ios Objective-C 中的“类别”是什么？
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What is “category” in Objective-C?
提问by wOlVeRiNe
Possible Duplicate:
How does a category work in Objective-C?
可能的重复：
类别在 Objective-C 中是如何工作的？
I am just getting started with Objective-C and was wondering when and where am i supposed to use category in objective C. is it a class or a protocol? An explanatory example would be of great help. Thanks
我刚刚开始使用 Objective-C，想知道我应该在何时何地在 Objective C 中使用类别。它是一个类还是一个协议？一个解释性的例子会很有帮助。谢谢
回答by Jhaliya
A category allows you to add methods to an existing class—even to one for which you do not have the source.
类别允许您向现有类添加方法，即使是您没有源的类。
Categories are a powerful feature that allows you to extend the functionality of existing classes without subclassing
类别是一项强大的功能，它允许您扩展现有类的功能而无需子类化
Check the apple doc for the Category in Objective-C
在 Apple 文档中查看Objective-C 中的Category
回答by Abizern
There is a section in the Objective-C 2.0 programming Language document about Categories and Extensions.
Objective-C 2.0 编程语言文档中有一个关于类别和扩展的部分。
As you are just getting started it's a good doc to have on hand to look things up.
由于您才刚刚开始，这是一个很好的文档，可以随时查看。
There is also a section on Categoriesin the Cocoa Core Competencies document, which is easier to get started with, and also has a lot of useful information for the beginner.
Cocoa Core Competencies文档中还有一个关于Categories的部分，比较容易上手，也有很多对初学者有用的信息。
