Cocos2d-x--实现Loading界面加载资源

转自：http://blog.csdn.net/zlqqhs/article/details/9269245

原理，使用

CCTextureCache::sharedTextureCache()->addImageAsync("background.png", this, callfuncO_selector(Assets::loadingCallBack));

加载纹理时，每加载一张纹理调用一次Assets::loadingCallBack，Assets::loadingCallBack实现进度条的进度跟进和判断跳转

步骤：

1.新建一个Cocos2d-x工程，保证能成功运行（我一直在说废话，呵呵）

2.在HelloWorldScene.h文件中修改和增加代码

3.在HelloWorldScene.cpp文件中修改和增加代码

4.新建SecondScene.h和SecondScene.cpp两个文件，用于加载完成后跳转

1.新建一个Cocos2d-x工程，保证能成功运行，没有其他的了

2.在HelloWorldScene.h文件中修改和增加代码

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1. HelloWorld(); 
2.  
3.     virtual bool init();   
4.  
5.     static cocos2d::CCScene* scene(); 
6.      
7.     CREATE_FUNC(Assets); 
8.  
9.     void loadingCallBack(cocos2d::CCObject *obj);//回调函数，每加载一张纹理就调用一次 
10.  
11.  
12. private: 
13.     cocos2d::CCLabelTTF *m_pLabelLoading;//文字标签，用于显示“Loading”字样 
14.     cocos2d::CCLabelTTF *m_pLabelPercent;//文字标签，用于显示百分比 
15.  
16.     int currentNum;//当前加载到第几张 
17.     int totalNum;//加载总数 

HelloWorld();    virtual bool init();      static cocos2d::CCScene* scene();        CREATE_FUNC(Assets);void loadingCallBack(cocos2d::CCObject *obj);//回调函数，每加载一张纹理就调用一次private:cocos2d::CCLabelTTF *m_pLabelLoading;//文字标签，用于显示“Loading”字样cocos2d::CCLabelTTF *m_pLabelPercent;//文字标签，用于显示百分比int currentNum;//当前加载到第几张int totalNum;//加载总数

3.在HelloWorldScene.cpp文件中修改和增加代码

构造函数，初始化currentNum和totalNum

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1. HelloWorld::HelloWorld():currentNum(0),totalNum(500) 
2. { 
3.      
4. } 

HelloWorld::HelloWorld():currentNum(0),totalNum(500){}

修改init()中的do代码块为：

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1. CC_BREAK_IF(! CCLayer::init()); 
2.  
3.         //取得屏幕大小 
4.         CCSize size = CCDirector::sharedDirector()->getWinSize(); 
5.  
6.         //文字标签，用于显示Loding字样和加载的进度 
7.         m_pLabelLoading =CCLabelTTF::create("Loading...", "Arial", 25); 
8.         m_pLabelPercent = CCLabelTTF::create("0%", "Arial", 25) ; 
9.  
10.         m_pLabelLoading->setPosition(ccp(size.width / 2, size.height / 2 + 50)); 
11.         m_pLabelPercent->setPosition(ccp(size.width / 2, size.height / 2)); 
12.  
13.         this->addChild(m_pLabelLoading); 
14.         this->addChild(m_pLabelPercent); 
15.  
16.         //加载HelloWorld.png纹理 
17.         for (int i = 0; i <500; i++) 
18.         { 
19.             //加载纹理，回调Assets::loadingCallBack 
20.             CCTextureCache::sharedTextureCache()->addImageAsync("HelloWorld.png", this, callfuncO_selector(Assets::loadingCallBack)); 
21.         } 
22.          
23.         bRet = true; 

CC_BREAK_IF(! CCLayer::init());//取得屏幕大小CCSize size = CCDirector::sharedDirector()->getWinSize();//文字标签，用于显示Loding字样和加载的进度m_pLabelLoading = CCLabelTTF::create("Loading...", "Arial", 25);m_pLabelPercent = CCLabelTTF::create("0%", "Arial", 25) ;m_pLabelLoading->setPosition(ccp(size.width / 2, size.height / 2 + 50));m_pLabelPercent->setPosition(ccp(size.width / 2, size.height / 2));this->addChild(m_pLabelLoading);this->addChild(m_pLabelPercent);//加载HelloWorld.png纹理for (int i = 0; i < 500; i++){//加载纹理，回调Assets::loadingCallBackCCTextureCache::sharedTextureCache()->addImageAsync("HelloWorld.png", this, callfuncO_selector(Assets::loadingCallBack));}        bRet = true;

回调函数loadingCallBack的实现：

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1. void Assets::loadingCallBack(cocos2d::CCObject *obj) 
2. { 
3.     //currentNum初始值为0，每加载一张纹理值自加1 
4.     ++currentNum; 
5.     char tmp[10]; 
6.     //求得百分比 
7.     sprintf(tmp, "%d%%", (int)(((float)currentNum / totalNum) * 100)); 
8.     //设置标签显示的内容 
9.     m_pLabelPercent->setString(tmp); 
10.  
11.     //如果当前加载的张数跟总数相等则进行场景跳转 
12.     if (currentNum == totalNum) 
13.     { 
14.         this->removeChild(m_pLabelPercent, true); 
15.         this->removeChild(m_pLabelLoading, true); 
16.         //场景跳转 
17.         CCScene *m_SecondScene =SecondScene::scene();   
18.         CCDirector::sharedDirector()->replaceScene(CCTransitionJumpZoom::create(1.0f,m_SecondScene)); 
19.     } 
20. } 

void Assets::loadingCallBack(cocos2d::CCObject *obj){//currentNum初始值为0，每加载一张纹理值自加1++currentNum;char tmp[10];//求得百分比sprintf(tmp, "%d%%", (int)(((float)currentNum / totalNum) * 100));//设置标签显示的内容m_pLabelPercent->setString(tmp);//如果当前加载的张数跟总数相等则进行场景跳转if (currentNum == totalNum){this->removeChild(m_pLabelPercent, true);this->removeChild(m_pLabelLoading, true);//场景跳转CCScene *m_SecondScene = SecondScene::scene();  CCDirector::sharedDirector()->replaceScene(CCTransitionJumpZoom::create(1.0f,m_SecondScene));}}

4.新建SecondScene.h和SecondScene.cpp两个文件，用于加载完成后跳转

新建场景的步骤详见http://blog.csdn.net/zlqqhs/article/details/9245125

将SecondScene.cpp文件下的init函数下的代码改为：

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1. //通过名字从CCTextureCache中取得纹理 
2.         CCTexture2D *texture = CCTextureCache::sharedTextureCache()->textureForKey("HelloWorld.png"); 
3.         //实例化精灵 
4.         CCSprite *m_sprite = CCSprite::createWithTexture(texture); 
5.         CC_BREAK_IF(!m_sprite); 
6.  
7.         //设置精灵位置 
8.         m_sprite->setPosition(ccp(100, 100)); 
9.  
10.         //添加精灵到场景 
11.         this->addChild(m_sprite); 
12.         bRet = true;