cocos2d-x 3.x学习之拖动滑块类

#include "cocos2d.h"
#include "extensions/GUI/CCControlExtension/CCControl.h"
#include "extensions/GUI/CCControlExtension/CCControlSlider.h"
using namespace cocos2d;
using namespace extension;
USING_NS_CC;
class HelloWorld : public Layer
{
protected:
    Label* _displayValueLabel;
public:
    static Scene* createScene();
    virtual bool init();
    void valueChanged(Ref* sender,Control::EventType controlEvent);
    void menuCloseCallback(cocos2d::Ref* pSender);
 
    CREATE_FUNC(HelloWorld);
};
#include "HelloWorldScene.h"
USING_NS_CC;
Scene* HelloWorld::createScene()
{
    auto scene = Scene::create();
    auto layer = HelloWorld::create();
    scene->addChild(layer);
    return scene;
}

bool HelloWorld::init()
{
    if ( !Layer::init() )
    {
        return false;
    }
    
    Size visibleSize = Director::getInstance()->getVisibleSize();
    Vec2 origin = Director::getInstance()->getVisibleOrigin();
    auto closeItem = MenuItemImage::create(
                                           "CloseNormal.png",
                                           "CloseSelected.png",
                                           CC_CALLBACK_1(HelloWorld::menuCloseCallback, this));
    
	closeItem->setPosition(Vec2(origin.x + visibleSize.width - closeItem->getContentSize().width/2 ,
                                origin.y + closeItem->getContentSize().height/2));
    auto menu = Menu::create(closeItem, NULL);
    menu->setPosition(Vec2::ZERO);
    this->addChild(menu, 1);
    //设置标签初始文字、位置、并添加为当前层的子节点
    _displayValueLabel = Label::createWithSystemFont("请使用拇指移动滑块", "Marker Felt", 32);
    _displayValueLabel->setPosition(visibleSize.width / 2,visibleSize.height / 2 + 100);
    this->addChild(_displayValueLabel);
    //创建一个拖动滑块
    auto slider = ControlSlider::create("sliderTrack.png", "sliderProgress.png","sliderThumb.png");
    //设置拖动滑块的范围最小值
    slider->setMinimumValue(0.0f);
    //设置拖动滑块范围最大值
    slider->setMaximumValue(10.0f);
    //绑定事件处理函数，当滑块被拖动时被调用
    slider->addTargetWithActionForControlEvents(this, cccontrol_selector(HelloWorld::valueChanged), Control::EventType::VALUE_CHANGED);
    slider->setPosition(visibleSize.width / 2,visibleSize.height / 2);
    this->addChild(slider);
    return true;
}
//事件处理函数，当滑块被拖动时被调用
void HelloWorld::valueChanged(Ref *sender, Control::EventType controlEvent){
  //将sender类型转成拖动滑块
    ControlSlider* pSlider = (ControlSlider*)sender;
  //获取滑块的当前值，并更新标签内
    _displayValueLabel->setString(StringUtils::format("滑块值=%.02f",pSlider->getValue()));
}