How to create groups in libGdx?

Question

Can any of you please demonstrate a simple example on how to use groups in libGdx ? so if i move the parent, then all the children will move with it and same goes for rotation and scaling.

I looked for tutorials and example online but it seems that the latest version of libGdx did some changes to the Stage class.

Thank you

Best is subjective, for me, making it from scratch is better (because I have plenty control of it), for others, stage2D may be better, so they don't have to bother with it too much, or they can integrate with other Stage2D features. — Gustavo Maciel, Jun 03 '14 at 16:03

score 5 · Accepted Answer · edited Oct 20 '15 at 15:24

Here is exactly what i needed to have, this class allow to create 3 images and rotate them as they are a single object, thank you all for your inputs.

public class LearnGdx extends ApplicationAdapter {

    public static final int WIDTH = 800;
    public static final int HEIGHT = 480;

    private Stage stage;
    private Group group;

    private float rotSpeed = 5;

    @Override
    public void create() {

        // Create a stage
        stage = new Stage(new StretchViewport(WIDTH, HEIGHT));

        // Create a group and add it to the stage.
        group = new Group();
        stage.addActor(group);

        // Create images and add them to the group.
        final Texture region = new Texture(Gdx.files.internal("circle.png"));
        Image img = new Image(region);
        Image img2 = new Image(region);
        Image img3 = new Image(region);

        img2.setColor(new Color(1, 0, 0, 1));
        img3.setColor(new Color(0, 0, 1, 1));

        group.addActor(img2);
        group.addActor(img3);
        group.addActor(img);

        // Images are positioned relative to the group...
        img.setPosition(0, 0);
        img2.setPosition(img.getWidth()/2, 0);
        img3.setPosition(-img.getWidth()/2, 0);

        // Group is positioned relative to the stage...
        group.setPosition(WIDTH / 2 - img.getWidth() / 2,
            HEIGHT / 2 - img.getHeight() / 2);
        group.setOrigin(img.getWidth()/2,img.getHeight()/2);

    }

    @Override
    public void render() {
        Gdx.gl.glClearColor(0, 0, 0, 1);
        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

        stage.act(Gdx.graphics.getDeltaTime());
        stage.draw();

        if (Gdx.input.isKeyPressed(Keys.LEFT)) {
            group.rotateBy(rotSpeed);
        }
        if (Gdx.input.isKeyPressed(Keys.RIGHT)) {
            group.rotateBy(-rotSpeed);
        }
    }
}

How to create groups in libGdx?

1 Answers1