@Subscribe public void onLocationChanged(LocationChangedEvent event) {
    // Stop existing download, if it exists.
    if (downloadTask != null) {
      downloadTask.cancel(true);
    }

    // Trigger a background download of an image for the new location.
    downloadTask = new DownloadTask();
    downloadTask.execute(String.format(URL, event.lat, event.lon));
  }
Display a map centered on the last known location.
otto-sample/src/main/java/com/squareup/otto/sample/LocationMapFragment.java