Xcode Storyboard - UITableViewCell UISwitch Value Changed - xcode

Question

I have am using Xcode storyboards and have a View Controller that has a UITableView which in turn has a custom UITableViewCell.
The UITableViewCell has a UISwitch in it and I want to know when the value has changed. I have a IBAction that successfully fires when the value is changed
- (IBAction)updateSwitchAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"In SettingsViewcontroller updateSwitchAtIndexPath row=|%d \n", indexPath.row);
}
However when it fires the app terminates
2014-07-10 23:38:10.037 reactor[2572:60b] -[UISwitch row]: unrecognized selector sent to instance 0x944b7e0
2014-07-10 23:38:10.072 reactor[2572:60b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UISwitch row]: unrecognized selector sent to instance 0x944b7e0'
*** First throw call stack:
(
0 CoreFoundation 0x01a281e4 __exceptionPreprocess + 180
1 libobjc.A.dylib 0x015758e5 objc_exception_throw + 44
2 CoreFoundation 0x01ac5243 -[NSObject(NSObject) doesNotRecognizeSelector:] + 275
3 CoreFoundation 0x01a1850b ___forwarding___ + 1019
4 CoreFoundation 0x01a180ee _CF_forwarding_prep_0 + 14
5 positivity 0x00003807 -[SettingsViewController updateSwitchAtIndexPath:] + 87
6 libobjc.A.dylib 0x0158782b -[NSObject performSelector:withObject:] + 70
7 UIKit 0x002373b9 -[UIApplication sendAction:to:from:forEvent:] + 108
8 UIKit 0x00237345 -[UIApplication sendAction:toTarget:fromSender:forEvent:] + 61
9 UIKit 0x00338bd1 -[UIControl sendAction:to:forEvent:] + 66
10 UIKit 0x00338fc6 -[UIControl _sendActionsForEvents:withEvent:] + 577
11 UIKit 0x004c97a5 __31-[UISwitch _handleLongPressNL:]_block_invoke + 85
12 UIKit 0x004c8666 -[_UISwitchInternalViewNeueStyle1 _setPressed:on:animated:shouldAnimateLabels:completion:] + 243
13 UIKit 0x004c9681 -[UISwitch _handleLongPressNL:] + 286
14 UIKit 0x005d14f4 _UIGestureRecognizerSendActions + 230
15 UIKit 0x005d0168 -[UIGestureRecognizer _updateGestureWithEvent:buttonEvent:] + 383
16 UIKit 0x005d1bdd -[UIGestureRecognizer _delayedUpdateGesture] + 60
17 UIKit 0x005d513d ___UIGestureRecognizerUpdate_block_invoke + 57
18 UIKit 0x005d50be _UIGestureRecognizerRemoveObjectsFromArrayAndApplyBlocks + 317
19 UIKit 0x005cb7ac _UIGestureRecognizerUpdate + 199
20 UIKit 0x00276a5a -[UIWindow _sendGesturesForEvent:] + 1291
21 UIKit 0x00277971 -[UIWindow sendEvent:] + 1021
22 UIKit 0x002495f2 -[UIApplication sendEvent:] + 242
23 UIKit 0x00233353 _UIApplicationHandleEventQueue + 11455
24 CoreFoundation 0x019b177f __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 15
25 CoreFoundation 0x019b110b __CFRunLoopDoSources0 + 235
26 CoreFoundation 0x019ce1ae __CFRunLoopRun + 910
27 CoreFoundation 0x019cd9d3 CFRunLoopRunSpecific + 467
28 CoreFoundation 0x019cd7eb CFRunLoopRunInMode + 123
29 GraphicsServices 0x03a1c5ee GSEventRunModal + 192
30 GraphicsServices 0x03a1c42b GSEventRun + 104
31 UIKit 0x00235f9b UIApplicationMain + 1225
32 positivity 0x00005dbd main + 141
33 libdyld.dylib 0x0206f701 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
Any help would be greatly appreciated

Answer 1

UISwitch does not have a property called "row." The way your IBOutlet is set up, you will actually get an UISwitch object as a parameter instead of NSIndexPath.
The better thing to do here is to use the delegate pattern. That way, the custom cell can notify the UIViewController (containing the UITableView) that the switch has been pressed.
So it would be more like:
- (IBAction)updateSwitchAtIndexPath:(UISwitch *)mySwitch
{
// notify the delegate about the switch update
if ([self.delegate respondsToSelector:#selector(switchWasPressed:)]) {
[self.delegate switchWasPressed:mySwitch];
}
}