ipad - UIWebView 抛出 NSUnknownKeyException iPad

Question

我有一个标签栏应用程序。一切正常，我可以在选项卡之间正常切换，除了当我切换到我的第二个选项卡 ProductViewClass 时， View 不会更新，它会在下面吐出控制台输出。除了 UIWebView 和 UILabel 之外，我在这个 View 中什么都没有。当我删除 UIWebView 它运行成功，当我添加另一个它仍然有效。只有当我将 IBOutlet 从我的文件所有者连接到 UIWebView 时，它才会停止工作。除了合成和发布productWebView之外，ProductWebView.m中唯一的非模板代码是这样的:

    NSString *urlString = @"http://www.google.com/";
    NSURL *theURL = [NSURL URLWithString:urlString];
    NSURLRequest *urlRequest = [NSURLRequest requestWithURL:theURL];
    [productWebView loadRequest:urlRequest];
    NSLog(@"Google loaded");

ProductWebView.h的整体如下:

#import <UIKit/UIKit.h>
@interface ProductViewClass : UIViewController {

    IBOutlet UIWebView *productWebView;
}

@property(nonatomic, retain) UIWebView *productWebView;
@end

这是控制台输出:

This GDB was configured as "x86_64-apple-darwin".Attaching to process 52523.
2011-01-30 19:18:28.907 FairCom[52523:40b] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<UIViewController 0x4d06eb0> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key productWebView.'
*** Call stack at first throw:
(
    0   CoreFoundation                      0x00da8be9 __exceptionPreprocess + 185
    1   libobjc.A.dylib                     0x00efd5c2 objc_exception_throw + 47
    2   CoreFoundation                      0x00da8b21 -[NSException raise] + 17
    3   Foundation                          0x000296cf _NSSetUsingKeyValueSetter + 135
    4   Foundation                          0x0002963d -[NSObject(NSKeyValueCoding) setValue:forKey:] + 285
    5   UIKit                               0x004a88d6 -[UIRuntimeOutletConnection connect] + 112
    6   CoreFoundation                      0x00d1f2cf -[NSArray makeObjectsPerformSelector:] + 239
    7   UIKit                               0x004a72ed -[UINib instantiateWithOwner:options:] + 1041
    8   UIKit                               0x004a9081 -[NSBundle(UINSBundleAdditions) loadNibNamed:owner:options:] + 168
    9   UIKit                               0x00361a94 -[UIViewController _loadViewFromNibNamed:bundle:] + 70
    10  UIKit                               0x0035f709 -[UIViewController loadView] + 120
    11  UIKit                               0x0035f5e3 -[UIViewController view] + 56
    12  UIKit                               0x00372230 -[UITabBarController transitionFromViewController:toViewController:transition:shouldSetSelected:] + 120
    13  UIKit                               0x00370d86 -[UITabBarController transitionFromViewController:toViewController:] + 64
    14  UIKit                               0x00372b7e -[UITabBarController _setSelectedViewController:] + 263
    15  UIKit                               0x003729ed -[UITabBarController _tabBarItemClicked:] + 352
    16  UIKit                               0x002b1a6e -[UIApplication sendAction:to:from:forEvent:] + 119
    17  UIKit                               0x004af1f2 -[UITabBar _sendAction:withEvent:] + 422
    18  UIKit                               0x002b1a6e -[UIApplication sendAction:to:from:forEvent:] + 119
    19  UIKit                               0x003401b5 -[UIControl sendAction:to:forEvent:] + 67
    20  UIKit                               0x00342647 -[UIControl(Internal) _sendActionsForEvents:withEvent:] + 527
    21  UIKit                               0x0034016c -[UIControl sendActionsForControlEvents:] + 49
    22  UIKit                               0x002b1a6e -[UIApplication sendAction:to:from:forEvent:] + 119
    23  UIKit                               0x003401b5 -[UIControl sendAction:to:forEvent:] + 67
    24  UIKit                               0x00342647 -[UIControl(Internal) _sendActionsForEvents:withEvent:] + 527
    25  UIKit                               0x003411f4 -[UIControl touchesEnded:withEvent:] + 458
    26  UIKit                               0x002d60d1 -[UIWindow _sendTouchesForEvent:] + 567
    27  UIKit                               0x002b737a -[UIApplication sendEvent:] + 447
    28  UIKit                               0x002bc732 _UIApplicationHandleEvent + 7576
    29  GraphicsServices                    0x016dea36 PurpleEventCallback + 1550
    30  CoreFoundation                      0x00d8a064 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 52
    31  CoreFoundation                      0x00cea6f7 __CFRunLoopDoSource1 + 215
    32  CoreFoundation                      0x00ce7983 __CFRunLoopRun + 979
    33  CoreFoundation                      0x00ce7240 CFRunLoopRunSpecific + 208
    34  CoreFoundation                      0x00ce7161 CFRunLoopRunInMode + 97
    35  GraphicsServices                    0x016dd268 GSEventRunModal + 217
    36  GraphicsServices                    0x016dd32d GSEventRun + 115
    37  UIKit                               0x002c042e UIApplicationMain + 1160
    38  FairCom                             0x00001be0 main + 102
    39  FairCom                             0x00001b71 start + 53
    40  ???                                 0x00000001 0x0 + 1
)
terminate called after throwing an instance of 'NSException'
sharedlibrary apply-load-rules all
(gdb) 

感谢您的帮助!

Answer 1

您正在加载 Nib 。在那个 Nib 中，你有一个名为 productWebView 的 socket 大概是连接到 WebView 。您看到的异常是告诉您 socket productWebView实际上并不存在。这就是它变得奇怪的地方。错误说对象 <UIViewController 0x4d06eb0>是缺少导出的那个。奇怪的是它说 UIViewController而不是实际 View Controller 子类的名称。听起来你有一个 nib，其中 File's Owner 被设置为你的 View Controller 子类之一，但在运行时你实际上只是使用 UIViewController 的一个实例。直接地。您应该验证所有代表选项卡栏 Controller 中选项卡的 View Controller 都是 UIViewController 的实际正确子类。而不仅仅是 UIViewController 的一个实例本身。