Libgdx游戏引擎之ScrollPane组件

这是一个不显示滚动条的水平ScrollPanel，通过手势控制ScrollPanel水平移动

2、示例代码

import com.badlogic.gdx.graphics.Color;
import com.badlogic.gdx.scenes.scene2d.Actor;
import com.badlogic.gdx.scenes.scene2d.InputEvent;
import com.badlogic.gdx.scenes.scene2d.InputListener;
import com.badlogic.gdx.scenes.scene2d.Touchable;
import com.badlogic.gdx.scenes.scene2d.ui.Image;
import com.badlogic.gdx.scenes.scene2d.ui.ImageButton;
import com.badlogic.gdx.scenes.scene2d.ui.ScrollPane;
import com.badlogic.gdx.scenes.scene2d.ui.Skin;
import com.badlogic.gdx.scenes.scene2d.ui.Table;
import com.badlogic.gdx.scenes.scene2d.utils.ClickListener;
import com.badlogic.gdx.scenes.scene2d.utils.TextureRegionDrawable;
import com.swallowgames.supermario.game.Assets;
import com.swallowgames.supermario.screen.MainScreen;
import com.swallowgames.supermario.utils.Utils;

public class ThemeScrollPanel extends ScrollPane{

    private ButtonClickListener clickListener;
    private MainScreen mainScreen;

    public ThemeScrollPanel(Actor widget, Skin skin) {
        super(widget, skin);
    }

    public ThemeScrollPanel (Actor widget, ScrollPaneStyle style) {
        super(widget, style);
    }

    public ThemeScrollPanel init(){

        clickListener = new ButtonClickListener();

        Table table = new Table();
        table.debug();

        ImageButton themeBackground = new ImageButton(new TextureRegionDrawable(Assets.instance.assetUI.theme1),
                new TextureRegionDrawable(Assets.instance.assetUI.theme1p));
        themeBackground.setUserObject(0);
        themeBackground.addCaptureListener(clickListener);
        table.add(themeBackground);
        table.columnDefaults(0);

        themeBackground = new ImageButton(new TextureRegionDrawable(Assets.instance.assetUI.theme2),
                new TextureRegionDrawable(Assets.instance.assetUI.theme2p));
        themeBackground.setUserObject(1);
        themeBackground.setTouchable(Touchable.disabled);
        themeBackground.addCaptureListener(clickListener);
        Image lock = new Image(new TextureRegionDrawable(Assets.instance.assetUI.lock));
        lock.setPosition((themeBackground.getWidth() - lock.getWidth())/2, (themeBackground.getHeight() - lock.getHeight())/2);
        themeBackground.addActor(lock);
        table.add(themeBackground).width(themeBackground.getWidth()).height(themeBackground.getHeight());
        table.columnDefaults(1);

        themeBackground = new ImageButton(new TextureRegionDrawable(Assets.instance.assetUI.theme3),
                new TextureRegionDrawable(Assets.instance.assetUI.theme3p));
        themeBackground.setUserObject(2);
        themeBackground.setTouchable(Touchable.disabled);
        themeBackground.addCaptureListener(clickListener);
        lock = new Image(new TextureRegionDrawable(Assets.instance.assetUI.lock));
        lock.setPosition((themeBackground.getWidth() - lock.getWidth())/2, (themeBackground.getHeight() - lock.getHeight())/2);
        themeBackground.addActor(lock);
        table.add(themeBackground).width(themeBackground.getWidth()).height(themeBackground.getHeight());;
        table.columnDefaults(2);

        themeBackground = new ImageButton(new TextureRegionDrawable(Assets.instance.assetUI.theme4),
                new TextureRegionDrawable(Assets.instance.assetUI.theme4p));
        themeBackground.setUserObject(3);
        themeBackground.setColor(Color.GRAY);
        themeBackground.setTouchable(Touchable.disabled);
        themeBackground.addCaptureListener(clickListener);
        lock = new Image(new TextureRegionDrawable(Assets.instance.assetUI.lock));
        lock.setPosition((themeBackground.getWidth() - lock.getWidth())/2, (themeBackground.getHeight() - lock.getHeight())/2);
        themeBackground.addActor(lock);
        lock.setColor(Color.GRAY);
        table.add(themeBackground).width(themeBackground.getWidth()).height(themeBackground.getHeight());;
        table.columnDefaults(3);

        table.pack();

        setWidget(table);
        setScrollingDisabled(false, true);
        addListener(new InputListener() {
            public boolean touchDown(InputEvent event, float x, float y, int pointer, int button) {
                event.stop();
                return true;
            }
        });
        setSmoothScrolling(true);
        setFlickScroll(false);
        setSize(themeBackground.getWidth()*2, table.getHeight());
        setPosition(Utils.xAxisCenter(getWidth()), Utils.yAxisCenter(getHeight()) - 20);
        return this;
    }

    public void setMainScreen(MainScreen mainScreen) {
        this.mainScreen = mainScreen;
    }

    class ButtonClickListener extends ClickListener {
        @Override
        public void touchUp(InputEvent event, float x, float y, int pointer, int button) {
            super.touchUp(event, x, y, pointer, button);
            Actor actor = event.getListenerActor();
            Integer themeIndex = (Integer)actor.getUserObject();
            mainScreen.addLevelWindow(themeIndex);
        }
    }
}

3、手势监听

import com.badlogic.gdx.input.GestureDetector.GestureAdapter;

public class MainScreenGestureListener extends GestureAdapter{

    private LevelWindow levelWindow;
    private ThemeScrollPanel themeScrollPanel;

    float panx = 0f;
    float pany = 0f;
    float panDeltaX = 0f;
    float panDeltaY = 0f;

    @Override
    public boolean pan(float x, float y, float deltaX, float deltaY) {
        if(levelWindow != null && levelWindow.getColor().a != 0f){
            this.panx = x;
            this.pany = y;
            this.panDeltaX = deltaX;
            this.panDeltaY = deltaY;
            return true;
        }else if(themeScrollPanel != null && themeScrollPanel.isVisible()){
            themeScrollPanel.setScrollX(themeScrollPanel.getScrollX()-deltaX);
            return true;
        }else{
            return false;
        }
    }

    public void setLevelWindow(LevelWindow levelWindow) {
        this.levelWindow = levelWindow;
    }

    public void setThemeScrollPanel(ThemeScrollPanel themeScrollPanel) {
        this.themeScrollPanel = themeScrollPanel;
    }

    @Override
    public boolean panStop(float x, float y, int pointer, int button) {
        if(levelWindow != null && levelWindow.isVisible()){
            if(panx == x && pany ==y && panDeltaX < 0f){//向左滑动
                levelWindow.nextPage();
            }
            if(panx == x && pany ==y && panDeltaX > 0f){//向右滑动
                levelWindow.prevPage();
            }
            return true;
        }else{
            return false;
        }
    }
}

4、代码说明
ScrollPane里面的内容是几张图片，使用的是一个Table组件布局。

需要注意的几句代码：

//控制位水平滑动

setScrollingDisabled(false, true);

//需要加上，具体也不知道是干叼的

addListener(new InputListener() {
public boolean touchDown(InputEvent event, float x, float y, int pointer, int button) {
event.stop();
return true;
}
});

//看方法名就知道是干嘛的
setSmoothScrolling(true);

//不显示自带的滚动条
setFlickScroll(false);

手势监听器，不清楚的可以去百度

@Override
public boolean pan(float x, float y, float deltaX, float deltaY) {
if(levelWindow != null && levelWindow.getColor().a != 0f){
this.panx = x;
this.pany = y;
this.panDeltaX = deltaX;
this.panDeltaY = deltaY;
return true;
}else if(themeScrollPanel != null && themeScrollPanel.isVisible()){
themeScrollPanel.setScrollX(themeScrollPanel.getScrollX()-deltaX);
return true;
}else{
return false;
}
}

这段代码，其中themeScrollPanel.setScrollX(themeScrollPanel.getScrollX()-deltaX);就是通过手势来移动滚动组件，

deltaX就是移动的速度。

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作者：龙少X100
来源：CSDN
原文：https://blog.csdn.net/xwl617756974/article/details/41929351
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