在符合ui_appearance_selector符合的属性上

Question

我正在尝试在uiview上浏览背景属性。

在我浏览之前，我要执行以下操作：

@implementation UIView (Cat1)
+(void)load {
NSArray *selectors = @[
                     //Highliter swizzling
                     NSStringFromSelector(@selector(setBackgroundColor:)),
                     NSStringFromSelector(@selector(backgroundColor))
                     ];
[[self appearance] setBackgroundColor:[UIColor redColor]];
for (NSString *name in selectors) {
    SEL originalSelector = NSSelectorFromString(name);
    SEL swizzledSelector = NSSelectorFromString([NSString stringWithFormat:@"swizzled_%@",name]);
    Method originalMethod = class_getInstanceMethod(self, originalSelector);
    Method swizzledMethod = class_getInstanceMethod(self, swizzledSelector);
    class_addMethod(self,
                    originalSelector,
                    class_getMethodImplementation(self, originalSelector),
                    method_getTypeEncoding(originalMethod));
    class_addMethod(self,
                    swizzledSelector,
                    class_getMethodImplementation(self, swizzledSelector),
                    method_getTypeEncoding(swizzledMethod));
    method_exchangeImplementations(originalMethod, swizzledMethod);
}

然后，当调用爆炸的方法时，除了调用原件外，我什么也没做任何事情：

-(void)swizzled_setBackgroundColor:(UIColor *)color {
[self iio_swizzled_setBackgroundColor:color];
}

然后，发生以下崩溃：2017-03-08 19:04:37.863 Develop-InsertViewer[69285:7916872] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Please file a radar on UIKit if you see this assertion.' *** First throw call stack: ( 0 CoreFoundation 0x0000000108506e65 __exceptionPreprocess + 165 1 libobjc.A.dylib 0x0000000107c7ddeb objc_exception_throw + 48 2 CoreFoundation 0x0000000108506cca +[NSException raise:format:arguments:] + 106 3 Foundation 0x00000001078ca5a2 -[NSAssertionHandler handleFailureInFunction:file:lineNumber:description:] + 169 4 UIKit 0x0000000106227b35 PushNextClassForSettingIMP + 469 5 UIKit 0x000000010622810a TaggingAppearanceObjectSetterIMP + 37 6 InsertFramework 0x00000001071332be -[UIView(Cat1) swizzled_setBackgroundColor:] + 62 7 UIKit 0x0000000105d78fca -[UILabel _commonInit] + 238 8 UIKit 0x0000000105d7913d -[UILabel initWithFrame:] + 94 9 UIKit 0x0000000105b9cc4e -[UIView init] + 62 10 0x0000000105533300 _TTOFCSo7UILabelcfT_S_ + 16 11 0x0000000105532e44 _TFCSo7UILabelCfT_S_ + 68 12 0x0000000105569be3 _TFC12InsertViewer21StarterViewControllercfT5coderCSo7NSCoder_GSqS0__ + 51 13 0x0000000105569d2d _TToFC12InsertViewer21StarterViewControllercfT5coderCSo7NSCoder_GSqS0__ + 45 14 UIKit 0x0000000105ecb7db -[UIClassSwapper initWithCoder:] + 241 15 UIKit 0x000000010609f822 UINibDecoderDecodeObjectForValue + 705 16 UIKit 0x000000010609f558 -[UINibDecoder decodeObjectForKey:] + 278 17 UIKit 0x0000000105ecb4b1 -[UIRuntimeConnection initWithCoder:] + 180 18 UIKit 0x000000010609f822 UINibDecoderDecodeObjectForValue + 705 19 UIKit 0x000000010609f9e3 UINibDecoderDecodeObjectForValue + 1154 20 UIKit 0x000000010609f558 -[UINibDecoder decodeObjectForKey:] + 278 21 UIKit 0x0000000105eca6c3 -[UINib instantiateWithOwner:options:] + 1255 22 UIKit 0x0000000106232c40 -[UIStoryboard instantiateViewControllerWithIdentifier:] + 181 23 UIKit 0x0000000106232d93 -[UIStoryboard instantiateInitialViewController] + 69 24 UIKit 0x0000000105b0dfa6 -[UIApplication _loadMainStoryboardFileNamed:bundle:] + 94 25 UIKit 0x0000000105b0e2d6 -[UIApplication _loadMainInterfaceFile] + 260 26 UIKit 0x0000000105b0cb54 -[UIApplication _runWithMainScene:transitionContext:completion:] + 1390 27 UIKit 0x0000000105b09e7b -[UIApplication workspaceDidEndTransaction:] + 188 28 FrontBoardServices 0x000000010b41e754 -[FBSSerialQueue _performNext] + 192 29 FrontBoardServices 0x000000010b41eac2 -[FBSSerialQueue _performNextFromRunLoopSource] + 45 30 CoreFoundation 0x0000000108432a31 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17 31 CoreFoundation 0x000000010842895c __CFRunLoopDoSources0 + 556 32 CoreFoundation 0x0000000108427e13 __CFRunLoopRun + 867 33 CoreFoundation 0x0000000108427828 CFRunLoopRunSpecific + 488 34 UIKit 0x0000000105b097cd -[UIApplication _run] + 402 35 UIKit 0x0000000105b0e610 UIApplicationMain + 171 36 Develop-InsertViewer 0x00000001055ae752 main + 114 37 libdyld.dylib 0x00000001095a192d start + 1 ) libc++abi.dylib: terminating with uncaught exception of type NSException

如果我在其他类上进行[自我外观]，例如uitoolbar

有什么想法？

Answer 1

外观系统瓶颈将所有属性都带入单个实现TaggingAppearanceObjectSetterIMP。该实现检查选择器的名称（使用_UIAppearanceTagObjectForSelector），并在关联的对象缓存中查看（存储在__UIAppearanceCustomizedSelectorsAssociationKey中）中。如果还不存在，它调用_TagForSelectorWithAxes来弄清楚其映射到该选择器并更新缓存。

您用自己的运行时骗局踩着相当复杂的运行时骗局中间。这并不令人震惊。

基本问题至少是该方法的名称必须是setBackgroundColor，而不是swizzled_setBackgroundColor。您可以通过在实际实施功能中散布而不是一种方法来在某种程度上解决这个问题。您可以查看 NSNotificationCenter+RNSwizzle.m的示例。

如果您仍然遇到其他微妙的问题，我不会感到惊讶。我的建议是（嗯，我的建议是"永远不要浪费生产代码，这太脆弱了"，但是如果您忽略了该建议……）在料斗中拔出外观代码，并通过实施方式进行跟踪，以确保所有内容都可以确保所有内容线条向上。并不复杂并不是，霍珀的伪代码模式几乎会向您展示发生了什么（我花了大约2分钟才能弄清楚我在这里发布的内容）。也就是说，这是一个非常棘手的实施细节，并且可以在没有警告的情况下很容易改变（导致新的崩溃）。如果您可以做到这一点而无需滚动，我强烈建议您这样做。