quick « 爱好玩

问题的产生

项目是用ccs1.6做的UI,在某个需求中,需要把一个Sprite的SpriteFrame clone一份,去构造另一个
代码类似于

local sprite = cc.ui.UIImage.new("file1.png")
sprite:pos(x,y):addTo(self)

local sprite2 = cc.ui.UIImage.new(sprite:clone():getSpriteFrame())
sprite2:pos(x2,y2):addTo(self)

local sprite = cc.ui.UIImage.new("file1.png")

sprite:pos(x,y):addTo(self)

local sprite2 = cc.ui.UIImage.new(sprite:clone():getSpriteFrame())

sprite2:pos(x2,y2):addTo(self)

这样并没有问题
但是如果sprite的SpriteFrame被set过一个新的,那sprite2得到的SpriteFrame,依然是老的

怎么回事?

查看源码,我们发现Node:clone()方法被重写了(在NodeEx.lua里)

function Node:clone()
    local cloneNode = self:createCloneInstance_()

    cloneNode:copyProperties_(self)
    cloneNode:copySpecialPeerVal_(self)
    cloneNode:copyCloneWidgetChildren_(self)

    return cloneNode
end

function Node:clone()

local cloneNode = self:createCloneInstance_()

cloneNode:copyProperties_(self)

cloneNode:copySpecialPeerVal_(self)

cloneNode:copyCloneWidgetChildren_(self)

return cloneNode

end

粗读一下代码,先克隆一个实例,然后克隆基础属性,最后递归把子节点也克隆了

那问题就应该出现在self:createCloneInstance_()上
查阅发现

function UIImage:createCloneInstance_()
    return UIImage.new(unpack(self.args_))
end

function UIImage:createCloneInstance_()

return UIImage.new(unpack(self.args_))

end

好吧…直接用构造参数返回一个实例是什么鬼

既然出事了,就弄弄大

我们发现所有UI组件的createCloneInstance_方法都有这个问题
写一段比较简单的代码

local label = cc.ui.UILabel.new({text = "before"})
label:pos(x,y):addTo(self)
label:setString("after")

local label2 = label:clone()
label2:pos(x2,y2):addTo(self)

local label = cc.ui.UILabel.new({text = "before"})

label:pos(x,y):addTo(self)

label:setString("after")

local label2 = label:clone()

label2:pos(x2,y2):addTo(self)

可以看到,屏幕上显示label显示after,label2显示before

如果不用UI组件呢?

我试了一下,直接使用Sprite和LabelTTF是没有问题的,那这个就可以定性为quick的bug了

发现问题

项目从3.3rc1升级到3.5后,很多触摸事件都变得不正常了

于是

在cocoachina上发现了这篇文章
已经有童鞋在github上提交了pr戳这里

然后

在编译simulator的时候,windows.h找不到,结果发现win7+vs2013是需要windows8.1的sdk百度盘

最后

问题解决了

懒加载

我最先接触懒加载(延时加载)是在Hibernate里,因为一次和数据库交互过多,导致应用程序卡顿,所以就延迟加载这些数据,等需要的时候再取.可以认为懒加载就是非即时的加载数据.

问题的产生

在游戏开发中,也会碰到一次处理太多数据造成游戏卡顿降帧,比较典型的比如”背包”模块,背包可以认为是一个ListView,由一个lua table里的一些元素作为数据源来构建,当用一个for循环去构造界面时,背包格子过多会导致游戏线程卡住,游戏降帧在所难免.如何做到不降帧?我们可以把一个复杂的逻辑分在多个帧里去做.

来看看代码

local LazyLoader = class("LazyLoader")

LazyLoader.ON_FUNC = "ON_FUNC"
LazyLoader.ON_CALLBACK = "ON_CALLBACK"

function LazyLoader:ctor(params)
    cc(self):addComponent("components.behavior.EventProtocol"):exportMethods()
    if params then
        self:setItemList(params.itemList)
        if params.func then
            self:onFunc(params.func)
        end
        if params.callback then
            self:onCallback(params.callback)
        end
    end
end

function LazyLoader:setItemList(itemList)
    self._itemList = itemList
    self._count = #self._itemList
end

function LazyLoader:onFunc(func)
    return self:addEventListener(LazyLoader.ON_FUNC, func)
end

function LazyLoader:onCallback(callback)
    return self:addEventListener(LazyLoader.ON_CALLBACK, callback)
end

function LazyLoader:start()
    if self.updateSchedulerEntry == nil then
        self.updateSchedulerEntry = cc.Director:getInstance():getScheduler():scheduleScriptFunc(handler(self,self.update),0,false)
        self._curIdx = 1
    end
end

function LazyLoader:update(dt)
    if self._curIdx >= self._count then
        if self.updateSchedulerEntry ~= nil then
            cc.Director:getInstance():getScheduler():unscheduleScriptEntry(self.updateSchedulerEntry)
        end
        self:dispatchEvent({name = LazyLoader.ON_CALLBACK})
        return
    end

    self:dispatchEvent({name = LazyLoader.ON_FUNC, item = self._itemList[self._curIdx], idx = self._curIdx})
    self._curIdx = self._curIdx + 1

end

return LazyLoader

local LazyLoader = class("LazyLoader")

LazyLoader.ON_FUNC = "ON_FUNC"

LazyLoader.ON_CALLBACK = "ON_CALLBACK"

function LazyLoader:ctor(params)

cc(self):addComponent("components.behavior.EventProtocol"):exportMethods()

if params then

self:setItemList(params.itemList)

if params.func then

self:onFunc(params.func)

end

if params.callback then

self:onCallback(params.callback)

end

function LazyLoader:setItemList(itemList)

self._itemList = itemList

self._count = #self._itemList

end

function LazyLoader:onFunc(func)

return self:addEventListener(LazyLoader.ON_FUNC, func)

end

function LazyLoader:onCallback(callback)

return self:addEventListener(LazyLoader.ON_CALLBACK, callback)

end

function LazyLoader:start()

if self.updateSchedulerEntry == nil then

self.updateSchedulerEntry = cc.Director:getInstance():getScheduler():scheduleScriptFunc(handler(self,self.update),0,false)

self._curIdx = 1

end

function LazyLoader:update(dt)

if self._curIdx >= self._count then

if self.updateSchedulerEntry ~= nil then

cc.Director:getInstance():getScheduler():unscheduleScriptEntry(self.updateSchedulerEntry)

end

self:dispatchEvent({name = LazyLoader.ON_CALLBACK})

return

end

self:dispatchEvent({name = LazyLoader.ON_FUNC, item = self._itemList[self._curIdx], idx = self._curIdx})

self._curIdx = self._curIdx + 1

end

return LazyLoader

用法

local lazy = LazyLoader.new()
local lazyLabel = cc.ui.UILabel.new({
    text = "aaaa",
    color = cc.c3b(255, 255, 255),
})
lazyLabel:align(display.LEFT_TOP,50,display.height - 270)
self:addChild(lazyLabel)
local itemList = {}
for i=1,10000 do
    itemList[i] = "No."..i
end
lazy:setItemList(itemList)
lazy:onFunc(function(event)
    lazyLabel:setString(event.item)
end)
lazy:onCallback(function(event)
    lazyLabel:setString("Finish!!!")
end)
lazy:start()

local lazy = LazyLoader.new()

local lazyLabel = cc.ui.UILabel.new({

text = "aaaa",

color = cc.c3b(255, 255, 255),

})

lazyLabel:align(display.LEFT_TOP,50,display.height - 270)

self:addChild(lazyLabel)

local itemList = {}

for i=1,10000 do

itemList[i] = "No."..i

end

lazy:setItemList(itemList)

lazy:onFunc(function(event)

lazyLabel:setString(event.item)

end)

lazy:onCallback(function(event)

lazyLabel:setString("Finish!!!")

end)

lazy:start()

Github

戳这里

ScrollView滚动视图

在游戏开发过程中,由于手机屏幕空间有限,加上手指的灵动性,滑动成了最好的替换翻页的操作方式
ScrollView就是在这种需求驱动下的产物

cc.ScrollView和cc.ui.UIScrollView

前者是cocos2dx3.3原生的c++类,继承于cc.Layer
后者是QuickUI组件中的lua类,继承于cc.ClippingRectangleNode

quick中的cc.ui.UIScrollView用法

local visibleSize = cc.Director:getInstance():getVisibleSize()
local viewRect = cc.rect(0,0,visibleSize.width,visibleSize.height)
local scrollView = cc.ui.UIScrollView.new({
    viewRect = viewRect
})
local scrollNode = display.newLayer()
scrollView:addScrollNode(scrollNode)
-- 注册滚动事件 通过event.name区分
scrollView:onScroll(function(event)
    -- TODO: sth
end)

local visibleSize = cc.Director:getInstance():getVisibleSize()

local viewRect = cc.rect(0,0,visibleSize.width,visibleSize.height)

local scrollView = cc.ui.UIScrollView.new({

viewRect = viewRect

})

local scrollNode = display.newLayer()

scrollView:addScrollNode(scrollNode)

-- 注册滚动事件通过event.name区分

scrollView:onScroll(function(event)

-- TODO: sth

end)

在实际运用过程中,我发现quick的滚动组件存在性能问题(windows上),一旦组件多了之后滚动不流畅,卡顿严重

原生cc.ScrollView用法

local visibleSize = cc.Director:getInstance():getVisibleSize()
local scrollView = cc.ScrollView:create(visibleSize)
local scrollNode = cc.Layer:create() -- 等同于display.newLayer()
scrollView:setContainer(scrollNode)
-- 为scrollView添加滚动事件
scrollView:setDelegate()
scrollView:registerScriptHandler(function()
    -- TODO: sth
end,0) -- 0为滚动事件 1为缩放事件

local visibleSize = cc.Director:getInstance():getVisibleSize()

local scrollView = cc.ScrollView:create(visibleSize)

local scrollNode = cc.Layer:create() -- 等同于display.newLayer()

scrollView:setContainer(scrollNode)

-- 为scrollView添加滚动事件

scrollView:setDelegate()

scrollView:registerScriptHandler(function()

-- TODO: sth

end,0) -- 0为滚动事件 1为缩放事件

在出现对话的时候,我们往往不希望文字一下子突然出现,于是有了这个需求

文字要慢慢的出现,但是点击时,一下子显示完

local TimerLabel = class("TimerLabel",function(params)
    return display.newTTFLabel(params)
end)

local TimerLabel = class("TimerLabel", function(params)
    return display.newTTFLabel(params)
end)

TimerLabel.ON_COUNT_DOWN = "ON_COUNT_DOWN"

function TimerLabel:ctor(params)
    cc(self):addComponent("components.behavior.EventProtocol"):exportMethods()
    self:setNodeEventEnabled(true)
    self._triggerTime = params.triggerTime or 0
    self._time = params.time
    self._format = params.format
    self:setString(self:formatTime(self._time,self._format))
end

function TimerLabel:formatTime(timeValue, format)
    if not timeValue then
        return "unknow time"
    end
    local as = math.floor(timeValue / 1000)
    local s = as % 60
    local am = math.floor(as / 60)
    local m = am % 60
    local h = math.floor(am / 60)

    local ss =  nil
    if s < 10 then
        ss = string.format("0%d", s)
    else
        ss = string.format("%d", s)
    end

    local ms =  nil
    if m < 10 then
        ms = string.format("0%d", m)
    else
        ms = string.format("%d", m)
    end

    local hs =  nil
    if h < 10 then
        hs = string.format("0%d", h)
    else
        hs = string.format("%d", h)
    end

    local newTimeString = string.gsub(format, "@H", hs)
    newTimeString = string.gsub(newTimeString, "@M", ms)
    newTimeString = string.gsub(newTimeString, "@S", ss)
    return newTimeString
end

function TimerLabel:update(dt)
    local lastTime = math.ceil(self._time / 1000)
    self._time = self._time - dt * 1000
    if self._time <= 0 then
        self._time = 0
    end

    local nowTime = math.ceil(self._time / 1000)
    if lastTime ~= nowTime then
        self:setString(self:formatTime(self._time,self._format))
    end

    if self._time <= self._triggerTime then
        self:dispatchEvent({name = TimerLabel.ON_COUNT_DOWN})
        if self._updateEntry then
            cc.Director:getInstance():getScheduler():unscheduleScriptEntry(self._updateEntry)
            self._updateEntry = nil
        end
    end
end

function TimerLabel:onEnter()
    self._updateEntry = cc.Director:getInstance():getScheduler():scheduleScriptFunc(handler(self,self.update),0,false)
end

function TimerLabel:onExit()
    if self._updateEntry then
        cc.Director:getInstance():getScheduler():unscheduleScriptEntry(self._updateEntry)
        self._updateEntry = nil
    end
end

return TimerLabel

local TimerLabel = class("TimerLabel",function(params)

return display.newTTFLabel(params)

end)

local TimerLabel = class("TimerLabel", function(params)

return display.newTTFLabel(params)

end)

TimerLabel.ON_COUNT_DOWN = "ON_COUNT_DOWN"

function TimerLabel:ctor(params)

cc(self):addComponent("components.behavior.EventProtocol"):exportMethods()

self:setNodeEventEnabled(true)

self._triggerTime = params.triggerTime or 0

self._time = params.time

self._format = params.format

self:setString(self:formatTime(self._time,self._format))

end

function TimerLabel:formatTime(timeValue, format)

if not timeValue then

return "unknow time"

end

local as = math.floor(timeValue / 1000)

local s = as % 60

local am = math.floor(as / 60)

local m = am % 60

local h = math.floor(am / 60)

local ss = nil

if s < 10 then

ss = string.format("0%d", s)

else

ss = string.format("%d", s)

end

local ms = nil

if m < 10 then

ms = string.format("0%d", m)

else

ms = string.format("%d", m)

end

local hs = nil

if h < 10 then

hs = string.format("0%d", h)

else

hs = string.format("%d", h)

end

local newTimeString = string.gsub(format, "@H", hs)

newTimeString = string.gsub(newTimeString, "@M", ms)

newTimeString = string.gsub(newTimeString, "@S", ss)

return newTimeString

end

function TimerLabel:update(dt)

local lastTime = math.ceil(self._time / 1000)

self._time = self._time - dt * 1000

if self._time <= 0 then

self._time = 0

end

local nowTime = math.ceil(self._time / 1000)

if lastTime ~= nowTime then

self:setString(self:formatTime(self._time,self._format))

end

if self._time <= self._triggerTime then

self:dispatchEvent({name = TimerLabel.ON_COUNT_DOWN})

if self._updateEntry then

cc.Director:getInstance():getScheduler():unscheduleScriptEntry(self._updateEntry)

self._updateEntry = nil

end

function TimerLabel:onEnter()

self._updateEntry = cc.Director:getInstance():getScheduler():scheduleScriptFunc(handler(self,self.update),0,false)

end

function TimerLabel:onExit()

if self._updateEntry then

cc.Director:getInstance():getScheduler():unscheduleScriptEntry(self._updateEntry)

self._updateEntry = nil

end

return TimerLabel

用法如下

    local typingLabel = TypingLabel.new({
        text = "这是一个打字机效果,n支持中英数组合,n数字123456英文abcdefg"
    })
    
    typingLabel:addEventListener(TypingLabel.ON_FINISH_TYPING,function(event)
        print("打字机结束")
    end)
    
    typingLabel:align(display.LEFT_TOP,50,display.height - 100):addTo(self)

local typingLabel = TypingLabel.new({

text = "这是一个打字机效果,n支持中英数组合,n数字123456英文abcdefg"

})

typingLabel:addEventListener(TypingLabel.ON_FINISH_TYPING,function(event)

print("打字机结束")

end)

typingLabel:align(display.LEFT_TOP,50,display.height - 100):addTo(self)

有倒计时功能的标签这个还是挺常见的

直接上代码吧

local TimerLabel = class("TimerLabel",function(params)
    return display.newTTFLabel(params)
end)

local TimerLabel = class("TimerLabel", function(params)
    return display.newTTFLabel(params)
end)

TimerLabel.ON_COUNT_DOWN = "ON_COUNT_DOWN"

function TimerLabel:ctor(params)
    cc(self):addComponent("components.behavior.EventProtocol"):exportMethods()
    self:setNodeEventEnabled(true)
    self._triggerTime = params.triggerTime or 0
    self._time = params.time
    self._format = params.format
    self:setString(self:formatTime(self._time,self._format))
end

function TimerLabel:formatTime(timeValue, format)
    if not timeValue then
        return "unknow time"
    end
    local as = math.floor(timeValue / 1000)
    local s = as % 60
    local am = math.floor(as / 60)
    local m = am % 60
    local h = math.floor(am / 60)

    local ss =  nil
    if s < 10 then
        ss = string.format("0%d", s)
    else
        ss = string.format("%d", s)
    end

    local ms =  nil
    if m < 10 then
        ms = string.format("0%d", m)
    else
        ms = string.format("%d", m)
    end

    local hs =  nil
    if h < 10 then
        hs = string.format("0%d", h)
    else
        hs = string.format("%d", h)
    end

    local newTimeString = string.gsub(format, "@H", hs)
    newTimeString = string.gsub(newTimeString, "@M", ms)
    newTimeString = string.gsub(newTimeString, "@S", ss)
    return newTimeString
end

function TimerLabel:update(dt)
    local lastTime = math.ceil(self._time / 1000)
    self._time = self._time - dt * 1000
    if self._time <= 0 then
        self._time = 0
    end

    local nowTime = math.ceil(self._time / 1000)
    if lastTime ~= nowTime then
        self:setString(self:formatTime(self._time,self._format))
    end

    if self._time <= self._triggerTime then
        self:dispatchEvent({name = TimerLabel.ON_COUNT_DOWN})
        if self._updateEntry then
            cc.Director:getInstance():getScheduler():unscheduleScriptEntry(self._updateEntry)
            self._updateEntry = nil
        end
    end
end

function TimerLabel:onEnter()
    self._updateEntry = cc.Director:getInstance():getScheduler():scheduleScriptFunc(handler(self,self.update),0,false)
end

function TimerLabel:onExit()
    if self._updateEntry then
        cc.Director:getInstance():getScheduler():unscheduleScriptEntry(self._updateEntry)
        self._updateEntry = nil
    end
end

return TimerLabel

local TimerLabel = class("TimerLabel",function(params)

return display.newTTFLabel(params)

end)

local TimerLabel = class("TimerLabel", function(params)

return display.newTTFLabel(params)

end)

TimerLabel.ON_COUNT_DOWN = "ON_COUNT_DOWN"

function TimerLabel:ctor(params)

cc(self):addComponent("components.behavior.EventProtocol"):exportMethods()

self:setNodeEventEnabled(true)

self._triggerTime = params.triggerTime or 0

self._time = params.time

self._format = params.format

self:setString(self:formatTime(self._time,self._format))

end

function TimerLabel:formatTime(timeValue, format)

if not timeValue then

return "unknow time"

end

local as = math.floor(timeValue / 1000)

local s = as % 60

local am = math.floor(as / 60)

local m = am % 60

local h = math.floor(am / 60)

local ss = nil

if s < 10 then

ss = string.format("0%d", s)

else

ss = string.format("%d", s)

end

local ms = nil

if m < 10 then

ms = string.format("0%d", m)

else

ms = string.format("%d", m)

end

local hs = nil

if h < 10 then

hs = string.format("0%d", h)

else

hs = string.format("%d", h)

end

local newTimeString = string.gsub(format, "@H", hs)

newTimeString = string.gsub(newTimeString, "@M", ms)

newTimeString = string.gsub(newTimeString, "@S", ss)

return newTimeString

end

function TimerLabel:update(dt)

local lastTime = math.ceil(self._time / 1000)

self._time = self._time - dt * 1000

if self._time <= 0 then

self._time = 0

end

local nowTime = math.ceil(self._time / 1000)

if lastTime ~= nowTime then

self:setString(self:formatTime(self._time,self._format))

end

if self._time <= self._triggerTime then

self:dispatchEvent({name = TimerLabel.ON_COUNT_DOWN})

if self._updateEntry then

cc.Director:getInstance():getScheduler():unscheduleScriptEntry(self._updateEntry)

self._updateEntry = nil

end

function TimerLabel:onEnter()

self._updateEntry = cc.Director:getInstance():getScheduler():scheduleScriptFunc(handler(self,self.update),0,false)

end

function TimerLabel:onExit()

if self._updateEntry then

cc.Director:getInstance():getScheduler():unscheduleScriptEntry(self._updateEntry)

self._updateEntry = nil

end

return TimerLabel

用法如下

    local timerLabel = TimerLabel.new({
        time = 60000,
        format = "TimerLabel演示:@M:@S"
    })

    timerLabel:addEventListener(TimerLabel.ON_COUNT_DOWN,function(event)
        print("倒计时结束")
    end)

    timerLabel:align(display.LEFT_TOP,50,display.height - 50):addTo(self)

local timerLabel = TimerLabel.new({

time = 60000,

format = "TimerLabel演示:@M:@S"

})

timerLabel:addEventListener(TimerLabel.ON_COUNT_DOWN,function(event)

print("倒计时结束")

end)

timerLabel:align(display.LEFT_TOP,50,display.height - 50):addTo(self)

除了text外,display.newTTFLabel里的所有参数都有效
新增了time参数(单位毫秒),format参数(支持H M S),triggerTime参数(触发事件,不传时为0)
倒计时结束会触发TimerLabel.ON_COUNT_DOWN

2.x时代的CCControlButton的确十分方便,策划们也十分喜欢按下有缩放的效果

到了3.x的项目,工具链已经相当完善,我使用的是cocos2dx3.2+quick3.2rc1+cocos code ide 1.0.1+cocos studio 1.6(以下简称ccs)

在ccs里建立的按钮,到了程序里实际上是UIPushButton

从quick的源码可以看出,UIPushButton继承于UIButton,UIButton继承于cc.Node

那么按下弹起的效果就得自己写了,好在quick扩展的方式很方便

local UIButton = require("framework.cc.ui.UIButton")

UIButtonEx = {}

function UIButtonEx.extend(btn)
	function btn:setPressedActionEnabled(enabled)
		if enabled then
			self.onPressed = function()
				self:setScale(0.9) --1.1
			end

			self.onRelease = function()
				self:setScale(1.0)
			end
			self:onButtonPressed(self.onPressed)
			self:onButtonRelease(self.onRelease)
		else
			if self.onPressed then
				self:removeEventListenersByEvent(UIButton.PRESSED_EVENT)
				self.onPressed = nil
			end
			if self.onRelease then
				self:removeEventListenersByEvent(UIButton.RELEASE_EVENT)
				self.onRelease = nil
			end

		end
	end
end

local UIButton = require("framework.cc.ui.UIButton")

UIButtonEx = {}

function UIButtonEx.extend(btn)

function btn:setPressedActionEnabled(enabled)

if enabled then

self.onPressed = function()

self:setScale(0.9) --1.1

end

self.onRelease = function()

self:setScale(1.0)

end

self:onButtonPressed(self.onPressed)

self:onButtonRelease(self.onRelease)

else

if self.onPressed then

self:removeEventListenersByEvent(UIButton.PRESSED_EVENT)

self.onPressed = nil

end

if self.onRelease then

self:removeEventListenersByEvent(UIButton.RELEASE_EVENT)

self.onRelease = nil

end

我用起来是全局的

在载入ccs之后,会遍历所有节点,找出node.__cname == “UIPushButton”的元素,然后UIButtonEx.extend(node); node:setPressedActionEnabled(true)就可以了

需要按钮放大的,把0.9改成1.1就行了

转自http://www.swfdiy.com/?p=1663

在quick-cocos2dx里，通过class() 函数进行类的定义

下面贴出quick-cocos2d-x-2.2.1-rc 里 class()的源码

function class(classname, super)
    local superType = type(super)
    local cls
 
    if superType ~= "function" and superType ~= "table" then
        superType = nil
        super = nil
    end
 
    if superType == "function" or (super and super.__ctype == 1) then
        -- inherited from native C++ Object
        cls = {}
 
        if superType == "table" then
            -- copy fields from super
            for k,v in pairs(super) do cls[k] = v end
            cls.__create = super.__create
            cls.super    = super
        else
            cls.__create = super
            cls.ctor = function() end
        end
 
        cls.__cname = classname
        cls.__ctype = 1
 
        function cls.new(...)
            local instance = cls.__create(...)
            -- copy fields from class to native object
            for k,v in pairs(cls) do instance[k] = v end
            instance.class = cls
            instance:ctor(...)
            return instance
        end
 
    else
        -- inherited from Lua Object
        if super then
            cls = {}
            setmetatable(cls, {__index = super})
            cls.super = super
        else
            cls = {ctor = function() end}
        end
 
        cls.__cname = classname
        cls.__ctype = 2 -- lua
        cls.__index = cls
 
        function cls.new(...)
            local instance = setmetatable({}, cls)
            instance.class = cls
            instance:ctor(...)
            return instance
        end
    end
 
    return cls
end

function class(classname, super)

local superType = type(super)

local cls

if superType ~= "function" and superType ~= "table" then

superType = nil

super = nil

end

if superType == "function" or (super and super.__ctype == 1) then

-- inherited from native C++ Object

cls = {}

if superType == "table" then

-- copy fields from super

for k,v in pairs(super) do cls[k] = v end

cls.__create = super.__create

cls.super = super

else

cls.__create = super

cls.ctor = function() end

end

cls.__cname = classname

cls.__ctype = 1

function cls.new(...)

local instance = cls.__create(...)

-- copy fields from class to native object

for k,v in pairs(cls) do instance[k] = v end

instance.class = cls

instance:ctor(...)

return instance

end

else

-- inherited from Lua Object

if super then

cls = {}

setmetatable(cls, {__index = super})

cls.super = super

else

cls = {ctor = function() end}

end

cls.__cname = classname

cls.__ctype = 2 -- lua

cls.__index = cls

function cls.new(...)

local instance = setmetatable({}, cls)

instance.class = cls

instance:ctor(...)

return instance

end

return cls

end

我们先考虑最简单的情况，在没有继承的情况下定义一个类ClassA

--ClassA.lua
local ClassA = class("ClassA")
ClassA.field1 = "this is field1"
return ClassA
--main.lua
local ClassA = require("ClassA")
local InstanceA = ClassA.new()

--ClassA.lua

local ClassA = class("ClassA")

ClassA.field1 = "this is field1"

return ClassA

--main.lua

local ClassA = require("ClassA")

local InstanceA = ClassA.new()

这种情况下， ClassA 跟InstanceA的关系如下图

InstanceA的metatable为ClassA, 而且ClassA.__index = ClassA, 因此，对于InstanceA找不到的属性，将在ClassA里进行查找。需要注意的是，ClassA里的属性比如field1, 是相当于类变量的概念，所有实例都公用该属性，并非各自维护该字段的拷贝。

下面如果要再定义ClassB, 从ClassA 进行继承

--ClassB.lua
local ClassB = class("ClassB", require("ClassA"))
 
return ClassB

--ClassB.lua

local ClassB = class("ClassB", require("ClassA"))

return ClassB

这种情况下， ClassB 跟InstanceB, ClassA的关系如下图

同理，InstanceB里没有定义的属性，将首先在ClassB里进行搜索，如果ClassB里搜不到，将向上追寻到ClassA里。

上面考虑的都只是针对纯Lua类，在实际情况中，我们需要对C++里生成的对象（userdata)进行扩展，可以如下定义

--ClassC.lua
local ClassC = class("ClassC", function() 
     --调用C++接口创建一个原生对象(userdata), 并且给该对象绑定一个peer（table), 这里我们以创建一个CCNode为例
     local node = CCNode:create()  --原生对象（userdata)
     local peer = {}              
     tolua.setpeer(node , peer )
     return node
end)
 
return ClassC

--ClassC.lua

local ClassC = class("ClassC", function()

--调用C++接口创建一个原生对象(userdata), 并且给该对象绑定一个peer（table), 这里我们以创建一个CCNode为例

local node = CCNode:create() --原生对象（userdata)

local peer = {}

tolua.setpeer(node , peer )

return node

end)

return ClassC

ClassC跟InstanceC的关系如下图

在调用InstanceC(实际上是一个userdata)上的某个方法时，首先会先去这个userdata绑定的peer这个table里寻找这个方法，如果找不到才会去c++那层调用。

所以我们可以通过给peer添加几个方法从而实现给InstanceC(userdata)扩展方法，实际情况上也确实如此，在quick里，有几个专门的类，CCNodeExtend,CCLayerExtend,CCSceneExtend,CCSpriteExtend，使用比如 CCNodeExtend.extend(someCCNodeInstance), 可以生成一个特殊的peer，这个peer的metatable为CCNodeExtend，这样我们就可以在someCCNodeInstance上调用CCNodeExtend定义了而原本CCNode没有的方法，从而实现扩展。

下面再考虑ClassD从ClassC继承的情况

--ClassD.lua
local ClassD = class("ClassD", require("ClassC"))
 
 
return ClassD

--ClassD.lua

local ClassD = class("ClassD", require("ClassC"))

return ClassD

关系图：

===================

最先是看到下面这篇文章的,也写的很棒

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