isKindOfClass, isMemberOfClass的区别

这两个方法常常会困惑我们，它们有什么区别呢？

定义

首先，我们来看看它们的定义。

isKindOfClass：

官方解释：Returns a Boolean value that indicates whether the receiver is an instance of given class or an instance of any class that inherits from that class.

isMemberOfClass：

官方解释：Returns a Boolean value that indicates whether the receiver is an instance of a given class.

使用

关于使用，在网上看到一个很形象的例子，这里就直接拿来用了。

这里有两个类，分别是继承于NSObject的Person，Person的Teacher

#import <Foundation/Foundation.h>   
  
@interface Person : NSObject  
{  
    NSString *name;  
}  
-(void)setName:(NSString*)n;  
  
@end  

 
#import "Person.h"   
  
@implementation Person  
-(void)setName:(NSString *)n  
{  
    name = n;  
}  
  
@end  

#import "Person.h"   
  
@interface Teacher : Person  
  
-(void)teach;  
  
@end  
 
#import "Teacher.h"   
  
@implementation Teacher  
-(void)teach  
{  
    NSLog(@"我教数学");  
}  
@end  

使用isKindOfClass的例子：

NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];  
Person *person = [[Person alloc] init];  
Teacher *teacher = [[Teacher alloc] init];  
  
//YES   
if ([teacher isKindOfClass:[Teacher class]]) {  
    NSLog(@"teacher 是 Teacher类或Teacher的子类");  
}  
//YES   
if ([teacher isKindOfClass:[Person class]]) {  
    NSLog(@"teacher 是 Person类或Person的子类");  
}  
//YES   
if ([teacher isKindOfClass:[NSObject class]]) {  
    NSLog(@"teacher 是 NSObject类或NSObject的子类");  
}  
[person release];  
[teacher release];  
[pool release];  

输出结果：

2012-07-04 14:34:17.315 ObjectiveCTest[2595:f803] teacher 是 Teacher类或Teacher的子类

2012-07-04 14:34:17.316 ObjectiveCTest[2595:f803] teacher 是 Person类或Person的子类

2012-07-04 14:34:17.316 ObjectiveCTest[2595:f803] teacher 是 NSObject类或NSObject的子类

使用isMemberOfClass的例子：

NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];  
   Person *person = [[Person alloc] init];  
   Teacher *teacher = [[Teacher alloc] init];  
     
   //YES   
   if ([teacher isMemberOfClass:[Teacher class]]) {  
        NSLog(@"teacher Teacher类的成员");  
   }  
   //NO   
   if ([teacher isMemberOfClass:[Person class]]) {  
       NSLog(@"teacher Person类的成员");  
   }  
   //NO   
   if ([teacher isMemberOfClass:[NSObject class]]) {  
       NSLog(@"teacher NSObject类的成员");  
   }  
   [person release];  
   [teacher release];  
   [pool release];  

输出结果：

2012-07-04 14:23:07.965 ObjectiveCTest[2460:f803] teacher Teacher类的成员

看了这两个例子，应该就会明白了。