Android :: Headset Button Is Being Pressed?

Does anyone know how to tell when the headset button is being pressed? I'd like to support the usb headsets and possibly bluetooth headsets. My app is a media player and ideally, I could register it somewhere so that if no app that uses the headset button has focus it button press would act as a play/pause command in my app. If the phone is ringing or a call is in progress, I'd like to be sensitive to that and let the button do what it normally does: pickup and hang up calls. we've been trying to chase the button down using this: Intent Filter headset Filter = new Intent Filter (Intent.ACTION_HEADSET_PLUG); headset Filter.addAction ("android.intent.action.HEADSET_STATE_CHANGED"); headsetFilter.addAction("android.bluetooth.intent.HEADSET_STATE"); headset Filter.addAction ("android.bluetooth.intent.HEADSET_STATE_CHANGED"); headset Filter.addAction ("android.bluetooth.intent.action.MODE_CHANGED"); headsetFilter.addAction("android.intent.action.MODE_CHANGED");