问题
I've almost finished converting a large Universal app to use Storyboards, but have one issue that is stumping me. I have created a Scene for a custom UIImagePickerController, but I can't figure out how to unwind from it. I know I could just dismiss the controller, but I want to use the unwind process to pass the image back to the original source view controller. When I try to do the manual unwind, I get the following exception:
'NSInvalidArgumentException', reason: 'Receiver (<MyImagePickerController: 0x7facdb838000>) has no segue with identifier 'unwindPickImage''
I think it is interesting that the crash log shows a call to
[UIViewController shouldPerformSegueWithIdentifier:sender:]
but if I implement that method in the MyImagePickerController class, it does not get called. Also, it is interesting that at the time of the crash, the view controller's _storyboardSequeTemplates private property is nil, but they are visually present in IB.
I have uploaded a demo project to Github that demonstrates this error and also several unwind segue patterns that I have used successfully elsewhere in the project to communicate between view controllers. Is is possible to use a manual unwind segue from a UIImagePickerController rather than using the old delegate pattern to return the image? If so, how? Thanks.
来源：https://stackoverflow.com/questions/26364690/manual-unwind-segue-from-uiimagepickercontroller-fails-with-receiver-has-no-seg