conformsToProtocol:@protocol()的理解和用法

@protocol MyProtocol

- (void) doSomething;

@end

@interface MyClass : NSObject<MyProtocol>//直接符合协议的类
{
}

@end

@implementation MyClass

- (void) doSomething {
}

@end

@interface MyOtherClass : MyClass//继承了符合协议的类，即其父类符合协议。
{

}

@end

@implementation MyOtherClass

- (void) doSomething {
}

@end


int main (int argc, const char * argv[])
{
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

    MyClass *obj_one = [MyClass new];
    BOOL one_conforms = [obj_one conformsToProtocol:@protocol(MyProtocol)];

    MyOtherClass *obj_two = [MyOtherClass new];

    //obj_two是类的实例对象，和父类相关，其父类符合协议，则其亦符合。

    BOOL two_conforms = [obj_two conformsToProtocol:@protocol(MyProtocol)];
    NSLog(@"obj_one conformsToProtocol: %d", one_conforms);//output:YES
    NSLog(@"obj_two conformsToProtocol: %d", two_conforms);//output:YES
    [pool drain]; return 0;
}

//Output:
    obj_one conformsToProtocol: 1
    obj_two conformsToProtocol: 1

//Whereas:
     MyOtherClass *obj_two = [MyOtherClass new];
     //class_conformsToProtocol是只检查当前类符不符合协议，和其父类无关。
     BOOL conforms_two = class_conformsToProtocol([obj_two class], @protocol(MyProtocol));
     NSLog(@"obj_two conformsToProtocol: %d", conforms_two);//output:NO

//Output:
     obj_two conformsToProtocol: 0