public static interface BluetoothHeadsetManager.BluetoothHeadsetObserver
void
onHeadsetConnected()
onHeadsetDisconnected()
onScoAudioConnected()
onScoAudioDisconnected()
void onHeadsetDisconnected()
void onHeadsetConnected()
void onScoAudioDisconnected()
void onScoAudioConnected()