App crashes with error unrecognized selector sent to instance - ios

Question

I am having an unrecognized selector sent to instance issue. I know which line I am having problem with, but I don't understand why it doesn't recognize it. (I tested this code in when I was creating my container views and it works just fine. But for some reason when I merge it to my main project I am getting this error.)
This is my console output:
2013-12-20 16:47:59.633[8545:70b] -[UIViewController decideViewController:]: unrecognized selector sent to instance 0x8b5c250
2013-12-20 16:47:59.659[8545:70b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UIViewController decideViewController:]: unrecognized selector sent to instance 0x8b5c250'
*** First throw call stack:
(
0 CoreFoundation 0x01c075e4 __exceptionPreprocess + 180
1 libobjc.A.dylib 0x0198a8b6 objc_exception_throw + 44
2 CoreFoundation 0x01ca4903 -[NSObject(NSObject) doesNotRecognizeSelector:] + 275
3 CoreFoundation 0x01bf790b ___forwarding___ + 1019
4 CoreFoundation 0x01bf74ee _CF_forwarding_prep_0 + 14
5 TProduct 0x0000566f -[GameViewController changeViews:] + 143
6 TProduct 0x00005404 -[GameViewController timerTick:] + 532
7 Foundation 0x015c1927 __NSFireTimer + 97
8 CoreFoundation 0x01bc5bd6 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 22
9 CoreFoundation 0x01bc55bd __CFRunLoopDoTimer + 1181
10 CoreFoundation 0x01bad628 __CFRunLoopRun + 1816
11 CoreFoundation 0x01bacac3 CFRunLoopRunSpecific + 467
12 CoreFoundation 0x01bac8db CFRunLoopRunInMode + 123
13 GraphicsServices 0x0387b9e2 GSEventRunModal + 192
14 GraphicsServices 0x0387b809 GSEventRun + 104
15 UIKit 0x006f8d3b UIApplicationMain + 1225
16 TProduct 0x000070fd main + 141
17 libdyld.dylib 0x0224570d start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
and this is the part that it doesn't recognize
GameViewController.m
-(void)changeViews:(NSString *)gameStateSegueIdentifier
{
NSLog(#"show view gameStateSegueIdentifier :%#",gameStateSegueIdentifier);
[self.containerController decideViewController:gameStateSegueIdentifier];
}
and this is the method I am calling
ContainerViewController.m
-(void)decideViewController:(NSString *)gameStateSegueIdentifier
{
if (gameStateSegueIdentifier == _currentSegueIdentifier) {
return;
}
while (gameStateSegueIdentifier != _currentSegueIdentifier) {
NSLog(#"this is the gameStateSegueIdentifier %#",gameStateSegueIdentifier);
NSLog(#"this is the currentSegueIdentifier %#",_currentSegueIdentifier);
[self changeViewControllers];
}
}
I understand that there are lots of "unrecognized selector sent to instance" questions already. But so far, I wasn't able to find an answer for my case. I appreciate the help.

Answer 1

The error message you're getting explains the problem:
2013-12-20 16:47:59.633[8545:70b] -[UIViewController decideViewController:]: unrecognized selector sent to instance 0x8b5c250
This is telling you that an instance of the class UIViewController got the message decideViewController:. UIViewController does not respond to this message. So, it seems that self.containerController is a UIViewController rather than a ContainerViewController. (If it was a ContainerViewController, it would say so in the error message.)
The fact that the property is declared as a ContainerViewController doesn't mean that there's actually a ContainerViewController in it. Go to where you actually create this object and assign it to that property, and ensure you're creating it as the correct class.

Answer 2

when the selector is not recognized you don't need to show the code for the selector, because it is not executed.
Show the property line of containerController.
Are you 100% sure that self.containerController is a ContainerViewController, your error message shows a UIViewController, so you are doing something special like cluster or a category?
Are you using #import "ContainerViewController"?
Is the method in the #implementation #end part?