Objective-C：将一个实现协议的类别添加到现有类中,是否使对象符

发布时间：2020-12-16 07:08:42 所属栏目：百科来源：网络整理

导读：Objective-C：将一个实现协议的Category添加到现有Class中,是否使从该类实例化的所有Object都符合该协议？进一步来说： [myObject conformsToProtocol:@protocol(ProtocolThatWasImplementedViaACategory)]; 返回TRUE？解决方法是的,确实如此 – 假设您在

Objective-C：将一个实现协议的Category添加到现有Class中,是否使从该类实例化的所有Object都符合该协议？

进一步来说：

[myObject conformsToProtocol:@protocol(ProtocolThatWasImplementedViaACategory)];

返回TRUE？

解决方法

是的,确实如此 – 假设您在类别的@interface声明中添加了适当的声明.你可以自己检查一下：

@interface MyClass : NSObject 
@end

@protocol  Dummy <NSObject>

-(void)dummyMethod;

@end

@interface MyClass (MyCategory) <Dummy>

@end

@implementation MyClass (MyCategory) 

+ (void)load {
    BOOL conforms = [self conformsToProtocol:@protocol(Dummy)];
    NSLog(@"conforms to Dummy? %@",@(conforms));
}

@end

输出是：

conforms to Dummy? 1

您可以阅读有关conformsToProtocol：如何在documentation中工作的说明：

A class is said to “conform to” a protocol if it adopts the protocol or inherits from another class that adopts it. Protocols are adopted by listing them within angle brackets after the interface declaration. For example,here MyClass adopts the (fictitious) AffiliationRequests and Normalization protocols:

@interface MyClass : NSObject <AffiliationRequests,Normalization>

（编辑：李大同）

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