Cocos2d-x 3.6 项目实战---贪吃蛇（2）

先来点简单的，说说帮助类。
帮助类非常简单，只是显示一个背景，一个”帮助信息”的Label和一个返回菜单而已。

HelpScene.h :

#ifndef __snakegame__HelpScene__
#define __snakegame__HelpScene__
#include "cocos2d.h"
USING_NS_CC;
class Help :public Layer
{
public:
    static Scene * createScene();
    CREATE_FUNC(Help);
    virtual bool init();
    void menuCallBack(Ref * object);
};
#endif /* defined(__snakegame__HelpScene__) */

HelpScene.cpp :

#include "HelpScene.h"
#include "MainMenu.h"

Scene * Help::createScene()
{
    auto scene = Scene::create();
    auto layer = Help::create();
    scene->addChild(layer);
    return scene;
}

bool  Help::init()
{
    if (!Layer::init())
    {
        return  false;
    }
    auto size = Director::getInstance()->getWinSize();
    //添加背景
    auto spriteBK = Sprite::create("menuback.png");
    spriteBK->setPosition(Point(size.width / 2,size.height / 2));
    spriteBK->setOpacity(70);//设置透明度
    this->addChild(spriteBK);
    //帮助信息
    auto labelScore = Label::createWithSystemFont("帮助信息","宋体",25);
    labelScore->setPosition(Point(size.width - 80,size.height - 50));
    this->addChild(labelScore);
    //返回按钮
    auto menuItemBack = MenuItemFont::create("Back",CC_CALLBACK_1(Help::menuCallBack,this));
    auto menu = Menu::create(menuItemBack,NULL);
    menu->setPosition(Point::ZERO);
    menuItemBack->setPosition(Point(size.width - menuItemBack->getContentSize().width - 100,menuItemBack->getContentSize().height + 10));
    this->addChild(menu);

    return true;
}
//点击返回按钮返回到主界面
void  Help::menuCallBack(Ref * object)
{
    auto scene = MainMenu::createScene();
    Director::getInstance()->replaceScene(scene);
}