加载 Xib 文件

http://www.cocoachina.com/ios/20150202/11086.html

http://www.jianshu.com/p/ea3f90cc744b

加载同名的 Xib 文件

1. 错误：

reason: '-[UIViewController _loadViewFromNibNamed:bundle:] loaded the "CheckOutView" nib but the view outlet was not set.'

解决