Objective-C: unrecognized selector sent to instance 0xba3e750 - ios

Question

I have written this code and when I run the program it throws exception: unrecognized selector sent to instance 0xba3e750
storyboard = [UIStoryboard storyboardWithName:#"Main" bundle:nil];
navigationController = [storyboard instantiateViewControllerWithIdentifier:#"SecondViewID"];
selected = navigationController.viewControllers[0];
when I put this line in comment
//selected = navigationController.viewControllers[0];
like that , the program doesn't throw exception.
this is whole exception
2014-06-12 20:59:44.749 passing image[2194:a0b] -[SecondViewController viewControllers]: unrecognized selector sent to instance 0xba3e750
2014-06-12 20:59:44.753 passing image[2194:a0b] * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[SecondViewController viewControllers]: unrecognized selector sent to instance 0xba3e750'
* First throw call stack:
(
0 CoreFoundation 0x017445e4 exceptionPreprocess + 180
1 libobjc.A.dylib 0x014c78b6 objc_exception_throw + 44
2 CoreFoundation 0x017e1903 -[NSObject(NSObject) doesNotRecognizeSelector:] + 275
3 CoreFoundation 0x0173490b ___forwarding_ + 1019
4 CoreFoundation 0x017344ee _CF_forwarding_prep_0 + 14
5 passing image 0x000056a2 -[ViewController viewDidLoad] + 466
6 UIKit 0x00349318 -[UIViewController loadViewIfRequired] + 696
7 UIKit 0x003495b4 -[UIViewController view] + 35
8 UIKit 0x002719fd -[UIWindow addRootViewControllerViewIfPossible] + 66
9 UIKit 0x00271d97 -[UIWindow _setHidden:forced:] + 312
10 UIKit 0x0027202d -[UIWindow _orderFrontWithoutMakingKey] + 49
11 UIKit 0x0027c89a -[UIWindow makeKeyAndVisible] + 65
12 UIKit 0x0022fcd0 -[UIApplication _callInitializationDelegatesForURL:payload:suspended:] + 1851
13 UIKit 0x002343a8 -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:] + 824
14 UIKit 0x0024887c -[UIApplication handleEvent:withNewEvent:] + 3447
15 UIKit 0x00248de9 -[UIApplication sendEvent:] + 85
16 UIKit 0x00236025 _UIApplicationHandleEvent + 736
17 GraphicsServices 0x037932f6 _PurpleEventCallback + 776
18 GraphicsServices 0x03792e01 PurpleEventCallback + 46
19 CoreFoundation 0x016bfd65 CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION + 53
20 CoreFoundation 0x016bfa9b __CFRunLoopDoSource1 + 523
21 CoreFoundation 0x016ea77c __CFRunLoopRun + 2156
22 CoreFoundation 0x016e9ac3 CFRunLoopRunSpecific + 467
23 CoreFoundation 0x016e98db CFRunLoopRunInMode + 123
24 UIKit 0x00233add -[UIApplication _run] + 840
25 UIKit 0x00235d3b UIApplicationMain + 1225
26 passing image 0x0000750d main + 141
27 libdyld.dylib 0x01e78725 start + 0
28 ??? 0x00000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)

Answer 1

instantiateViewControllerWithIdentifier: returns a UIViewController, but you're storing it in a UINavigationController when you shouldn't. When you try to access a UINavigationController property (viewControllers), it crashed because UIViewController doesn't have a property named viewControllers.
Try storing the return of the method instantiateViewControllerWithIdentifier: in a UIViewController instead of a UINavigationController :
UIViewController * viewController = [storyboard instantiateViewControllerWithIdentifier:#"SecondViewID"];
selected = viewController.navigationController.viewControllers[0];