cocos2d-x的main函数代码很少，把一些复杂的接口封装到AppDelegate类里了，“AppDelegate”从词意可以得出是app的代理类，而一些最早的场景都会在AppDelegate类里实现。我们先看一下main.cpp
int APIENTRY _tWinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPTSTR lpCmdLine,
int nCmdShow)
{
UNREFERENCED_PARAMETER(hPrevInstance);
UNREFERENCED_PARAMETER(lpCmdLine); #ifdef USE_WIN32_CONSOLE
AllocConsole();
freopen("CONIN$", "r", stdin);
freopen("CONOUT$", "w", stdout);
freopen("CONOUT$", "w", stderr);
#endif // create the application instance
AppDelegate app; //实例化一个cocos2d_x程序
CCEGLView* eglView = CCEGLView::sharedOpenGLView(); //创建一个视口
eglView->setFrameSize(, ); //设置视口的大小 int ret = CCApplication::sharedApplication()->run(); //运行cocos2d_x的实例 #ifdef USE_WIN32_CONSOLE
FreeConsole();
#endif return ret;
}
AppDelegate类的实现如下：
class AppDelegate : private cocos2d::CCApplication
{
public:
AppDelegate();
virtual ~AppDelegate(); /**
@brief Implement CCDirector and CCScene init code here.
@return true Initialize success, app continue.
@return false Initialize failed, app terminate.
*/
//程序启动时自动进入的函数在这里我们一般初始化场景
virtual bool applicationDidFinishLaunching(); /**
@brief The function be called when the application enter background
@param the pointer of the application
*/
//程序进入后台时执行的操作
virtual void applicationDidEnterBackground(); /**
@brief The function be called when the application enter foreground
@param the pointer of the application
*/
//程序从后台到前台执行调用的函数
virtual void applicationWillEnterForeground();
};
在主函数里 实例化 AppDelegate 时会自动调用
virtual bool applicationDidFinishLaunching();
（为什么会到用它？以后会深入研究）
函数的实现：
bool AppDelegate::applicationDidFinishLaunching()
{
// initialize director
CCDirector *pDirector = CCDirector::sharedDirector();
pDirector->setOpenGLView(CCEGLView::sharedOpenGLView()); // turn on display FPS
//打开帧的显示(右下角的数字)
pDirector->setDisplayStats(false); // set FPS. the default value is 1.0/60 if you don't call this
//设置FPS
pDirector->setAnimationInterval(1.0 / ); // create a scene. it's an autorelease object
//创建helloWorld场景
CCScene *pScene = HelloWorld::scene(); // run
//执行场景
pDirector->runWithScene(pScene);
return true;
}
helloworld的场景类如下：
class HelloWorld : public cocos2d::CCLayer
{
public:
// Here's a difference. Method 'init' in cocos2d-x returns bool, instead of returning 'id' in cocos2d-iphone
//但调用create成员函数式会自动执行init函数
virtual bool init(); // there's no 'id' in cpp, so we recommand to return the exactly class pointer
//返回helloworld场景
static cocos2d::CCScene* scene(); // a selector callback
//关闭场景函数
void menuCloseCallback(CCObject* pSender); // implement the "static node()" method manually
CREATE_FUNC(HelloWorld);
};
CCScene* HelloWorld::scene()
{
CCScene * scene = NULL;
do
{
// 'scene' is an autorelease object
//创建一个场景
scene = CCScene::create();
//判断场景是否创建成功
CC_BREAK_IF(! scene); // 'layer' is an autorelease object
//创建一个helloworld布景，这时会会调用init()
HelloWorld *layer = HelloWorld::create();
//判断helloworld布景是否成功
CC_BREAK_IF(! layer); // add layer as a child to scene
//添加helloworld布景到场景
scene->addChild(layer);
} while (); // return the scene
return scene;
} // on "init" you need to initialize your instance
bool HelloWorld::init()
{
bool bRet = false;
do
{
//////////////////////////////////////////////////////////////////////////
// super init first
////////////////////////////////////////////////////////////////////////// CC_BREAK_IF(! CCLayer::init()); //////////////////////////////////////////////////////////////////////////
// add your codes below...
////////////////////////////////////////////////////////////////////////// // 1. Add a menu item with "X" image, which is clicked to quit the program. // Create a "close" menu item with close icon, it's an auto release object.
CCMenuItemImage *pCloseItem = CCMenuItemImage::create(
"CloseNormal.png",
"CloseSelected.png",
this,
menu_selector(HelloWorld::menuCloseCallback));
CC_BREAK_IF(! pCloseItem); // Place the menu item bottom-right conner.
pCloseItem->setPosition(ccp(CCDirector::sharedDirector()->getWinSize().width - , )); // Create a menu with the "close" menu item, it's an auto release object.
CCMenu* pMenu = CCMenu::create(pCloseItem, NULL);
pMenu->setPosition(CCPointZero);
CC_BREAK_IF(! pMenu); // Add the menu to HelloWorld layer as a child layer.
this->addChild(pMenu, ); // 2. Add a label shows "Hello World". // Create a label and initialize with string "Hello World".
CCLabelTTF* pLabel = CCLabelTTF::create("Hello World", "Arial", );
CCLabelTTF* pLabel2 = CCLabelTTF::create("My name is CharlesXue","Arial",);
CC_BREAK_IF(! pLabel2); CC_BREAK_IF(! pLabel); // Get window size and place the label upper.
CCSize size = CCDirector::sharedDirector()->getWinSize();
pLabel->setPosition(ccp(size.width / , size.height - ));
pLabel2->setPosition(ccp(size.width / ,size.height - )); // Add the label to HelloWorld layer as a child layer.
this->addChild(pLabel, );
this->addChild(pLabel2,);
// 3. Add add a splash screen, show the cocos2d splash image.
CCSprite* pSprite = CCSprite::create("HelloWorld.png");
CC_BREAK_IF(! pSprite); // Place the sprite on the center of the screen
pSprite->setPosition(ccp(size.width/, size.height/)); // Add the sprite to HelloWorld layer as a child layer.
this->addChild(pSprite, ); bRet = true;
} while (); return bRet;
} void HelloWorld::menuCloseCallback(CCObject* pSender)
{
// "close" menu item clicked
CCDirector::sharedDirector()->end();
}