NSMethodSignature和NSInvocation的用法

最新推荐文章于 2021-05-21 14:22:16 发布
转载 最新推荐文章于 2021-05-21 14:22:16 发布 · 316 阅读 · 0

本文介绍 Objective-C 中的消息转发机制，包括 SMethodSignature 的作用及其实现方式。通过 NSMethodSignature 和 NSInvocation 实现了对方法签名的封装，支持方法的动态调用和参数传递，展示了如何通过消息转发实现类的行为扩展。

转自http://blog.youkuaiyun.com/dean19900504/article/details/8737862

SMethodSignature顾名思义应该就是“方法签名”，类似于C++中的编译器时的函数签名。
官方定义该类为对方法的参数、返回类似进行封装，协同NSInvocation实现消息转发。
通过消息转发可以用B实现A的方法。也是一种多重继承的解决方法。 
<p style="margin-top: 0px; margin-bottom: 10px; padding-top: 0px; padding-bottom: 0px;"><span class="kwd" style="color: rgb(0, 0, 136);">interface</span><span class="pln"> </span><span class="typ" style="color: rgb(102, 0, 102);">LOCBird</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">:</span><span class="pln"> </span><span class="typ" style="color: rgb(102, 0, 102);">NSObject</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">{</span>
<span class="pln"> </span><span class="typ" style="color: rgb(102, 0, 102);">NSString</span><span class="pun" style="color: rgb(102, 102, 0);">*</span><span class="pln"> name_</span><span class="pun" style="color: rgb(102, 102, 0);">;</span>
<span class="pln">    </span>
<span class="pun" style="color: rgb(102, 102, 0);">}</span>
<span class="lit" style="color: rgb(0, 102, 102);">@end</span>


<span class="lit" style="color: rgb(0, 102, 102);">@implementation</span><span class="pln"> </span><span class="typ" style="color: rgb(102, 0, 102);">LOCBird</span>

<span class="pun" style="color: rgb(102, 102, 0);">-</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">(</span><span class="pln">id</span><span class="pun" style="color: rgb(102, 102, 0);">)</span><span class="pln">init</span>
<span class="pun" style="color: rgb(102, 102, 0);">{</span>
<span class="pln"> </span><span class="kwd" style="color: rgb(0, 0, 136);">self</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">=</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">[</span><span class="kwd" style="color: rgb(0, 0, 136);">super</span><span class="pln"> init</span><span class="pun" style="color: rgb(102, 102, 0);">];</span>
<span class="pln"> </span><span class="kwd" style="color: rgb(0, 0, 136);">if</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">(</span><span class="kwd" style="color: rgb(0, 0, 136);">self</span><span class="pun" style="color: rgb(102, 102, 0);">)</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">{</span>
<span class="pln">  name_ </span><span class="pun" style="color: rgb(102, 102, 0);">=</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">[[</span><span class="typ" style="color: rgb(102, 0, 102);">NSString</span><span class="pln"> alloc</span><span class="pun" style="color: rgb(102, 102, 0);">]</span><span class="pln"> initWithString</span><span class="pun" style="color: rgb(102, 102, 0);">:@</span><span class="str" style="color: rgb(0, 136, 0);">"I am a Bird!!"</span><span class="pun" style="color: rgb(102, 102, 0);">];</span>
<span class="pln">  </span>
<span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">}</span>
<span class="pln"> </span><span class="kwd" style="color: rgb(0, 0, 136);">return</span><span class="pln"> </span><span class="kwd" style="color: rgb(0, 0, 136);">self</span><span class="pun" style="color: rgb(102, 102, 0);">;</span>
<span class="pun" style="color: rgb(102, 102, 0);">}</span>

<span class="pun" style="color: rgb(102, 102, 0);">-</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">(</span><span class="kwd" style="color: rgb(0, 0, 136);">void</span><span class="pun" style="color: rgb(102, 102, 0);">)</span><span class="pln">dealloc</span>
<span class="pun" style="color: rgb(102, 102, 0);">{</span>
<span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">[</span><span class="pln">name_ release</span><span class="pun" style="color: rgb(102, 102, 0);">];</span>
<span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">[</span><span class="kwd" style="color: rgb(0, 0, 136);">super</span><span class="pln"> dealloc</span><span class="pun" style="color: rgb(102, 102, 0);">];</span>
<span class="pun" style="color: rgb(102, 102, 0);">}</span>

<span class="pun" style="color: rgb(102, 102, 0);">-</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">(</span><span class="typ" style="color: rgb(102, 0, 102);">NSMethodSignature</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">*)</span><span class="pln">methodSignatureForSelector</span><span class="pun" style="color: rgb(102, 102, 0);">:(</span><span class="pln">SEL</span><span class="pun" style="color: rgb(102, 102, 0);">)</span><span class="pln">aSelector</span>
<span class="pun" style="color: rgb(102, 102, 0);">{</span>
<span class="pln"> </span><span class="typ" style="color: rgb(102, 0, 102);">NSMethodSignature</span><span class="pun" style="color: rgb(102, 102, 0);">*</span><span class="pln"> signature </span><span class="pun" style="color: rgb(102, 102, 0);">=</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">[</span><span class="kwd" style="color: rgb(0, 0, 136);">super</span><span class="pln"> methodSignatureForSelector</span><span class="pun" style="color: rgb(102, 102, 0);">:</span><span class="pln">aSelector</span><span class="pun" style="color: rgb(102, 102, 0);">];</span>
<span class="pln"> </span><span class="kwd" style="color: rgb(0, 0, 136);">if</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">(</span><span class="pln">signature</span><span class="pun" style="color: rgb(102, 102, 0);">==</span><span class="kwd" style="color: rgb(0, 0, 136);">nil</span><span class="pun" style="color: rgb(102, 102, 0);">)</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">{</span>
<span class="pln">  signature </span><span class="pun" style="color: rgb(102, 102, 0);">=</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">[</span><span class="pln">name_ methodSignatureForSelector</span><span class="pun" style="color: rgb(102, 102, 0);">:</span><span class="pln">aSelector</span><span class="pun" style="color: rgb(102, 102, 0);">];</span>
<span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">}</span>
<span class="pln"> </span><span class="typ" style="color: rgb(102, 0, 102);">NSUInteger</span><span class="pln"> argCount </span><span class="pun" style="color: rgb(102, 102, 0);">=</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">[</span><span class="pln">signature numberOfArguments</span><span class="pun" style="color: rgb(102, 102, 0);">];</span>
<span class="pln"> </span><span class="kwd" style="color: rgb(0, 0, 136);">for</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">(</span><span class="typ" style="color: rgb(102, 0, 102);">NSInteger</span><span class="pln"> i</span><span class="pun" style="color: rgb(102, 102, 0);">=</span><span class="lit" style="color: rgb(0, 102, 102);">0</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">;</span><span class="pln"> i</span><span class="pun" style="color: rgb(102, 102, 0);"><</span><span class="pln">argCount </span><span class="pun" style="color: rgb(102, 102, 0);">;</span><span class="pln"> i</span><span class="pun" style="color: rgb(102, 102, 0);">++)</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">{</span>
<span class="pln">  </span><span class="typ" style="color: rgb(102, 0, 102);">NSLog</span><span class="pun" style="color: rgb(102, 102, 0);">(@</span><span class="str" style="color: rgb(0, 136, 0);">"%s"</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">,</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">[</span><span class="pln">signature getArgumentTypeAtIndex</span><span class="pun" style="color: rgb(102, 102, 0);">:</span><span class="pln">i</span><span class="pun" style="color: rgb(102, 102, 0);">]);</span>
<span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">}</span>
<span class="pln"> </span><span class="typ" style="color: rgb(102, 0, 102);">NSLog</span><span class="pun" style="color: rgb(102, 102, 0);">(@</span><span class="str" style="color: rgb(0, 136, 0);">"returnType:%s ,returnLen:%d"</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">,</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">[</span><span class="pln">signature methodReturnType</span><span class="pun" style="color: rgb(102, 102, 0);">]</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">,</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">[</span><span class="pln">signature methodReturnLength</span><span class="pun" style="color: rgb(102, 102, 0);">]);</span>
<span class="pln"> </span><span class="typ" style="color: rgb(102, 0, 102);">NSLog</span><span class="pun" style="color: rgb(102, 102, 0);">(@</span><span class="str" style="color: rgb(0, 136, 0);">"signature:%@"</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">,</span><span class="pln"> signature</span><span class="pun" style="color: rgb(102, 102, 0);">);</span>
<span class="pln"> </span><span class="kwd" style="color: rgb(0, 0, 136);">return</span><span class="pln"> signature</span><span class="pun" style="color: rgb(102, 102, 0);">;</span>
<span class="pun" style="color: rgb(102, 102, 0);">}</span>

<span class="pun" style="color: rgb(102, 102, 0);">-</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">(</span><span class="kwd" style="color: rgb(0, 0, 136);">void</span><span class="pun" style="color: rgb(102, 102, 0);">)</span><span class="pln">forwardInvocation</span><span class="pun" style="color: rgb(102, 102, 0);">:(</span><span class="typ" style="color: rgb(102, 0, 102);">NSInvocation</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">*)</span><span class="pln">anInvocation</span>
<span class="pun" style="color: rgb(102, 102, 0);">{</span>
<span class="pln"> </span><span class="typ" style="color: rgb(102, 0, 102);">NSLog</span><span class="pun" style="color: rgb(102, 102, 0);">(@</span><span class="str" style="color: rgb(0, 136, 0);">"forwardInvocation:%@"</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">,</span><span class="pln"> anInvocation</span><span class="pun" style="color: rgb(102, 102, 0);">);</span>
<span class="pln"> SEL seletor </span><span class="pun" style="color: rgb(102, 102, 0);">=</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">[</span><span class="pln">anInvocation selector</span><span class="pun" style="color: rgb(102, 102, 0);">];</span>
<span class="pln"> </span><span class="kwd" style="color: rgb(0, 0, 136);">if</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">([</span><span class="pln">name_ respondsToSelector</span><span class="pun" style="color: rgb(102, 102, 0);">:</span><span class="pln">seletor</span><span class="pun" style="color: rgb(102, 102, 0);">])</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">{</span>
<span class="pln">  </span><span class="pun" style="color: rgb(102, 102, 0);">[</span><span class="pln">anInvocation invokeWithTarget</span><span class="pun" style="color: rgb(102, 102, 0);">:</span><span class="pln">name_</span><span class="pun" style="color: rgb(102, 102, 0);">];</span>
<span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">}</span>
<span class="pln"> </span>
<span class="pun" style="color: rgb(102, 102, 0);">}</span>

<span class="lit" style="color: rgb(0, 102, 102);">@end</span></p><p style="margin-top: 0px; margin-bottom: 10px; padding-top: 0px; padding-bottom: 0px;">
</p><p style="margin-top: 0px; margin-bottom: 10px; padding-top: 0px; padding-bottom: 0px;"><span class="com" style="color: rgb(136, 0, 0);">//调用</span></p><p style="margin-top: 0px; margin-bottom: 10px; padding-top: 0px; padding-bottom: 0px;"><span class="com" style="color: rgb(136, 0, 0);"> id bird = [[LOCBird alloc] init];</span>
<span class="pln"> </span><span class="typ" style="color: rgb(102, 0, 102);">NSLog</span><span class="pun" style="color: rgb(102, 102, 0);">(@</span><span class="str" style="color: rgb(0, 136, 0);">"len= %d"</span><span class="pun" style="color: rgb(102, 102, 0);">,</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">[</span><span class="pln">bird length</span><span class="pun" style="color: rgb(102, 102, 0);">]);</span></p>
输出 参考
表 6-1  Objective-C类型编码

编码

含义

c

char

i

int

s

short

l

long

在64位程序中，l为32位。

q

long long

C

unsigned char

I

unsigned int

S

unsigned short

L

unsigned long

Q

unsigned long long

f

float

d

double

B

C++标准的bool或者C99标准的_Bool

v

void

*

字符串（char *）

@

对象（无论是静态指定的还是通过id引用的）

#

类（Class）

:

方法选标（SEL）

[array type]

数组

{name=type...}

结构体

(name=type...)

联合体

bnum

num个bit的位域

^type

type类型的指针

?

未知类型（其它时候，一般用来指函数指针）

使用方法 
<p style="margin-top: 0px; margin-bottom: 10px; padding-top: 0px; padding-bottom: 0px;"><span class="pun" style="color: rgb(102, 102, 0);">-(</span><span class="kwd" style="color: rgb(0, 0, 136);">void</span><span class="pun" style="color: rgb(102, 102, 0);">)</span><span class="pln"> initWithTarget</span><span class="pun" style="color: rgb(102, 102, 0);">:(</span><span class="pln">id</span><span class="pun" style="color: rgb(102, 102, 0);">)</span><span class="pln"> rec selector</span><span class="pun" style="color: rgb(102, 102, 0);">:(</span><span class="pln">SEL</span><span class="pun" style="color: rgb(102, 102, 0);">)</span><span class="pln"> cb</span><span class="pun" style="color: rgb(102, 102, 0);">{</span>
<span class="pln">    anchorPoint_ </span><span class="pun" style="color: rgb(102, 102, 0);">=</span><span class="pln"> ccp</span><span class="pun" style="color: rgb(102, 102, 0);">(</span><span class="lit" style="color: rgb(0, 102, 102);">0.5f</span><span class="pun" style="color: rgb(102, 102, 0);">,</span><span class="pln"> </span><span class="lit" style="color: rgb(0, 102, 102);">0.5f</span><span class="pun" style="color: rgb(102, 102, 0);">);</span>
<span class="pln">    </span><span class="typ" style="color: rgb(102, 0, 102);">NSMethodSignature</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">*</span><span class="pln"> sig </span><span class="pun" style="color: rgb(102, 102, 0);">=</span><span class="pln"> </span><span class="kwd" style="color: rgb(0, 0, 136);">nil</span><span class="pun" style="color: rgb(102, 102, 0);">;</span>
<span class="pln">    </span><span class="kwd" style="color: rgb(0, 0, 136);">if</span><span class="pun" style="color: rgb(102, 102, 0);">(</span><span class="pln"> rec </span><span class="pun" style="color: rgb(102, 102, 0);">&&</span><span class="pln"> cb </span><span class="pun" style="color: rgb(102, 102, 0);">)</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">{</span>
<span class="pln">        sig </span><span class="pun" style="color: rgb(102, 102, 0);">=</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">[</span><span class="pln">rec methodSignatureForSelector</span><span class="pun" style="color: rgb(102, 102, 0);">:</span><span class="pln">cb</span><span class="pun" style="color: rgb(102, 102, 0);">];</span>
<span class="pln">        invocation </span><span class="pun" style="color: rgb(102, 102, 0);">=</span><span class="pln"> </span><span class="kwd" style="color: rgb(0, 0, 136);">nil</span><span class="pun" style="color: rgb(102, 102, 0);">;</span>
<span class="pln">        invocation </span><span class="pun" style="color: rgb(102, 102, 0);">=</span><span class="pln"> </span><span class="pun" style="color: rgb(102, 102, 0);">[</span><span class="typ" style="color: rgb(102, 0, 102);">NSInvocation</span><span class="pln"> invocationWithMethodSignature</span><span class="pun" style="color: rgb(102, 102, 0);">:</span><span class="pln">sig</span><span class="pun" style="color: rgb(102, 102, 0);">];</span>
<span class="pln">        </span><span class="pun" style="color: rgb(102, 102, 0);">[</span><span class="pln">invocation setTarget</span><span class="pun" style="color: rgb(102, 102, 0);">:</span><span class="pln">rec</span><span class="pun" style="color: rgb(102, 102, 0);">];</span>
<span class="pln">        </span><span class="pun" style="color: rgb(102, 102, 0);">[</span><span class="pln">invocation setSelector</span><span class="pun" style="color: rgb(102, 102, 0);">:</span><span class="pln">cb</span><span class="pun" style="color: rgb(102, 102, 0);">];</span>
<span class="pln">        </span><span class="pun" style="color: rgb(102, 102, 0);">[</span><span class="pln">invocation setArgument</span><span class="pun" style="color: rgb(102, 102, 0);">:&</span><span class="kwd" style="color: rgb(0, 0, 136);">self</span><span class="pln"> atIndex</span><span class="pun" style="color: rgb(102, 102, 0);">:</span><span class="lit" style="color: rgb(0, 102, 102);">2</span><span class="pun" style="color: rgb(102, 102, 0);">];</span>
<span class="pln">        </span><span class="pun" style="color: rgb(102, 102, 0);">[</span><span class="pln">invocation retain</span><span class="pun" style="color: rgb(102, 102, 0);">];</span>
<span class="pln">    </span><span class="pun" style="color: rgb(102, 102, 0);">}</span>
<span class="pun" style="color: rgb(102, 102, 0);">}</span></p>
当 [invocation invoke ];是调用SEL。上述第二个参数为自身。


用 NSMethodSignature和 NSInvocation实现编码
[plain]  view plain copy
  1. - (void)encodeWithCoder:(NSCoder *)encoder{  
  2.     NSDictionary *attrDic = [self getKeyAndObjectForDictionry];  
  3.     if (attrDic == nil) {  
  4.         return;  
  5.     }  
  6.     NSEnumerator *keyEnum = [attrDic keyEnumerator];  
  7.     id attributeName;  
  8.     while ((attributeName = [keyEnum nextObject])) {  
  9.         SEL getSel = NSSelectorFromString(attributeName);  
  10.         if ([self respondsToSelector:getSel]) {  
  11.             NSMethodSignature *signature = nil;  
  12.             signature = [self methodSignatureForSelector:getSel];  
  13.             NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:signature];  
  14.             [invocation setTarget:self];  
  15.             [invocation setSelector:getSel];  
  16.             NSObject *valueObj = nil;  
  17.             [invocation invoke];  
  18.             [invocation getReturnValue:&valueObj];  
  19.               
  20.             if (valueObj) {  
  21.                 [encoder encodeObject:valueObj forKey:attributeName];  
  22.             }  
  23.         }  
  24.     }  
  25. }  

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方法的一般调用方式：1、performSelector:withObject；2、NSInvocation什么时候使用NSInvocation:performSelector:withObject能完成简单的调用。但是对于>2个的参数或者有返回值的处理，那performSelector:withObject就显得费力了，这种情况下，我使用NSInvocation就显得相对简单些。NSMethodSi
NSObject,NSProxy以及异常处理
阿超的博客
03-17 868
参考资料： https://my.oschina.net/iq19900204/blog/411450http://blog.youkuaiyun.com/devday/article/details/7418022http://ios.jobbole.com/87856/1. NSProxy和NSObject基本所有的iOS中的类都是NSObject的字类，但是NSProxy不是。 NSProxy是一个虚
iOS 多线程 performSelector 与 NSInvocation的使用——iOS 编码复习(三)(多线程1)
u012297622的博客
03-04 1141
上一篇我们有分析runtime的大概实现过程，我们知道了objc_msgsend这个东西。它说的就是c语言的消息分发底层的大概实现。那么我们在iOS开发的过程中，实际会使用到的最直接的基于runtime机制的消息方法不就是performselector方法嘛！今天，我们就来分析一下这个东西：（同样成果是基于自己实践与看别人的博客的基础，所以也唠叨一下，希望各位可以多看看别人的博客哦，或者自己写写）
runtime 消息发送和转发 动态创建类添加属性方法等
09-06
如果返回`nil`，runtime会进入第二阶段转发，调用`- (NSMethodSignature *)methodSignatureForSelector:(SEL)aSelector`获取方法签名，然后调用`- (void)forwardInvocation:(NSInvocation *)anInvocation`。...
NSMethodSignature和NSInvocation
bigtiger1648的专栏
04-07 1326
一、NSMethodSignature + (nullable NSMethodSignature *)signatureWithObjCTypes:(const char *)types; //类方法 唯一初始化方法 对指定方法进行签名 //types 参数C字符串， Code Meaning c A char
NSMethodSignature, NSInvocation源码分析
weixin_33672400的博客
06-11 240
Tips void 的字面意思是 "无类型"，void * 则为 "无类型 指针" void *可以指定任何类型的数据。 复制代码NSMethodSignature 通过类型编码，构造一个方法签名，比如: @:* ,返回参数是id，传入参数是 char *，一般在 Objective-C 中类型编码返回值 第一个参数是返回值，第二个参数是 SEL。 + (nullable NSMethodSign...
使用NSMethodSignature和NSInvocation实现消息转发
freshForIphone的专栏
03-21 6177
参考： [1]http://developer.apple.com/library/ios/#documentation/Cocoa/Reference/Foundation/Classes/NSInvocation_Class/Reference/Reference.html [2]http://developer.apple.com/library/ios/#documentation/C
iOS开发之NSMethodSignature（方法签名）
逝水无情的博客
05-21 1643
OC中方法调用有三种： 第一种：直接调用 - (void)viewDidLoad { [super viewDidLoad]; [self printStr1:@"hello"]; } - (void)printStr1:(NSString*)str{ NSLog(@"printStr1 %@",str); } 第二种：通过performSelector - (void)viewDidLoad { [super viewDidLoad]; [sel
[消息传递之二]－NSMethodSignature练习
灵眼儿上方
01-05 1851
#import @interface MyInvoc : NSObject { NSString* _name; } -(NSInteger) myLen:(NSString*) aStr; -(NSMethodSignature*) methodSignatureForSelector:(SEL)aSelector; -(void)forwardInvocation:(NSIn
聊聊NSInvocation和NSMethodSignature
Deft_MKJing的博客
05-19 1137
前言 咱们这里不会通过源码介绍Runtime，已经有很多文章介绍了，而且太晦涩，读起来不舒服，也不会介绍Runtime的一些基本原理，这个作为iOS开发最熟悉了，只是通过一些我们平时用到的操作，来宏观的介绍NSInvocation和NSMethodSignature，随便聊聊，做一些简单的记录，还记得刚接触这个的时候咱们脑海里面的问号吗？ 什么是方法，什么是选择器，什么是方法签名，什么是IMP，什么是消息？下面简单的回顾下 Selector 选择器是方法的名称。你肯定对以下选择器非常熟悉：alloc，ini
关于NSInvocation-Tagert事件的多个参数实现方法
shang1219178163的专栏
01-12 965
main.h [html] view plaincopy #import Foundation/Foundation.h>   #import "MyClass.h"      int main (int argc, const char * argv[])   {          NSAutoreleasePool * poo
iOS消息转发机制解析与实现方法
运行时会调用类的 `+ (BOOL)resolveInstanceMethod:(SEL)sel` 或 `+ (BOOL)resolveClassMethod:(SEL)sel` 方法，分别用于实例方法和类方法。开发者可以在这个方法中动态地为类添加一个方法实现（IMP），从而让对象...
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