什么是配置 libgdx 屏幕的正确位置

Hello I am working out a game and I wonder how to dispose resources as I am experiencing memory problems.

我有这样的事情:

public SplashScreen implements Screen {
    @Override
    public void render(float delta) {
    }
    @Override
    public void dispose() {
        if (batch != null)
            batch.dispose();
        batch = null;
    }
}

public MapScreen implements Screen {
    @Override
    public void render(float delta) {
    }
    @Override
    public void show() {
        splashScreenInstance.dispose();
    }
    @Override
    public void dispose() {
        if (mesh != null)
        mesh.dispose();
        mesh = null;
    }
}

一旦调用 MapScreen 的 show 方法，我就会处理启动画面.以前我将屏幕设置为 MapScree.仍然调用了 splashScreenInstance 的渲染方法，并且我收到了空指针异常.为什么会这样?