问题：
Control Fun[3929:60b] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<JAViewController 0x10920f570> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key sliderChanged.'
*** First throw call stack:
(
0 CoreFoundation 0x0000000101947495 __exceptionPreprocess + 165
1 libobjc.A.dylib 0x00000001016a699e objc_exception_throw + 43
2 CoreFoundation 0x00000001019cb919 -[NSException raise] + 9
3 Foundation 0x0000000101287530 -[NSObject(NSKeyValueCoding) setValue:forKey:] + 259
4 CoreFoundation 0x0000000101943400 -[NSArray makeObjectsPerformSelector:] + 224
5 UIKit 0x00000001004ae8a6 -[UINib instantiateWithOwner:options:] + 1131
6 UIKit 0x0000000100348b0c -[UIViewController _loadViewFromNibNamed:bundle:] + 245
7 UIKit 0x0000000100349149 -[UIViewController loadView] + 112
8 UIKit 0x00000001003493b7 -[UIViewController loadViewIfRequired] + 75
9 UIKit 0x0000000100349777 -[UIViewController view] + 29
10 UIKit 0x000000010028996b -[UIWindow addRootViewControllerViewIfPossible] + 58
11 UIKit 0x0000000100289c70 -[UIWindow _setHidden:forced:] + 282
12 UIKit 0x0000000100292ffa -[UIWindow makeKeyAndVisible] + 51
13 UIKit 0x000000010024ec98 -[UIApplication _callInitializationDelegatesForURL:payload:suspended:] + 1788
14 UIKit 0x0000000100252a0c -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:] + 660
15 UIKit 0x0000000100263d4c -[UIApplication handleEvent:withNewEvent:] + 3189
16 UIKit 0x0000000100264216 -[UIApplication sendEvent:] + 79
17 UIKit 0x0000000100254086 _UIApplicationHandleEvent + 578
18 GraphicsServices 0x0000000103ac071a _PurpleEventCallback + 762
19 GraphicsServices 0x0000000103ac01e1 PurpleEventCallback + 35
20 CoreFoundation 0x00000001018c9679 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 41
21 CoreFoundation 0x00000001018c944e __CFRunLoopDoSource1 + 478
22 CoreFoundation 0x00000001018f2903 __CFRunLoopRun + 1939
23 CoreFoundation 0x00000001018f1d83 CFRunLoopRunSpecific + 467
24 UIKit 0x00000001002522e1 -[UIApplication _run] + 609
25 UIKit 0x0000000100253e33 UIApplicationMain + 1010
26 Control Fun 0x00000001000015e3 main + 115
27 libdyld.dylib 0x0000000101fdf5fd start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)
解决：
找到sliderChanged对应控件的connection,删掉多余的。