Android - detect if red/green keys are hard or soft

Every phone has two keys, nicknamed the "green" key and the "red" key and used to answer or hangup an incoming call. On Android phones, some phones have physical hardware keys for these two tasks; for example, the HTC g1. Other Android phones do not have physical keys. Instead, they display soft keys - areas on the screen that act like these keys. What I want is a code method that returns a boolean. True if the phone has hardware red/green keys and false if it does not. ## Deliverables I do not need a full app; just this one method that I can embed in my code. I appreciate that this work may simply be a one-line call to to the appropriate Android API.