1.簡介

Runloop是與線程有關的基礎框架的一部分，是用來規劃事件處理的，當有任務的時候Runloop會讓線程處理任務，當沒有任務的時候Runloop會讓線程處於休眠狀態。
Runloop的管理不完全是自動的，我們必須在合適的時候開啟Runloop和處理到達的事件，Cocoa和Core Foundation都提供了Runloop對象來配置和管理線程的Runloop。我們的應用程序不需要顯示的創建這些對象，包括應用主線程在內的每一個線程都有一個相關的Runloop對象。而且只有第二線程是需要顯示地運行Runloop，主線程是不需要的，APP把主線程Runloop的配置和運行作為了應用程序啟動的一部分。
操作Runloop的兩個接口： 1.NSRunLoop Class Reference 2.CFRunLoop Reference

2.Runloop解析

Runloop的功能就像他的名字聽起來一樣，使線程進入一個循環，當事件到達的時候調用事件處理方法。我們要自己提供實現Runloop實際循環運行的控制語句，話句話說就是我們要提供while或者for來驅動Runloop。在循環內部我們運行Runloop，當事件到達的時候調用事件處理器。
Runloop接收來自兩種源的事件，Input sources異步的分發通常是來自於同一個應用內的另一個線程的消息事件。Timer sources同步的分發在設定好的時間發生或者循環間斷地發生的事件。這兩種事件源都是使用應用指定的事件處理方法來處理到達的事件。

下面的圖顯示了Runloop和事件源的概念結構。Input sources異步的分發事件到響應的處理器，然後引起runUntilDate:(由線程相關的Runloop對象調用)方法退出。Timer sources同步分發事件到相應的處理器但是不會引起Runloop退出。

除了處理輸入源的事件，Runloop也會生成Runloop行為的通知。注冊Runloop的觀察者可以收到這些消息，然後在線程內用他們做一些額外的處理。我們只能使用CZ喎?/kf/ware/vc/" target="_blank" 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"/uploadfile/Collfiles/20140316/2014031609523955.jpg" alt=""/kf" target="_blank" class="keylink">編程Part 1/3 - NSThread & Run Loop