title: What are common design patterns in Cocoa Touch?
body: <p>In Java community, design pattern is very common term. </p>
  
  <p>In Object C and Cocoa touch world, there are also some design patterns, such as MVC, target-action, delegate, KVO etc. </p>
  
  <p>The purpose question here is to hear more professional experience from guru. After all, some patterns are common used in iOS development. Just like some are very common in J2EE world. </p>
  
  <p>So question maybe how many common patterns in iOS development field ?  Let me put some here</p>
  
  <ul>
  <li>MVC </li>
  <li>delegate, target-action ( communication between V and C ) </li>
  <li>KVC KVO Notification ( comm between M and C ) </li>
  <li>Singleton 
  ....
  ....</li>
  </ul>