This is a circular slider to select a value from 0 to 360. The control is a subclass of UIControl and it is drawn using Core Graphics.
I built this slider for a tutorial about building custom controls in iOS.
You can find the full tutorial here: http://www.thinkandbuild.it/how-to-build-a-custom-control-in-ios/.
Get all the logs you need and fix bugs, crashes, and other issues in minutes instead of days. With Instabug you will automatically receive device data, network logs, and reproduction steps with every bug and crash report. It only takes a line of code to integrate and is perfect for teams that are now working remotely. See more detailed features comparison and try Instabug for free here.