public override void onCallEnded(Call call)
            {
                CallEndCause cause = call.Details.EndCause;

                Log.d(TAG, "Call ended. Reason: " + cause.ToString());
                outerInstance.mAudioPlayer.stopProgressTone();
                VolumeControlStream = AudioManager.USE_DEFAULT_STREAM_TYPE;
                string endMsg = "Call ended: " + call.Details.ToString();

                Toast.makeText(outerInstance, endMsg, Toast.LENGTH_LONG).show();

                outerInstance.endCall();
            }
 public override void onClick(View v)
 {
     outerInstance.endCall();
 }