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来自故事板的loadNibNamed

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这是一个场景:一个带有两个viewcontroller类的简单应用程序和一个带有1个viewcontroller的storyboard . ViewController 'Super'继承自 UIViewcontroller 并实现 - loadView 而另一个视图控制器'Sub'继承自'Super' . 故事板中的视图控制器类是'Sub' .

在代码中:

@implementation SOSuperViewController
- (void)loadView {
    self.view = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.view.backgroundColor = [UIColor redColor];
    NSLog(@"%@=> %@", NSStringFromClass([self superclass]), NSStringFromSelector(_cmd));
} 
@end

@implementation SOSubViewController
- (void)awakeFromNib {
    //Outlets are lazy loaded so self.view it is not really set here
    [super awakeFromNib];

    NSLog(@"%@=> %@", NSStringFromClass([self class]), NSStringFromSelector(_cmd));
}

@end

故事板中视图控制器的类是 SOSubViewController . 执行应用程序时,您可以看到'Sub'控制器中调用的 awakeFromNib 以及'Super'控制器中调用的 loadView ,结果是'Super'中的 loadView 中设置的屏幕为红色 .

第一个问题是:有没有办法避免'Super'在'Super'被调用让'Sub'从故事板获取视图?

如果使用xib而不是故事板,我会在'Sub'中实现 loadView 来从xib文件中获取视图,例如:

- (void)loadView {
    self.view = [[[NSBundle mainBundle] loadNibNamed:@"SOView" owner:self options:nil] firstObject];
}

但我不知道使用故事板的nib文件的名称,而是如果设置我需要使用nibBundle和nibName属性:

- (void)loadView {
    if (self.nibBundle && self.nibName) {
        [self.nibBundle loadNibNamed:self.nibName owner:self options:nil];
    }
}

但那崩溃了:

2014-04-10 11:55:11.872 loadViewTest[8941:60b] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Could not load NIB in bundle: 'NSBundle </Users/nlg/Library/Application Support/iPhone Simulator/7.1/Applications/E36DFC3A-4222-4CE4-A954-CC1C3891DCE1/loadViewTest.app> (loaded)' with name 'vXZ-lx-hvc-view-kh9-bI-dsS''
*** First throw call stack:
(
    0   CoreFoundation                      0x017ec1e4 __exceptionPreprocess + 180
    1   libobjc.A.dylib                     0x0156b8e5 objc_exception_throw + 44
    2   CoreFoundation                      0x017ebfbb +[NSException raise:format:] + 139
    3   UIKit                               0x004e0b7b -[UINib instantiateWithOwner:options:] + 951
    4   UIKit                               0x004e2ada -[NSBundle(UINSBundleAdditions) loadNibNamed:owner:options:] + 165
    5   loadViewTest                        0x00002cff -[SOSuperViewController loadView] + 319
    6   UIKit                               0x0034a0d3 -[UIViewController loadViewIfRequired] + 78
    7   UIKit                               0x0034a5d9 -[UIViewController view] + 35
    8   UIKit                               0x0026a267 -[UIWindow addRootViewControllerViewIfPossible] + 66
    9   UIKit                               0x0026a5ef -[UIWindow _setHidden:forced:] + 312
    10  UIKit                               0x0026a86b -[UIWindow _orderFrontWithoutMakingKey] + 49
    11  UIKit                               0x002753c8 -[UIWindow makeKeyAndVisible] + 65
    12  UIKit                               0x00225bc0 -[UIApplication _callInitializationDelegatesForURL:payload:suspended:] + 2097
    13  UIKit                               0x0022a667 -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:] + 824
    14  UIKit                               0x0023ef92 -[UIApplication handleEvent:withNewEvent:] + 3517
    15  UIKit                               0x0023f555 -[UIApplication sendEvent:] + 85
    16  UIKit                               0x0022c250 _UIApplicationHandleEvent + 683
    17  GraphicsServices                    0x037e1f02 _PurpleEventCallback + 776
    18  GraphicsServices                    0x037e1a0d PurpleEventCallback + 46
    19  CoreFoundation                      0x01767ca5 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 53
    20  CoreFoundation                      0x017679db __CFRunLoopDoSource1 + 523
    21  CoreFoundation                      0x0179268c __CFRunLoopRun + 2156
    22  CoreFoundation                      0x017919d3 CFRunLoopRunSpecific + 467
    23  CoreFoundation                      0x017917eb CFRunLoopRunInMode + 123
    24  UIKit                               0x00229d9c -[UIApplication _run] + 840
    25  UIKit                               0x0022bf9b UIApplicationMain + 1225
    26  loadViewTest                        0x0000309d main + 141
    27  libdyld.dylib                       0x01e33701 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

第二个问题是:是否可以使用没有任何xib文件的故事板加载笔尖?

作为好奇心,我刚刚发现self.nibName的值是vXZ-lx-hvc-view-kh9-bI-dsS,其中#object id是storyboard中的viewcontroller#-view-#object id for viewcontroller中的视图#哪种看起来正确 .

1 回答

  • 3

    你不能 .

    loadNibName 应该在你的情况下加载一个名为 SOView.xib 的笔尖 .

    如果你只是想加载视图,你可以在单独的 xib 文件中创建视图,但是当我们处理故事板时,我们只在其中添加 UIViewController (当然,它可以包含自定义视图) .

    要从故事栏中实例化方法,请使用以下方法:

    [self.storyboard instantiateViewControllerWithIdentifier:@"myControllerID"];
    

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