwindingToViewController:(UIViewController *)toViewController
fromViewController:(UIViewController *)fromViewController
identifier:(NSString *)identifier
{
if (toViewController == self.topViewController && fromViewController.presentingViewController == self)
return [toViewController segueForUnwindingToViewController:toViewController
fromViewController:fromViewController
identifier:identifier];
else
return [super segueForUnwindingToViewController:toViewController
fromViewController:fromViewController
identifier:identifier];
}
#end
It works on iOS 8 for both landscape/portrait iPad and landscape/portrait iPhone. The logic should be robust enough to survive on iOS 9.
It is/must be a behavior of the popOver segue, in normal situations or regularly we need that the popOver keeps in view, if the segue show something important is annoying that we lost that information just because we rotate the device, I guess that that is the reason of that native behavior. So if we want for it to dismiss automaticly we have to make that behaivor by our own, this works:
in the method - (void)viewDidLoadin the detailViewController.m add this:
[[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
[[NSNotificationCenter defaultCenter]
addObserver:self selector:#selector(orientationChanged:)
name:UIDeviceOrientationDidChangeNotification
object:[UIDevice currentDevice]];
then create this method:
- (void) orientationChanged:(NSNotification *)note{
UIDevice * device = note.object;
//CGRect rect = [[self view] frame];
switch(device.orientation)
{
default:
[self dismissViewControllerAnimated:YES completion:nil];
break; }}
You said that in a single view happens what you want, but I've never seen that behavior when I used popOvers.
mbeaty's fix is great but as others have pointed out, this bug seems to know be fixed in iOS 9 and it also doesn't work well for universal device design. I have adapted his answer to handle both situations. Here is the code:
#IBAction func yourUnwindSegue(segue: UIStoryboardSegue) {
if #available(iOS 9, *) {
return // bug fixed in iOS 9, just return and let it work correctly
}
// do the fix for iOS 8 bug
// access your SplitViewController somehow, this is one example
let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
let splitVC = appDelegate.window!.rootViewController as! YourSplitViewController
// if the source isn't being dismissed and the splitView isn't
// collapsed (ie both windows are showing), do the hack to
// force it to dismiss
if !segue.sourceViewController.isBeingDismissed() && splitVC.collapsed == false {
segue.sourceViewController.dismissViewControllerAnimated(true, completion: nil)
}
}
This first checks if iOS 9 is running and just exit as the bug seems to be fixed. This will prevent the multiple views getting dismissed issue. Also to make sure this fix is only done when the splitView is showing two windows (to make it happen only on iPads and iPhone 6 Plus in landscape as well as future devices) I added the check to make sure it is not collapsed.
I have not exhaustively check this but it seems to work. Also not that my app is set for a min of iOS 7, I don't know if this bug existed then so you may need to look into that if you support below iOS 8.

-segueForUnwindingToViewController: fromViewController: identifier: not being called

I have created a custom segue that presents a view controller inside a container that is very similar with Apple's own modal view controllers (I've implemented it as a UIViewController subclass).
I'm now trying to create a custom unwind segue but there's no way I can get the method -segueForUnwindingToViewController: fromViewController: identifier: to be called.
I've also implemented -viewControllerForUnwindSegueAction: fromViewController: withSender: on my container so I can point to the correct view controller (the one that presented this modal) but then the method that should be asked for my custom unwind segue doesn't get called anywhere.
Right now, the only way for me to dismiss this modal is to do it on the -returned: method.
Did anyone could successfully do this with a custom unwind segue?
EDIT:
A little bit more code and context
My unwind view controller is configured in the storyboard, not programatically.
I have these pieces of code related to the unwind segues in my controllers:
PresenterViewController.m
I'm using a custom method to dismiss my custom modals here (-dismissModalViewControllerWithCompletionBlock:).
- (UIStoryboardSegue *)segueForUnwindingToViewController:(UIViewController *)toViewController
fromViewController:(UIViewController *)fromViewController
identifier:(NSString *)identifier {
return [[MyModalUnwindSegue alloc] initWithIdentifier:identifier
source:fromViewController
destination:toViewController];
}
-(IBAction)returned:(UIStoryboardSegue *)segue {
if ([segue.identifier isEqualToString:#"InfoUnwindSegue"]) {
[self dismissModalViewControllerWithCompletionBlock:^{}];
}
}
MyModalViewController.m
Here I only use -viewControllerForUnwindSegueAction: fromViewController: withSender: to point to the view controller that I should be unwind to.
- (UIViewController *)viewControllerForUnwindSegueAction:(SEL)action
fromViewController:(UIViewController *)fromViewController
withSender:(id)sender {
return self.myPresentingViewController;
}
The behavior I was expecting was that MyModalViewController was called to point to the view controller that should handle the unwinding and then this view controller had his -segueForUnwindingToViewController: fromViewController: identifier: method called before -returned: gets called.
Right now -segueForUnwindingToViewController: fromViewController: identifier: never gets called.
I must also say that I already tried different configurations. Everywhere I put my method to return the unwind segue it never gets called. I've read that I can subclass a navigation controller and then it gets called but I don't know how it would fit in my solution.
EDIT 2: Additional info
I've checked that MyModalViewController has his -segueForUnwindingToViewController: fromViewController: identifier: method called when I want to dismiss a regular modal view controller presented by it. This may be because he's the top most UIViewController in the hierarchy.
After checking this I've subclassed UINavigationController and used this subclass instead to contain my PresenterViewController. I was quite surprised to notice that his -segueForUnwindingToViewController: fromViewController: identifier: method is called as well.
I believe that only view controllers that serve as containers have this method called. That's something that makes little sense for me as they are not the only ones presenting other view controllers, their children are also doing so.
It's not OK for me to create logic in this subclass to choose which segue class to use as this class has no knowledge of what their children did.
Apple forums are down for the moment so no way to get their support right now. If anyone has any more info on how this works please help! I guess the lack of documentation for this is a good indicator of how unstable this still is.
To add to the answer from #Jeremy, I got unwinding from a modal UIViewController to a UIViewController contained within a UINavigationController to work properly (I.e how I expected it to) using the following within my UINavigationController subclass.
// Pass to the top-most UIViewController on the stack.
- (UIStoryboardSegue *)segueForUnwindingToViewController:(UIViewController *)
toViewController fromViewController:(UIViewController *)
fromViewController identifier:(NSString *)identifier {
UIViewController *controller = self.topViewController;
return [controller segueForUnwindingToViewController:toViewController
fromViewController:fromViewController
identifier:identifier];
}
.. and then implementing the segueForUnwindingToViewController as usual in the actual ViewController inside the UINavigationController.
This method should be declared on the parent controller. So if you're using a Navigation Controller with a custom segue, subclass UINavigationController and define this method on it. If you would rather define it on one of the UINavigationController's child views, you can override canPerformUnwindSegueAction:fromViewController:withSender on the UINavigationController to have it search the children for a handler.
If you're using an embedded view (container view), then define it on the parent view controller.
See the last 10 minutes of WWDC 2012 Session 407 - Adopting Storyboards in Your App to understand why this works!
If you're using a UINavigationController and your segue is calling pushViewController then in order to use a custom unwind segue you'll need to subclass UINavigationController and override - (UIStoryboardSegue *)segueForUnwindingToViewController:(UIViewController *)toViewController fromViewController:(UIViewController *)fromViewController identifier:(NSString *)identifier.
Say I have a custom unwind segue called CloseDoorSegue. My UINavigationController subclass implementation might look something like:
- (UIStoryboardSegue *)segueForUnwindingToViewController:(UIViewController *)toViewController fromViewController:(UIViewController *)fromViewController identifier:(NSString *)identifier {
UIStoryboardSegue* theSegue;
if ([identifier isEqualToString:#"CloseDoor"]) {
theSegue = [CloseBookSegue segueWithIdentifier:identifier source:fromViewController destination:toViewController performHandler:^(void){}];
} else {
theSegue = [super segueForUnwindingToViewController:toViewController fromViewController:fromViewController identifier:identifier];
}
return theSegue;
}
Set your UINavigationController subclass as the navigation controller class in the storyboard. You should be good to go provided you have setup the Exit event correctly with "CloseDoor" as the identifier. Also be sure to call 'popViewControllerAnimated' in your unwind segue instead of dismiss to keep in line with UINavigationControllers push/pop mechanism.
iOS development Library
There is a discussion on iOS development Library along with this method.
- segueForUnwindingToViewController:fromViewController:identifier:
Make sure your MyModalViewController is the container role rather than a subcontroller of a container. If there is something like [anotherVC addChildViewController:myModalViewController];,you should put the segueForUnwindingToViewController method in some kind of "AnotherVC.m" file.
Discussion
If you implement a custom container view controller that
also uses segue unwinding, you must override this method. Your method
implementation should instantiate and return a custom segue object
that performs whatever animation and other steps that are necessary to
unwind the view controllers.

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