以tableView为例:

static int lua_cocos2d_TableView_registerScriptHandler(lua_State* L)
{
//...
if (!toluafix_isfunction(L,2,"LUA_FUNCTION",&tolua_err) ||
!tolua_isnumber(L,3,&tolua_err) )
{
goto tolua_lerror;
}
#endif
LUA_FUNCTION handler = ( toluafix_ref_function(L,0)); 注册到lua注册表中 LUA_FUNCTION 就是 int 以后lua函数可以通过handler来拿到
ScriptHandlerMgr::HandlerType handlerType = (ScriptHandlerMgr::HandlerType) ((int)tolua_tonumber(L,0) + (int)ScriptHandlerMgr::HandlerType::SCROLLVIEW_SCROLL);

将handler加入到脚本处理管理器中去。handler可以通过self和handlerType来拿到
ScriptHandlerMgr::getInstance()->addObjectHandler((void*)self,handler,handlerType);
//...
}


class LUA_TableViewDataSource:public Ref,public TableViewDataSource
{
public:
LUA_TableViewDataSource(){}
virtual ~LUA_TableViewDataSource(){}

//这里的size是通过lua函数执行来获取
virtual Size tableCellSizeForIndex(TableView *table,ssize_t idx) override
{
if (nullptr != table )
{
//获取handler
int handler = ScriptHandlerMgr::getInstance()->getObjectHandler((void*)table,ScriptHandlerMgr::HandlerType::TABLECELL_SIZE_FOR_INDEX);
if (0 != handler)
{
LuaTableViewEventData eventData(&idx);
BasicScriptData data(table,&eventData);//对数据进行封装
float width = 0.0;
float height = 0.0;
//处理TABLECELL_SIZE_FOR_INDEX事件，lua需要先向脚本管理器中注册TABLECELL_SIZE_FOR_INDEX事件
LuaEngine::getInstance()->handleEvent(ScriptHandlerMgr::HandlerType::TABLECELL_SIZE_FOR_INDEX,(void*)&data,[&](lua_State* L,int numReturn){
//这个回调是在lua的TABLECELL_SIZE_FOR_INDEX处理函数处理完后 执行
CCASSERT(numReturn == 2,"tableCellSizeForIndex return count error");
height = (float)tolua_tonumber(L,-1,0);
lua_pop(L,1);
width = (float)tolua_tonumber(L,1);
//height 和 width是lua处理函数留在栈顶的
});

return Size(width,height);
}
}

return Size::ZERO;
}

};


//LuaStack处理有回调的函数
int LuaStack::executeFunction(int handler,int numArgs,int numResults,const std::function<void(lua_State*,int)>& func)
{
//..
//全局log函数
lua_getglobal(_state,"__G__TRACKBACK__"); /* L: ... func arg1 arg2 ... G */
if (!lua_isfunction(_state,-1))
{
lua_pop(_state,1); /* L: ... func arg1 arg2 ... */
}
else
{
lua_insert(_state,functionIndex - 1); /* L: ... G func arg1 arg2 ... */
traceCallback = functionIndex - 1;
}

int error = 0;
++_callFromLua;
error = lua_pcall(_state,numArgs,numResults,traceCallback); /* L: ... [G] ret1 ret2 ... retResults*/
//traceCallback是错误处理函数,numResults指定返回的参数个数，然后返回值会push到栈顶
--_callFromLua;
//..
// get return value,don't pass LUA_MULTRET to numResults,
do {

if (numResults <= 0 || nullptr == func)
break;

func(_state,numResults); //回调执行

} while (0);
//..
}