could be probably xcode malfunctioning - ios

Question

I am trying to add an observer to a NSNotificatonCenter notification that I posted in code earlier but Xcode gives that exception
Terminating app due to uncaught exception
'NSInvalidArgumentException', reason:
'+[TurkI_s_Manga.DisplayMangaViewController setStuff:]: unrecognized
selector sent to class 0x102ffd650'.
I am using the same structure three times in my code and only one of them causes that exception. So I tried to check the selector before try to use it like this:
println(self.respondsToSelector("setStuff:"))
if self.respondsToSelector("setStuff:"){
println("it responses to selector set stuff")
NSNotificationCenter.defaultCenter().addObserver(DisplayMangaViewController.self, selector: "setStuff:", name: "pagesNotification", object: UrlAndNameList.self)
}
This code block prints true and then it responses to the selector set stuff but when observer receives the notification it gives the exception mentioned above.
Any help would be appreciated, thanks.

Answer 1

From my above comment: You are adding the type (class) as an observer (which could work if setStuff is a type method). What you probably want is
NSNotificationCenter.defaultCenter().addObserver(self, ...)
to add the instance self as an observer.

Answer 2

You are checking whether one thing (self) responds to a selector, and then you add another thing (DisplayMangaViewController.self) as an observer, which doesn't respond to the selector. So please explain why you would think that's Xcode's fault and not your own mistake.
First rule of debugging: When things go wrong, it is your fault. You did something wrong. Find what you did wrong. There are millions of developers using Xcode. Do you really think if it got something trivial like this wrong, you wouldn't hear about it everywhere?