An instance of the WKInterfaceButton class implements a button on the interface of a iOS Watch application.
A WKInterfaceButton
object represents a tappable area on the screen of a iOS Watch application. The content of that area is filled with text and an optional background color or image. When tapped by the user, the button calls its associated action method, which you define on the owning interface controller. Use that action method to initiate tasks and update your app’s interface.