IOS高级开发～Runtime（一）

IOSobject-c
IOS, runtime

一些公用类：

@interface CustomClass : NSObject

  • (void) fun1;

@end

@implementation CustomClass

  • (void) fun1

{

<span class="s2">NSLog</span>(<span class="s4">@"fun1"</span>);

}

@end

 

@interface TestClass : NSObject

@end

@implementation TestClass

@end

 

别忘记引入库：#include<objc/runtime.h>

1、对象拷贝：id object_copy(id obj, size_t size)

  • (void) copyObj

{

CustomClass *obj = [CustomClassnew];

<span class="s3">NSLog</span>(<span class="s4">@"%p"</span>, &amp;obj);

<span class="s1">id</span> objTest = <span class="s3">object_copy</span>(obj,<span class="s1">sizeof</span>(obj));

<span class="s3">NSLog</span>(<span class="s4">@"%p"</span>, &amp;objTest);

[objTest <span class="s5">fun1</span>];

}

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** id object_dispose(id obj)**

  • (void) objectDispose

{

CustomClass *obj = [CustomClassnew];

object_dispose(obj);

[obj <span class="s3">release</span>];

[obj <span class="s4">fun1</span>];

}

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(id obj, Class cls) ／

Class object_getClass(id obj)

  • (void) setClassTest

{

CustomClass *obj = [CustomClassnew];

[obj <span class="s4">fun1</span>];

<span class="s3">Class</span> aClass =<span class="s3">object_setClass</span>(obj, [<span class="s4">CustomClassOther</span><span class="s3">class</span>]);

//obj 对象的类被更改了 swap the isa to an isa

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

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

[obj <span class="s4">fun2</span>];

}

  • (void) getClassTest

{

CustomClass *obj = [CustomClassnew];

<span class="s3">Class</span> aLogClass =<span class="s3">object_getClass</span>(obj);

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

}

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

  • (void) getClassName

{

CustomClass *obj = [CustomClassnew];

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

<span class="s3">NSLog</span>(<span class="s4">@"className:%@"</span>, className);

}

 

*5、给一个类添加方法 *

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

const char *types)

/**

  • 一个参数

  • /

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

<span class="s3">NSLog</span>(<span class="s4">@"%@"</span>, str);

return10;//随便返回个值

}

  • (void) oneParam {

    TestClass *instance = [[TestClassalloc]init];

// 方法添加

<span class="s3">class_addMethod</span>([<span class="s7">TestClass</span><span class="s3">class</span>],<span class="s2">@selector</span>(ocMethod:), (<span class="s2">IMP</span>)<span class="s7">cfunction</span>,<span class="s4">"i@:@"</span>);

<span class="s2">if</span> ([instance <span class="s3">respondsToSelector</span>:<span class="s2">@selector</span>(ocMethod:)]) {

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

} <span class="s2">else</span>

{

    <span class="s3">NSLog</span>(<span class="s4">@"Sorry"</span>);

}

<span class="s2">int</span> a = (<span class="s2">int</span>)[instance<span class="s3">ocMethod</span>:<span class="s4">@"</span><span class="s8">我是一个</span><span class="s4">OC</span><span class="s8">的</span><span class="s4">method</span><span class="s8">，</span><span class="s4">C</span><span class="s8">函数实现</span><span class="s4">"</span>];

<span class="s3">NSLog</span>(<span class="s4">@"a:%d"</span>, a);

}

 

/**

  • 两个参数

  • /

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

<span class="s4">NSLog</span>(<span class="s5">@"%@-%@"</span>, str, str1);

return20;//随便返回个值

}

  • (void) twoParam {

    TestClass *instance = [[TestClassalloc]init];

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

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

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

} <span class="s3">else</span>

{

    <span class="s4">NSLog</span>(<span class="s5">@"Sorry"</span>);

}

int a = (int)[instanceocMethodA:@”我是一个OC的method，C函数实现“ :@”—–我是第二个参数“];

<span class="s4">NSLog</span>(<span class="s5">@"a:%d"</span>, 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)

官方文档：

https://developer.apple.com/library/mac/#documentation/Cocoa/Reference/ObjCRuntimeRef/Reference/reference.html

https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/ObjCRuntimeGuide/Articles/ocrtTypeEncodings.html

 

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