cocos2dx 分享某类的静态实例方法与调用

获取当前某类的静态实例方法：如下代码，举例类名为：  PlayScene
在 .h 文件中声明：
class PlayScene : public CCLayer
{
public:
    //获取当前PlayScene的静态实例(分享）
    static PlayScene* sharedPlay();
    static CCScene* createPlayScene();
    virtual bool init();
    CREATE_FUNC(PlayScene);

};
在 .cpp 文件中定义：
#include "PlayScene.h"
static PlayScene* ps;

PlayScene* PlayScene::sharedPlay()
{
    if(ps)
    {
        return ps;
    }
    return NULL;
}

CCScene* PlayScene::createPlayScene()
{
    CCScene* scene = CCScene::create();
    PlayScene* layer = PlayScene::create();
    scene->addChild(layer);
    return scene;
}

bool PlayScene::init()
{
    if(!CCLayer::init())
    {
        return false;
    }
    ps = this;
}
调用举例：
    //游戏主角子弹与怪物的碰撞检测，当发生碰撞时当从游戏中去除相碰撞的子弹与怪物
    //getEemyArray()为定义在PlayScene类中得到怪物数组的函数，
    for(int i = 0; i < PlayScene::sharedPlay()->getEnemyArray()->count(); i ++)
    {
        Enemy* enemy = (Enemy*) PlayScene::sharedPlay()->getEnemyArray()->objectAtIndex(i);
        if(this->boundingBox().intersectsRect(enemy->boundingBox()))
        {
            PlayScene::sharedPlay()->getEnemyArray()->removeObject(enemy); //从怪物数组中去除对象
            PlayScene::sharedPlay()->removeChild(enemy, true); //从游戏的当前层上去除相撞怪物
            PlayScene::sharedPlay()->removeChild(this, true); //从游戏当前层上去除相撞子弹
        }
    }