/**
  * Called by {@link MainActivity} when a sensor's reading changes. Rotates sky plot according to
  * bearing.
  */
 public void onSensorChanged(SensorEvent event) {
   switch (event.sensor.getType()) {
     case Sensor.TYPE_ORIENTATION:
       gpsStatusView.setOrientation(event.values[0], event.values[1], event.values[2]);
       break;
   }
 }
 /** Called by {@link MainActivity} when the status of the GPS changes. Updates GPS display. */
 public void onGpsStatusChanged(
     GpsStatus status, int satsInView, int satsUsed, Iterable<GpsSatellite> sats) {
   gpsSats.setText(String.valueOf(satsUsed) + "/" + String.valueOf(satsInView));
   gpsTtff.setText(String.valueOf(status.getTimeToFirstFix() / 1000));
   gpsStatusView.showSats(sats);
   gpsSnrView.showSats(sats);
 }