A extension class makes you easier to use frame. Are you tired with writting frame.
一个帮助你简化frame的扩展类。 ####BEFORE

CGRectMake(self.view.frame.origin.x,self.view.frame.origin.y,self.view.frame.size.width,self.view.frame.size.height * 0.9)

Now you got UIView+Extension,Frame is way easier to use.
现在有了UIView+Extension事情就简单了。 ####NOW

CGRectMake(self.view.x,self.view.y,self.view.width,self.view.height * 0.9)

#How to Use Drag UIView+Extension.h,UIView+Extension.m to you project. Then import "UIView+Extension.h". 将UIView+Extension.h,UIView+Extension.m加入你的工程，在使用的文件import "UIView+Extension.h"。