simple app crashing? - iphone

Question

I have a very simple window based app, i am simply putting a navigation view controller as window's root view controller and it's crashing. This is the only thing i changed in the template project:
#interface AppDelegate : NSObject <UIApplicationDelegate> {
UINavigationController *navigationController;
}
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
// Override point for customization after application launch.
navigationController = [[UINavigationController alloc] init];
[[self window] setRootViewController:navigationController];
[self.window makeKeyAndVisible];
return YES;
}
It crashes saying:
2011-05-26 20:18:57.194 ZebraSDKTest[5560:207] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<UICustomObject 0x8b3d760> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key navigationController.'
*** Call stack at first throw:
(
0 CoreFoundation 0x00dbf5a9 __exceptionPreprocess + 185
1 libobjc.A.dylib 0x00f13313 objc_exception_throw + 44
2 CoreFoundation 0x00dbf4e1 -[NSException raise] + 17
3 Foundation 0x00791677 _NSSetUsingKeyValueSetter + 135
4 Foundation 0x007915e5 -[NSObject(NSKeyValueCoding) setValue:forKey:] + 285
5 UIKit 0x0020d30c -[UIRuntimeOutletConnection connect] + 112
6 CoreFoundation 0x00d358cf -[NSArray makeObjectsPerformSelector:] + 239
7 UIKit 0x0020bd23 -[UINib instantiateWithOwner:options:] + 1041
8 UIKit 0x0020dab7 -[NSBundle(UINSBundleAdditions) loadNibNamed:owner:options:] + 168
9 UIKit 0x0001317a -[UIApplication _loadMainNibFile] + 172
10 UIKit 0x00013cf4 -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:] + 291
11 UIKit 0x0001e617 -[UIApplication handleEvent:withNewEvent:] + 1533
12 UIKit
0x00016abf -[UIApplication sendEvent:] + 71
13 UIKit 0x0001bf2e _UIApplicationHandleEvent + 7576
14 GraphicsServices 0x00ff8992 PurpleEventCallback + 1550
15 CoreFoundation 0x00da0944 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 52
16 CoreFoundation 0x00d00cf7 __CFRunLoopDoSource1 + 215
17 CoreFoundation 0x00cfdf83 __CFRunLoopRun + 979
18 CoreFoundation 0x00cfd840 CFRunLoopRunSpecific + 208
19 CoreFoundation 0x00cfd761 CFRunLoopRunInMode + 97
20 UIKit 0x000137d2 -[UIApplication _run] + 623
21 UIKit 0x0001fc93 UIApplicationMain + 1160
22 ZebraSDKTest 0x00002549 main + 121
23 ZebraSDKTest 0x000024c5 start + 53
)

Answer 1

Looks like you have a connection to a former existing UINavigationController IBOutlet in one of your nib files.
Start with MainWindow.xib and check for such a connection.

Answer 2

I had this problem occurring on the simulator only, but on the device it was working fine.
I tried cleaning the project, restarting Xcode, debugging, emptying the simulator data, the whole works.
In the end it was resolved by uninstalling the app from the simulator and reinstalling it. No idea why that worked, but it solved it!