action中调用函数方法别忘了冒号1. 各个视图之间的关系要分辨清楚
2. MVC (Model-View-Controller). In this pattern, models keep track of your app’s data, views display your user interface and make up the content of an app, and controllers manage your views
3. func addTarget(target: AnyObject?, action: Selector, forControlEvents controlEvents: UIControlEvents) action中调用函数方法别忘了冒号