请教cocos2dx-lua继承问题

[wb197]

function GameScene:ctor()
print("GameScene:ctor called......")
self._visibleSize = cc.Director:getInstance():getVisibleSize()
self._origin = cc.Director:getInstance():getVisibleOrigin()
self._schedulerID = nil
self._rootNode = nil

print("width:%d, height:%d", self._visibleSize.width, self._visibleSize.height)
self._animation = nil
end

程序运行时能够得到值并打印输出

function GameScene:onLoginPush(pSender, touch_type)
print(string.format("width:%d, height:%d", self._visibleSize.width, self._visibleSize.height))
end

程序运行时就会报
[LUA-print] ----------------------------------------
[LUA-print] LUA ERROR: [string "GameScene.lua"]:90: attempt to index field '_visibleSize' (a nil value)

错误呢？

[wb197]

明明在ctor中定义了成员变量，在按键响应中要处理却得到nil value，这是何解？以下附完整代码，求熟手赐教…… require "Cocos2d" require "Cocos2dConstants" -- 在GameScene中保留动画节点不行，在GameScene中持有会丢失，在使用时会变成nil，故此使用全局变量来持有 gLoginAnimation = nil --gUserName = nil --gPassWord = nil local GameScene = class("GameScene",function() return cc.Scene:create() end) function GameScene.extend(target) local t = tolua.getpeer(target) if not t then t = {} tolua.setpeer(target, t) end setmetatable(t, GameScene) return target end function GameScene.create() local scene = GameScene.new() local layer = GameScene.extend(cc.Layer:create()) local rootNode = ccs.SceneReader:getInstance():createNodeWithSceneFile("publish/Login_ls1.json") scene.rootNode = rootNode layer:addChild(rootNode) scene:addChild(layer) local animNode = rootNode:getChildByTag(10006) local comRender = animNode:getComponent("CCArmature") local armature = comRender:getNode() local animation = armature:getAnimation() animation:pause() GameScene._animation = animation -- GameScene:setAnimation(animation) gLoginAnimation = animation local UINode = rootNode:getChildByTag(10012) assert(UINode) local uiReader = UINode:getComponent("UIFrames") assert(uiReader) local uiLayer = uiReader:getNode() assert(uiLayer) local button = uiLayer:getChildByName("login_Button") assert(button) button:addTouchEventListener(scene.onLoginPush) local textFieldUserName = uiLayer:getChildByName("name_TextField") assert(textFieldUserName) local textFieldPassWord = uiLayer:getChildByName("password_TextField") assert(textFieldPassWord) gPassWord = textFieldPassWord gUserName = textFieldUserName return scene end function GameScene:ctor() print("GameScene:ctor called......") self._visibleSize = cc.Director:getInstance():getVisibleSize() self._origin = cc.Director:getInstance():getVisibleOrigin() self._schedulerID = nil self._rootNode = nil print("width:%d, height:%d", self._visibleSize.width, self._visibleSize.height) self._animation = nil end function GameScene:setAnimation(pAnim) self._animation = pAnim end function GameScene:onLoginPush(pSender, touch_type) -- if touch_type == ccui.TouchEventType.ended then -- self._animation:play() -- gLoginAnimation:resume() -- end print(string.format("width:%d, height:%d", self._visibleSize.width, self._visibleSize.height)) local userName = gUserName:getStringValue() local passWord = gPassWord:getStringValue() print(string.format("userName:%s", userName)) print(string.format("passWord:%s", passWord)) gLoginAnimation:resume() end return GameScene

[笨木头]

你这样调用这句：button:addTouchEventListener(function(pSender, touch_type) scene:onLoginPush(pSender, touch_type) end) 应该就没问题了~ (注意要scene:onLoginPush，是冒号不是点号，不然是不会有self参数的~)

[笨木头]

引用 4 楼 wb197 的回复:

问题还是没有完全解决，如果有了self指针，那么self._animation为何还是nil value呢？

你赋值是这样的：GameScene._animation 和你创建出来的scene没有关系，所以你的scene自然就没有这个值了。 你return的是scene，这个不能混乱~ 你多看看Lua的语法（关于元表、元方法、继承方面的），然后多试试，可能就不会这么模糊了

[wb197]

问题解决了，还要完整的写一个内联function才行？不过这解决的方式有点不太优雅，如果都要这样来写回调函数，那很难将代码格式化规范化啊

[wb197]

问题还是没有完全解决，如果有了self指针，那么self._animation为何还是nil value呢？

[wb197]

哦，原来调用setAnimation也要用scene:setAnimation才行，初步明白冒号的作用了。