iOS, UIWebView Page Control Display

Question

This is the page control for UIWebView (when displaying PDF - iOS 8). I like the background colour style its using, but am unsure of what it is called or how to implement in my custom UIView?

(note. to anyone that has not seen this in a live environment, its more than just a gradient)

Answer 1

阅读文档-CAGradientLayer ，然后签出该线程 。