LibGDX ScalingViewport不会更改位置

Question

I am trying to develop an Android app and I have stumbled across a really nasty problem.

I am trying to use a different viewport from my "main" one for a different stage to control certain elements. I have started using Scaling viewport with Scaling.none, as it seems the most appropriate for what I am looking for. The problem is, when I try to change its position, it simply does not move! It just stays in the center of the screen. Here is the code I am using in the contructor for the viewports:

viewport = new StretchViewport(720, 1280, cam);
viewport.apply();
cam.position.set(cam.viewportWidth / 2, cam.viewportHeight / 2,0);

secondaryViewport = new ScalingViewport(Scaling.none, 480, 421);
secondaryViewport.setScreenPosition(240, 0);

Can't Scaling viewports be moved?

EDIT: Here is my render() method:

@Override
public void render(SpriteBatch sb) {
    cam.update();
    secondaryViewport.getCamera().update();
    sb.setProjectionMatrix(cam.combined);
    Gdx.gl.glViewport(0, 0, Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
    sb.begin();
    sb.setColor(Color.WHITE);
    sb.draw(bg, cam.position.x - cam.viewportWidth / 2, 0, cam.viewportWidth, cam.viewportHeight);
    sb.end();
    stage.getViewport().apply();
    stage.draw();
    stage.act();
    secondaryStage.getViewport().apply();
    secondaryStage.draw();
    secondaryStage.act();

}

Answer 1

By default camera position of Viewport is at at 0,0,0

Use this secondaryViewport.getCamera().position.set(100,100,0); to change position of secondaryViewport.

secondaryViewport = new ScalingViewport(Scaling.none, 480, 421);

By this statement you're creating a new Camera that is different from the camera which is used in your StretchViewport .

Answer 2

好的，解决方法是

secondaryStage.getViewport().setScreenPosition(x, y);