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iOS runtime 运行时机制

iOS runtime 运行时机制

作者: kwalter | 来源:发表于2016-05-04 18:00 被阅读67次

一些公用类:

@interfaceCustomClass :NSObject

- (void) fun1;

@end

@implementationCustomClass

- (void) fun1

{

NSLog(@"fun1");

}

@end

@interfaceTestClass :NSObject

@end

@implementationTestClass

@end

别忘记引入库:#include

1、对象拷贝:idobject_copy(idobj, size_t size)

- (void) copyObj

{

CustomClass*obj = [CustomClassnew];

NSLog(@"%p", &obj);

idobjTest =object_copy(obj,sizeof(obj));

NSLog(@"%p", &objTest);

[objTestfun1];

}

打印结果:

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

说明:

object_copy 函数实现了对象的拷贝。

2、对象释放idobject_dispose(idobj)

- (void) objectDispose

{

CustomClass*obj = [CustomClassnew];

object_dispose(obj);

[objrelease];

[objfun1];

}

打印结果:程序crash

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

3、更改对象的类/获取对象的类

Class object_setClass(idobj, Class cls)  /

Class object_getClass(idobj)

- (void) setClassTest

{

CustomClass*obj = [CustomClassnew];

[objfun1];

ClassaClass =object_setClass(obj, [CustomClassOtherclass]);

//obj对象的类被更改了swap the isa to an isa

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

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

[objfun2];

}

- (void) getClassTest

{

CustomClass*obj = [CustomClassnew];

ClassaLogClass =object_getClass(obj);

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

}

4、获取对象的类名constchar*object_getClassName(idobj)

- (void) getClassName

{

CustomClass*obj = [CustomClassnew];

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

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

}

5、给一个类添加方法

BOOLclass_addMethod(Class cls,SELname,IMPimp,

constchar*types)

/**

*一个参数

*

*/

intcfunction(idself,SEL_cmd,NSString*str) {

NSLog(@"%@", str);

return10;//随便返回个值

}

- (void) oneParam {

TestClass*instance = [[TestClassalloc]init];

//方法添加

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

if([instancerespondsToSelector:@selector(ocMethod:)]) {

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

}else

{

NSLog(@"Sorry");

}

inta = (int)[instanceocMethod:@"我是一个OC的method,C函数实现"];

NSLog(@"a:%d", a);

}

/**

*两个参数

*

*/

intcfunctionA(idself,SEL_cmd,NSString*str,NSString*str1) {

NSLog(@"%@-%@", str, str1);

return20;//随便返回个值

}

- (void) twoParam {

TestClass*instance = [[TestClassalloc]init];

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

if([instancerespondsToSelector:@selector(ocMethodA::)]) {

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

}else

{

NSLog(@"Sorry");

}

inta = (int)[instanceocMethodA:@"我是一个OC的method,C函数实现":@"-----我是第二个参数"];

NSLog(@"a:%d", a);

}

相关文档及说明:

Obj-C的方法(method)就是一个至少需要两个参数(self,_cmd)的C函数

IMP有点类似函数指针,指向具体的Method实现。

向一个类动态添加方法

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

参数说明:

cls:被添加方法的类

name:可以理解为方法名

imp:实现这个方法的函数

types:一个定义该函数返回值类型和参数类型的字符串

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

其中types参数为"i@:@“,按顺序分别表示:

i:返回值类型int,若是v则表示void

@:参数id(self)

::SEL(_cmd)

@:id(str)

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