com.idp.engine.ui.graphics.actors.listview.ScrollBar.java Source code

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Here is the source code for com.idp.engine.ui.graphics.actors.listview.ScrollBar.java

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package com.idp.engine.ui.graphics.actors.listview;

import com.badlogic.gdx.graphics.Color;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.Batch;
import com.badlogic.gdx.math.Interpolation;
import com.badlogic.gdx.scenes.scene2d.Action;
import com.badlogic.gdx.scenes.scene2d.Actor;
import com.badlogic.gdx.scenes.scene2d.actions.Actions;
import com.idp.engine.resources.assets.IdpColorPixmap;

/**
 * Scrollbar element for ListView.
 * Can be horizontal or vertical - orientation is automatically picked from the {@link ListView}.
 * Properties:
 *   thickness - thickness of the scrollbar in pixels
 *   offset - offset of the left(top) side of scrollbar from the right(bottom) side of the {@link ListView}.
 *   texture - visual representation of a scrollbar
 *   fadeDuration - duration of a fade animation
 *   fadeDelay - delay from the end of a scroll action or a touch up event to the start of a fadeout action
 *   normalAlpha - alpha that applied to the texture when the scrollbar is shown
 *
 * @author dhabensky <dhabensky@idp-crew.com>
 */
public class ScrollBar extends Actor {

    private final ListView listView;

    private float thickness;
    private float offset;
    private final IdpColorPixmap tex;

    private float fadeDuration;
    private float fadeDelay;
    private float normalAlpha;

    public ScrollBar(ListView parent) {
        if (parent == null)
            throw new NullPointerException();
        this.listView = parent;

        this.thickness = 2;
        this.offset = 4;
        this.tex = new IdpColorPixmap();
        tex.setColor(Color.WHITE);
        this.fadeDuration = 0.2f;
        this.fadeDelay = 0.5f;
        this.normalAlpha = 0.8f;
        setColor(new Color(0.4f, 0.4f, 0.4f, normalAlpha));
    }

    public float getThickness() {
        return thickness;
    }

    public void setThickness(float thickness) {
        this.thickness = thickness;
    }

    public float getOffset() {
        return offset;
    }

    public void setOffset(float offset) {
        this.offset = offset;
    }

    public Texture getTexture() {
        return tex.getTexture();
    }

    public float getFadeDuration() {
        return fadeDuration;
    }

    public void setFadeDuration(float fadeDuration) {
        this.fadeDuration = fadeDuration;
    }

    public float getFadeDelay() {
        return fadeDelay;
    }

    public void setFadeDelay(float fadeDelay) {
        this.fadeDelay = fadeDelay;
    }

    public float getNormalAlpha() {
        return normalAlpha;
    }

    public void setNormalAlpha(float normalAlpha) {
        this.normalAlpha = normalAlpha;
    }

    @Override
    public void draw(Batch batch, float parentAlpha) {

        com.idp.engine.ui.graphics.actors.listview.ContentWrapper content = listView.getContentWrapper();

        if (content.isNotFull() || content.getSize() <= 0)
            return;

        float contentSize = content.getSize();
        if (content.isTopOverScrollFixed())
            contentSize -= content.getTopOverScroll();
        if (content.isBottomOverScrollFixed())
            contentSize -= content.getBottomOverScroll();

        float size = (content.isHorizontal() ? listView.getWidth() : listView.getHeight());
        float length = size * size / contentSize;
        float f = -content.getClampedOffset();
        float pos = f / ((contentSize - size)) * (size - length);

        Color c = getColor();
        batch.setColor(c.r, c.g, c.b, c.a * parentAlpha);

        if (content.isHorizontal()) {
            batch.draw(tex.getTexture(), pos, listView.getHeight() - offset - thickness, length, thickness);
        } else {
            batch.draw(tex.getTexture(), listView.getWidth() - offset - thickness, pos, thickness, length);
        }
    }

    /**
     * Shows scroll bar.
     * Alpha goes from 0 to normalAlpha.
     */
    public void fadeIn() {
        if (state == FadeState.IN)
            return;
        state = FadeState.IN;
        clearActions();
        addAction(Actions.sequence(Actions.alpha(normalAlpha, fadeDuration, Interpolation.pow2Out),
                setFadeState(FadeState.NULL)));
    }

    /**
     * Hides scroll bar.
     * Alpha goes from normalAlpha to 0.
     */
    public void fadeOut() {
        if (state == FadeState.OUT)
            return;
        if (state != FadeState.IN)
            clearActions();
        state = FadeState.OUT;
        addAction(Actions.sequence(Actions.delay(fadeDelay), Actions.alpha(0, fadeDuration, Interpolation.pow2Out),
                setFadeState(FadeState.NULL)));
    }

    /**
     * Creates (but not adds it to the scrollbar) action that will fade out scrollbar after {@code fadeDelay} seconds.
     * @return newly created delayed fadeout action
     */
    Action delayedFadeOut() {
        return Actions.addAction(Actions.sequence(Actions.delay(fadeDelay), setFadeState(FadeState.OUT),
                Actions.alpha(0, fadeDuration, Interpolation.pow2Out), setFadeState(FadeState.NULL)), this);
    }

    private static enum FadeState {
        IN, OUT, NULL
    }

    private FadeState state;

    private Action setFadeState(final FadeState state) {
        return new Action() {
            public boolean act(float delta) {
                ScrollBar.this.state = state;
                return true;
            }
        };
    }
}