libgdx 渲染地图的小问题

先看代码

public class GameScreen implements Screen {
 
    public MyGdxGame myGdxGame;
 
    public TiledMap map;
    public Stage stage;
    private OrthographicCamera camera;
    private OrthogonalTiledMapRenderer render;
     
    SpriteBatch spriteBatch;
 
    public GameScreen(MyGdxGame game) {
        myGdxGame = game;
 
        camera = new OrthographicCamera(480,800);
        camera.setToOrtho(true, 480, 800);
         
        map = new TmxMapLoader().load("level.tmx");
         
        render = new OrthogonalTiledMapRenderer(map, 1/32);
         
    }
     
    @Override
    public void render(float delta) {
        // TODO Auto-generated method stub
        Gdx.gl.glClearColor(1, 1, 1, 1);
        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
         
        camera.update();
        render.setView(camera);
        render.render();
 
    }
 
    @Override
    public void resize(int width, int height) {
        // TODO Auto-generated method stub
 
    }
 
    @Override
    public void show() {
        // TODO Auto-generated method stub
 
    }
 
    @Override
    public void hide() {
        // TODO Auto-generated method stub
 
    }
 
    @Override
    public void pause() {
        // TODO Auto-generated method stub
 
    }
 
    @Override
    public void resume() {
        // TODO Auto-generated method stub
 
    }
 
    @Override
    public void dispose() {
        // TODO Auto-generated method stub
 
    }
 
}

这段代码，不能把地图显示出来，不知道为什么
刚学libgdx，学到这个地图渲染的问题，网上资料太少，就看着gitbub上的wiki自己摸索着写的，

不知道错在哪里？请大神们不吝赐教！谢谢

我用的版本是 1.0的

地图资源不能上传，我放在了 网盘里：

http://pan.baidu.com/share/link?shareid=3996070344&uk=1963808313