bool HelloWorld::init(){	bool bRet = false;	do	{		CC_BREAK_IF(!CCLayer::init());		//CCControlPotentiometer參數是底座，進度條，控制按鈕圖片資源		CCControlPotentiometer * potentiometer = CCControlPotentiometer::create("potentiometerTrack.png",			"potentiometerProgress.png","potentiometerButton.png");		//設置最大值和最小值以及初值		potentiometer->setMaximumValue(100.0);		potentiometer->setMinimumValue(0.0);		potentiometer->setValue(50);		potentiometer->setPosition(ccp(240,160));		this->addChild(potentiometer);		//添加事件監聽		potentiometer->addTargetWithActionForControlEvents(this,cccontrol_selector(HelloWorld::valueChanged),			CCControlEventValueChanged);		bRet = true;	}	while(0);	return bRet;}void HelloWorld::valueChanged(CCObject * pSender,CCControlEvent controlEvent){	CCControlPotentiometer * potentiometer = (CCControlPotentiometer *)pSender;	CCString * string = CCString::createWithFormat("%f",potentiometer->getValue());	CCLog(string->getCString());}