Purpose UIControlStateSelected

Question

Three other UIControlStates are clear to me, but I cannot understand the purpose of UIControlStateSelected. What / when does a UIControl subclass enter this state?

Answer 1

In the event that a button is selected or pressed, etc. Many people use this particular option to modify images on an object to show the selected state for a brief moment of its selection.

I also used it in tables to simplify cell reuse by checking selected states and updating a table cell based on if it is selected or not.