【Cocos2d-x】新手自学(七)百分比读取进度加载图片资源到缓存(2.0.1版本)

昨天下载了最新的cocos2d-x   是2.0.1版本的...所以本文章是参考2.0版本的例子写的...

可以发现,2.0版本后不单单只有一个帧率了..还多了两个参数.第一个参数可以理解为场景中的对象个数吧.第二个还不清楚...

1. 创建好一个工程后,先修改对于的.h文件

 class HelloWorld : public cocos2d::CCLayer
 {
 public:
     virtual bool init();
     static cocos2d::CCScene* scene();
     HelloWorld();

     void addSprite();//用于加载完成后添加精灵
     void loadingCallBack(cocos2d::CCObject *obj);//读进度回调函数

     LAYER_CREATE_FUNC(HelloWorld);

 private:
     cocos2d::CCLabelTTF *m_pLableLoading;
     cocos2d::CCLabelTTF *m_pLabelPercent;
     int m_nNumberOfSprites;
     int m_nNumberOfLoadedSprites;
 };

2. 然后在对应的cpp文件中完成各种函数

 //原例子中的代码都是在构造函数中写的.在这里构造函数只用于初始化了两个成员变量
 HelloWorld::HelloWorld():m_nNumberOfSprites(20),m_nNumberOfLoadedSprites(0)
 {

 }

 bool HelloWorld::init()
 {
     bool bRet = false;
     do
     {
         CC_BREAK_IF(! CCLayer::init());
         CCSize size = CCDirector::sharedDirector()->getWinSize();

         //创建读条时的标签
         m_pLableLoading = CCLabelTTF::create("Loading...","Arial",20);
         m_pLabelPercent = CCLabelTTF::create("%0","Arial",30);

         m_pLabelPercent->setPosition(CCPointMake(size.width/2, size.height/2 +50));
         m_pLableLoading->setPosition(CCPointMake(size.width/2, size.height/2 -10));

         this->addChild(m_pLableLoading);
         this->addChild(m_pLabelPercent);

         //加载图片到Cache...每加载一次就调用我们自己写的回调函数
         CCTextureCache::sharedTextureCache()->addImageAsync("img/bg.png", this, callfuncO_selector(HelloWorld::loadingCallBack));
         CCTextureCache::sharedTextureCache()->addImageAsync("img/01.png", this, callfuncO_selector(HelloWorld::loadingCallBack));
         CCTextureCache::sharedTextureCache()->addImageAsync("img/02.png", this, callfuncO_selector(HelloWorld::loadingCallBack));
         CCTextureCache::sharedTextureCache()->addImageAsync("img/03.png", this, callfuncO_selector(HelloWorld::loadingCallBack));
         CCTextureCache::sharedTextureCache()->addImageAsync("img/04.png", this, callfuncO_selector(HelloWorld::loadingCallBack));
         CCTextureCache::sharedTextureCache()->addImageAsync("img/05.png", this, callfuncO_selector(HelloWorld::loadingCallBack));
         CCTextureCache::sharedTextureCache()->addImageAsync("img/06.png", this, callfuncO_selector(HelloWorld::loadingCallBack));
         CCTextureCache::sharedTextureCache()->addImageAsync("img/07.png", this, callfuncO_selector(HelloWorld::loadingCallBack));
         CCTextureCache::sharedTextureCache()->addImageAsync("img/08.png", this, callfuncO_selector(HelloWorld::loadingCallBack));
         CCTextureCache::sharedTextureCache()->addImageAsync("img/09.png", this, callfuncO_selector(HelloWorld::loadingCallBack));
         CCTextureCache::sharedTextureCache()->addImageAsync("img/10.png", this, callfuncO_selector(HelloWorld::loadingCallBack));
         CCTextureCache::sharedTextureCache()->addImageAsync("img/11.png", this, callfuncO_selector(HelloWorld::loadingCallBack));
         CCTextureCache::sharedTextureCache()->addImageAsync("img/12.png", this, callfuncO_selector(HelloWorld::loadingCallBack));
         CCTextureCache::sharedTextureCache()->addImageAsync("img/13.png", this, callfuncO_selector(HelloWorld::loadingCallBack));
         CCTextureCache::sharedTextureCache()->addImageAsync("img/14.png", this, callfuncO_selector(HelloWorld::loadingCallBack));
         CCTextureCache::sharedTextureCache()->addImageAsync("img/15.png", this, callfuncO_selector(HelloWorld::loadingCallBack));
         CCTextureCache::sharedTextureCache()->addImageAsync("img/16.png", this, callfuncO_selector(HelloWorld::loadingCallBack));
         CCTextureCache::sharedTextureCache()->addImageAsync("img/17.png", this, callfuncO_selector(HelloWorld::loadingCallBack));
         CCTextureCache::sharedTextureCache()->addImageAsync("img/18.png", this, callfuncO_selector(HelloWorld::loadingCallBack));
         CCTextureCache::sharedTextureCache()->addImageAsync("img/19.png", this, callfuncO_selector(HelloWorld::loadingCallBack));

         bRet = true;
     } while (0);

     return bRet;
 }

3. 代码很多都是重复的..只是加载的图片不一样,大家注意加载的图片路径就可以了..接下来实现回调函数

 //回调函数
 void HelloWorld::loadingCallBack(CCObject *obj)
 {
     ++m_nNumberOfLoadedSprites;//每调用一次就+1
     char tmp[10];

     //这里格式化,因为我们只加载了20张图片,所以除以总数后就是0.05,所以每加载一次就涨5%
     sprintf(tmp,"%%%d",(int)(((float)m_nNumberOfLoadedSprites / m_nNumberOfSprites) * 100));
     m_pLabelPercent->setString(tmp);//重设标签的内容

     //判断,如果全部加载完成后,就执行
     if (m_nNumberOfLoadedSprites == m_nNumberOfSprites)
     {
         //移除那两个标签文字..
         this->removeChild(m_pLableLoading, true);
         this->removeChild(m_pLabelPercent, true);
         //调用自己写的函数..从新绘制场景内容
         addSprite();
     }

 }

4. 实现addSprite()函数，这个函数从新初始化了场景..然后显示

 void HelloWorld::addSprite()
 {
     CCSize size = CCDirector::sharedDirector()->getWinSize();

     //创建背景图片
     CCSprite *bg = CCSprite::create("img/bg.png");
     bg->setPosition(CCPointMake(size.width/2, size.height/2));

     //创建其他小图片
     CCSprite *s1 = CCSprite::create("img/01.png");
     CCSprite *s2 = CCSprite::create("img/02.png");
     CCSprite *s3 = CCSprite::create("img/03.png");
     CCSprite *s4 = CCSprite::create("img/04.png");
     CCSprite *s5 = CCSprite::create("img/05.png");
     CCSprite *s6 = CCSprite::create("img/06.png");
     CCSprite *s7 = CCSprite::create("img/07.png");
     CCSprite *s8 = CCSprite::create("img/08.png");
     CCSprite *s9 = CCSprite::create("img/09.png");
     CCSprite *s10 = CCSprite::create("img/10.png");
     CCSprite *s11 = CCSprite::create("img/11.png");
     CCSprite *s12 = CCSprite::create("img/12.png");
     CCSprite *s13 = CCSprite::create("img/13.png");
     CCSprite *s14 = CCSprite::create("img/14.png");
     CCSprite *s15 = CCSprite::create("img/15.png");
     CCSprite *s16 = CCSprite::create("img/16.png");
     CCSprite *s17 = CCSprite::create("img/17.png");
     CCSprite *s18 = CCSprite::create("img/18.png");
     CCSprite *s19 = CCSprite::create("img/19.png");

     //设置位置
     s1->setPosition(CCPointMake(70, size.height/2));
     s2->setPosition(CCPointMake(90, size.height/2));
     s3->setPosition(CCPointMake(110, size.height/2));
     s4->setPosition(CCPointMake(130, size.height/2));
     s5->setPosition(CCPointMake(150, size.height/2));
     s6->setPosition(CCPointMake(170, size.height/2));
     s7->setPosition(CCPointMake(190, size.height/2));
     s8->setPosition(CCPointMake(210, size.height/2));
     s9->setPosition(CCPointMake(230, size.height/2));
     s10->setPosition(CCPointMake(250, size.height/2));
     s11->setPosition(CCPointMake(270, size.height/2));
     s12->setPosition(CCPointMake(290, size.height/2));
     s13->setPosition(CCPointMake(310, size.height/2));
     s14->setPosition(CCPointMake(330, size.height/2));
     s15->setPosition(CCPointMake(350, size.height/2));
     s16->setPosition(CCPointMake(370, size.height/2));
     s17->setPosition(CCPointMake(390, size.height/2));
     s18->setPosition(CCPointMake(410, size.height/2));
     s19->setPosition(CCPointMake(430, size.height/2));

     //添加进入场景
     this->addChild(bg);

     this->addChild(s1);
     this->addChild(s2);
     this->addChild(s3);
     this->addChild(s4);
     this->addChild(s5);
     this->addChild(s6);
     this->addChild(s7);
     this->addChild(s8);
     this->addChild(s9);
     this->addChild(s10);
     this->addChild(s11);
     this->addChild(s12);
     this->addChild(s13);
     this->addChild(s14);
     this->addChild(s15);
     this->addChild(s16);
     this->addChild(s17);
     this->addChild(s18);
     this->addChild(s19);
 }

这样,运行的时候就会出现读条界面了,但是闪的很快,比较电脑的处理能力还是很快的嘛..可以在回调函数里面设置一个断点，就会发现是5%的增长..

就我的理解来说,这一个例子的思路,首先是把图片加载进入内存.然后出发一次回调函数,更新读条进度..直到100%就调用另外函数...

图片的话,随便弄个几张就好了.显示效果的话,注意设置位置就行，也可以用我的图片啦：

http://115.com/file/anpzdgqa#img.rar

by...XX