isKindOfClass 和 isMemeberOfClass 区别

http://www.linuxidc.com/Linux/2012-07/64453.htm

1、新建Person类继承NSObject,新建Teacher类继承Person

1.1、新建Person类

1. #import<Foundation/Foundation.h>
3. @interfacePerson:NSObject
4. {
5. NSString*name;
6. }
7. -(void)setName:(NSString*)n;
9. @end

1. #import"Person.h"
3. @implementationPerson
4. -(void)setName:(NSString*)n
5. {
6. name=n;
7. }
9. @end

1.2新建Teacher类

1. #import"Person.h"
3. @interfaceTeacher:Person
5. -(void)teach;
7. @end

1. #import"Teacher.h"
3. @implementationTeacher
4. -(void)teach
5. {
6. NSLog(@"我教数学");
7. }
8. @end

1.3 我们先实验下isMemberOfClass方法。

1. NSAutoreleasePool*pool=[[NSAutoreleasePoolalloc]init];
2. Person*person=[[Personalloc]init];
3. Teacher*teacher=[[Teacheralloc]init];
5. //YES
6. if([teacherisMemberOfClass:[Teacherclass]]){
7. NSLog(@"teacherTeacher类的成员");
8. }
9. //NO
10. if([teacherisMemberOfClass:[Personclass]]){
11. NSLog(@"teacherPerson类的成员");
12. }
13. //NO
14. if([teacherisMemberOfClass:[NSObjectclass]]){
15. NSLog(@"teacherNSObject类的成员");
16. }
17. [personrelease];
18. [teacherrelease];
19. [poolrelease];

打印结果：

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

只有第一个判断打印出来，isMemberOfClass判断是否是属于这类的实例，是否跟父类有关系他不管。

1.4isMemberOfClass方法

1. NSAutoreleasePool*pool=[[NSAutoreleasePoolalloc]init];
2. Person*person=[[Personalloc]init];
3. Teacher*teacher=[[Teacheralloc]init];
5. //YES
6. if([teacherisKindOfClass:[Teacherclass]]){
7. NSLog(@"teacher是Teacher类或Teacher的子类");
8. }
9. //YES
10. if([teacherisKindOfClass:[Personclass]]){
11. NSLog(@"teacher是Person类或Person的子类");
12. }
13. //YES
14. if([teacherisKindOfClass:[NSObjectclass]]){
15. NSLog(@"teacher是NSObject类或NSObject的子类");
16. }
17. [personrelease];
18. [teacherrelease];
19. [poolrelease];

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

三个结果都打印出来了。

2、

-(BOOL) respondsToSelector: selector 判读实例是否有这样方法

+(BOOL) instancesRespondToSelector: 判断类是否有这个方法。此方法是类方法，不能用在类的对象

2.1respondsToSelector的使用

这里不写对象的创建和释放了，参考上面的代码

1. //YES
2. if([teacherrespondsToSelector:@selector(setName:)]==YES){
3. NSLog(@"teacherrespondstosetSize:method");
4. }
6. //NO
7. if([teacherrespondsToSelector:@selector(abcde)]==YES){
8. NSLog(@"teacherrespondstononExistantmethod");
9. }
11. //YES
12. if([TeacherrespondsToSelector:@selector(alloc)]==YES){
13. NSLog(@"teacherclassrespondstoallocmethod\n");
14. }

打印结果：

2012-07-04 14:39:49.853 ObjectiveCTest[2723:f803] teacher responds to setSize: method

2012-07-04 14:39:49.854 ObjectiveCTest[2723:f803] teacher class responds to alloc method

中间的那个判断我随便写了个selector,当然没有了。respondsToSelector 检查类方法 alloc返回YES

2.2instancesRespondToSelector

1. //NO
2. if([PersoninstancesRespondToSelector:@selector(teach)]==YES){
3. NSLog(@"Personinstancerespondstoteachmethod");
4. }
6. //YES
7. if([TeacherinstancesRespondToSelector:@selector(teach)]==YES){
8. NSLog(@"Teacherinstancerespondstoteachmethod");
9. }
10. //YES
11. if([TeacherinstancesRespondToSelector:@selector(setName:)]==YES){
12. NSLog(@"TeacherinstancerespondstosetName:method");
13. }

打印结果：

1. 2012-07-0414:52:29.378ObjectiveCTest[2961:f803]Teacherinstancerespondstoteachmethod
2. 2012-07-0414:52:29.379ObjectiveCTest[2961:f803]TeacherinstancerespondstosetName:method

3、Objective-C的id类型

C++ 使用的是强类型：对象必须符合其类型，否则不能通过编译。在 Objective-C 中，id类型类似于(void*) ,可以指向任何类的实例。而不需要强制转换。

下面看看使用，

先把Teacher类中的 teach方法修改一下，改成

-(void)teach

{

NSLog(@"%@教数学",name);

}

然后实现并调用

1. NSAutoreleasePool*pool=[[NSAutoreleasePoolalloc]init];
2. Person*person=[[Personalloc]init];
3. Teacher*teacher=[[Teacheralloc]init];
5. idp=person;
6. idt=teacher;
7. [tsetName:@"张三老师"];
8. [tteach];
10. [personrelease];
11. [teacherrelease];
12. [poolrelease];

打印结果：

1. 2012-07-0414:57:55.905ObjectiveCTest[3085:f803]张三老师教数学