在创建完了工程之后，我们可以看到AppDelegate这个文件，我们打开看下这里面有什么：
AppDelegate::AppDelegate() { //1，构造AppDelegate
}
AppDelegate::~AppDelegate()
{
}
bool AppDelegate::applicationDidFinishLaunching() {//3，在2初始化完之后进入，结束初始化appDelegate
// initialize director
CCDirector* pDirector = CCDirector::sharedDirector();
CCEGLView* pEGLView = CCEGLView::sharedOpenGLView();
pDirector->setOpenGLView(pEGLView);
// turn on display FPS
pDirector->setDisplayStats(true);
// set FPS. the default value is 1.0/60 if you don't call this
pDirector->setAnimationInterval(1.0 / 60);
CCScene * pScene = CCScene::create();
GameDemoManager * pLayer = new GameDemoManager();
pLayer->initGame();
pLayer->autorelease();
pScene->addChild(pLayer);
pDirector->runWithScene(pScene);
return true;
}
// This function will be called when the app is inactive. When comes a phone call,it's be invoked too
void AppDelegate::applicationDidEnterBackground() {//4,当手机处于后台运行的时候，进入该处
CCDirector::sharedDirector()->stopAnimation();
// if you use SimpleAudioEngine, it must be pause
// SimpleAudioEngine::sharedEngine()->pauseBackgroundMusic();
}
// this function will be called when the app is active again
void AppDelegate::applicationWillEnterForeground() { /,2，构造完了AppDelegate之后进入初始化application
CCDirector::sharedDirector()->startAnimation();
// if you use SimpleAudioEngine, it must resume here
// SimpleAudioEngine::sharedEngine()->resumeBackgroundMusic();
}
从上面分析：
AppDelegate其实就是整个程序的入口，它的初始化步骤就是上面的1-3，4则是在手机后台运行该程序时所调用的
