为什么UISwitch onImage / offImage属性不适用于iOS 7？
有这两个选项/属性，并贬低他们的意义是什么？
从Apple文档：
offImage The image displayed while the switch is in the off position. @property(nonatomic, retain) UIImage *offImage Discussion In iOS 7, this property has no effect. In iOS 6, this image represents the interior contents of the switch. The image you specify is composited with the switch's rounded bezel and thumb to create the final appearance. Availability Available in iOS 6.0 and later. Declared In UISwitch.h 我现在应该怎么做？ 用UIButtonsreplace所有的UISwitch？
使用UIButton的selected属性将其用作开关。 为UIButton的UIControlStateSelected和UIControlStateNormal设置图像来自定义它。