@Override
 protected void onDestroy() {
   super.onDestroy();
   MeetingHelper.removeInterPhoneCallback(this);
   MeetingMsgReceiver.removeVoiceMeetingListener(this);
 }
 @Override
 protected void onResume() {
   super.onResume();
   MeetingHelper.addInterPhoneCallback(this);
   MeetingMsgReceiver.addVoiceMeetingListener(this);
 }