一些公用類：

@interface CustomClass : NSObject

- (void) fun1;

@end

@implementation CustomClass

- (void) fun1

{

    NSLog(@"fun1");

}

@end

@interface TestClass : NSObject

@end

@implementation TestClass

@end

別忘記引入庫：#include<objc/runtime.h>

1、物件拷貝：id object_copy(id obj, size_t size)

- (void) copyObj

{

CustomClass *obj = [CustomClassnew];

    NSLog(@"%p", &obj);

    id objTest = object_copy(obj,sizeof(obj));

    NSLog(@"%p", &objTest);

    [objTest fun1];

}

列印結果：

2013-07-26 15:35:11.547 HighOC[6859:c07] 0xbfffdf64

2013-07-26 15:35:11.547 HighOC[6859:c07] 0xbfffdf60

2013-07-26 15:35:11.547 HighOC[6859:c07] fun1

說明：

2、物件釋放 id object_dispose(id obj)

- (void) objectDispose

{

CustomClass *obj = [CustomClassnew];

object_dispose(obj);

    [obj release];

    [obj fun1];

}

malloc: *** error for object 0x758e6d0: pointer being freed was not allocated

3、更改物件的類／獲取物件的類  

Class object_setClass(id

Class object_getClass(id obj)

- (void) setClassTest

{

CustomClass *obj = [CustomClassnew];

    [obj fun1];

    Class aClass =object_setClass(obj, [CustomClassOtherclass]);

//obj 物件的類被更改了    swap the isa to an isa

NSLog(@"aClass:%@",NSStringFromClass(aClass));

NSLog(@"obj class:%@",NSStringFromClass([objclass]));

    [obj fun2];

}

- (void) getClassTest

{

CustomClass *obj = [CustomClassnew];

    Class aLogClass =object_getClass(obj);

NSLog(@"%@",NSStringFromClass(aLogClass));

}

4、獲取物件的類名constchar *object_getClassName(id obj)

- (void) getClassName

{

CustomClass *obj = [CustomClassnew];

NSString *className = [NSStringstringWithCString:object_getClassName(obj)encoding:NSUTF8StringEncoding];

    NSLog(@"className:%@", className);

}

5、給一個類新增方法 

BOOL class_addMethod(Class cls,SEL name,IMP imp, 

const char *types)

/**

  *一個引數

  *

  */

int cfunction(id self, SEL _cmd, NSString *str) {

    NSLog(@"%@", str);

return10;//隨便返回個值

}

- (void) oneParam {

    TestClass *instance = [[TestClassalloc]init];

//    方法新增

    class_addMethod([TestClassclass],@selector(ocMethod:), (IMP)cfunction,"[email protected]:@");

    if ([instance respondsToSelector:@selector(ocMethod:)]) {

NSLog(@"Yes, instance respondsToSelector:@selector(ocMethod:)");

    } else

    {

        NSLog(@"Sorry");

    }

    int a = (int)[instanceocMethod:@"我是一個OC的method，C函式實現"];

    NSLog(@"a:%d", a);

}

/**

  *兩個引數

  *

  */

int cfunctionA(id self, SEL _cmd, NSString *str, NSString *str1) {

    NSLog(@"%@-%@", str, str1);

return20;//隨便返回個值

}

- (void) twoParam {

    TestClass *instance = [[TestClassalloc]init];

    class_addMethod([TestClassclass],@selector(ocMethodA::), (IMP)cfunctionA,"[email protected]:@@");

    if ([instance respondsToSelector:@selector(ocMethodA::)]) {

NSLog(@"Yes, instance respondsToSelector:@selector(ocMethodA::)");

    } else

    {

        NSLog(@"Sorry");

    }

int a = (int)[instanceocMethodA:@"我是一個OC的method，C函式實現" :@"-----我是第二個引數"];

    NSLog(@"a:%d", a);

}

相關文件及說明：

Obj-C的方法（method）就是一個至少需要兩個引數（self，_cmd）的C函式

 IMP有點類似函式指標，指向具體的Method實現。

向一個類動態新增方法

 BOOL class_addMethod(Class cls, SEL name, IMP imp, const char *types)

引數說明：

 cls：被新增方法的類

 name：可以理解為方法名

 imp：實現這個方法的函式

 types：一個定義該函式返回值型別和引數型別的字串

 class_addMethod([TestClass class], @selector(ocMethod:), (IMP)testFunc, "[email protected]:@");

其中types引數為"[email protected]:@“，按順序分別表示：

 i：返回值型別int，若是v則表示void

 @：引數id(self)

 :：SEL(_cmd)

 @：id(str)

官方文件：