@Override
  public void onPause() {
    super.onPause();

    GameLoop.instance().stopLevelAndLoop();

    stars_creator.stopSpawningStars();

    adView.pause();
    MediaController.stopLoopingSound();
  }
  @Override
  public void onResume() {
    super.onResume();

    GameLoop.instance().startLevelAndLoop(this, null);

    stars_creator.startSpawningStars();

    // set GameTextViews here, as the text may have updated since onCreate
    // (user plays game, gets new record, and goes back to mainActivity)
    SharedPreferences gameMeta = getSharedPreferences(MainActivity.GAME_META_DATA_PREFS, 0);
    GameTextView score = (GameTextView) findViewById(R.id.high_score);
    score.setText(formatInt(gameMeta.getInt(HIGHEST_SCORE, 0)));
    GameTextView days = (GameTextView) findViewById(R.id.max_day);
    days.setText(formatInt(gameMeta.getInt(MAX_LEVEL, 0)));

    adView.resume();
    MediaController.playSoundClip(this, R.raw.background_intro, true);
  }