NSInvalidArgumentException: unrecognized selector sent to instance | SWIFT - ios

Question

I realize this question has been asked many times, but it seems to be caused by many different things and is very situational.
My trace:
2015-02-27 16:20:06.289 RTApp[43486:1122681] -[RTApp.conversationVC keyboardWasShown]: unrecognized selector sent to instance 0x7f866a766830
2015-02-27 16:20:06.291 RTApp[43486:1122681] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[RTApp.conversationVC keyboardWasShown]: unrecognized selector sent to instance 0x7f866a766830'
*** First throw call stack:
(
0 CoreFoundation 0x00000001071b8f35 __exceptionPreprocess + 165
1 libobjc.A.dylib 0x0000000106e51bb7 objc_exception_throw + 45
2 CoreFoundation 0x00000001071c004d -[NSObject(NSObject) doesNotRecognizeSelector:] + 205
3 CoreFoundation 0x000000010711827c ___forwarding___ + 988
4 CoreFoundation 0x0000000107117e18 _CF_forwarding_prep_0 + 120
5 CoreFoundation 0x0000000107188cec __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__ + 12
6 CoreFoundation 0x00000001070888a4 _CFXNotificationPost + 2484
7 Foundation 0x00000001069af6b8 -[NSNotificationCenter postNotificationName:object:userInfo:] + 66
8 UIKit 0x0000000107c75eb8 -[UIInputWindowController postEndNotifications:withInfo:] + 527
9 UIKit 0x0000000107c77725 __77-[UIInputWindowController moveFromPlacement:toPlacement:starting:completion:]_block_invoke572 + 354
10 UIKit 0x0000000107617113 -[UIViewAnimationBlockDelegate _didEndBlockAnimation:finished:context:] + 326
11 UIKit 0x00000001075fee6a -[UIViewAnimationState sendDelegateAnimationDidStop:finished:] + 209
12 UIKit 0x00000001075ff1a0 -[UIViewAnimationState animationDidStop:finished:] + 76
13 QuartzCore 0x0000000105c4c7ee _ZN2CA5Layer23run_animation_callbacksEPv + 308
14 libdispatch.dylib 0x0000000108de57f4 _dispatch_client_callout + 8
15 libdispatch.dylib 0x0000000108dce8fb _dispatch_main_queue_callback_4CF + 949
16 CoreFoundation 0x0000000107120fe9 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 9
17 CoreFoundation 0x00000001070e3eeb __CFRunLoopRun + 2043
18 CoreFoundation 0x00000001070e3486 CFRunLoopRunSpecific + 470
19 GraphicsServices 0x000000010aa0f9f0 GSEventRunModal + 161
20 UIKit 0x00000001075a5420 UIApplicationMain + 1282
21 RTApp 0x000000010563623e top_level_code + 78
22 RTApp 0x000000010563627a main + 42
23 libdyld.dylib 0x0000000108e1a145 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
And the function in question:
func keyboardWasShown(notification: NSNotification){
let dict:NSDictionary = notification.userInfo!
let s:NSValue = dict.valueForKey(UIKeyboardFrameEndUserInfoKey) as NSValue
let rect:CGRect = s.CGRectValue()
UIView.animateWithDuration(0.3, delay: 0, options: .CurveLinear, animations: {
self.resultsScrollView.frame.origin.y = self.scrollViewOriginalY - rect.height
self.frameMessageView.frame.origin.y = self.frameMessageOriginalY - rect.height
var bottomOffset:CGPoint = CGPointMake(0, self.resultsScrollView.contentSize.height - self.resultsScrollView.bounds.size.height)
self.resultsScrollView.setContentOffset(bottomOffset, animated: false)
}, completion: {
(finished:Bool) in
})
}
So this should just be pushing the view up so it's not covered by the keyboard as you type. But as soon as I pull the keyboard up, it crashes. It would be great if Xcode told you what line the error is on, but that would be too easy..
Does this mean the function doesn't recognizer the parameter I'm passing in to it? Or why can't it recognize the 'selector'?

Answer 1

Judging by the error message reason: '-[RTApp.conversationVC keyboardWasShown]: unrecognized selector you used the wrong selector when you added the Notification Observer.
You should use Selector("keyboardWasShown:") instead of Selector("keyboardWasShown") because your method has one parameter.