ios - Swizzling 符合 UI_APPEARANCE_SELECTOR 的属性

Question

我正在尝试调整 UIView 上的 backgroundColor 属性。

在我调酒之前，我执行以下操作:

@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 swizzled 方法时，除了调用原始方法之外，我什么都不做:

-(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(例如 UIToolBar)上执行 [自我外观]，也会发生这种情况

任何的想法？？

Answer 1

外观系统将所有属性限制在单个实现中 TaggingAppearanceObjectSetterIMP .该实现检查选择器的名称(使用 _UIAppearanceTagObjectForSelector )并在关联的对象缓存(存储在 __UIAppearanceCustomizedSelectorsAssociationKey 中)中查找。如果它不存在，它会调用 _TagForSelectorWithAxes找出映射到该选择器的内容，并更新缓存。

您使用自己的运行时诡计直接陷入了相当复杂的运行时诡计的中间。这爆炸了并不令人震惊......:D

基本问题至少是方法的名称必须是 setBackgroundColor ，不是 swizzled_setBackgroundColor .您可以通过混入实际的实现函数而不是方法来解决这个问题。你可以看看 NSNotificationCenter+RNSwizzle.m 以手动执行此操作的示例。

如果在修复该问题后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“永远不要混合生产代码，它太脆弱了，”但如果你忽略了这个建议......)在 Hopper 中拉出外观代码并跟踪实现，这样您就可以确保一切都对齐。这并不复杂，Hopper 的伪代码模式几乎可以向您展示发生了什么(我花了大约 2 分钟才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现细节，它很容易在没有警告的情况下改变(导致新的崩溃)。如果您可以在不混淆的情况下做到这一点，我强烈建议您这样做。