Apples's Scrolling Example Crashes - iphone

Question

I am trying to run the Apple's Scrolling Sample Code, but I get following Error:
Scrolling[45877:207] Unknown class ScrollingAppDelegate in Interface Builder file.
Scrolling[45877:207] Unknown class ScrollingViewController in Interface Builder file.
Scrolling[45877:207] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<UICustomObject 0x4b33330> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key viewController.'
*** Call stack at first throw:
(
0 CoreFoundation 0x00f0cbe9 __exceptionPreprocess + 185
1 libobjc.A.dylib 0x010615c2 objc_exception_throw + 47
2 CoreFoundation 0x00f0cb21 -[NSException raise] + 17
3 Foundation 0x000306cf _NSSetUsingKeyValueSetter + 135
4 Foundation 0x0003063d -[NSObject(NSKeyValueCoding) setValue:forKey:] + 285
5 UIKit 0x004af8d6 -[UIRuntimeOutletConnection connect] + 112
6 CoreFoundation 0x00e832cf -[NSArray makeObjectsPerformSelector:] + 239
7 UIKit 0x004ae2ed -[UINib instantiateWithOwner:options:] + 1041
8 UIKit 0x004b0081 -[NSBundle(UINSBundleAdditions) loadNibNamed:owner:options:] + 168
9 UIKit 0x002ba943 -[UIApplication _loadMainNibFile] + 172
10 UIKit 0x002bb4ca -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:] + 291
11 UIKit 0x002c5db2 -[UIApplication handleEvent:withNewEvent:] + 1533
12 UIKit 0x002be202 -[UIApplication sendEvent:] + 71
13 UIKit 0x002c3732 _UIApplicationHandleEvent + 7576
14 GraphicsServices 0x01842a36 PurpleEventCallback + 1550
15 CoreFoundation 0x00eee064 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 52
16 CoreFoundation 0x00e4e6f7 __CFRunLoopDoSource1 + 215
17 CoreFoundation 0x00e4b983 __CFRunLoopRun + 979
18 CoreFoundation 0x00e4b240 CFRunLoopRunSpecific + 208
19 CoreFoundation 0x00e4b161 CFRunLoopRunInMode + 97
20 UIKit 0x002bafa8 -[UIApplication _run] + 636
21 UIKit 0x002c742e UIApplicationMain + 1160
22 Scrolling 0x0000279c main + 102
23 Scrolling 0x0000272d start + 53
)
terminate called after throwing an instance of 'NSException'
The weird thing is, that I can't find those connections in the MainWindow.xib (The only xib file). The Outlets are properly connected to the AppDelegate and MyViewController classes.

Answer 1

The Runtime cannot find a way to create an instance of the classes "ScrollingAppDelegate" and "ScrollingViewController", which are serialized in the xib file. So it defaults to UICustomObject, which you don't have either.
Are you sure those classes exist in your source file(s) and that they are compiled correctly (i.e., part of the "Compile" build phase)?
Also check the spelling and the capitalization of the classes. It has to match between the xib files and the source files.
If something is wrong, there could be a yellow warning dot in the xib file (bottom-right). Click it for more info.
Finally, the sample code is marked as iOS4+. Do you have iOS 4 on your device?