Superclass for your stages in libGDX

AbstractStretchStage.java

package de.reimerm.hammerize;

import com.badlogic.gdx.graphics.OrthographicCamera;
import com.badlogic.gdx.scenes.scene2d.Stage;
import com.badlogic.gdx.utils.Scaling;
import com.badlogic.gdx.utils.viewport.ScalingViewport;

/**
 * Created by Marius Reimer on 15-Sep-16.
 */
public abstract class AbstractStage extends Stage {

    public AbstractStage() {
        super(new ScalingViewport(Scaling.stretch, 800, 480,
                new OrthographicCamera(800, 480)));
        getCamera().position.set(getCamera().viewportWidth / 2, getCamera().viewportHeight / 2, 0f);
        getCamera().update();
    }
}