Disabling UIBarButtonItems in Nav Bar and Stopping Secondary Popvers
The issue is as follows: I have an iOS 9 app (Swift) with a nav bar that houses a bunch of UIBarButtonItems with segues to several UINavigationControllers that finally display tables, views etc. as popovers. Of course tapping one of these buttons does not automatically disable the other UIBarButtonItems in the nav bar and the user is free to tap them. With a popover already displaying however we get the following warning as this is against the HIG and also grounds for rejection:
Attempt to present UINavigationControllerViewController which is already presenting (null)
To take care of the issue once a popover is displaying a) the remaining UIBarButtonItems need to be disabled and b) displaying additional popovers needs to be halted.
So what is the best cause of action here? The isBeingPresented flag of the popover's view controller is not available in the governing view controller because one can't create outlets of one view controller in another and the navigationController's viewControllers array doesn't include external navigation controllers or their descendants.
My lame workaround involves a global appIsPresentingPopover Bool which is set to true in viewDidLoad and to false in viewDidDisappear in the mentioned view controllers. That Bool is then tested in the governing view controller's prepareForSegue method to stop additional popovers from displaying. It is also kvo'ed to disable any enabled UIBarButtonItems which now all have an outlet. Ugly!
What is the standard way of handling this common scenario?
Surprisingly simple solution and much more elegant than my initial attempt. I added segue identifiers for all involved popups and a UIViewController class variable. In prepareForSegue I set the variable to the destination view controller. Then in shouldPerformSegueWithIdentifier I simply check whether that popover variable is nil. If it is not, I dismiss the UIViewController and set it to nil. Finally I also followed Beau Nouvelle's suggestion and kept those buttons lit so users can switch directly between popovers. Thanks again.