将标签链接到 IBOutlet 会给出 NSUnknownKeyException

Question

我创建了一个 TabBarView。在其中一个选项卡上，我有一个带有多个标签的视图。效果很好。

当我将 Interface Builder 中的标签连接到文件的所有者（相应的 IBOutlet）时，当我打开该选项卡时，应用程序崩溃并出现以下错误：

2011-05-15 18:36:29.070 AeroNav[958:707] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<UIViewController 0x18afe0> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key speedLabel.'
*** Call stack at first throw:
(
0   CoreFoundation                      0x312a664f __exceptionPreprocess + 114
1   libobjc.A.dylib                     0x34a07c5d objc_exception_throw + 24
2   CoreFoundation                      0x312a63cd -[NSException dealloc] + 0
3   Foundation                          0x351c7edb -[NSObject(NSKeyValueCoding) setValue:forUndefinedKey:] + 182
4   Foundation                          0x351809cb _NSSetUsingKeyValueSetter + 90
5   Foundation                          0x35180217 -[NSObject(NSKeyValueCoding) setValue:forKey:] + 194
6   Foundation                          0x3516242f -[NSObject(NSKeyValueCoding) setValue:forKeyPath:] + 130
7   UIKit                               0x369848df -[UIRuntimeOutletConnection connect] + 66
8   CoreFoundation                      0x3123ed7b -[NSObject(NSObject) performSelector:] + 18
9   CoreFoundation                      0x3123e99d -[NSArray makeObjectsPerformSelector:] + 388
10  UIKit                               0x36983847 -[UINib instantiateWithOwner:options:] + 586
11  UIKit                               0x36984e09 -[NSBundle(UINSBundleAdditions) loadNibNamed:owner:options:] + 92
12  UIKit                               0x368fe5e9 -[UIViewController _loadViewFromNibNamed:bundle:] + 36
13  UIKit                               0x368cbfa5 -[UIViewController loadView] + 80
14  UIKit                               0x367b0ebf -[UIViewController view] + 30
15  UIKit                               0x367ee1db -[UITabBarController transitionFromViewController:toViewController:transition:shouldSetSelected:] + 66
16  UIKit                               0x367ee18d -[UITabBarController transitionFromViewController:toViewController:] + 32
17  UIKit                               0x367eda33 -[UITabBarController _setSelectedViewController:] + 186
18  UIKit                               0x36872ceb -[UITabBarController setSelectedViewController:] + 14
19  UIKit                               0x36872be7 -[UITabBarController _tabBarItemClicked:] + 226
20  CoreFoundation                      0x31216571 -[NSObject(NSObject) performSelector:withObject:withObject:] + 24
21  UIKit                               0x36796ec9 -[UIApplication sendAction:to:from:forEvent:] + 84
22  UIKit                               0x36796e69 -[UIApplication sendAction:toTarget:fromSender:forEvent:] + 32
23  UIKit                               0x36872a8b -[UITabBar _sendAction:withEvent:] + 270
24  CoreFoundation                      0x31216571 -[NSObject(NSObject) performSelector:withObject:withObject:] + 24
25  UIKit                               0x36796ec9 -[UIApplication sendAction:to:from:forEvent:] + 84
26  UIKit                               0x36796e69 -[UIApplication sendAction:toTarget:fromSender:forEvent:] + 32
27  UIKit                               0x36796e3b -[UIControl sendAction:to:forEvent:] + 38
28  UIKit                               0x36796b8d -[UIControl(Internal) _sendActionsForEvents:withEvent:] + 356
29  UIKit                               0x367d0bd9 -[UIControl sendActionsForControlEvents:] + 16
30  UIKit                               0x36872815 -[UITabBar(Static) _buttonUp:] + 80
31  CoreFoundation                      0x31216571 -[NSObject(NSObject) performSelector:withObject:withObject:] + 24
32  UIKit                               0x36796ec9 -[UIApplication sendAction:to:from:forEvent:] + 84
33  UIKit                               0x36796e69 -[UIApplication sendAction:toTarget:fromSender:forEvent:] + 32
34  UIKit                               0x36796e3b -[UIControl sendAction:to:forEvent:] + 38
35  UIKit                               0x36796b8d -[UIControl(Internal) _sendActionsForEvents:withEvent:] + 356
36  UIKit                               0x36797423 -[UIControl touchesEnded:withEvent:] + 342
37  UIKit                               0x36795bf5 -[UIWindow _sendTouchesForEvent:] + 368
38  UIKit                               0x3679556f -[UIWindow sendEvent:] + 262
39  UIKit                               0x3677e313 -[UIApplication sendEvent:] + 298
40  UIKit                               0x3677dc53 _UIApplicationHandleEvent + 5090
41  GraphicsServices                    0x36452e77 PurpleEventCallback + 666
42  CoreFoundation                      0x3127da97 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 26
43  CoreFoundation                      0x3127f83f __CFRunLoopDoSource1 + 166
44  CoreFoundation                      0x3128060d __CFRunLoopRun + 520
45  CoreFoundation                      0x31210ec3 CFRunLoopRunSpecific + 230
46  CoreFoundation                      0x31210dcb CFRunLoopRunInMode + 58
47  GraphicsServices                    0x3645241f GSEventRunModal + 114
48  GraphicsServices                    0x364524cb GSEventRun + 62
49  UIKit                               0x367a8d69 -[UIApplication _run] + 404
50  UIKit                               0x367a6807 UIApplicationMain + 670
51  AeroNav                             0x00002423 main + 70
52  AeroNav                             0x000023d8 start + 40
)
terminate called after throwing an instance of 'NSException'

我已读到它可能与 xib 不匹配（正确连接）与其相关视图控制器。我不知道如何检查或解决这个问题？

这就是我的头文件的样子：

//Stats.h
#import <UIKit/UIKit.h>
@interface Stats : UIViewController
{
    IBOutlet UILabel *speedLabel;
    IBOutlet UILabel *headingLabel;
}
@end

如果有人有任何提示或其他类似帖子的链接，我将不胜感激！

先感谢您！