com.badlogic.gdx.scenes.scene2d.ui.Widget.java Source code

Introduction

Here is the source code for com.badlogic.gdx.scenes.scene2d.ui.Widget.java

Source

/*******************************************************************************
 * Copyright 2011 See AUTHORS file.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/

package com.badlogic.gdx.scenes.scene2d.ui;

import com.badlogic.gdx.graphics.g2d.Batch;
import com.badlogic.gdx.scenes.scene2d.Actor;
import com.badlogic.gdx.scenes.scene2d.Group;
import com.badlogic.gdx.scenes.scene2d.Stage;
import com.badlogic.gdx.scenes.scene2d.utils.Layout;

/** An {@link Actor} that participates in layout and provides a minimum, preferred, and maximum size.
 * <p>
 * The default preferred size of a widget is 0 and this is almost always overridden by a subclass. The default minimum size
 * returns the preferred size, so a subclass may choose to return 0 if it wants to allow itself to be sized smaller. The default
 * maximum size is 0, which means no maximum size.
 * <p>
 * See {@link Layout} for details on how a widget should participate in layout. A widget's mutator methods should call
 * {@link #invalidate()} or {@link #invalidateHierarchy()} as needed.
 * @author mzechner
 * @author Nathan Sweet */
public class Widget extends Actor implements Layout {
    private boolean needsLayout = true;
    private boolean fillParent;
    private boolean layoutEnabled = true;

    public float getMinWidth() {
        return getPrefWidth();
    }

    public float getMinHeight() {
        return getPrefHeight();
    }

    public float getPrefWidth() {
        return 0;
    }

    public float getPrefHeight() {
        return 0;
    }

    public float getMaxWidth() {
        return 0;
    }

    public float getMaxHeight() {
        return 0;
    }

    public void setLayoutEnabled(boolean enabled) {
        layoutEnabled = enabled;
        if (enabled)
            invalidateHierarchy();
    }

    public void validate() {
        if (!layoutEnabled)
            return;

        Group parent = getParent();
        if (fillParent && parent != null) {
            float parentWidth, parentHeight;
            Stage stage = getStage();
            if (stage != null && parent == stage.getRoot()) {
                parentWidth = stage.getWidth();
                parentHeight = stage.getHeight();
            } else {
                parentWidth = parent.getWidth();
                parentHeight = parent.getHeight();
            }
            setSize(parentWidth, parentHeight);
        }

        if (!needsLayout)
            return;
        needsLayout = false;
        layout();
    }

    /** Returns true if the widget's layout has been {@link #invalidate() invalidated}. */
    public boolean needsLayout() {
        return needsLayout;
    }

    public void invalidate() {
        needsLayout = true;
    }

    public void invalidateHierarchy() {
        if (!layoutEnabled)
            return;
        invalidate();
        Group parent = getParent();
        if (parent instanceof Layout)
            ((Layout) parent).invalidateHierarchy();
    }

    protected void sizeChanged() {
        invalidate();
    }

    public void pack() {
        setSize(getPrefWidth(), getPrefHeight());
        validate();
    }

    public void setFillParent(boolean fillParent) {
        this.fillParent = fillParent;
    }

    /** If this method is overridden, the super method or {@link #validate()} should be called to ensure the widget is laid out. */
    public void draw(Batch batch, float parentAlpha) {
        validate();
    }

    public void layout() {
    }
}