CCControlPotentiometer是电位计按钮，和CCControlSlider的用法很相似。关于控件使用时的一些配置，请参见文章：UI开发之控件类-CCControlButton。

bool HelloWorld::init()
{
	bool bRet = false;
	do
	{
		CC_BREAK_IF(!CCLayer::init());

		//CCControlPotentiometer参数是底座，进度条，控制按钮图片资源
		CCControlPotentiometer * potentiometer = CCControlPotentiometer::create("potentiometerTrack.png",
			"potentiometerProgress.png","potentiometerButton.png");
		//设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);

		//添加事件监听
		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());
}