The root interface in the collection hierarchy.

集合层级的根接口。

youdao

At its root, interface design is concerned with the treatment and arrangement of visual elements to communicate behavior and information.

从根本上讲，界面设计的工作重点在于如何处理和组织好视觉元素，从而有效地传达出行为和信息。

youdao

The system asks the top-most full-screen view controller (typically the root view controller) for its supported interface orientations whenever the device rotates or whenever a view controller is presented with the full-screen modal presentation style.

ENGADGET: Apple seeds iOS 6 beta 4 to developers: here's the changelog