Is it possible to detect if an Android phone has a trackball?

My application requires users to hold down the trackball in order to access an a开发者_开发百科dvanced menu. Not all phones have a trackball, however, so I need to remove this requirement for such phones. Is there a way to detect if the phone has a trackball?

Use the Configuration object, specifically the navigation and navigationHidden fields. You can get a Configuration object via getResources().getConfiguration().