Slider always has default width in table

Question

I created a slider inside of a table like shown in the following code example as I know that the minimum width of the background is used for the slider width:

public OptionScreen(MainClass game) {
    super(game);
    preference = new PreferencesHelper();
    font = this.getDefaultFont(25);
    this.table = new Table();
    if (Config.DEBUG)
        this.table.debug();

    // add volumenlabel
    LabelStyle style = new LabelStyle(font, Color.WHITE);
    volumenLabel = new Label(Config.VOLUMEN_LABLE, style);
    table.add(volumenLabel).colspan(2);
    table.row();
    // add slider
    Skin skin = new Skin();
    skin.add("sliderbackground",
            this.game.manager.get("data/sliderbackground.png"));
    skin.add("sliderknob", this.game.manager.get("data/sliderknob.png"));

    SliderStyle sliderStyle = new SliderStyle();
    sliderStyle.background = skin.getDrawable("sliderbackground");
    sliderStyle.background.setMinWidth(600f);
    sliderStyle.knob = skin.getDrawable("sliderknob");

    volumenSlider = new Slider(0f, 1f, 0.1f, false, sliderStyle);
    volumenSlider.setValue(preference.getVolumen()); // load current volumen
    volumenSlider.addListener(new ChangeListener() {

        @Override
        public void changed(ChangeEvent event, Actor actor) {
            volumeValue.setText(String.format("%.01f",
                    volumenSlider.getValue()));
            // sett the preference
            preference.setVolumen(volumenSlider.getValue());
        }
    });
    // add volslider to stage
    table.add(volumenSlider);
    volumenLabel.invalidate();

    // table
    style = new LabelStyle(font, Color.WHITE);
    // set current volumen
    volumeValue = new Label(
            String.format("%.01f", volumenSlider.getValue()), style);
    volumenLabel.setAlignment(2);
    table.add(volumeValue).width(50f);
    table.row();

    initBackButton();

    // init table
    table.setPosition(Config.VIRTUAL_VIEW_WIDTH / 2,
            Config.VIRTUAL_VIEW_HEIGHT / 2 - Config.BLOCK_SIZE * 10);

    // add a nice fadeIn to the whole table :)
    table.setColor(0, 0, 0, 0f);
    table.addAction(Actions.fadeIn(2f)); // alpha fade
    table.addAction(Actions.moveTo(Config.VIRTUAL_VIEW_WIDTH / 2,
            Config.VIRTUAL_VIEW_HEIGHT / 2, 2f)); // move to center of the
                                                    // screen
    // add to stage
    this.stage.addActor(table);
}

The slide is inside a table with no width set. I already took a look if the width is set and if the calculation for the prefWidth of the slider does uses the set 600f.

Math.max(style.knob == null ? 0 : style.knob.getMinWidth(), style.background.getMinWidth())

Is the calculation for the width of the slider inside the Sliderclass. If I calculate that and log it, it loggs the desired 600f.

Everything seems right to me but the slider is rendered way to small for the 600 I set.

The background and knobtextures are 24x24.

So I hope you guys can tell me what I am doing wrong.

Answer 1

The folution is, that it's inside an table so the width is defined by the table width attibut for the spec. col and row.

So the fix is pretty short:

table.add(volumenSlider).width(600).height(60);

And its 600width and 60 height.

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The wiki got edited to be more clear about this:

UI widgets do not set their own size and position. Instead, the parent widget sets the size and position of each child. Widgets provide a minimum, preferred, and maximum size that the parent can use as hints. Some parent widgets, such as Table, can be given constraints on how to size and position the children. To give a widget a specific size in a layout, the widget's minimum, preferred, and maximum size are left alone and size constraints are set in the parent.

Layout at Wiki