问如何在playN中实现动画效果

EN

class MyGame extends Game {
    private Animator anim;
    private float _elapsed = 0;

    public void init() {
        anim = Animator.create();

        anim.tweenScale(aLayer).from(0).to(50).linear();
    }

    public void paint(float alpha) {
        anim.update(_elapsed + alpha * updateRate());
    }

    public void update(float delta) {
        _elapsed += delta;
    }
}