生成敌人和发动机

Question

我是AndEngine的新手，我打算做一个游泳鱼游戏。 我需要随机生成水母和鲨鱼作为鱼类需要避免的敌人。

我的问题是每当我运行它时，会出现多个水母而不是只有一只水母正在移动，因为我希望它能够被动画化。 我在网上看到了一个代码并将其应用到我的代码中，在这里：

// Spawning jellyfish, triggers every 5 seconds
private void createJellyfishSpawnTimeHandler() {
    TimerHandler spriteTimerHandler;
    float mEffectSpawnDelay = 5f;
    spriteTimerHandler = new TimerHandler(mEffectSpawnDelay, true, new ITimerCallback() {
            @Override
            public void onTimePassed(TimerHandler pTimerHandler) {
                    addJellyfish();
            }
    });
    getEngine().registerUpdateHandler(spriteTimerHandler);
}

// Loading jellyfish resources    
private void loadJellyfishResources(){
    this.animatedBitmapTextureAtlas = new BuildableBitmapTextureAtlas(this.getTextureManager(), 512, 256,TextureOptions.NEAREST);
    this.jellyfishTextureRegion = BitmapTextureAtlasTextureRegionFactory.createTiledFromAsset(this.animatedBitmapTextureAtlas, this, "jellyfish_tiled.png", 4, 1);
    try {
            this.animatedBitmapTextureAtlas.build(new BlackPawnTextureAtlasBuilder<IBitmapTextureAtlasSource, BitmapTextureAtlas>(0, 0, 1));
            this.animatedBitmapTextureAtlas.load();
    } catch (TextureAtlasBuilderException e) {
            Debug.e(e);
    }
    jellyfishToBeAdded = new LinkedList<Sprite>();
}

// adds a jellyfish at a random location and let it move along the x-axis
private void addJellyfish() {
    // for location
    int x = (int) (camera.getWidth() + jellyfishTextureRegion.getWidth());
    int y = rand.nextInt(high-low) + low;

    jellyfishTarget = new AnimatedSprite(x, y, jellyfishTextureRegion.deepCopy(), this.getVertexBufferObjectManager());
    jellyfishTarget.animate(250);
    scene.attachChild(jellyfishTarget);

    int actualDuration = 15;

    MoveXModifier mod = new MoveXModifier(actualDuration, jellyfishTarget.getX(), -jellyfishTarget.getWidth());
            jellyfishTarget.registerEntityModifier(mod.deepCopy());

    jellyfishToBeAdded.add(jellyfishTarget);
 }