使用 UIColor RGB black 作为 NSMutableDictionary 中的键时出现问题
我可以整天将 UIColor 对象设置为 NSMutableDictionary 中的键，一切都很好，很开心...
例如：
[myDict setObject:foo forKey:[UIColor redColor]];
这很好用...除非我尝试使用以下内容：
UIColor *black = [[UIColor alloc] initWithRed:0 green:0 blue:0 alpha:1];
[myDict setObject:foo forKey:black];
这总是给我：
-[UIDeviceRGBColor copyWithZone: ]: 无法识别的选择器发送到实例 0x691be80
我在 RGB 色彩空间中定义黑色的原因对于这个问题并不重要，只需知道我必须这样定义它即可。我不明白的是为什么这个并且只有这个颜色给我带来了问题，为什么错误是 copyWithZone 错误？
根据记录，[UIColor blackColor] 作为键，但因为它不是 RGB 色彩空间，所以不适合我的应用程序。
I can set UIColor objects as keys in an NSMutableDictionary all day long and everything is fine and happy...
For instance:
[myDict setObject:foo forKey:[UIColor redColor]];
That works just fine... UNLESS I try to use the following:
UIColor *black = [[UIColor alloc] initWithRed:0 green:0 blue:0 alpha:1];
[myDict setObject:foo forKey:black];
That always gives me:
-[UIDeviceRGBColor copyWithZone:]: unrecognized selector sent to instance 0x691be80
The reasons for why I'm defining black in the RGB colorspace are unimportant to this question, just know that I must define it that way. What I don't understand is why is this and only this color causing me a problem, and why is it that the error is a copyWithZone error?
For the record, [UIColor blackColor] works as a key, but because it isn't an RGB colorspace it is not suitable for my application.
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看起来更好的问题是“为什么其他所有 UIColor 实例都充当键”？
NSMutableDictionary 中的键“必须符合 NSCopying 协议”。
UIColor对象不符合该协议 根据文档，因此理论上您无法将它们用作字典中的键。在实践中，我可能会猜测您会从
UIColor隐藏的类簇中获取各种具体子类，也许其中一些子类实际上支持 NSCopying，但UIDeviceRGBColor代码> 似乎没有。您可以将 UIColor 对象包装在一个支持 NSCopying 的薄包装对象中，并覆盖
-isEqualTo:等以使比较正常工作，然后在字典。It looks like the better question is "why does every other UIColor instance work as a key"?
Keys in an NSMutableDictionary "must conform to the NSCopying protocol".
UIColorobjects don't conform to that protocol per the documentation, so you're theoretically unable to use them as keys in a dictionary.In practice, I might guess that you're getting various concrete subclasses from a class cluster that's hidden by
UIColor, and maybe some of them do, in fact, support NSCopying, butUIDeviceRGBColordoes not seem to.You could wrap the UIColor object in a thin wrapper object that did support NSCopying, and override
-isEqualTo:etc to get the comparisons to work correctly, and then use those wrappers in the dictionary.