public GameScreen(NinjaGamePrototype game) { this.game = game; new WorldController(); WorldModel.get().addObserver(SoundSystem.get()); WorldModel.get().getNinja().addObserver(SoundSystem.get()); InputMultiplexer multiplexer = new InputMultiplexer(); multiplexer.addProcessor(new SongController()); multiplexer.addProcessor(new NinjaController()); Gdx.input.setInputProcessor(multiplexer); @SuppressWarnings("rawtypes") Iterator it; it = WorldModel.get().getEnemies().iterator(); while (it.hasNext()) { EnemyModel enemy = (EnemyModel) it.next(); enemy.addObserver(SoundSystem.get()); } }