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()));
}