cocos2d-x lua与c++简单交互

version: cocos2d-x 3.6

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本文讲述lua与c++的一些简单交互：

1. lua通过消息方式调用c++无参接口
2. c++调用lua带参接口

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1.通过消息方式调用无参接口

接收方监听消息命令，发送方发送消息请求。

1. c++层监听消息

//在appdelegate启动时监听

void communication_cpp_lua::registerAllEvent()

{

    Director::getInstance()->getEventDispatcher()->addCustomEventListener("LUA_TO_CPP_FACEBOOK_LOGIN", std::bind(&communication_cpp_lua::facebookLogin, this, std::placeholders::_1));

}

void communication_cpp_lua::facebookLogin(EventCustom * evt)

{

    CCLOG("lua call cpp facebook login");

    //FX::PluginUser *pUser = FX::PluginManager::getInstance()->getPluginUser();

    //pUser->setLoginListener(this);

    //pUser->login();

}

1. lua层发送命令请求

local event = cc.EventCustom:new("LUA_TO_CPP_FACEBOOK_LOGIN")

cc.Director:getInstance():getEventDispatcher():dispatchEvent(event)

请确保lua层发送消息前，c++层以注册了消息监听。

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2.c++回调带参数的lua接口

c++调用lua无参数的接口也可使用消息方式，但是当调用带参数接口时，如下为直接调用方式：

1. lua层接口 (记得函数要放在全局里面)

-------------------------------------------------------------

-- glocal

-- cpp direct call

-------------------------------------------------------------

-- parm: int string string string string

function cc.exports.onFacebookLogin(retCode, msg, id, name, picture)

    print("cc.exports.onFacebookLogin")

    -- TODO

end

1. c++层调用
   
   注意事项：

• 调用时lua函数所在文件的路径
• 如果参数过多(或为数组)，就将参数转为json，那么参数就只有一个了(json字符串)

void communication_cpp_lua::onLoginResult(FX::LoginResultCode ret, const char* msg)

{

    CCLOG("INFO: %s ---> retCode = %d, msg = %s", __FUNCTION__, ret, msg);

    FX::PluginUser *pUser = FX::PluginManager::getInstance()->getPluginUser();

    FX::UserInfo userinfo = pUser->getUserInfo();

	//注意函数调用，参数入栈顺序

    std::vector<std::pair<std::string,__String*>> parm;

    parm.push_back(std::make_pair("number", __String::createWithFormat("%d", ret)));

    parm.push_back(std::make_pair("string", __String::create(msg)));

    parm.push_back(std::make_pair("string", __String::create(userinfo.id)));

    parm.push_back(std::make_pair("string", __String::create(userinfo.name)));

    parm.push_back(std::make_pair("string", __String::create(userinfo.picture)));

	this->callLuaFuncWithParam("utils/communication_lua_cpp.lua", "onFacebookLogin", &parm);

}

//带参执行Lua方法无返回值

const void communication_cpp_lua::callLuaFuncWithParam(const char* luaFileName, const char* functionName, std::vector<std::pair<std::string,__String*>>* para)

{

    lua_State*  ls = LuaEngine::getInstance()->getLuaStack()->getLuaState();

    int isOpen = luaL_dofile(ls, FileUtils::getInstance()->fullPathForFilename(luaFileName).c_str());

    if(isOpen!=0)

	{

        CCLOG("Open Lua Error: %i", isOpen);

    }

    lua_getglobal(ls, functionName);

    int countnum = para->size();

    for (std::vector<std::pair<std::string,__String*>>::iterator itor = para->begin(); itor != para->end(); ++itor)

	{

        std::string typestr = itor->first;

		__String* strnr = itor->second;

		if(typestr == "string")

		{

			lua_pushstring(ls, strnr->getCString());

		}

		else if(typestr == "number")

		{

			lua_pushnumber(ls, strnr->intValue());

		}

		else if(typestr == "bool")

		{

			lua_pushboolean(ls, strnr->boolValue());

		}

		else

		{

			CCASSERT(false, "not surport this type");

		}

	}

    /*

     lua_call

     第二个参数:函数的参数个数

     第三个参数:函数返回值个数

     */

    lua_call(ls, countnum, 0);

//lua有返回值

// 	const char* iResult = lua_tostring(ls, -1);

// 	return iResult;

}