cocos2dx 3.x 声音播放、音量调节

1. playBackgroudMusic() 

playBackgroudMusic 只适合播放持续时间比较长的声音文件，比如背景音乐。

 bool PlayMusic::init()
 {
     if ( !Layer::init() )
     {
         return false;
     }

     bool bRet = false;

     do{
         CocosDenshion::SimpleAudioEngine::sharedEngine()->playBackgroundMusic("sky_city.mp3",true);
         bRet = true;

     }while(0);

     return bRet;

 }

2. playEffect()

playEffect 适合播放战斗的打斗声音、技能释放的声音。

 bool PlayMusic::init()
 {
     if ( !Layer::init() )
     {
         return false;
     }

     bool bRet = false;

     do{
         //CocosDenshion::SimpleAudioEngine::sharedEngine()->playBackgroundMusic("sky_city.mp3",true);
         CocosDenshion::SimpleAudioEngine::sharedEngine()->playEffect("error.wav");
         bRet = true;

     }while(0);

     return bRet;

 }

3. 圆形音量按钮 ControlPotentiometer

一个圆形音量按钮由底座、进度条、控制按钮三部分组成。创建好音量按钮之后，它具备调节音量的功能，只有鼠标放在控制按钮上拖到一次，进度条就会改变显示范围，当然如果想控制音量，还需要加入监听事件。

 bool PlayMusic::init()
 {
     if ( !Layer::init() )
     {
         return false;
     }
     ControlPotentiometer* potentiometer = ControlPotentiometer::create("potentiometerTrack.png","potentiometerProgress.png","potentiometerButton.png");
     potentiometer->setPosition(Point(200,200));

     //监听进度值改变事件
     potentiometer->addTargetWithActionForControlEvents(this,cccontrol_selector(PlayMusic::onValueChange),Control::EventType::VALUE_CHANGED);

     this->addChild(potentiometer);

     return true;

 }
 void PlayMusic::onValueChange(Ref* psender,Control::EventType event)
 {
     ControlPotentiometer* potentiometer = (ControlPotentiometer*)psender;
     String* valueStr = String::createWithFormat("%f",potentiometer->getValue());
     log(valueStr->getCString());
 }

4. 音量控制按钮

ControlSlider 也是有底部、进度条、控制按钮三部分组成。用法和ControlPotentiometer几乎一样。

 ControlSlider* slider = ControlSlider::create("background.png","progress.png","sliderThumb.png");
 slider->setPosition(ccp(300,200));
 //设置滑动条的范围
 slider->setMinimumValue(0);
 slider->setMaximumValue(1000);
 //设置滑动条当前值
 slider->setValue(300);
 slider->addTargetWithActionForControlEvents(this,cccontrol_selector(PlayMusic::sliderChange),Control::EventType::VALUE_CHANGED);
 this->addChild(slider);

 void PlayMusic::sliderChange(Ref* psender,Control::EventType event)
 {
     ControlSlider* slider = (ControlSlider*)psender;
     String* valueStr = String::createWithFormat("%f",slider->getValue());
     log(valueStr->getCString());
 }