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

  //设置一个显示字符串的label
  CCLabelTTF * title = CCLabelTTF::create("slider value = 0.00","Arial",32);
  title->setPosition(ccp(240,200));
  //设置label的tag为1，方便以后获取
  this->addChild(title,0,1);

  //这三张图片分别是底部，进度条，控制按钮
  CCControlSlider * slider = CCControlSlider::create("sliderTrack.png","sliderProgress.png",
   "sliderThumb.png");

  //设置slider的最大值最小值
  slider->setMaximumValue(100);
  slider->setMinimumValue(0);
  //为slider添加事件监听函数
  slider->addTargetWithActionForControlEvents(this,cccontrol_selector(HelloWorld::valueChanged),
   CCControlEventValueChanged);
  //设置位置
  slider->setPosition(ccp(240,160));
  this->addChild(slider);

  //使用CCControlSlider实现血量条，只要将第三个控制按钮改为透明的就可以了，就会貌似血量条了
  CCControlSlider * slider2 = CCControlSlider::create("sliderTrack.png","progress.png","sliderThumb2.png");
  //通过以下函数使得认为的不能改变它的值
  slider2->setTouchEnabled(false);
  slider2->setMaximumValue(100);
  slider2->setMinimumValue(0);
  //可以添加事件处理函数，在事件处理函数中改变它的value
  slider2->setValue(100);
  slider2->setPosition(ccp(240,100));
  this->addChild(slider2);

    bRet = true;
  } while (0);

  return bRet;
}

//注意这个函数需要传入的俩个参数类型
void HelloWorld::valueChanged(CCObject * pSender,CCControlEvent controlEvent)
 {
 CCControlSlider * slider = (CCControlSlider *)pSender;
 CCLabelTTF * title = (CCLabelTTF *)this->getChildByTag(1);
 //使用CCLabelTTF的时候尽量不要重新改变它的内容，这里是为了简便起见
 title->setString(CCString::createWithFormat("slider value = %0.02f",slider->getValue())->getCString());
 }