什么是尖括号“< ...>”在Obj-C类接口中？ [英] What are the angle brackets "<…>" in an Obj-C class interface for?

问题描述

任何人都可以告诉我什么尖括号< ...>在Obj-C类接口中做？像这样... http://snipt.net/robhawkes/cocoa-class-interface

@interface MapMeViewController：UIViewController< CLLocationManagerDelegate，MKReverseGeocoderDelegate，MKMapViewDelegate，UIAlertViewDelegate> {…

我以前有网络语言（PHP，JavaScript）和ActionScript的编程经验。从我的观点，他们看起来像一些类型的声明，像我们确保 MapMeViewController 是一个 CLLocationManagerDelegate，MKReverseGeocoderDelegate，MKMapViewDelegate或UIAlertViewDelegate 类，它们是 UIViewController 类。

有关 @interface 语法的文档似乎没有提及。

解决方案

类接口定义中的尖括号表示您的类符合的协议。

一个协议几乎就像一个接口在Java或C＃中，另外一个Objective-C协议中的方法可以是可选的。

另外在Objective-可以声明变量，参数或实例变量以符合多个协议。示例

  NSObject< NSCoding，UITableViewDelegate> * myVariable; 
  

在这种情况下，类必须是 NSObject 或者一个子类（只有 NSProxy ，它的子类会失败），它也必须符合 NSCoding 和<$ c / c>

在Java或C＃中，只有通过实际声明该类才能实现。

Can anyone tell me what the angle brackets "<…>" in an Obj-C class interface do? Like this… http://snipt.net/robhawkes/cocoa-class-interface

@interface MapMeViewController : UIViewController <CLLocationManagerDelegate, MKReverseGeocoderDelegate, MKMapViewDelegate, UIAlertViewDelegate> { …

I've previous programming experience with web languages (PHP, JavaScript) and ActionScript. From my view they look like some sort of type declaration, like we're making sure MapMeViewController is a CLLocationManagerDelegate, MKReverseGeocoderDelegate, MKMapViewDelegate, or UIAlertViewDelegate class that they are a UIViewController class. Perhaps?

Documentation about the @interface syntax don't seem to mention this.

解决方案

The angle brackets in a class interface definition indicates the protocols that your class is conforming to.

A protocol is almost like an interface in Java or C#, with the addition that methods in an Objective-C protocol can be optional.

Additionaly in Objective-C you can declare a variable, argument or instance variable to conform to several protocols as well. Example

NSObject<NSCoding, UITableViewDelegate> *myVariable;

In this case the class must be NSObject or a subclass (only NSProxy and its subclasses would fail), and it must also conform to both NSCoding and UITableViewDelegate protocols.

In Java or C# this would only be possible by actually declaring said class.

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