LibGDX未运行render()方法

我在使用LibGDX时遇到问题。

我有一个 Screen 并且 render 方法我有:

public class LoadingScreen implements Screen{
private OrthographicCamera guiCam;
private TankChallenge tankChallenge;
private SpriteBatch batcher;
private GL10 OpenGL;

public LoadingScreen(TankChallenge tankChallenge) {
    this.tankChallenge=tankChallenge;
    Gdx.graphics.setTitle("RobotChallange Beta - Loading");

    float AR = Gdx.graphics.getHeight()/Gdx.graphics.getWidth();
    guiCam = new OrthographicCamera(10,10 * AR);
    guiCam.position.set(10f/2,AR*10f/2,0);
    batcher = new SpriteBatch();

    OpenGL = Gdx.graphics.getGL10();
    //loadAssets();
}

@Override
public void render(float delta) {
    OpenGL.glClearColor(1, 0.5f, 1, 1);
    OpenGL.glClear(GL10.GL_COLOR_BUFFER_BIT);

    System.out.print("e");
    guiCam.update();
    Sprite sp = new Sprite();
    sp.setColor(1f,1f,0, 1);
    sp.setSize(100,100);
    sp.setOrigin(20, 0);

    batcher.setProjectionMatrix(guiCam.combined);
    batcher.begin();
    batcher.disableBlending();
    sp.draw(batcher);
    batcher.end();
}

我通过在实现中设置它来调用它 ApplicationListener 班我知道它即将进入加载屏幕,因为标题实际上设置为“机器人挑战测试版-加载”。