main.lua:45: 尝试索引全局 'heroClass' (一个 nil 值) 堆栈回溯: main.lua:45: in main chunk答案

【问题标题】：main.lua:45: attempt to index global 'heroClass' (a nil value) stack traceback: main.lua:45: in main chunkmain.lua:45: 尝试索引全局 'heroClass' (一个 nil 值) 堆栈回溯: main.lua:45: in main chunk
【发布时间】：2015-04-07 17:51:38
【问题描述】：

我是新手，正在尝试从子类 heroClass 中创建一个 NEW HERO

CharacterClass.lua 中的代码：

local CharacterClass = 
{
 name = " ",
 hp = " ",
 velocity = " ";
}


function CharacterClass:new(o, nameCharacter, hpCharacter, velocityCharacter)
  local o = o or {}
  setmetatable( o, self )
  self.__index = self 
  self.name = nameCharacter
  self.hp = hpCharacter
  self.velocity = velocityCharacter

  return o
end

-- CREATING HERO INHERIT

local heroClass = CharacterClass:new()
function heroClass:new (o, name, hp, velocity, playerId, color)
  local o = o or CharacterClass:new(o, name, hp, velocity)
  setmetatable(o, self)
  self.__index = self

  return o 
end

main.lua 中的代码

local CharacterClass = require( "CharacterClass" )

local heroClassMain = heroClass:new()

运行代码后出现此错误

main.lua:45: attempt to index global 'heroClass' (a nil value) stack traceback: main.lua:45: in main chunk

PS：当我在 main 中创建一个 NEW CharacterClass 时，它可以完美运行，但是当我尝试创建一个 NEW heroClass（子类）时，我收到错误！

有人知道怎么回事吗？谢谢！

【问题讨论】：

标签： lua coronasdk

【解决方案1】：

修改你的CharacterClass.lua如下：

local CharacterClass = {
  name = " ",
  hp = " ",
  velocity = " ",
}

function CharacterClass:new(o, nameCharacter, hpCharacter, velocityCharacter)
  -- same as before
end

-- CREATING HERO INHERIT

local heroClass = CharacterClass:new()

function heroClass:new (o, name, hp, velocity, playerId, color)
  -- same as before
end

return {heroClass = heroClass, CharacterClass = CharacterClass }

现在，当您在 main.lua 中使用 require 时，还需要做一些事情：

local classModule = require "CharacterClass"
local CharacterClass, heroClass = classModule.CharacterClass, classModule.heroClass
local heroClassMian = heroClass:new()

以前，您的 heroClass 子类未提供给 main.lua 文件。这就是导致错误回溯的原因。

【讨论】：