public void pauseOrResumeConference() {
   LinphoneCore lc = LinphoneManager.getLc();
   if (lc.isInConference()) {
     lc.leaveConference();
   } else {
     lc.enterConference();
   }
 }
 public void pauseOrResumeCall(LinphoneCall call) {
   LinphoneCore lc = LinphoneManager.getLc();
   if (call != null && LinphoneUtils.isCallRunning(call)) {
     if (call.isInConference()) {
       lc.removeFromConference(call);
       if (lc.getConferenceSize() <= 1) {
         lc.leaveConference();
       }
     } else {
       lc.pauseCall(call);
       pause.setBackgroundResource(R.drawable.pause_on);
     }
   } else if (call != null) {
     if (call.getState() == State.Paused) {
       lc.resumeCall(call);
       pause.setBackgroundResource(R.drawable.pause_off);
     }
   }
 }