cocos2dx-lua使用UIListView制作二级折叠菜单

折叠菜单，用过jquery accordion的同学都知道是啥玩艺儿~，图片效果就是介样：

cocos2dx不带有此控件，因此我们动手来实现一个。

原理很简单，展开的时候往listview里insertCustomItem，收起的时候从listview里removeItem。下面给出一个功能丰富的折叠菜单控件。
先看控件主类：

--[[
    二级折叠菜单组

    构造：
    local groupData = {
        {
            title = '分类1',
            items = {
                { id = 1, count = 20, lv = 19 },
                { id = 2, count = 21, lv = 21 },
                { id = 3, count = 22, lv = 23 },
            }
        },
        {
            title = '图腾',
            items = {
                { id = 500001, count = 32, lv = 19 },
                { id = 500002, count = 21, lv = 65 },
                { id = 500003, count = 22, lv = 27 },
            }
        },
        {
            title = '武器',
            items = {
                { id = 101002, count = 20, lv = 45 },
                { id = 101003, count = 21, lv = 34 },
            }
        },
    }
    self._goodsCateList = gm.Common.UIMenuList.new( cc.size( 310, 510 ), groupData )

    -- 必须设置标题类型和内容类型，重写可改变样式
    self._goodsCateList:setClass( gm.Market.MarketMenuTitle, gm.Market.MarketMenuItem )
    
    -- 可选参数，是否可同时展开多个分组，默认false
    self._goodsCateList.showMulti = true

    -- 可选参数，是否默认选中组中第一个item
    self._goodsCateList.autoSelectFirstItem = true

    -- 可选参数，选中的title索引，默认为1
    self._goodsCateList.defaultGroup = 1

    -- 可选参数，选中的item索引，默认为1
    self._goodsCateList.defaultItem = 1

    加入舞台：
    self._goodsCateList:addToParent( self._bg, { x = 0, y = 0 } )

    @author cc
--]]

gm = gm or {}
rm = rm or {} 

local gm = gm
local rm = rm 

gm.Common                       = gm.Common or {}
gm.Common.UIMenuList            = class( "Common.UIMenuList" )
gm.Common.UIMenuList._name      = "Common.UIMenuList"

local g = gm.Common.UIMenuList

---------------------------------------------------------------------------------
--                                                                             --
--                          以下定义私有部分                                   --
--                                                                             --
---------------------------------------------------------------------------------

local function log( ... )
    print( '>>>>gm.Common.UIMenuList<<<<:', ...)
end

-- 点击标题项
function g:_onTouchTitle( sender )
    local titleInst = sender._inst

    -- 收缩点击项
    if titleInst.selected then
        self:_unSelectTitleInst( titleInst )
        return
    end

    -- 如果同时只展开一个分组，则隐藏上次展开的
    if not self._showMulti and self._selectedTitle then
        self:_unSelectTitleInst( self._selectedTitle )
    end

    -- 展开点击项
    local index = self._listView:getIndex( sender )
    local group = titleInst.data
    local itemInst
    for itemIdx, itemData in ipairs( group.items ) do
        itemInst = self:_createItemInst( itemData )
        self._listView:insertCustomItem( itemInst.ui, index + itemIdx )

        -- 将第一项设置为当前选中的内容项
        if self._autoSelectFirstItem and itemIdx == 1 then
            self.selectedItem = itemInst
        end 
    end

    -- 设置当前选中的标题项
    self.selectedTitle = titleInst
end

-- 点击内容项
function g:_onTouchItem( sender, eventType )
    if eventType == ccui.TouchEventType.ended then
        self.selectedItem = sender._inst
    end
    if self._itemClickFunc then
        self._itemClickFunc( sender, eventType )
    end
end

-- 收起标题项对应的分组
function g:_unSelectTitleInst( titleInst )
    local index = self._listView:getIndex( titleInst.ui )
    local group = titleInst.data
    local itemInst

    for i = 1, #group.items do

        -- 析构删除项
        itemInst = self._listView:getItem( index + 1 )._inst
        itemInst:finalize()

        -- 选中项被删除
        if self._selectedItem and self._selectedItem == itemInst then
            self._selectedItem = nil
        end

        self._listView:removeItem( index + 1 )
    end
    titleInst.selected = false

    if titleInst == self._selectedTitle then
        self._selectedTitle = nil
    end
end

-- 创建标题项
function g:_createTitleInst( data )
    if not self._titleCls then
        log( '没有设置标题类型!' )
        return
    end

    local titleInst = self._titleCls.new( )
    titleInst.data = data
    titleInst.ui._inst = titleInst
    makeTouchHandle( self, titleInst.ui, self._onTouchTitle )
    return titleInst
end

-- 创建内容项
function g:_createItemInst( data )
    if not self._itemCls then
        log( '没有设置内容类型!' )
        return
    end

    local itemInst = self._itemCls.new( )
    itemInst.data = data
    itemInst.ui._inst = itemInst
    makeTouchHandle2( self, itemInst.ui, self._onTouchItem )
    return itemInst
end

-- 初始化
function g:_initialize( )
    self._listView = ccui.ListView:create()
    self._listView:setBounceEnabled( true )
    self._listView:setDirection( ccui.ScrollViewDir.vertical )
    self._listView:setSize( self._size )

    if not self._groupData then
        log( '分组数据为空!' )
        return
    end
    
    local titleInst, itemInst
    self._titleInstList = {}

    for groupIdx, group in ipairs( self._groupData ) do

        titleInst = self:_createTitleInst( group )
        self._listView:pushBackCustomItem( titleInst.ui )
        table.insert( self._titleInstList, titleInst )

        -- 展开默认分组
        if self._defaultGroupIdx and groupIdx == self._defaultGroupIdx then
            self.selectedTitle = titleInst
            
            for itemIdx, itemData in ipairs( group.items ) do

                itemInst = self:_createItemInst( itemData )
                self._listView:pushBackCustomItem( itemInst.ui )

                -- 选中默认项
                if self._defaultItemIdx and itemIdx == self._defaultItemIdx then
                    self.selectedItem = itemInst
                end
            end
        end
    end
end

---------------------------------------------------------------------------------
--                                                                               --
--                        以下定义set, get 部分函数                               --
--                                                                               --
---------------------------------------------------------------------------------

function g:_getUi( )
    return self._listView
end

-- 是否同时展开多个组
function g:_setShowMulti( value )
    self._showMulti = value
end

-- 获取数据
function g:_getGroupData( )
    return self._groupData
end

function g:_setGroupData( value )
    self._groupData = value
end

-- 设置默认展开的分组索引
-- @i value
function g:_setDefaultGroup( value )
    self._defaultGroupIdx = value
end

-- 设置默认选中的item索引
--@i value 
function g:_setDefaultItem( value )
    self._defaultItemIdx = value
end

-- 获取选中的标题项
function g:_getSelectedTitle( )
    return self._selectedTitle
end

function g:_setSelectedTitle( value )
    value.selected = true
    self._selectedTitle = value
    rm.BindManager.propertyChanged( self, "selectedTitle" )
end

-- 获取选中的内容项
function g:_getSelectedItem( )
    return self._selectedItem
end

function g:_setSelectedItem( value )
    if self._selectedItem then
        self._selectedItem.selected = false 
    end
    value.selected = true
    self._selectedItem = value
    rm.BindManager.propertyChanged( self, "selectedItem" )
end

-- 设置点击item项的回调函数
function g:_setItemClickFunc( value )
    self._itemClickFunc = value
end

-- 设置是否自动选中组中第一个item
function g:_setAutoSelectFirstItem( value )
    self._autoSelectFirstItem = value
end

---------------------------------------------------------------------------------
--                                                                             --
--                          以下定义公共部分                                   --
--                                                                             --
---------------------------------------------------------------------------------

-- 构造
-- @t size cc.size类型
-- @t groupData 分组数据，结构如{ { title = tData, items = { iData1, iData2 } }, ... }
function g:ctor( size, groupData )
    self._size = size or cc.size( 200, 200 )
    self._groupData = groupData
    self._titleInstList = nil
    self._defaultGroupIdx = nil
    self._defaultItemIdx = nil
    self._selectedTitle = nil
    self._selectedItem = nil
    self._titleCls = nil
    self._itemCls = nil
    self._showMulti = false
    self._autoSelectFirstItem = false
    self._itemClickFunc = nil
end

-- 设置标题项和内容项类型
-- @t titleClass 继承自gm.Common.UIMenuItem，重写可改变样式
-- @t itemClass  继承自gm.Common.UIMenuItem，重写可改变样式
function g:setClass( titleClass, itemClass )
    self._titleCls = titleClass
    self._itemCls = itemClass
end

-- 添加到舞台
-- @widget parent 父显示对象
-- @t        pos    位置，{ x = , y = }
-- @i        zOrder 层级
function g:addToParent( parent, pos, zOrder )
    if not parent then
        log( '父显示对象不可为空!' )
        return
    end
    self:_initialize()
    zOrder = zOrder or 1
    pos = pos or cc.p( 0, 0 )
    self._listView:setPosition( pos )
    parent:addChild( self._listView, zOrder )
end

-- 刷新当前展开的分组，只可在互斥（showMulti = false）模式下使用
-- @t group 数据，结构如{ title = tData, items = { iData1, iData2 } }
function g:refreshSelectedTitle( group )
    if not self._selectedTitle then return end
    self:refreshTitle( self._selectedTitle, group )
end

-- 刷新指定位置的分组
-- @i titleIndex     分组索引
-- @t group         组数据
function g:refreshTitleAtIndex( titleIndex, group )
    local title = self._titleInstList( titleIndex )
    self:refreshTitle( title, group )
end

-- 刷新指定分组
-- @t             某个分组
-- @t group     组数据
function g:refreshTitle( title, group )
    local index = self._listView:getIndex( title.ui )
    local prevNumItems = title.selected and #title.data.items or 0
    local currNumItems = #group.items
    local deltaNum = prevNumItems - currNumItems
    local itemInst

    -- 设置title数据
    title:_setData( group )
    self._groupData[ table.indexOf( self._titleInstList, title ) ] = group

    -- title没展开，以下无需执行
    if not title.selected then return end

    -- 设置item数据
    for itemIdx, itemData in ipairs( group.items ) do
        if itemIdx <= prevNumItems then
            itemInst = self._listView:getItem( index + itemIdx )._inst    
            itemInst:_setData( itemData )
        else
            itemInst = self:_createItemInst( itemData )
            self._listView:insertCustomItem( itemInst.ui, index + itemIdx )
        end
    end

    -- 旧数量比当前数量多，需要删除多余的item
    if deltaNum > 0 then
        for i = 1, deltaNum do
            itemInst = self._listView:getItem( index + currNumItems + 1 )._inst
            itemInst:finalize()

            -- 选中项被删除
            if self._selectedItem and self._selectedItem == itemInst then
                self._selectedItem = nil
            end

            self._listView:removeItem( index + currNumItems + 1 )
        end
    end
end

-- 刷新整个控件
-- @t 控件数据，结构如构造函数同名参数所示
function g:refresh( groupData )
    self._groupData = groupData
    if not self._groupData then
        log( '分组数据为空!' )
        return
    end

    local prevNumTitles = #self._titleInstList
    local currNumTitles = #groupData
    local deltaNum = prevNumTitles - currNumTitles
    local titleInst
    
    -- 刷新所有分组
    for groupIdx, group in ipairs( groupData ) do
        if groupIdx <= prevNumTitles then 
            titleInst = self._titleInstList[ groupIdx ]
            self:refreshTitle( titleInst, group )
        else
            titleInst = self:_createTitleInst( group )
            self._listView:pushBackCustomItem( titleInst.ui )
            table.insert( self._titleInstList, titleInst )
        end
    end
    
    -- 新分组比旧分组少，需要删除多余的title
    if deltaNum > 0 then
        local numListItems = #self._listView:getItems()

        -- 清空全部
        if currNumTitles == 0 then
            for i = numListItems - 1, 0, -1 do
                titleInst = self._listView:getItem( i )._inst
                titleInst:finalize()
            end
            self._listView:removeAllItems()
            self._titleInstList = {}
            self._selectedTitle = nil
            self._selectedItem = nil
            return
        end

        local lastTitleInst = self._titleInstList[ currNumTitles ]
        local index = self._listView:getIndex( lastTitleInst.ui ) + ( lastTitleInst.selected and #lastTitleInst.data.items or 0 )

        for i = numListItems - 1, index + 1, -1 do
            -- 析构被删除的title
            titleInst = self._listView:getItem( i )._inst
            titleInst:finalize()

            -- 选中title被删除
            if self._selectedTitle and self._selectedTitle == titleInst then
                self._selectedTitle = nil
            end

            -- 选中项被删除
            if self._selectedItem and self._selectedItem == titleInst then
                self._selectedItem = nil
            end

            self._listView:removeItem( i )
        end

        -- 从title列表中移除
        for i = prevNumTitles, currNumTitles + 1, -1 do
            table.remove( self._titleInstList, i )
        end
    end
end

-- 析构
function g:finalize()
    if self._listView then
        self._listView:removeFromParent()
        self._listView = nil
    end
    self._titleInstList = nil
    self._groupData = nil
    self._itemClickFunc = nil
end

 我们把折叠菜单抽象成标题项(title)和内容项(item)，title即指标题项，展开标题项显示出来的内容项叫item。title和item均从uimenuitem派生而来，这们做的好处是我们可以方便的更改折叠菜单标题项和内容项的样式。

下面来看看uimenuitem.lua:

--[[
    折叠菜单项

    @author cc
--]]

gm = gm or {}
rm = rm or {} 

local gm = gm
local rm = rm 

gm.Common                       = gm.Common or {}
gm.Common.UIMenuItem            = class( "Common.UIMenuItem" )
gm.Common.UIMenuItem._name      = "Common.UIMenuItem"

local g = gm.Common.UIMenuItem

---------------------------------------------------------------------------------
--                                                                             --
--                          以下定义私有部分                                   --
--                                                                             --
---------------------------------------------------------------------------------


---------------------------------------------------------------------------------
--                                                                               --
--                        以下定义set, get 部分函数                               --
--                                                                               --
---------------------------------------------------------------------------------

-- 获取显示对象
function g:_getUi( )
    return self._ui
end

function g:_getData( )
    return self._data
end

-- 设置数据
function g:_setData( value )
    self._data = value
end

function g:_getSelected( )
    return self._selected
end

-- 设置选中状态
function g:_setSelected( value )
    self._selected = value
end

---------------------------------------------------------------------------------
--                                                                             --
--                          以下定义公共部分                                   --
--                                                                             --
---------------------------------------------------------------------------------

-- 构造
function g:ctor( )
    self._selected = false
    self._data = nil

    self:initialize()
end

-- 初始化
function g:initialize( )
    self._ui = nil
end

-- 析构
function g:finalize( )
    if self._ui then
        self._ui:removeFromParent( )
        self._ui = nil
    end
end

下面举个简单的使用例子，

local groupData = {
        {
            title = { cate = 1, cate_desc = '技能书' },
            items = {
                {
                    sub_cate = 1, sub_cate_desc = '一级技能书',
                },
                {
                    sub_cate = 2, sub_cate_desc = '二级技能书',
                },
                {
                    sub_cate = 3, sub_cate_desc = '三级技能书',
                }
            }
        },
        {
            title = { cate = 2, cate_desc = '宝石' },
            items = {
                {
                    sub_cate = 1, sub_cate_desc = '攻击宝石',
                },
                {
                    sub_cate = 2, sub_cate_desc = '暴击宝石',
                }
            }
        },
        {
            title = { cate = 3, cate_desc = '月石' },
            items = {
                {
                    sub_cate = 1, sub_cate_desc = '很好的月石',
                }
            }
        },
    }

    self._goodsCateList = gm.Common.UIMenuList.new( cc.size( 204, 482 ), groupData )
    self._goodsCateList:setClass( gm.Market.MarketMenuTitle, gm.Market.MarketMenuItem )
    self._goodsCateList.showMulti = true
    self._goodsCateList.defaultGroup = 1
    self._goodsCateList.defaultItem = 1
    self._goodsCateList:addToParent( self._bg, cc.p( 15, 24 ) )

这里方便演示手写了分类数据，但一般情况下是用遍历生成的。通过上面这段代码，我们生成了一个折叠菜单，效果即本文首部的演示图片。

这里用到的两个类gm.Market.MarketMenuTitle和gm.Market.MarketMenuItem即是用来自定义折叠菜单样式的，代码也一块贴出：

--[[
    市场折叠菜单标题项

    @author cc
--]]

gm = gm or {}
rm = rm or {} 

local gm = gm
local rm = rm 

gm.Market                               = gm.Market or {}
gm.Market.MarketMenuTitle            = class( "Market.MarketMenuTitle", gm.Common.UIMenuItem )
gm.Market.MarketMenuTitle._name      = "Market.MarketMenuTitle"

local g = gm.Market.MarketMenuTitle

---------------------------------------------------------------------------------
--                                                                             --
--                          以下定义私有部分                                   --
--                                                                             --
---------------------------------------------------------------------------------


---------------------------------------------------------------------------------
--                                                                               --
--                        以下定义set, get 部分函数                               --
--                                                                               --
---------------------------------------------------------------------------------

-- 设置数据
function g:_setData( value )
    self._data = value

    self._labelName:setText( value.title.cate_desc )
end

-- 设置选中状态
function g:_setSelected( value )
    self._selected = value

    local texture = value and 'tab_btn_4.png' or 'tab_btn_3.png'
    self._imgBg:loadTexture( texture, ccui.TextureResType.plistType )
end

---------------------------------------------------------------------------------
--                                                                             --
--                          以下定义公共部分                                   --
--                                                                             --
---------------------------------------------------------------------------------

-- -- 构造
-- function g:ctor( )
--     g.super.ctor( self )
-- end

-- 初始化
function g:initialize( )
    g.super.initialize( self )
    self._ui = ccs.GUIReader:getInstance():widgetFromJsonFile('ui/new_market_menu_title.json')

    self._labelName = self._ui:getChildByName('LabName')
    self._imgBg = self._ui:getChildByName('ImgBg')
end

-- -- 析构
-- function g:finalize( )
--     g.super.finalize( self )
-- end

--[[
    市场折叠菜单内容项

    @author cc
--]]

gm = gm or {}
rm = rm or {} 

local gm = gm
local rm = rm 

gm.Market                               = gm.Market or {}
gm.Market.MarketMenuItem            = class( "Market.MarketMenuItem", gm.Common.UIMenuItem )
gm.Market.MarketMenuItem._name      = "Market.MarketMenuItem"

local g = gm.Market.MarketMenuItem

---------------------------------------------------------------------------------
--                                                                             --
--                          以下定义私有部分                                   --
--                                                                             --
---------------------------------------------------------------------------------


---------------------------------------------------------------------------------
--                                                                               --
--                        以下定义set, get 部分函数                               --
--                                                                               --
---------------------------------------------------------------------------------

-- 设置数据
function g:_setData( value )
    self._data = value

    self._labelName:setText( value.sub_cate_desc )
end

-- 设置选中状态
function g:_setSelected( value )
    self._selected = value

    self._imgSelected:setVisible( value )
end

---------------------------------------------------------------------------------
--                                                                             --
--                          以下定义公共部分                                   --
--                                                                             --
---------------------------------------------------------------------------------

-- 构造
function g:ctor( )
    g.super.ctor( self )
end

-- 初始化
function g:initialize( )
    g.super.initialize( self )
    self._ui = ccs.GUIReader:getInstance():widgetFromJsonFile('ui/new_market_menu_item.json')

    self._labelName = self._ui:getChildByName('LabName')
    self._imgSelected = self._ui:getChildByName('ImgSelected')
end

-- 析构
function g:finalize( )
    g.super.finalize( self )
end

折叠菜单，用过jquery accordion的同学都知道是啥玩艺儿~，图片效果就是介样：

cocos2dx不带有此控件，因此我们动手来实现一个。

原理很简单，展开的时候往listview里insertCustomItem，收起的时候从listview里removeItem。下面给出一个功能丰富的折叠菜单控件。
先看控件主类：

--[[
    二级折叠菜单组

    构造：
    local groupData = {
        {
            title = '分类1',
            items = {
                { id = 1, count = 20, lv = 19 },
                { id = 2, count = 21, lv = 21 },
                { id = 3, count = 22, lv = 23 },
            }
        },
        {
            title = '图腾',
            items = {
                { id = 500001, count = 32, lv = 19 },
                { id = 500002, count = 21, lv = 65 },
                { id = 500003, count = 22, lv = 27 },
            }
        },
        {
            title = '武器',
            items = {
                { id = 101002, count = 20, lv = 45 },
                { id = 101003, count = 21, lv = 34 },
            }
        },
    }
    self._goodsCateList = gm.Common.UIMenuList.new( cc.size( 310, 510 ), groupData )

    -- 必须设置标题类型和内容类型，重写可改变样式
    self._goodsCateList:setClass( gm.Market.MarketMenuTitle, gm.Market.MarketMenuItem )
    
    -- 可选参数，是否可同时展开多个分组，默认false
    self._goodsCateList.showMulti = true

    -- 可选参数，是否默认选中组中第一个item
    self._goodsCateList.autoSelectFirstItem = true

    -- 可选参数，选中的title索引，默认为1
    self._goodsCateList.defaultGroup = 1

    -- 可选参数，选中的item索引，默认为1
    self._goodsCateList.defaultItem = 1

    加入舞台：
    self._goodsCateList:addToParent( self._bg, { x = 0, y = 0 } )

    @author cc
--]]

gm = gm or {}
rm = rm or {} 

local gm = gm
local rm = rm 

gm.Common                       = gm.Common or {}
gm.Common.UIMenuList            = class( "Common.UIMenuList" )
gm.Common.UIMenuList._name      = "Common.UIMenuList"

local g = gm.Common.UIMenuList

---------------------------------------------------------------------------------
--                                                                             --
--                          以下定义私有部分                                   --
--                                                                             --
---------------------------------------------------------------------------------

local function log( ... )
    print( '>>>>gm.Common.UIMenuList<<<<:', ...)
end

-- 点击标题项
function g:_onTouchTitle( sender )
    local titleInst = sender._inst

    -- 收缩点击项
    if titleInst.selected then
        self:_unSelectTitleInst( titleInst )
        return
    end

    -- 如果同时只展开一个分组，则隐藏上次展开的
    if not self._showMulti and self._selectedTitle then
        self:_unSelectTitleInst( self._selectedTitle )
    end

    -- 展开点击项
    local index = self._listView:getIndex( sender )
    local group = titleInst.data
    local itemInst
    for itemIdx, itemData in ipairs( group.items ) do
        itemInst = self:_createItemInst( itemData )
        self._listView:insertCustomItem( itemInst.ui, index + itemIdx )

        -- 将第一项设置为当前选中的内容项
        if self._autoSelectFirstItem and itemIdx == 1 then
            self.selectedItem = itemInst
        end 
    end

    -- 设置当前选中的标题项
    self.selectedTitle = titleInst
end

-- 点击内容项
function g:_onTouchItem( sender, eventType )
    if eventType == ccui.TouchEventType.ended then
        self.selectedItem = sender._inst
    end
    if self._itemClickFunc then
        self._itemClickFunc( sender, eventType )
    end
end

-- 收起标题项对应的分组
function g:_unSelectTitleInst( titleInst )
    local index = self._listView:getIndex( titleInst.ui )
    local group = titleInst.data
    local itemInst

    for i = 1, #group.items do

        -- 析构删除项
        itemInst = self._listView:getItem( index + 1 )._inst
        itemInst:finalize()

        -- 选中项被删除
        if self._selectedItem and self._selectedItem == itemInst then
            self._selectedItem = nil
        end

        self._listView:removeItem( index + 1 )
    end
    titleInst.selected = false

    if titleInst == self._selectedTitle then
        self._selectedTitle = nil
    end
end

-- 创建标题项
function g:_createTitleInst( data )
    if not self._titleCls then
        log( '没有设置标题类型!' )
        return
    end

    local titleInst = self._titleCls.new( )
    titleInst.data = data
    titleInst.ui._inst = titleInst
    makeTouchHandle( self, titleInst.ui, self._onTouchTitle )
    return titleInst
end

-- 创建内容项
function g:_createItemInst( data )
    if not self._itemCls then
        log( '没有设置内容类型!' )
        return
    end

    local itemInst = self._itemCls.new( )
    itemInst.data = data
    itemInst.ui._inst = itemInst
    makeTouchHandle2( self, itemInst.ui, self._onTouchItem )
    return itemInst
end

-- 初始化
function g:_initialize( )
    self._listView = ccui.ListView:create()
    self._listView:setBounceEnabled( true )
    self._listView:setDirection( ccui.ScrollViewDir.vertical )
    self._listView:setSize( self._size )

    if not self._groupData then
        log( '分组数据为空!' )
        return
    end
    
    local titleInst, itemInst
    self._titleInstList = {}

    for groupIdx, group in ipairs( self._groupData ) do

        titleInst = self:_createTitleInst( group )
        self._listView:pushBackCustomItem( titleInst.ui )
        table.insert( self._titleInstList, titleInst )

        -- 展开默认分组
        if self._defaultGroupIdx and groupIdx == self._defaultGroupIdx then
            self.selectedTitle = titleInst
            
            for itemIdx, itemData in ipairs( group.items ) do

                itemInst = self:_createItemInst( itemData )
                self._listView:pushBackCustomItem( itemInst.ui )

                -- 选中默认项
                if self._defaultItemIdx and itemIdx == self._defaultItemIdx then
                    self.selectedItem = itemInst
                end
            end
        end
    end
end

---------------------------------------------------------------------------------
--                                                                               --
--                        以下定义set, get 部分函数                               --
--                                                                               --
---------------------------------------------------------------------------------

function g:_getUi( )
    return self._listView
end

-- 是否同时展开多个组
function g:_setShowMulti( value )
    self._showMulti = value
end

-- 获取数据
function g:_getGroupData( )
    return self._groupData
end

function g:_setGroupData( value )
    self._groupData = value
end

-- 设置默认展开的分组索引
-- @i value
function g:_setDefaultGroup( value )
    self._defaultGroupIdx = value
end

-- 设置默认选中的item索引
--@i value 
function g:_setDefaultItem( value )
    self._defaultItemIdx = value
end

-- 获取选中的标题项
function g:_getSelectedTitle( )
    return self._selectedTitle
end

function g:_setSelectedTitle( value )
    value.selected = true
    self._selectedTitle = value
    rm.BindManager.propertyChanged( self, "selectedTitle" )
end

-- 获取选中的内容项
function g:_getSelectedItem( )
    return self._selectedItem
end

function g:_setSelectedItem( value )
    if self._selectedItem then
        self._selectedItem.selected = false 
    end
    value.selected = true
    self._selectedItem = value
    rm.BindManager.propertyChanged( self, "selectedItem" )
end

-- 设置点击item项的回调函数
function g:_setItemClickFunc( value )
    self._itemClickFunc = value
end

-- 设置是否自动选中组中第一个item
function g:_setAutoSelectFirstItem( value )
    self._autoSelectFirstItem = value
end

---------------------------------------------------------------------------------
--                                                                             --
--                          以下定义公共部分                                   --
--                                                                             --
---------------------------------------------------------------------------------

-- 构造
-- @t size cc.size类型
-- @t groupData 分组数据，结构如{ { title = tData, items = { iData1, iData2 } }, ... }
function g:ctor( size, groupData )
    self._size = size or cc.size( 200, 200 )
    self._groupData = groupData
    self._titleInstList = nil
    self._defaultGroupIdx = nil
    self._defaultItemIdx = nil
    self._selectedTitle = nil
    self._selectedItem = nil
    self._titleCls = nil
    self._itemCls = nil
    self._showMulti = false
    self._autoSelectFirstItem = false
    self._itemClickFunc = nil
end

-- 设置标题项和内容项类型
-- @t titleClass 继承自gm.Common.UIMenuItem，重写可改变样式
-- @t itemClass  继承自gm.Common.UIMenuItem，重写可改变样式
function g:setClass( titleClass, itemClass )
    self._titleCls = titleClass
    self._itemCls = itemClass
end

-- 添加到舞台
-- @widget parent 父显示对象
-- @t        pos    位置，{ x = , y = }
-- @i        zOrder 层级
function g:addToParent( parent, pos, zOrder )
    if not parent then
        log( '父显示对象不可为空!' )
        return
    end
    self:_initialize()
    zOrder = zOrder or 1
    pos = pos or cc.p( 0, 0 )
    self._listView:setPosition( pos )
    parent:addChild( self._listView, zOrder )
end

-- 刷新当前展开的分组，只可在互斥（showMulti = false）模式下使用
-- @t group 数据，结构如{ title = tData, items = { iData1, iData2 } }
function g:refreshSelectedTitle( group )
    if not self._selectedTitle then return end
    self:refreshTitle( self._selectedTitle, group )
end

-- 刷新指定位置的分组
-- @i titleIndex     分组索引
-- @t group         组数据
function g:refreshTitleAtIndex( titleIndex, group )
    local title = self._titleInstList( titleIndex )
    self:refreshTitle( title, group )
end

-- 刷新指定分组
-- @t             某个分组
-- @t group     组数据
function g:refreshTitle( title, group )
    local index = self._listView:getIndex( title.ui )
    local prevNumItems = title.selected and #title.data.items or 0
    local currNumItems = #group.items
    local deltaNum = prevNumItems - currNumItems
    local itemInst

    -- 设置title数据
    title:_setData( group )
    self._groupData[ table.indexOf( self._titleInstList, title ) ] = group

    -- title没展开，以下无需执行
    if not title.selected then return end

    -- 设置item数据
    for itemIdx, itemData in ipairs( group.items ) do
        if itemIdx <= prevNumItems then
            itemInst = self._listView:getItem( index + itemIdx )._inst    
            itemInst:_setData( itemData )
        else
            itemInst = self:_createItemInst( itemData )
            self._listView:insertCustomItem( itemInst.ui, index + itemIdx )
        end
    end

    -- 旧数量比当前数量多，需要删除多余的item
    if deltaNum > 0 then
        for i = 1, deltaNum do
            itemInst = self._listView:getItem( index + currNumItems + 1 )._inst
            itemInst:finalize()

            -- 选中项被删除
            if self._selectedItem and self._selectedItem == itemInst then
                self._selectedItem = nil
            end

            self._listView:removeItem( index + currNumItems + 1 )
        end
    end
end

-- 刷新整个控件
-- @t 控件数据，结构如构造函数同名参数所示
function g:refresh( groupData )
    self._groupData = groupData
    if not self._groupData then
        log( '分组数据为空!' )
        return
    end

    local prevNumTitles = #self._titleInstList
    local currNumTitles = #groupData
    local deltaNum = prevNumTitles - currNumTitles
    local titleInst
    
    -- 刷新所有分组
    for groupIdx, group in ipairs( groupData ) do
        if groupIdx <= prevNumTitles then 
            titleInst = self._titleInstList[ groupIdx ]
            self:refreshTitle( titleInst, group )
        else
            titleInst = self:_createTitleInst( group )
            self._listView:pushBackCustomItem( titleInst.ui )
            table.insert( self._titleInstList, titleInst )
        end
    end
    
    -- 新分组比旧分组少，需要删除多余的title
    if deltaNum > 0 then
        local numListItems = #self._listView:getItems()

        -- 清空全部
        if currNumTitles == 0 then
            for i = numListItems - 1, 0, -1 do
                titleInst = self._listView:getItem( i )._inst
                titleInst:finalize()
            end
            self._listView:removeAllItems()
            self._titleInstList = {}
            self._selectedTitle = nil
            self._selectedItem = nil
            return
        end

        local lastTitleInst = self._titleInstList[ currNumTitles ]
        local index = self._listView:getIndex( lastTitleInst.ui ) + ( lastTitleInst.selected and #lastTitleInst.data.items or 0 )

        for i = numListItems - 1, index + 1, -1 do
            -- 析构被删除的title
            titleInst = self._listView:getItem( i )._inst
            titleInst:finalize()

            -- 选中title被删除
            if self._selectedTitle and self._selectedTitle == titleInst then
                self._selectedTitle = nil
            end

            -- 选中项被删除
            if self._selectedItem and self._selectedItem == titleInst then
                self._selectedItem = nil
            end

            self._listView:removeItem( i )
        end

        -- 从title列表中移除
        for i = prevNumTitles, currNumTitles + 1, -1 do
            table.remove( self._titleInstList, i )
        end
    end
end

-- 析构
function g:finalize()
    if self._listView then
        self._listView:removeFromParent()
        self._listView = nil
    end
    self._titleInstList = nil
    self._groupData = nil
    self._itemClickFunc = nil
end

 我们把折叠菜单抽象成标题项(title)和内容项(item)，title即指标题项，展开标题项显示出来的内容项叫item。title和item均从uimenuitem派生而来，这们做的好处是我们可以方便的更改折叠菜单标题项和内容项的样式。

下面来看看uimenuitem.lua:

--[[
    折叠菜单项

    @author cc
--]]

gm = gm or {}
rm = rm or {} 

local gm = gm
local rm = rm 

gm.Common                       = gm.Common or {}
gm.Common.UIMenuItem            = class( "Common.UIMenuItem" )
gm.Common.UIMenuItem._name      = "Common.UIMenuItem"

local g = gm.Common.UIMenuItem

---------------------------------------------------------------------------------
--                                                                             --
--                          以下定义私有部分                                   --
--                                                                             --
---------------------------------------------------------------------------------


---------------------------------------------------------------------------------
--                                                                               --
--                        以下定义set, get 部分函数                               --
--                                                                               --
---------------------------------------------------------------------------------

-- 获取显示对象
function g:_getUi( )
    return self._ui
end

function g:_getData( )
    return self._data
end

-- 设置数据
function g:_setData( value )
    self._data = value
end

function g:_getSelected( )
    return self._selected
end

-- 设置选中状态
function g:_setSelected( value )
    self._selected = value
end

---------------------------------------------------------------------------------
--                                                                             --
--                          以下定义公共部分                                   --
--                                                                             --
---------------------------------------------------------------------------------

-- 构造
function g:ctor( )
    self._selected = false
    self._data = nil

    self:initialize()
end

-- 初始化
function g:initialize( )
    self._ui = nil
end

-- 析构
function g:finalize( )
    if self._ui then
        self._ui:removeFromParent( )
        self._ui = nil
    end
end

下面举个简单的使用例子，

local groupData = {
        {
            title = { cate = 1, cate_desc = '技能书' },
            items = {
                {
                    sub_cate = 1, sub_cate_desc = '一级技能书',
                },
                {
                    sub_cate = 2, sub_cate_desc = '二级技能书',
                },
                {
                    sub_cate = 3, sub_cate_desc = '三级技能书',
                }
            }
        },
        {
            title = { cate = 2, cate_desc = '宝石' },
            items = {
                {
                    sub_cate = 1, sub_cate_desc = '攻击宝石',
                },
                {
                    sub_cate = 2, sub_cate_desc = '暴击宝石',
                }
            }
        },
        {
            title = { cate = 3, cate_desc = '月石' },
            items = {
                {
                    sub_cate = 1, sub_cate_desc = '很好的月石',
                }
            }
        },
    }

    self._goodsCateList = gm.Common.UIMenuList.new( cc.size( 204, 482 ), groupData )
    self._goodsCateList:setClass( gm.Market.MarketMenuTitle, gm.Market.MarketMenuItem )
    self._goodsCateList.showMulti = true
    self._goodsCateList.defaultGroup = 1
    self._goodsCateList.defaultItem = 1
    self._goodsCateList:addToParent( self._bg, cc.p( 15, 24 ) )

这里方便演示手写了分类数据，但一般情况下是用遍历生成的。通过上面这段代码，我们生成了一个折叠菜单，效果即本文首部的演示图片。

这里用到的两个类gm.Market.MarketMenuTitle和gm.Market.MarketMenuItem即是用来自定义折叠菜单样式的，代码也一块贴出：

--[[
    市场折叠菜单标题项

    @author cc
--]]

gm = gm or {}
rm = rm or {} 

local gm = gm
local rm = rm 

gm.Market                               = gm.Market or {}
gm.Market.MarketMenuTitle            = class( "Market.MarketMenuTitle", gm.Common.UIMenuItem )
gm.Market.MarketMenuTitle._name      = "Market.MarketMenuTitle"

local g = gm.Market.MarketMenuTitle

---------------------------------------------------------------------------------
--                                                                             --
--                          以下定义私有部分                                   --
--                                                                             --
---------------------------------------------------------------------------------


---------------------------------------------------------------------------------
--                                                                               --
--                        以下定义set, get 部分函数                               --
--                                                                               --
---------------------------------------------------------------------------------

-- 设置数据
function g:_setData( value )
    self._data = value

    self._labelName:setText( value.title.cate_desc )
end

-- 设置选中状态
function g:_setSelected( value )
    self._selected = value

    local texture = value and 'tab_btn_4.png' or 'tab_btn_3.png'
    self._imgBg:loadTexture( texture, ccui.TextureResType.plistType )
end

---------------------------------------------------------------------------------
--                                                                             --
--                          以下定义公共部分                                   --
--                                                                             --
---------------------------------------------------------------------------------

-- -- 构造
-- function g:ctor( )
--     g.super.ctor( self )
-- end

-- 初始化
function g:initialize( )
    g.super.initialize( self )
    self._ui = ccs.GUIReader:getInstance():widgetFromJsonFile('ui/new_market_menu_title.json')

    self._labelName = self._ui:getChildByName('LabName')
    self._imgBg = self._ui:getChildByName('ImgBg')
end

-- -- 析构
-- function g:finalize( )
--     g.super.finalize( self )
-- end

--[[
    市场折叠菜单内容项

    @author cc
--]]

gm = gm or {}
rm = rm or {} 

local gm = gm
local rm = rm 

gm.Market                               = gm.Market or {}
gm.Market.MarketMenuItem            = class( "Market.MarketMenuItem", gm.Common.UIMenuItem )
gm.Market.MarketMenuItem._name      = "Market.MarketMenuItem"

local g = gm.Market.MarketMenuItem

---------------------------------------------------------------------------------
--                                                                             --
--                          以下定义私有部分                                   --
--                                                                             --
---------------------------------------------------------------------------------


---------------------------------------------------------------------------------
--                                                                               --
--                        以下定义set, get 部分函数                               --
--                                                                               --
---------------------------------------------------------------------------------

-- 设置数据
function g:_setData( value )
    self._data = value

    self._labelName:setText( value.sub_cate_desc )
end

-- 设置选中状态
function g:_setSelected( value )
    self._selected = value

    self._imgSelected:setVisible( value )
end

---------------------------------------------------------------------------------
--                                                                             --
--                          以下定义公共部分                                   --
--                                                                             --
---------------------------------------------------------------------------------

-- 构造
function g:ctor( )
    g.super.ctor( self )
end

-- 初始化
function g:initialize( )
    g.super.initialize( self )
    self._ui = ccs.GUIReader:getInstance():widgetFromJsonFile('ui/new_market_menu_item.json')

    self._labelName = self._ui:getChildByName('LabName')
    self._imgSelected = self._ui:getChildByName('ImgSelected')
end

-- 析构
function g:finalize( )
    g.super.finalize( self )
end