[Swift 3] Error: unrecognized selector sent to instance

Problem

self.present(alertController, animated: true, completion: nil)

當 compiling 時，出現下列 error:

2017-06-21 11:04:57.574 HelloWorlDemo[2244:87318] -[HelloWorlDemo.ViewController helloWorldBtn:]: unrecognized selector sent to instance 0x7fc2d2e0f110

2017-06-21 11:04:57.586 HelloWorlDemo[2244:87318] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[HelloWorlDemo.ViewController helloWorldBtn:]: unrecognized selector sent to instance 0x7fc2d2e0f110'

*** First throw call stack:

(

0   CoreFoundation                      0x000000010ba65b0b __exceptionPreprocess + 171

1   libobjc.A.dylib                     0x0000000108df5141 objc_exception_throw + 48

2   CoreFoundation                      0x000000010bad5134 -[NSObject(NSObject) doesNotRecognizeSelector:] + 132

3   CoreFoundation                      0x000000010b9ec840 ___forwarding___ + 1024

4   CoreFoundation                      0x000000010b9ec3b8 _CF_forwarding_prep_0 + 120

5   UIKit                               0x00000001092c8d82 -[UIApplication sendAction:to:from:forEvent:] + 83

6   UIKit                               0x000000010944d5ac -[UIControl sendAction:to:forEvent:] + 67

7   UIKit                               0x000000010944d8c7 -[UIControl _sendActionsForEvents:withEvent:] + 450

8   UIKit                               0x000000010944c802 -[UIControl touchesEnded:withEvent:] + 618

9   UIKit                               0x00000001093367ea -[UIWindow _sendTouchesForEvent:] + 2707

10  UIKit                               0x0000000109337f00 -[UIWindow sendEvent:] + 4114

11  UIKit                               0x00000001092e4a84 -[UIApplication sendEvent:] + 352

12  UIKit                               0x0000000109ac85d4 __dispatchPreprocessedEventFromEventQueue + 2926

13  UIKit                               0x0000000109ac0532 __handleEventQueue + 1122

14  CoreFoundation                      0x000000010ba0bc01 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17

15  CoreFoundation                      0x000000010b9f10cf __CFRunLoopDoSources0 + 527

16  CoreFoundation                      0x000000010b9f05ff __CFRunLoopRun + 911

17  CoreFoundation                      0x000000010b9f0016 CFRunLoopRunSpecific + 406

18  GraphicsServices                    0x000000010d970a24 GSEventRunModal + 62

19  UIKit                               0x00000001092c7134 UIApplicationMain + 159

20  HelloWorlDemo                       0x000000010881d9e7 main + 55

21  libdyld.dylib                       0x000000010ca0565d start + 1

22  ???                                 0x0000000000000001 0x0 + 1

)

libc++abi.dylib: terminating with uncaught exception of type NSException

(lldb) 

Solution

Swift 3.0 已改版，需將參數 animated 設定值為 false 即可：

self.present(alertController, animated: false, completion: nil)