问题
How this UIPageViewController can be controlled by this header which seems to be UISegmentedControl?
回答1:
The top bar looks like a custom control with an interesting indicator line.
This could be accomplished by putting the 2 view controllers on a UIScrollView side by side.
In the UIScrollViewDelegate implement scrollViewDidScroll and update the indicator line offset accordingly.
来源：https://stackoverflow.com/questions/30141474/ios-is-this-uipageviewcontroller-controlled-by-uisegmentedcontrol-or-what-is