我的Github地址 :Jerry4me,本文章的demo链接 :JRReactiveCocoa

RAC与MVVM如今已经不是一个新鲜的玩意了,对于介绍他们两的精品文章更是大把,这篇文章主要是用来记录自己学习RAC的过程以及RAC的一些用法,以防以后要用到的时候却记不起来了.

具体RAC的用法以及本文出现的代码均能在我的Github上,另外附有2个MVVM的小demo. 欢迎大家查看,赏脸的给个star~

RAC编程思想

编程学的是思想,学一样东西最主要是学会它的思想,那才是它的灵魂,而不是学习调用方法而已.

RAC又被称为FRP,函数响应式编程.

何为函数式? 把操作写成一系列嵌套的函数或者方法调用

何为响应式? 不需要考虑调用顺序,只考虑结果. 一个属性,一个请求改变马上引发一系列改变.

 
          1 
        
          2 
        
         data  
         stream 
           
         -> 
           
         ( 
         filter 
         , 
           
         combine 
         map 
         . 
         ) 
           
         another  
         stream 
        
         stream是基于时间上的事件流

所以RAC即糅合了函数式和响应式编程的优点,使用RAC编程不需要考虑代码调用顺序,只需要考虑结果. 把每一个操作都写成一系列的嵌套的方法,使代码变得高内聚,低耦合.

RAC使用场景

数据随着时间而产生,例如以下三点 :

UI操作,连续的动作和动画部分,例如某些控件跟随滚动
网络库,因为数据是在一定时间后才返回回来,不是立刻返回的
刷新的业务逻辑,当触发点是多种的时候,业务往往会变得很复杂,用delegate,notification,observe混用,难以统一. 这时用RAC能保证上层的高度一致性,从而简化逻辑上分层.

RAC类关系图

RAC类的关系图如下,下面会抽出一部分类进行讲解,另外有部分类与用法会在github上的demo上看得到,还有部分类将不在本文中出现,本文(demo)只说明了一些常用的类与方法.

ReactiveCocoa类图.png

信号源

RACStream.ng

RACSignal

RACSignal只会向订阅者发送三种事件 :next,error和completed.

RACSignal的一系列功能是通过类簇来实现的. 如 :

 
       <div class="crayon-nums-content" style="border: none; margin: 0px; padding-right: 0px; padding-left: 0px; background: none; text-align: left; white-space: nowrap; padding-top: 5px !important; padding-bottom: 3px !important; line-height: 15px !important;"> 
        <div class="crayon-num" data-line="crayon-58ddab04b2935343065731-1" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          1 
        </div> 
        <div class="crayon-num crayon-striped-num" data-line="crayon-58ddab04b2935343065731-2" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          2 
        </div> 
        <div class="crayon-num" data-line="crayon-58ddab04b2935343065731-3" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          3 
        </div> 
        <div class="crayon-num crayon-striped-num" data-line="crayon-58ddab04b2935343065731-4" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          4 
        </div> 
        <div class="crayon-num" data-line="crayon-58ddab04b2935343065731-5" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          5 
        </div> 
       </div></td> 
      <td class="crayon-code" style="font-size: 13px; text-align: center; width: 902px; background: none; border: none !important; margin: 0px !important; padding: 0px !important; vertical-align: top !important; font-family: Monaco,monospace !important;"> 
       <div class="crayon-pre" style="margin: 0px; padding-right: 0px; padding-left: 0px; text-align: left; white-space: pre; overflow: visible; tab-size: 4; border: none !important; padding-top: 5px !important; padding-bottom: 3px !important; background: none !important; line-height: 15px !important;"> 
        <div class="crayon-line" id="crayon-58ddab04b2935343065731-1" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">RACEmptySignal</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>：空信号，用来实现 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">RACSignal</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>的 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span> 
         <span class="crayon-o" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;">+</span> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">empty</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span><a href="/tag/fangfa/" target="_blank" class="keywords">方法</a>； 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935343065731-2" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">RACReturnSignal</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>：一元信号，用来实现 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;">+</span> 
         <span class="crayon-st" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: bold !important;">return</span> 
         <span class="crayon-o" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;">:</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span><a href="/tag/fangfa/" target="_blank" class="keywords">方法</a>； 
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935343065731-3" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">RACDynamicSignal</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>：动态信号，使用一个 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">block</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>来实现<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>行为，我们在使用 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;">+</span> 
         <span class="crayon-v" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,122) !important;">createSignal</span> 
         <span class="crayon-o" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span><a href="/tag/fangfa/" target="_blank" class="keywords">方法</a>时创建的就是该类的实例； 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935343065731-4" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">RACErrorSignal</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>：<a href="/tag/cuowu/" target="_blank" class="keywords">错误</a>信号，用来实现 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,122) !important;">error</span> 
         <span class="crayon-o" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span><a href="/tag/fangfa/" target="_blank" class="keywords">方法</a>； 
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935343065731-5" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">RACChannelTerminal</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>：通道终端，代表 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">RACChannel</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>的一个终端，用来实现双向绑定。 
        </div> 
       </div></td> 
     </tr> 
    </tbody> 
   </table> 
  </div> 
 </div> 
 <p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding-top: 0px; padding-bottom: 0px; font-size: 15px; color: rgb(46,sans-serif;">核心<a href="/tag/fangfa/" target="_blank" class="keywords">方法</a> :<code style="border: 0px; margin: 0px; padding: 0px; font-family: Monaco,monospace;">-subscribe:</code>.</p> 
 <h3 style="border: 0px; margin: 0px 0px 20px; padding: 0px; font-size: 20px; font-stretch: normal; line-height: 30px; font-family: "Microsoft YaHei",sans-serif; color: rgb(46,46);">RACSubject</h3> 
 <p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding-top: 0px; padding-bottom: 0px; font-size: 15px; color: rgb(46,sans-serif;">继承自RACSignal,是可以手动控制的信号,相当于RACSignal的可变版本.</p> 
 <p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding-top: 0px; padding-bottom: 0px; font-size: 15px; color: rgb(46,sans-serif;">能作为信号源被<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>,又能作为<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>其他信号源(实现了RACSubscriber协议).</p> 
 <p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding-top: 0px; padding-bottom: 0px; font-size: 15px; color: rgb(46,sans-serif;">RACSubject有三个用来实现不同<a href="/tag/gongneng/" target="_blank" class="keywords">功能</a>的子类 :</p> 
 <div id="crayon-58ddab04b2935953110636" class="crayon-syntax crayon-theme-github crayon-font-monaco crayon-os-pc print-yes notranslate" data-settings=" minimize scroll-always" style="margin: 12px 0px; padding: 0px; box-sizing: border-box; text-size-adjust: none; width: 610px; font-family: Monaco,102) !important;"></span> 
   <div class="crayon-tools" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none; position: absolute; right: 0px; height: 19.5px !important; line-height: 19.5px !important; font-weight: inherit !important;"> 
    <div class="crayon-button crayon-nums-button crayon-pressed" title="切换是否显示行编号" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none -24px 0px no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") -24px -32px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-plain-button" title="纯文本显示代码" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px -48px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-wrap-button" title="切换自动换行" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px -112px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-copy-button" title="复制代码" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px -16px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-popup-button" title="在新窗口中显示代码" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px 0px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
   </div> 
  </div> 
  <div class="crayon-plain-wrap" style="border: none; background: none; margin: 0px !important; padding: 0px !important; height: auto !important;"> 
   <textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly style="border-width: initial; border-style: none; outline: none; display: block; -webkit-appearance: none; padding: 0px 5px; width: 608px; height: 73.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; border-radius: 0px; box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0,170)!important">
          2 
        </div> 
        <div class="crayon-num" style="border-top:none; border-right:1px solid rgb(222,170)!important">
          3 
        </div> 
       </div> </td> 
      <td class="crayon-code" style="font-size:13px; text-align:center; width:581px; background:none; border:none!important; margin:0px!important; padding:0px!important; vertical-align:top!important; font-family:Monaco,monospace!important"> 
       <div class="crayon-pre" style="margin:0px; padding-right:0px; padding-left:0px; text-align:left; white-space:pre; overflow:visible; border:none!important; padding-top:5px!important; padding-bottom:3px!important; background:none!important; line-height:15px!important"> 
        <div class="crayon-line" id="crayon-58ddab04b2935953110636-1" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important"> 
         <span class="crayon-i" style="border:0px; margin:0px; padding:0px; font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">RACGroupedSignal</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span>：分组信号，用来实现 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span> 
         <span class="crayon-i" style="border:0px; margin:0px; padding:0px; font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">RACSignal</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span>的分组<a href="/tag/gongneng/" target="_blank" class="keywords">功能</a>； 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935953110636-2" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important"> 
         <span class="crayon-i" style="border:0px; margin:0px; padding:0px; font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">RACBehaviorSubject</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span>：重演最后值的信号，当被<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>时，会向<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者发送它最后接收到的值； 
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935953110636-3" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important"> 
         <span class="crayon-i" style="border:0px; margin:0px; padding:0px; font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">RACReplaySubject</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span>：重演信号，保存发送过的值，当被<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>时，会向<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者重新发送这些值。 
        </div> 
       </div> </td> 
     </tr> 
    </tbody> 
   </table> 
  </div> 
 </div> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> </p> 
 <hr style="border-right:0px solid rgb(232,sans-serif"> 
 <h3 style="border:0px; margin:0px 0px 20px; padding:0px; font-size:20px; line-height:30px; font-family:"Microsoft YaHei",46)"> RACSequence</h3> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> 代表的是一个不可变的值的序列. 不能被<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>,但是能与RACSignal之间非常方便地进行转换.</p> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> RACSequence由两部分组成 :<code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">head</code>和<code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">tail</code>,head是序列中的第一个对象,tail则是其余的全部对象.</p> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> RACSequence存在的最大意义就是简化OC中的集合操作. 并且RACSequence所包含的值默认是懒计算的,所以不知不觉中提高了我们应用的<a href="/tag/xingneng/" target="_blank" class="keywords">性能</a>.</p> 
 <h3 style="border:0px; margin:0px 0px 20px; padding:0px; font-size:20px; line-height:30px; font-family:"Microsoft YaHei",46)"> push-driven与pull-driven</h3> 
 <ul style="border:0px; margin:0px 0px 20px; padding:0px; font-size:15px; list-style-position:outside; color:rgb(46,sans-serif"> 
  <li style="border:0px; margin:0px 0px 5px 30px; padding:0px">RACSignal : push-driven,生产一个吃一个,类似于工厂的主动生产模式,生产出产品就push给供销商.</li> 
  <li style="border:0px; margin:0px 0px 5px 30px; padding:0px">RACSequence : pull-driven,吃一个生产一个,类似于工厂的被动生产模式,供销商过来pull的时候才现做产品.</li> 
 </ul> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> 对于RACSignal的push-driven模式来说,没有供销商(<code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">subscriber</code>)签合同要产品,当然就不生产了. 只有一个以上准备收货的供销商时,工厂才开始生产. 这就是RACSignal的休眠(cold)和激活(hot)状态,也就是<code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">冷信号</code>和<code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">热信号</code>. 一般情况下RACSignal创建以后都处于cold状态,当有人去<code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">subscribe</code>才变成hot状态.</p> 
 <h2 style="border:0px; margin:0px 0px 20px; padding:0px; font-size:24px; line-height:36px; font-family:"Microsoft YaHei",46)"> 冷信号与热信号</h2> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> 热信号 : 主动,即使你没有<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>事件,仍然会时刻推送. 热信号可以有多个<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者,是一对多的关系,信号可以与<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者<span style="border:0px; margin:0px; padding:0px">共享</span>信息.</p> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> 冷信号 : 被动,只有当你<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>的时候,它才会发布消息. 冷信号只能一对一,当有不同的<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者,消息是<span style="border:0px; margin:0px; padding:0px">重新完整</span>发送的.</p> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> ps : 任何的信号转换即是对原有信号进行<span style="border:0px; margin:0px; padding:0px"><a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a></span>从而产生新的信号. (例如 :<code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">Map</code>,monospace">FlattenMap</code>等等)</p> 
 <h4 style="border:0px; margin:0px 0px 20px; padding:0px; font-size:16px; line-height:24px; font-family:"Microsoft YaHei",46)"> 如何区分热信号和冷信号</h4> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> Subject类似于直播,错过了就不再处理,而Signal类似于点播,每次<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>都从头开始重新发送.</p> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> 我们能得出 :</p> 
 <div id="crayon-58ddab04b2935510664607" class="crayon-syntax crayon-theme-github crayon-font-monaco crayon-os-pc print-yes notranslate" style="margin:12px 0px; padding:0px; width:610px; font-family:Monaco,102)!important"></span> 
   <div class="crayon-tools" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none; position:absolute; right:0px; height:19.5px!important; line-height:19.5px!important; font-weight:inherit!important"> 
    <div class="crayon-button crayon-nums-button crayon-pressed" title="切换是否显示行编号" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none -24px 0px no-repeat; height:inherit; line-height:15px; display:inline; position:relative; width:24px; font-size:inherit!important; font-weight:inherit!important; float:left!important"> 
     <div class="crayon-button-icon" style="border:none; margin:-8px 0px 0px; padding:0px; font-family:inherit; width:24px; position:absolute; left:0px; top:9.75px; font-size:inherit!important; height:16px!important; line-height:inherit!important; font-weight:inherit!important"> 
     </div> 
    </div> 
    <div class="crayon-button crayon-plain-button" title="纯文本显示代码" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none 0px center no-repeat; height:inherit; line-height:15px; display:inline; position:relative; width:24px; font-size:inherit!important; font-weight:inherit!important; float:left!important"> 
     <div class="crayon-button-icon" style="border:none; margin:-8px 0px 0px; padding:0px; font-family:inherit; width:24px; position:absolute; left:0px; top:9.75px; font-size:inherit!important; height:16px!important; line-height:inherit!important; font-weight:inherit!important"> 
     </div> 
    </div> 
    <div class="crayon-button crayon-wrap-button" title="切换自动换行" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none 0px center no-repeat; height:inherit; line-height:15px; display:inline; position:relative; width:24px; font-size:inherit!important; font-weight:inherit!important; float:left!important"> 
     <div class="crayon-button-icon" style="border:none; margin:-8px 0px 0px; padding:0px; font-family:inherit; width:24px; position:absolute; left:0px; top:9.75px; font-size:inherit!important; height:16px!important; line-height:inherit!important; font-weight:inherit!important"> 
     </div> 
    </div> 
    <div class="crayon-button crayon-copy-button" title="复制代码" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none 0px center no-repeat; height:inherit; line-height:15px; display:inline; position:relative; width:24px; font-size:inherit!important; font-weight:inherit!important; float:left!important"> 
     <div class="crayon-button-icon" style="border:none; margin:-8px 0px 0px; padding:0px; font-family:inherit; width:24px; position:absolute; left:0px; top:9.75px; font-size:inherit!important; height:16px!important; line-height:inherit!important; font-weight:inherit!important"> 
     </div> 
    </div> 
    <div class="crayon-button crayon-popup-button" title="在新窗口中显示代码" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none 0px center no-repeat; height:inherit; line-height:15px; display:inline; position:relative; width:24px; font-size:inherit!important; font-weight:inherit!important; float:left!important"> 
     <div class="crayon-button-icon" style="border:none; margin:-8px 0px 0px; padding:0px; font-family:inherit; width:24px; position:absolute; left:0px; top:9.75px; font-size:inherit!important; height:16px!important; line-height:inherit!important; font-weight:inherit!important"> 
     </div> 
    </div> 
   </div> 
  </div> 
  <div class="crayon-plain-wrap" style="border:none; background:none; margin:0px!important; padding:0px!important; height:auto!important"> 
   <textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly style="border-width: initial; border-style: none; outline: none; display: block; -webkit-appearance: none; padding: 0px 5px; width: 608px; height: 58.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; border-radius: 0px; box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0,238) !important;"> 
       <div class="crayon-nums-content" style="border: none; margin: 0px; padding-right: 0px; padding-left: 0px; background: none; text-align: left; white-space: nowrap; padding-top: 5px !important; padding-bottom: 3px !important; line-height: 15px !important;"> 
        <div class="crayon-num" data-line="crayon-58ddab04b2935510664607-1" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          1 
        </div> 
        <div class="crayon-num crayon-striped-num" data-line="crayon-58ddab04b2935510664607-2" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          2 
        </div> 
       </div></td> 
      <td class="crayon-code" style="font-size: 13px; text-align: center; width: 581px; background: none; border: none !important; margin: 0px !important; padding: 0px !important; vertical-align: top !important; font-family: Monaco,monospace !important;"> 
       <div class="crayon-pre" style="margin: 0px; padding-right: 0px; padding-left: 0px; text-align: left; white-space: pre; overflow: visible; tab-size: 4; border: none !important; padding-top: 5px !important; padding-bottom: 3px !important; background: none !important; line-height: 15px !important;"> 
        <div class="crayon-line" id="crayon-58ddab04b2935510664607-1" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-cn" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,153) !important;">1.</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">RACSubject</span>及其子类是热信号 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935510664607-2" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-cn" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,153) !important;">2.</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">RACSignal</span>排除 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">RACSubject</span>类以外的都是冷信号 
        </div> 
       </div></td> 
     </tr> 
    </tbody> 
   </table> 
  </div> 
 </div> 
 <p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding-top: 0px; padding-bottom: 0px; font-size: 15px; color: rgb(46,sans-serif;"></p> 
 <h4 style="border: 0px; margin: 0px 0px 20px; padding: 0px; font-size: 16px; font-stretch: normal; line-height: 24px; font-family: "Microsoft YaHei",46);">将冷信号转化成热信号</h4> 
 <p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding-top: 0px; padding-bottom: 0px; font-size: 15px; color: rgb(46,sans-serif;">RAC帮我们封装了一套可以轻松将冷信号转换成热信号的API :</p> 
 <div id="crayon-58ddab04b2935049453068" class="crayon-syntax crayon-theme-github crayon-font-monaco crayon-os-pc print-yes notranslate" data-settings=" minimize scroll-always" style="margin: 12px 0px; padding: 0px; box-sizing: border-box; text-size-adjust: none; width: 610px; font-family: Monaco,102) !important;"></span> 
   <div class="crayon-tools" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none; position: absolute; right: 0px; height: 19.5px !important; line-height: 19.5px !important; font-weight: inherit !important;"> 
    <div class="crayon-button crayon-nums-button crayon-pressed" title="切换是否显示行编号" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none -24px 0px no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") -24px -32px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-plain-button" title="纯文本显示代码" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px -48px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-wrap-button" title="切换自动换行" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px -112px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-expand-button" title="点击展开代码" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px -96px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-copy-button" title="复制代码" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px -16px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-popup-button" title="在新窗口中显示代码" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px 0px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
   </div> 
  </div> 
  <div class="crayon-plain-wrap" style="border: none; background: none; margin: 0px !important; padding: 0px !important; height: auto !important;"> 
   <textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly style="border-width: initial; border-style: none; outline: none; display: block; -webkit-appearance: none; padding: 0px 5px; width: 608px; height: 109.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; border-radius: 0px; box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0,170)!important">
          3 
        </div> 
        <div class="crayon-num crayon-striped-num" style="border-top:none; border-right:1px solid rgb(222,170)!important">
          4 
        </div> 
        <div class="crayon-num" style="border-top:none; border-right:1px solid rgb(222,170)!important">
          5 
        </div> 
       </div> </td> 
      <td class="crayon-code" style="font-size:13px; text-align:center; width:728px; background:none; border:none!important; margin:0px!important; padding:0px!important; vertical-align:top!important; font-family:Monaco,monospace!important"> 
       <div class="crayon-pre" style="margin:0px; padding-right:0px; padding-left:0px; text-align:left; white-space:pre; overflow:visible; border:none!important; padding-top:5px!important; padding-bottom:3px!important; background:none!important; line-height:15px!important"> 
        <div class="crayon-line" id="crayon-58ddab04b2935049453068-1" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important"> 
         <span class="crayon-o" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important">-</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,51)!important">(</span> 
         <span class="crayon-e " style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:teal!important">RACMulticastConnection *</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51)!important">)</span> 
         <span class="crayon-v" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,122)!important">publish</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51)!important">;</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935049453068-2" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important"> 
         <span class="crayon-o" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,122)!important">multicast</span> 
         <span class="crayon-o" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important">:</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51)!important">(</span> 
         <span class="crayon-e " style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:teal!important">RACSubject *</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,122)!important">subject</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51)!important">;</span> 
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        <div class="crayon-line" id="crayon-58ddab04b2935049453068-3" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important"> 
         <span class="crayon-o" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,51)!important">(</span> 
         <span class="crayon-e " style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:teal!important">RACSignal *</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,122)!important">replay</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51)!important">;</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935049453068-4" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important"> 
         <span class="crayon-o" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,122)!important">replayLast</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51)!important">;</span> 
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935049453068-5" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important"> 
         <span class="crayon-o" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,122)!important">replayLazily</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51)!important">;</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span> 
         <span class="crayon-c" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(153,153)!important; font-style:italic!important">// 跟replay的区别是replayLazily会在第一次<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>的时候才<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>sourceSignal</span> 
        </div> 
       </div> </td> 
     </tr> 
    </tbody> 
   </table> 
  </div> 
 </div> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> 其中最重要的就是<code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">- (RACMulticastConnection *)multicast:(RACSubject *)subject;</code>,其他几个<a href="/tag/fangfa/" target="_blank" class="keywords">方法</a>都是间接<a href="/tag/diaoyong/" target="_blank" class="keywords">调用</a>它的.</p> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> 本质 : 使用一个Subject来<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>原始信号,并让其他<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>这个Subject,由于RACSubject本身为热信号,所以源信号此时就像由冷信号变成了热信号.</p> 
 <hr style="border-right:0px solid rgb(232,46)"> <a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者</h1> 
 <h2 style="border:0px; margin:0px 0px 20px; padding:0px; font-size:24px; line-height:36px; font-family:"Microsoft YaHei",46)"> RACSubscriber</h2> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> 其中<code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">-sendNext:</code>,monospace">-sendError:</code>和<code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">-sendCompleted</code>分别用来从RACSignal接收<code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">completed</code>事件,而<code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">-didSubscribeWithDisposable:</code>则用来接收代表某次<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>的disposable对象.</p> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> 一个RACDisposable对象就代表这一次<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>,并且我们可以用它来取消这次<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>.</p> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> RACSubscriber就是真正的<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者,而RACPassthroughSubscriber可以使得一个<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者可以<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>多个信号源,即拥有多个RACDisposable对象,并能随时取消其中的任何一次<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>. 为了实现这个<a href="/tag/gongneng/" target="_blank" class="keywords">功能</a>,RAC就引入了RACPassthroughSubscriber类,它是RACSubscriber类的一个装饰器,封装了一个真正的<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者 RACSubscriber 对象,它负责转发所有事件给这个真正的<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者,而当此次<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>被取消时,它就会停止转发</p> 
 <h2 style="border:0px; margin:0px 0px 20px; padding:0px; font-size:24px; line-height:36px; font-family:"Microsoft YaHei",46)"> RACMulticastConnection</h2> 
 <div style="border:0px; margin:0px; padding:0px; font-size:15px; color:rgb(46,sans-serif; text-align:center">
   RACMulticastConnection.png 
 </div> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> 使得不管外面有多少个<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者,对源信号的<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>只会有一次. 为了防止<span style="border:0px; margin:0px; padding:0px">副作用</span>的产生,使用的便是multicast机制</p> 
 <h3 style="border:0px; margin:0px 0px 20px; padding:0px; font-size:20px; line-height:30px; font-family:"Microsoft YaHei",46)"> multicast的机制</h3> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> 机制一 : 能防止某信号被多次<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>时<a href="/tag/diaoyong/" target="_blank" class="keywords">调用</a>多次didSubscribe block产生副作用.</p> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> 机制二 : 实现replay,即每当有<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>时,会将之前缓存中的sendNext重新发送给该<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者.</p> 
 <h3 style="border:0px; margin:0px 0px 20px; padding:0px; font-size:20px; line-height:30px; font-family:"Microsoft YaHei",46)"> 副作用</h3> 
 <ul style="border:0px; margin:0px 0px 20px; padding:0px; font-size:15px; list-style-position:outside; color:rgb(46,sans-serif"> 
  <li style="border:0px; margin:0px 0px 5px 30px; padding:0px"><a href="/tag/hanshu/" target="_blank" class="keywords">函数</a>的处理过程中,<a href="/tag/xiugai/" target="_blank" class="keywords">修改</a>了外部的变量(例如 : <a href="/tag/quanjubianliang/" target="_blank" class="keywords">全局变量</a>,成员变量等)</li> 
  <li style="border:0px; margin:0px 0px 5px 30px; padding:0px"><a href="/tag/hanshu/" target="_blank" class="keywords">函数</a>的处理过程中,出发了一些额外的动作(例如 : 发送了一个全局的Notification,在console打印了一行信息,保存了<a href="/tag/wenjian/" target="_blank" class="keywords">文件</a>,触发了网络,更新了屏幕等)</li> 
  <li style="border:0px; margin:0px 0px 5px 30px; padding:0px"><a href="/tag/hanshu/" target="_blank" class="keywords">函数</a>的处理过程中,受到外部变量的影响(例如 : <a href="/tag/quanjubianliang/" target="_blank" class="keywords">全局变量</a>,成员变量等,block中捕获到的外部变量也算)</li> 
  <li style="border:0px; margin:0px 0px 5px 30px; padding:0px"><a href="/tag/hanshu/" target="_blank" class="keywords">函数</a>的处理过程中,受到线程锁的影响</li> 
 </ul> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> 以上都算副作用. 然而<span style="border:0px; margin:0px; padding:0px">冷信号</span>有可能因为有多个<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>而产生极大的副作用,例如发送了同一个网络请求若干次,同一个计算做了若干次等等,这些问题都可以通过把这个<span style="border:0px; margin:0px; padding:0px">冷信号</span>转化成<span style="border:0px; margin:0px; padding:0px">热信号</span>得以<a href="/tag/jiejue/" target="_blank" class="keywords">解决</a>.</p> 
 <div id="crayon-58ddab04b2935918651820" class="crayon-syntax crayon-theme-github crayon-font-monaco crayon-os-pc print-yes notranslate" style="margin:12px 0px; padding:0px; width:610px; font-family:Monaco,102)!important"></span> 
   <div class="crayon-tools" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none; position:absolute; right:0px; height:19.5px!important; line-height:19.5px!important; font-weight:inherit!important"> 
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  <div class="crayon-plain-wrap" style="border:none; background:none; margin:0px!important; padding:0px!important; height:auto!important"> 
   <textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly style="border-width: initial; border-style: none; outline: none; display: block; -webkit-appearance: none; padding: 0px 5px; width: 608px; height: 499.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; border-radius: 0px; box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0,238) !important;"> 
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          24 
        </div> 
        <div class="crayon-num" data-line="crayon-58ddab04b2935918651820-25" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          25 
        </div> 
        <div class="crayon-num crayon-striped-num" data-line="crayon-58ddab04b2935918651820-26" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          26 
        </div> 
        <div class="crayon-num" data-line="crayon-58ddab04b2935918651820-27" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          27 
        </div> 
        @H_<a href="/tag/502/" target="_blank" class="keywords">502</a>_793@
          28 
        </div> 
        <div class="crayon-num" data-line="crayon-58ddab04b2935918651820-29" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          29 
        </div> 
        <div class="crayon-num crayon-striped-num" data-line="crayon-58ddab04b2935918651820-30" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          30 
        </div> 
        <div class="crayon-num" data-line="crayon-58ddab04b2935918651820-31" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          31 
        </div> 
       </div></td> 
      <td class="crayon-code" style="font-size: 13px; text-align: center; width: 611px; background: none; border: none !important; margin: 0px !important; padding: 0px !important; vertical-align: top !important; font-family: Monaco,monospace !important;"> 
       <div class="crayon-pre" style="margin: 0px; padding-right: 0px; padding-left: 0px; text-align: left; white-space: pre; overflow: visible; tab-size: 4; border: none !important; padding-top: 5px !important; padding-bottom: 3px !important; background: none !important; line-height: 15px !important;"> 
        <div class="crayon-line" id="crayon-58ddab04b2935918651820-1" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-e " style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">RACSignal *</span> 
         <span class="crayon-v" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,122) !important;">signal</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;">=</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">[</span> 
         <span class="crayon-e" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">RACSignal </span> 
         <span class="crayon-v" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;">:</span> 
         <span class="crayon-o" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;">^</span> 
         <span class="crayon-e " style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">RACDisposable *</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">(</span> 
         <span class="crayon-e" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">id </span> 
         <span class="crayon-v" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,122) !important;">subscriber</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">)</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,51) !important;">{</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935918651820-2" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"></span> 
         <span class="crayon-e" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">NSLog</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">(</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">@</span> 
         <span class="crayon-s" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(221,17,68) !important;">"创建"</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">)</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">;</span> 
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935918651820-3" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">
           
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935918651820-4" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"></span> 
         <span class="crayon-c" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(153,153) !important; font-style: italic !important;">/* 发送网络请求 */</span> 
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935918651820-5" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"></span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">[</span> 
         <span class="crayon-e" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">subscriber </span> 
         <span class="crayon-v" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,122) !important;">sendNext</span> 
         <span class="crayon-o" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;">:</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,68) !important;">"data"</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">;</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935918651820-6" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,122) !important;">sendCompleted</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">;</span> 
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935918651820-7" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">
           
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935918651820-8" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"></span> 
         <span class="crayon-st" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: bold !important;">return</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,51) !important;">[</span> 
         <span class="crayon-e" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">RACDisposable </span> 
         <span class="crayon-v" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,122) !important;">disposableWithBlock</span> 
         <span class="crayon-o" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;">^</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">{</span> 
        </div> 
        @H_<a href="/tag/404/" target="_blank" class="keywords">404</a>_899@ 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span> 
         <span class="crayon-e" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">NSLog</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,68) !important;">"销毁"</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">;</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935918651820-10" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,51) !important;">}</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">;</span> 
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935918651820-11" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">;</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935918651820-12" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">
           
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935918651820-13" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">[</span> 
         <span class="crayon-e" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">signal </span> 
         <span class="crayon-v" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,122) !important;">subscribeNext</span> 
         <span class="crayon-o" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,51) !important;">(</span> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">id</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,122) !important;">x</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">{</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span> 
         <span class="crayon-c" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(153,153) !important; font-style: italic !important;">// 第一个<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935918651820-14" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,68) !important;">"id = %@"</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">,</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,51) !important;">;</span> 
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935918651820-15" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">;</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935918651820-16" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">
           
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935918651820-17" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,153) !important; font-style: italic !important;">// 第二个<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935918651820-18" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,68) !important;">"id2 = %@"</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">;</span> 
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935918651820-19" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">;</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935918651820-20" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">
           
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935918651820-21" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-c" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(153,153) !important; font-style: italic !important;">/*</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935918651820-22" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-c" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(153,153) !important; font-style: italic !important;">控制台<a href="/tag/shuchu/" target="_blank" class="keywords">输出</a>为 :</span> 
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935918651820-23" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-c" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(153,153) !important; font-style: italic !important;"> 2017-03-13 15:48:09.632 使用cocoapods[41347:10397774] 创建</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935918651820-24" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-c" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(153,153) !important; font-style: italic !important;"> 2017-03-13 15:48:09.634 使用cocoapods[41347:10397774] id = data</span> 
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935918651820-25" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-c" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(153,153) !important; font-style: italic !important;"> 2017-03-13 15:48:09.636 使用cocoapods[41347:10397774] 销毁</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935918651820-26" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-c" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(153,153) !important; font-style: italic !important;"> 2017-03-13 15:48:09.637 使用cocoapods[41347:10397774] 创建</span> 
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935918651820-27" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-c" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(153,153) !important; font-style: italic !important;"> 2017-03-13 15:48:09.638 使用cocoapods[41347:10397774] id2 = data</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935918651820-28" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-c" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(153,153) !important; font-style: italic !important;"> 2017-03-13 15:48:09.639 使用cocoapods[41347:10397774] 销毁</span> 
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935918651820-29" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">
           
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935918651820-30" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-c" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(153,153) !important; font-style: italic !important;"> 由此可见有多个<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>了该信号源的话,就会多次<a href="/tag/diaoyong/" target="_blank" class="keywords">调用</a>信号源block中的<a href="/tag/fangfa/" target="_blank" class="keywords">方法</a>,产生副作用</span> 
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935918651820-31" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-c" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(153,153) !important; font-style: italic !important;">*/</span> 
        </div> 
       </div></td> 
     </tr> 
    </tbody> 
   </table> 
  </div> 
 </div> 
 <p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding-top: 0px; padding-bottom: 0px; font-size: 15px; color: rgb(46,sans-serif;"></p> 
 <hr style="border-right: 0px solid rgb(232,232); border-bottom: 0px solid rgb(232,232); border-left: 0px solid rgb(232,232); border-top-style: solid; border-top-color: rgb(232,232); border-image: initial; margin: 0px 0px 20px; padding: 0px; font-size: 15px; clear: both; height: 0px; color: rgb(46,sans-serif;"> 
 <h1 style="border: 0px; margin: 0px 0px 20px; padding: 0px; font-size: 26px; font-stretch: normal; line-height: 40px; font-family: "Microsoft YaHei",46);">调度器</h1> 
 <h2 style="border: 0px; margin: 0px 0px 20px; padding: 0px; font-size: 24px; font-stretch: normal; line-height: 36px; font-family: "Microsoft YaHei",46);">RACScheduler</h2> 
 <p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding-top: 0px; padding-bottom: 0px; font-size: 15px; color: rgb(46,sans-serif;">RAC中对GCD的简单封装. 子类如下 :</p> 
 <div id="crayon-58ddab04b2935275101333" class="crayon-syntax crayon-theme-github crayon-font-monaco crayon-os-pc print-yes notranslate" data-settings=" minimize scroll-always" style="margin: 12px 0px; padding: 0px; box-sizing: border-box; text-size-adjust: none; width: 610px; font-family: Monaco,102) !important;"></span> 
   <div class="crayon-tools" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none; position: absolute; right: 0px; height: 19.5px !important; line-height: 19.5px !important; font-weight: inherit !important;"> 
    <div class="crayon-button crayon-nums-button crayon-pressed" title="切换是否显示行编号" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none -24px 0px no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") -24px -32px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-plain-button" title="纯文本显示代码" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px -48px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-wrap-button" title="切换自动换行" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px -112px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-expand-button" title="点击展开代码" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px -96px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-copy-button" title="复制代码" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px -16px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-popup-button" title="在新窗口中显示代码" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px 0px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
   </div> 
  </div> 
  <div class="crayon-plain-wrap" style="border: none; background: none; margin: 0px !important; padding: 0px !important; height: auto !important;"> 
   <textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly style="border-width: initial; border-style: none; outline: none; display: block; -webkit-appearance: none; padding: 0px 5px; width: 608px; height: 94.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; border-radius: 0px; box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0,170)!important">
          4 
        </div> 
       </div> </td> 
      <td class="crayon-code" style="font-size:13px; text-align:center; width:863px; background:none; border:none!important; margin:0px!important; padding:0px!important; vertical-align:top!important; font-family:Monaco,monospace!important"> 
       <div class="crayon-pre" style="margin:0px; padding-right:0px; padding-left:0px; text-align:left; white-space:pre; overflow:visible; border:none!important; padding-top:5px!important; padding-bottom:3px!important; background:none!important; line-height:15px!important"> 
        <div class="crayon-line" id="crayon-58ddab04b2935275101333-1" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important"> 
         <span class="crayon-i" style="border:0px; margin:0px; padding:0px; font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">RACImmediateScheduler</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span>：立即执行调度的任务，这是唯一一个<a href="/tag/zhichi/" target="_blank" class="keywords">支持</a>同步执行的调度器； 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935275101333-2" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important"> 
         <span class="crayon-i" style="border:0px; margin:0px; padding:0px; font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">RACQueueScheduler</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span>：一个抽象的队列调度器，在一个 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span> 
         <span class="crayon-i" style="border:0px; margin:0px; padding:0px; font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">GCD</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span>串行列队中异步调度所有任务； 
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935275101333-3" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important"> 
         <span class="crayon-i" style="border:0px; margin:0px; padding:0px; font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">RACTargetQueueScheduler</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span>：继承自 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span> 
         <span class="crayon-i" style="border:0px; margin:0px; padding:0px; font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">RACQueueScheduler</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span>，在一个以一个任意的 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span>队列为 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span> 
         <span class="crayon-i" style="border:0px; margin:0px; padding:0px; font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">target</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span>的串行队列中异步调度所有任务； 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935275101333-4" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important"> 
         <span class="crayon-i" style="border:0px; margin:0px; padding:0px; font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">RACSubscriptionScheduler</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span>：一个只用来调度<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>的调度器。 
        </div> 
       </div> </td> 
     </tr> 
    </tbody> 
   </table> 
  </div> 
 </div> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,46)"> 清洁工</h1> 
 <h2 style="border:0px; margin:0px 0px 20px; padding:0px; font-size:24px; line-height:36px; font-family:"Microsoft YaHei",46)"> RACDisposable</h2> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> 在<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>信号源的过程中,可能会产生副作用或者消耗一定的资源,所以在取消<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>或完成<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>的时候我们就需要做一些资源回收和辣鸡清理的工作. 核心<a href="/tag/fangfa/" target="_blank" class="keywords">方法</a>为<code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">-dispose</code></p> 
 <div id="crayon-58ddab04b2935086818527" class="crayon-syntax crayon-theme-github crayon-font-monaco crayon-os-pc print-yes notranslate" style="margin:12px 0px; padding:0px; width:610px; font-family:Monaco,102)!important"></span> 
   <div class="crayon-tools" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none; position:absolute; right:0px; height:19.5px!important; line-height:19.5px!important; font-weight:inherit!important"> 
    <div class="crayon-button crayon-nums-button crayon-pressed" title="切换是否显示行编号" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none -24px 0px no-repeat; height:inherit; line-height:15px; display:inline; position:relative; width:24px; font-size:inherit!important; font-weight:inherit!important; float:left!important"> 
     <div class="crayon-button-icon" style="border:none; margin:-8px 0px 0px; padding:0px; font-family:inherit; width:24px; position:absolute; left:0px; top:9.75px; font-size:inherit!important; height:16px!important; line-height:inherit!important; font-weight:inherit!important"> 
     </div> 
    </div> 
    <div class="crayon-button crayon-plain-button" title="纯文本显示代码" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none 0px center no-repeat; height:inherit; line-height:15px; display:inline; position:relative; width:24px; font-size:inherit!important; font-weight:inherit!important; float:left!important"> 
     <div class="crayon-button-icon" style="border:none; margin:-8px 0px 0px; padding:0px; font-family:inherit; width:24px; position:absolute; left:0px; top:9.75px; font-size:inherit!important; height:16px!important; line-height:inherit!important; font-weight:inherit!important"> 
     </div> 
    </div> 
    <div class="crayon-button crayon-wrap-button" title="切换自动换行" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none 0px center no-repeat; height:inherit; line-height:15px; display:inline; position:relative; width:24px; font-size:inherit!important; font-weight:inherit!important; float:left!important"> 
     <div class="crayon-button-icon" style="border:none; margin:-8px 0px 0px; padding:0px; font-family:inherit; width:24px; position:absolute; left:0px; top:9.75px; font-size:inherit!important; height:16px!important; line-height:inherit!important; font-weight:inherit!important"> 
     </div> 
    </div> 
    <div class="crayon-button crayon-expand-button" title="点击展开代码" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none 0px center no-repeat; height:inherit; line-height:15px; display:inline; position:relative; width:24px; font-size:inherit!important; font-weight:inherit!important; float:left!important"> 
     <div class="crayon-button-icon" style="border:none; margin:-8px 0px 0px; padding:0px; font-family:inherit; width:24px; position:absolute; left:0px; top:9.75px; font-size:inherit!important; height:16px!important; line-height:inherit!important; font-weight:inherit!important"> 
     </div> 
    </div> 
    <div class="crayon-button crayon-copy-button" title="复制代码" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none 0px center no-repeat; height:inherit; line-height:15px; display:inline; position:relative; width:24px; font-size:inherit!important; font-weight:inherit!important; float:left!important"> 
     <div class="crayon-button-icon" style="border:none; margin:-8px 0px 0px; padding:0px; font-family:inherit; width:24px; position:absolute; left:0px; top:9.75px; font-size:inherit!important; height:16px!important; line-height:inherit!important; font-weight:inherit!important"> 
     </div> 
    </div> 
    <div class="crayon-button crayon-popup-button" title="在新窗口中显示代码" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none 0px center no-repeat; height:inherit; line-height:15px; display:inline; position:relative; width:24px; font-size:inherit!important; font-weight:inherit!important; float:left!important"> 
     <div class="crayon-button-icon" style="border:none; margin:-8px 0px 0px; padding:0px; font-family:inherit; width:24px; position:absolute; left:0px; top:9.75px; font-size:inherit!important; height:16px!important; line-height:inherit!important; font-weight:inherit!important"> 
     </div> 
    </div> 
   </div> 
  </div> 
  <div class="crayon-plain-wrap" style="border:none; background:none; margin:0px!important; padding:0px!important; height:auto!important"> 
   <textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly style="border-width: initial; border-style: none; outline: none; display: block; -webkit-appearance: none; padding: 0px 5px; width: 608px; height: 94.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; border-radius: 0px; box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0,238) !important;"> 
       <div class="crayon-nums-content" style="border: none; margin: 0px; padding-right: 0px; padding-left: 0px; background: none; text-align: left; white-space: nowrap; padding-top: 5px !important; padding-bottom: 3px !important; line-height: 15px !important;"> 
        <div class="crayon-num" data-line="crayon-58ddab04b2935086818527-1" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          1 
        </div> 
        <div class="crayon-num crayon-striped-num" data-line="crayon-58ddab04b2935086818527-2" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          2 
        </div> 
        <div class="crayon-num" data-line="crayon-58ddab04b2935086818527-3" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          3 
        </div> 
        <div class="crayon-num crayon-striped-num" data-line="crayon-58ddab04b2935086818527-4" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          4 
        </div> 
       </div></td> 
      <td class="crayon-code" style="font-size: 13px; text-align: center; width: 2637px; background: none; border: none !important; margin: 0px !important; padding: 0px !important; vertical-align: top !important; font-family: Monaco,monospace !important;"> 
       <div class="crayon-pre" style="margin: 0px; padding-right: 0px; padding-left: 0px; text-align: left; white-space: pre; overflow: visible; tab-size: 4; border: none !important; padding-top: 5px !important; padding-bottom: 3px !important; background: none !important; line-height: 15px !important;"> 
        <div class="crayon-line" id="crayon-58ddab04b2935086818527-1" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">RACSerialDisposable</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>：作为 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">disposable</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>的容器使用，可以包含一个 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>对象，并且允许将这个 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>对象通过原子操作交换出来； 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935086818527-2" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">RACKVOTrampoline</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>：代表一次 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">KVO</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>观察，并且可以用来停止观察； 
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935086818527-3" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">RACCompoundDisposable</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>：跟 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">RACSerialDisposable</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>一样， 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">RACCompoundDisposable</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>也是作为 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>的容器使用。不同的是，它可以包含多个 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>对象，并且<a href="/tag/zhichi/" target="_blank" class="keywords">支持</a>手动<a href="/tag/tianjia/" target="_blank" class="keywords">添加</a>和移除 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>对象，有点类似于可变数组 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">NSMutableArray</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>。而当一个 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">RACCompoundDisposable</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>对象被 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">disposed</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>时，它会<a href="/tag/diaoyong/" target="_blank" class="keywords">调用</a>其所包含的所有 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>对象的 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;">-</span> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">dispose</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span><a href="/tag/fangfa/" target="_blank" class="keywords">方法</a>，有点类似于 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">autoreleasepool</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>的作用 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">;</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935086818527-4" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">RACScopedDisposable</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>：当它被 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span> 
         <span class="crayon-i" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">dealloc</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span>的时候<a href="/tag/diaoyong/" target="_blank" class="keywords">调用</a>本身的 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span><a href="/tag/fangfa/" target="_blank" class="keywords">方法</a>。 
        </div> 
       </div></td> 
     </tr> 
    </tbody> 
   </table> 
  </div> 
 </div> 
 <p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding-top: 0px; padding-bottom: 0px; font-size: 15px; color: rgb(46,sans-serif;">总的来说就是在适当的时机<a href="/tag/diaoyong/" target="_blank" class="keywords">调用</a>disposable对象的<code style="border: 0px; margin: 0px; padding: 0px; font-family: Monaco,monospace;">-dispose</code><a href="/tag/fangfa/" target="_blank" class="keywords">方法</a>而已.</p> 
 <hr style="border-right: 0px solid rgb(232,46);">RAC常见宏</h1> 
 <p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding-top: 0px; padding-bottom: 0px; font-size: 15px; color: rgb(46,sans-serif;"><a href="/tag/yongfa/" target="_blank" class="keywords">用法</a>在demo中</p> 
 <div id="crayon-58ddab04b2935924773377" class="crayon-syntax crayon-theme-github crayon-font-monaco crayon-os-pc print-yes notranslate" data-settings=" minimize scroll-always" style="margin: 12px 0px; padding: 0px; box-sizing: border-box; text-size-adjust: none; width: 610px; font-family: Monaco,102) !important;"></span> 
   <div class="crayon-tools" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none; position: absolute; right: 0px; height: 19.5px !important; line-height: 19.5px !important; font-weight: inherit !important;"> 
    <div class="crayon-button crayon-nums-button crayon-pressed" title="切换是否显示行编号" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none -24px 0px no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") -24px -32px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-plain-button" title="纯文本显示代码" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px -48px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-wrap-button" title="切换自动换行" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px -112px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-expand-button" title="点击展开代码" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px -96px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-copy-button" title="复制代码" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px -16px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-popup-button" title="在新窗口中显示代码" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px 0px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
   </div> 
  </div> 
  <div class="crayon-plain-wrap" style="border: none; background: none; margin: 0px !important; padding: 0px !important; height: auto !important;"> 
   <textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly style="border-width: initial; border-style: none; outline: none; display: block; -webkit-appearance: none; padding: 0px 5px; width: 608px; height: 169.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; border-radius: 0px; box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0,170)!important">
          5 
        </div> 
        <div class="crayon-num crayon-striped-num" style="border-top:none; border-right:1px solid rgb(222,170)!important">
          6 
        </div> 
        <div class="crayon-num" style="border-top:none; border-right:1px solid rgb(222,170)!important">
          7 
        </div> 
        <div class="crayon-num crayon-striped-num" style="border-top:none; border-right:1px solid rgb(222,170)!important">
          8 
        </div> 
        <div class="crayon-num" style="border-top:none; border-right:1px solid rgb(222,170)!important">
          9 
        </div> 
       </div> </td> 
      <td class="crayon-code" style="font-size:13px; text-align:center; width:640px; background:none; border:none!important; margin:0px!important; padding:0px!important; vertical-align:top!important; font-family:Monaco,monospace!important"> 
       <div class="crayon-pre" style="margin:0px; padding-right:0px; padding-left:0px; text-align:left; white-space:pre; overflow:visible; border:none!important; padding-top:5px!important; padding-bottom:3px!important; background:none!important; line-height:15px!important"> 
        <div class="crayon-line" id="crayon-58ddab04b2935924773377-1" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important"> 
         <span class="crayon-cn" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,153)!important">1.</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span> 
         <span class="crayon-e" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:teal!important">RAC</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,122)!important">TARGET</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51)!important">[</span> 
         <span class="crayon-v" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,122)!important">KEYPATH</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,122)!important">NIL_VALUE</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51)!important">]</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,224)!important"></span> 
         <span class="crayon-o" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span>总是出现在等号左边 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,224)!important"> </span>等号右边是一个 
         <span class="crayon-i" style="border:0px; margin:0px; padding:0px; font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">RACSignal</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935924773377-2" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">
           
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935924773377-3" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important"> 
         <span class="crayon-cn" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,153)!important">2.</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span> 
         <span class="crayon-e" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:teal!important">RACObserve</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,224)!important"> </span>产生一个 
         <span class="crayon-i" style="border:0px; margin:0px; padding:0px; font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">RACSignal</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935924773377-4" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">
           
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935924773377-5" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important"> 
         <span class="crayon-cn" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,153)!important">3.</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,51)!important">@</span> 
         <span class="crayon-e" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:teal!important">weakify</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51)!important">(</span> 
         <span class="crayon-r" style="border:0px; margin:0px; padding:0px; font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:bold!important">self</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,224)!important"> </span>和 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,51)!important">@</span> 
         <span class="crayon-e" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:teal!important">strongify</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51)!important">)</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935924773377-6" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">
           
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935924773377-7" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important"> 
         <span class="crayon-cn" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,153)!important">4.</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span> 
         <span class="crayon-i" style="border:0px; margin:0px; padding:0px; font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">RACTuplePack</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,122)!important">RACTupleUnpack</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,224)!important"> </span>压包与解包 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935924773377-8" style="border:none; margin:0px; padding:0px 5px; font-family:inherit; background:none; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">
           
        </div> 
        @H_640_1<a href="/tag/403/" target="_blank" class="keywords">403</a>@ 
         <span class="crayon-cn" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,153)!important">5.</span> 
         <span class="crayon-h" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,51)!important">@</span> 
         <span class="crayon-e" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:teal!important">keypath</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51)!important">.</span> 
         <span class="crayon-m" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(128,128)!important">property</span> 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,224)!important"> </span>产生一个字符串 
         <span class="crayon-sy" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51)!important">@</span> 
         <span class="crayon-s" style="border:0px; margin:0px; padding:0px; font-size:inherit!important; font-family:inherit; height:inherit; line-height:inherit!important; font-weight:inherit!important; color:rgb(221,68)!important">"property"</span> 
        </div> 
       </div> </td> 
     </tr> 
    </tbody> 
   </table> 
  </div> 
 </div> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,46)"> RAC中潜在的内存泄漏及<a href="/tag/jiejuefangfa/" target="_blank" class="keywords">解决方法</a></h1> 
 <h3 style="border:0px; margin:0px 0px 20px; padding:0px; font-size:20px; line-height:30px; font-family:"Microsoft YaHei",46)"> RACObserve</h3> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> 如果在block中使用到了RACObserve,则必须<a href="/tag/jiashang/" target="_blank" class="keywords">加上</a><code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">@weakify</code>和<code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">@strongify</code>,尽管没有<a href="/tag/xianshi/" target="_blank" class="keywords">显示</a>使用到了<code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">self</code>. 文档事例如下 :</p> 
 <div id="crayon-58ddab04b2935483603969" class="crayon-syntax crayon-theme-github crayon-font-monaco crayon-os-pc print-yes notranslate" style="margin:12px 0px; padding:0px; width:610px; font-family:Monaco,102)!important"></span> 
   <div class="crayon-tools" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none; position:absolute; right:0px; height:19.5px!important; line-height:19.5px!important; font-weight:inherit!important"> 
    <div class="crayon-button crayon-nums-button crayon-pressed" title="切换是否显示行编号" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none -24px 0px no-repeat; height:inherit; line-height:15px; display:inline; position:relative; width:24px; font-size:inherit!important; font-weight:inherit!important; float:left!important"> 
     <div class="crayon-button-icon" style="border:none; margin:-8px 0px 0px; padding:0px; font-family:inherit; width:24px; position:absolute; left:0px; top:9.75px; font-size:inherit!important; height:16px!important; line-height:inherit!important; font-weight:inherit!important"> 
     </div> 
    </div> 
    <div class="crayon-button crayon-plain-button" title="纯文本显示代码" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none 0px center no-repeat; height:inherit; line-height:15px; display:inline; position:relative; width:24px; font-size:inherit!important; font-weight:inherit!important; float:left!important"> 
     <div class="crayon-button-icon" style="border:none; margin:-8px 0px 0px; padding:0px; font-family:inherit; width:24px; position:absolute; left:0px; top:9.75px; font-size:inherit!important; height:16px!important; line-height:inherit!important; font-weight:inherit!important"> 
     </div> 
    </div> 
    <div class="crayon-button crayon-wrap-button" title="切换自动换行" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none 0px center no-repeat; height:inherit; line-height:15px; display:inline; position:relative; width:24px; font-size:inherit!important; font-weight:inherit!important; float:left!important"> 
     <div class="crayon-button-icon" style="border:none; margin:-8px 0px 0px; padding:0px; font-family:inherit; width:24px; position:absolute; left:0px; top:9.75px; font-size:inherit!important; height:16px!important; line-height:inherit!important; font-weight:inherit!important"> 
     </div> 
    </div> 
    <div class="crayon-button crayon-expand-button" title="点击展开代码" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none 0px center no-repeat; height:inherit; line-height:15px; display:inline; position:relative; width:24px; font-size:inherit!important; font-weight:inherit!important; float:left!important"> 
     <div class="crayon-button-icon" style="border:none; margin:-8px 0px 0px; padding:0px; font-family:inherit; width:24px; position:absolute; left:0px; top:9.75px; font-size:inherit!important; height:16px!important; line-height:inherit!important; font-weight:inherit!important"> 
     </div> 
    </div> 
    <div class="crayon-button crayon-copy-button" title="复制代码" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none 0px center no-repeat; height:inherit; line-height:15px; display:inline; position:relative; width:24px; font-size:inherit!important; font-weight:inherit!important; float:left!important"> 
     <div class="crayon-button-icon" style="border:none; margin:-8px 0px 0px; padding:0px; font-family:inherit; width:24px; position:absolute; left:0px; top:9.75px; font-size:inherit!important; height:16px!important; line-height:inherit!important; font-weight:inherit!important"> 
     </div> 
    </div> 
    <div class="crayon-button crayon-popup-button" title="在新窗口中显示代码" style="border:none; margin:0px; padding:0px; font-family:inherit; background:none 0px center no-repeat; height:inherit; line-height:15px; display:inline; position:relative; width:24px; font-size:inherit!important; font-weight:inherit!important; float:left!important"> 
     <div class="crayon-button-icon" style="border:none; margin:-8px 0px 0px; padding:0px; font-family:inherit; width:24px; position:absolute; left:0px; top:9.75px; font-size:inherit!important; height:16px!important; line-height:inherit!important; font-weight:inherit!important"> 
     </div> 
    </div> 
   </div> 
  </div> 
  <div class="crayon-plain-wrap" style="border:none; background:none; margin:0px!important; padding:0px!important; height:auto!important"> 
   <textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly style="border-width: initial; border-style: none; outline: none; display: block; -webkit-appearance: none; padding: 0px 5px; width: 608px; height: 124.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; border-radius: 0px; box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0,238) !important;"> 
       <div class="crayon-nums-content" style="border: none; margin: 0px; padding-right: 0px; padding-left: 0px; background: none; text-align: left; white-space: nowrap; padding-top: 5px !important; padding-bottom: 3px !important; line-height: 15px !important;"> 
        <div class="crayon-num" data-line="crayon-58ddab04b2935483603969-1" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          1 
        </div> 
        @H_<a href="/tag/404/" target="_blank" class="keywords">404</a>_1474@
          2 
        </div> 
        <div class="crayon-num" data-line="crayon-58ddab04b2935483603969-3" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          3 
        </div> 
        <div class="crayon-num crayon-striped-num" data-line="crayon-58ddab04b2935483603969-4" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          4 
        </div> 
        <div class="crayon-num" data-line="crayon-58ddab04b2935483603969-5" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          5 
        </div> 
        <div class="crayon-num crayon-striped-num" data-line="crayon-58ddab04b2935483603969-6" style="border-top: none; border-right: 1px solid rgb(222,170) !important;">
          6 
        </div> 
       </div></td> 
      <td class="crayon-code" style="font-size: 13px; text-align: center; width: 682px; background: none; border: none !important; margin: 0px !important; padding: 0px !important; vertical-align: top !important; font-family: Monaco,monospace !important;"> 
       <div class="crayon-pre" style="margin: 0px; padding-right: 0px; padding-left: 0px; text-align: left; white-space: pre; overflow: visible; tab-size: 4; border: none !important; padding-top: 5px !important; padding-bottom: 3px !important; background: none !important; line-height: 15px !important;"> 
        <div class="crayon-line" id="crayon-58ddab04b2935483603969-1" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">@</span> 
         <span class="crayon-e" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">weakify</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">(</span> 
         <span class="crayon-r" style="border: 0px; margin: 0px; padding: 0px; font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: bold !important;">self</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">;</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935483603969-2" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-e " style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">RACSignal *</span> 
         <span class="crayon-v" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,122) !important;">signal3</span> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,51) !important;">[</span> 
         <span class="crayon-e" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">anotherSignal </span> 
         <span class="crayon-v" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,122) !important;">flattenMap</span> 
         <span class="crayon-o" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,51) !important;">(</span> 
         <span class="crayon-e " style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">NSArrayController *</span> 
         <span class="crayon-v" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,122) !important;">arrayController</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">{</span> 
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935483603969-3" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,153) !important; font-style: italic !important;">// Avoids a retain cycle because of RACObserve implicitly referencing self</span> 
        </div> 
        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935483603969-4" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,51) !important;">@</span> 
         <span class="crayon-e" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">strongify</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">;</span> 
        </div> 
        <div class="crayon-line" id="crayon-58ddab04b2935483603969-5" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-h" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,224) !important;"> </span> 
         <span class="crayon-e" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">RACObserve</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">(</span> 
         <span class="crayon-v" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(0,122) !important;">items</span> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,51) !important;">;</span> 
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        <div class="crayon-line crayon-striped-line" id="crayon-58ddab04b2935483603969-6" style="border: none; margin: 0px; padding: 0px 5px; font-family: inherit; background: none; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"> 
         <span class="crayon-sy" style="border: 0px; margin: 0px; padding: 0px; font-size: inherit !important; font-family: inherit; height: inherit; line-height: inherit !important; font-weight: inherit !important; color: rgb(51,sans-serif;"></p> 
 <h3 style="border: 0px; margin: 0px 0px 20px; padding: 0px; font-size: 20px; font-stretch: normal; line-height: 30px; font-family: "Microsoft YaHei",sans-serif;">RACSubject实例进行<code style="border: 0px; margin: 0px; padding: 0px; font-family: Monaco,monospace;">map</code>操作之后,发送完毕一定要<a href="/tag/diaoyong/" target="_blank" class="keywords">调用</a><code style="border: 0px; margin: 0px; padding: 0px; font-family: Monaco,monospace;">-sendCompleted</code>,否则会出现内存泄漏; 而RACSignal实例不管是否进行<code style="border: 0px; margin: 0px; padding: 0px; font-family: Monaco,monospace;">map</code>操作,不管是否<a href="/tag/diaoyong/" target="_blank" class="keywords">调用</a><code style="border: 0px; margin: 0px; padding: 0px; font-family: Monaco,都不会出现内存泄漏.</p> 
 <p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding-top: 0px; padding-bottom: 0px; font-size: 15px; color: rgb(46,sans-serif;">原因 : 因为RACSubject是热信号,为了保证未来有事件发生的时候,<a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者可以收到信息,所以需要对<span style="border: 0px; margin: 0px; padding: 0px;">持有</span><a href="/tag/dingyue/" target="_blank" class="keywords">订阅</a>者!</p> 
 <p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding-top: 0px; padding-bottom: 0px; font-size: 15px; color: rgb(46,sans-serif;">ps : 几乎所有操作底层都会<a href="/tag/diaoyong/" target="_blank" class="keywords">调用</a><code style="border: 0px; margin: 0px; padding: 0px; font-family: Monaco,monospace;">bind</code>这样一个<a href="/tag/fangfa/" target="_blank" class="keywords">方法</a>,<a href="/tag/baokuo/" target="_blank" class="keywords">包括</a>但不限于以下<a href="/tag/fangfa/" target="_blank" class="keywords">方法</a> :<code style="border: 0px; margin: 0px; padding: 0px; font-family: Monaco,monospace;">map</code>,<code style="border: 0px; margin: 0px; padding: 0px; font-family: Monaco,monospace;">filter</code>,monospace;">merge</code>,monospace;">combineLatest</code>,monospace;">flattenMap</code>…</p> 
 <div id="crayon-58ddab04b2935121267505" class="crayon-syntax crayon-theme-github crayon-font-monaco crayon-os-pc print-yes notranslate" data-settings=" minimize scroll-always" style="margin: 12px 0px; padding: 0px; box-sizing: border-box; text-size-adjust: none; width: 610px; font-family: Monaco,102) !important;"></span> 
   <div class="crayon-tools" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none; position: absolute; right: 0px; height: 19.5px !important; line-height: 19.5px !important; font-weight: inherit !important;"> 
    <div class="crayon-button crayon-nums-button crayon-pressed" title="切换是否显示行编号" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none -24px 0px no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") -24px -32px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
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     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px -48px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
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    <div class="crayon-button crayon-wrap-button" title="切换自动换行" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px -112px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-copy-button" title="复制代码" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px -16px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
    </div> 
    <div class="crayon-button crayon-popup-button" title="在新窗口中显示代码" style="border: none; margin: 0px; padding: 0px; font-family: inherit; background: none 0px center no-repeat; height: inherit; line-height: 15px; display: inline; position: relative; width: 24px; font-size: inherit !important; font-weight: inherit !important; float: left !important;"> 
     <div class="crayon-button-icon" style="border: none; margin: -8px 0px 0px; padding: 0px; font-family: inherit; background: url("../images/toolbar/buttons.png") 0px 0px; width: 24px; position: absolute; left: 0px; top: 9.75px; font-size: inherit !important; height: 16px !important; line-height: inherit !important; font-weight: inherit !important;"></div> 
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          4 
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 </div> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> 所以 : 对信号操作完成记得发送<code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">-sendCompleted</code>. (或者<code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">-sendError</code>).</p> 
 <h3 style="border:0px; margin:0px 0px 20px; padding:0px; font-size:20px; line-height:30px; font-family:"Microsoft YaHei",46)"> 线程安全</h3> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> Signal events是线性的,不会出现并发的情况,除非<a href="/tag/xianshi/" target="_blank" class="keywords">显示</a>地指定Scheduler. 所以<code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">-subscribeNext:</code>里的block不需要加锁,其他的events会依次排队,直到block处理完成.</p> 
 <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px; font-size:15px; color:rgb(46,sans-serif"> 为了方便调试,最好给信号指定Name :<code style="border:0px; margin:0px; padding:0px; font-family:Monaco,monospace">-setName</code><span style="font-family:Monaco,monospace">WithFormat:</span></p> 
 <div style="border:0px; margin:0px; padding:0px; font-size:15px; color:rgb(46,sans-serif"> 
  <hr style="border-right:0px solid rgb(232,232); margin:0px 0px 20px; padding:0px; clear:both; height:0px"> 
  <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px"> 参考<a href="/tag/wenzhang/" target="_blank" class="keywords">文章</a> :</p> 
  <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px"> <a target="_blank" href="javascript:void()" class="outlink" data="/link?url=http://yulingtianxia.com/blog/2015/05/21/ReactiveCocoa-and-MVVM-an-Introduction/" rel="nofollow" style="border:0px; margin:0px; padding:0px; text-decoration:none; color:rgb(0,204)">ReactiveCocoa 和 MVVM 入门</a></p> 
  <p style="border:0px; margin-top:0px; margin-bottom:20px; padding-top:0px; padding-bottom:0px"> 转自：http://ios.jobbole.com/93066/</p> 
 </div> 
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