Drawing Your Own Button

The SBGButton example source code shows to implement a button class from scatch: It draws the button and responds to user interaction itself. This section discusses the key methods.

Because the SBGButton class is a new class derived from UIView, Interface Builder knows nothing about it. Therefore, the example is built using the NIB-less version of the calculator. The applicationDidFinishLaunching method is responsible for adding SBGButtons to the calculator user interface.