After using presentViewController existing segues can't be found - ios

Question

I am returning to my login view using the code below. The view loads correctly and everything looks fine. All buttons work etc.
JALoginViewController *loginVC = [[JALoginViewController alloc] init];
UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:loginVC];
navigationController.modalPresentationStyle = UIModalPresentationFormSheet;
[self.navigationController presentModalViewController:navigationController animated:YES];
However, if a user tries to log in again, the segue that takes them to the next scene can't be found.
I'm using performSegueWithIdentifier if the users login credentials are correct, like this:
[self performSegueWithIdentifier:#"loginSegue" sender:self];
This is the error I receive:
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Receiver (<JALoginViewController: 0x8d614b0>) has no segue with identifier 'loginSegue''
I've done lots of searching on Google and through the docs for the solution to this, the closet I've got (at least I think) is this question. The explain and solution sound like they could be correct and relevant, but I can't put them into practice.
Documents I've read and tried:
initWithRootViewController
popToRootViewController - The current root view controller is for a tab bar - not the login scene I need so as far as I'm aware I can't use this.
popViewControl
pushViewControl - This works to an effect, I don't think it is the correct way though. I don't want there to be navigation bar and I don't want my tab bar to appear when the user returns to the login scene.
I've tried various methods with limited / no effect. At this stage any help would be greatly appreciated.
Please let me know if I haven't provided enough information.
Thanks
JA
Edit - Zoomed out image of storyboard
![Zoomed out image of Storyboard][1]

Answer 1

On the basis of the screen snapshot of the revised question, from your rightmost red-highlighted scene, you should be able to:
[self.tabBarController dismissViewControllerAnimated:YES completion:nil];
and you'll be back at that initial screen (I'm assuming you did modal segue from initial screen to your tab bar controller).
Original answer:
If you want to manually push to a view controller, rather than creating it via alloc/init, you should use
UIViewController *controller = [self.storyboard instantiateViewControllerWithIdentifier:#"loginsSceneStoryboardIdHere"];
or, if that view controller was the "initial" scene (the one with the simple arrow coming in from the left), you could use
UIViewController *controller = [self.storyboard instantiateInitialViewController];
And you shouldn't be manually creating the navigation controller, either. If the loginVC needs a navigation controller, you should embed that scene in a navigation controller right in the Interface Builder, then give that new navigation controller its own unique storyboard identifier, and then you can
UIViewController *controller = [self.storyboard instantiateViewControllerWithIdentifier:#"navControllerSceneStoryboardIdHere"];
[self presentViewController:controller animated:YES completion:nil];
I must confess that I'm worried by this whole "return to login via pushViewController" construct. I assume you know that you're not "returning" to it, but creating a new copy of it. If you push/modal from A to B and then B to C and then C to A, you're holding 4 views and their controllers in memory, two copies of A and one of B and one of C (which is, obviously, not good). I just wanted to make sure you don't have a circular set of segues and/or push/presentViewController references.
If the login is the initial scene in your app and if you've been doing only push segues (no modal segues along the way), you can do a:
[self.navigationController popToRootViewControllerAnimated:YES];
That will take you to the top level view controller, and it will pop off and release all of the intervening scenes.
If you're using iOS 6, you can avail yourself of the unwind segue, which can achieve the same functionality, but it doesn't care whether the preceding segues were pushes or modals.
There are lots of ways of skinning the cat, but generally doing a new presentViewController to the first scene in your storyboard is a very bad idea.