第一个Hello world（1）

把新创建的空项目中的HelloworldScene类删除掉，自己写一个.

一步步学习，不能投机取巧，先从最简单的hello world开始!

#ifndef __HelloCpp__LoadingLayer__
#define __HelloCpp__LoadingLayer__

#include "cocos2d.h"

/** @brief 游戏启动层类
 *
 *  游戏启动会创建此类对象，通过工厂方法创建一个场景，并将自己（层）加入到场景中
 */
class LoadingLayer : public cocos2d::CCLayer
{
public:
    // 初始化函数
    virtual bool init();
    
    // 工厂方法，生成场景对象
    static cocos2d::CCScene * scene();
    
    // 关闭菜单的回调
    void menuCloseCallback(CCObject *pSender);
    
    // 静态创建类对象
    static LoadingLayer * create();
};

#endif /* defined(__HelloCpp__LoadingLayer__) */

#include "LoadingLayer.h"

USING_NS_CC;

CCScene * LoadingLayer::scene()
{
    // 使用工厂方法生成scene
    CCScene *pScene = CCScene::create();
    
    // 使用工厂方法生成启动层对象
    LoadingLayer *pLayer = LoadingLayer::create();
    
    // 把启动层对象加入到场景中
    pScene->addChild(pLayer);
    
    return pScene;
}

bool LoadingLayer::init()
{
    if (!CCLayer::init()) {
        return false;
    }
    
    CCSize visibleSize = CCDirector::sharedDirector()->getVisibleSize();
    CCPoint origin = CCDirector::sharedDirector()->getVisibleOrigin();
    
    // 添加图片菜单项
    CCMenuItemImage *pCloseItem = CCMenuItemImage::create("CloseNormal.png",
                                                          "CloseSelected.png",
                                                          this,
                                                          menu_selector(LoadingLayer::menuCloseCallback));
    // 设置菜单项在屏幕的位置
    pCloseItem->setPosition(ccp(origin.x + visibleSize.width - pCloseItem->getContentSize().width / 2,
                                origin.y + pCloseItem->getContentSize().height / 2));
    
    // 创建菜单并添加到层中
    CCMenu *pMenu = CCMenu::create(pCloseItem, NULL);
    pMenu->setPosition(CCPointZero);
    this->addChild(pMenu, 1);
    
    // 创建标题
    CCLabelTTF *pLabel = CCLabelTTF::create("Hello World", "Arial", 24);
    pLabel->setPosition(ccp(origin.x + visibleSize.width / 2,
                            origin.y + visibleSize.height / 2));
    this->addChild(pLabel, 1);
    
    // 添加精灵
    CCSprite *pSprite = CCSprite::create("HelloWorld.png");
    pSprite->setPosition(ccp(visibleSize.width / 2 + origin.x,
                             visibleSize.height / 2 + origin.y));
    this->addChild(pSprite, 0);
    
    return true;
}

LoadingLayer * LoadingLayer::create()
{
    LoadingLayer *pRet = new LoadingLayer();
    if (pRet && pRet->init()) {
        pRet->autorelease();
        return pRet;
    }
    
    delete pRet;
    pRet = NULL;
    
    return NULL;
}

void LoadingLayer::menuCloseCallback(cocos2d::CCObject *pSender)
{
    CCDirector::sharedDirector()->end();
#if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS)
    exit(0);
#endif
    return;
}