一.概述

本文缩写说明：sv = ScrollView, item代表ScrollView的一个子节点

如果对sv熟系程度还不够，请阅读基础篇：

Cocos2dx-lua ScrollView[一]基础篇-CSDN博客

本文介绍sv的一种封装类库，来实现快速创建sv，有如下几个优点：

1.item的位置通过参数控制，提高开发效率

2.免去了调用sv的API，提高开发效率

3.分帧创建，提高性能

4.可通过参数控制，复用item类似tableview，提高性能

二.效果演示

2.1 item不复用

2.2 item复用

三.代码实现

3.1 说明

a.下面2个模块需要require

b.svUtil是比较复杂的，有必要阅读代码掌握运行原理

c.item数量较多时才有必要用need_dynamic参数

d.代码原封不动搬到工程里基本可以正常运行(当然哪里出了问题读者得会排查，本文基本喂饭喂到嘴里了)

3.2 辅助定时器模块：GlobalTimeTicket

GlobalTimeTicket = GlobalTimeTicket or {}

auto_id = auto_id or 0
function autoId()
    auto_id = auto_id + 1
    return auto_id
end
-- 获取单例
-- New和不New只是一层一层调用__init和__delete，对于单例没有影响
function GlobalTimeTicket:getInstance()
    if not self.is_init then 
        self.scheduler = cc.Director:getInstance():getScheduler()
        self.schedulers = {}
        self.is_init = true
        self.is_stop = nil
    end
    return self
end

-- 定时回调 通用版
-- call_back : function     回调函数    必填
-- interval  : int          时间间隔    默认1 秒
-- limit_time: int          限制次数    默认0 无限
-- with_name : any          定时器标识  默认自增id
-- 返回用于删除的标识
-- simple    : local id = GlobalTimeTicket:getInstance():add(fun) ; GlobalTimeTicket:getInstance():remove(id)
--           : GlobalTimeTicket:getInstance():add(fun, 0.1, 1)              -- 次数达到自动删除
--           : GlobalTimeTicket:getInstance():add(fun, 0.1, 3, "name")      
function GlobalTimeTicket:add(call_back, interval, limit_time, with_name)
    if self.is_stop then return end
    with_name = with_name or autoId()
    if nil == call_back or self.schedulers == nil or nil ~= self.schedulers[with_name] then return end    -- 已经有定义了，不能重复

    limit_time = limit_time or 0
    interval = interval or 1
    local schedul_hander = self.scheduler:scheduleScriptFunc(function(dt)
        if self.is_stop then return end
        if call_back ~= nil then
            if limit_time == 1 then 
                self:remove(with_name)
            elseif limit_time > 1 then 
                limit_time = limit_time - 1
            end
            call_back(dt)
        end
    end, interval, false)
    self.schedulers[with_name] = schedul_hander
    return with_name
end

-- 删除一个定时器
function GlobalTimeTicket:remove(with_name)
    if with_name == nil then return end
    local schedul_hander = self.schedulers[with_name] 
    if schedul_hander ~= nil then
        self.scheduler:unscheduleScriptEntry(schedul_hander)
        self.schedulers[with_name] = nil 
    end
end

-- 清除所有定时器
function GlobalTimeTicket:removeAll()
    for _, v in pairs(self.schedulers) do 
        self.scheduler:unscheduleScriptEntry(v)
    end
    self.schedulers = {}
end

function GlobalTimeTicket:hasTicket(with_name)
    local schedul_hander = self.schedulers[with_name] 
    if schedul_hander ~= nil then
        return true
    end
    return false
end

function GlobalTimeTicket:getSchedulers()
    return self.schedulers
end

-- 停止定时器
function GlobalTimeTicket:stop()
    self.is_stop = true
    self:removeAll()
end

3.3 sv封装模块:svUtil

----------------------------------------------------------------------------------- example -----------------------------------------------------------------------------------
--[[
    self.scr_lyt = AM.getNode(self.midPanel, "scr_lyt")
	local setting = {
		item_class = moonActivityPanelItem,
		start_x = 24.5, space_x = 0,
		start_y = 5, space_y = 10,
		item_width = 621, item_height = 126,
		row = 0, col = 1,
		--need_dynamic = true
	}
	self.item_scrollview = svUtil.new(self.scr_lyt, cc.p(0,0) , ScrollViewDir.vertical, ScrollViewStartPos.top, self.scr_lyt:getContentSize(), setting)
	local svData = {}
	self.item_scrollview:setData(svData)
]]
----------------------------------------------------------------------------------- example -----------------------------------------------------------------------------------
display.DEFAULT_FPS = 60
ScrollViewDir = ScrollViewDir or {
    vertical = 1,
    horizontal = 2,
}

ScrollViewStartPos = ScrollViewStartPos or {
    top = 1,
    bottom = 2
}

function tableLen(table)
    local len = 0
    if table then
        for _ in pairs(table) do
            len = len + 1
        end
    end
    return len
end

function createScrollView(width,height,x,y,parent_wnd,type)
    local scroll_view = ccui.ScrollView:create()
    scroll_view:setBounceEnabled(true)
    scroll_view:setScrollBarEnabled(false)
    if type == ccui.ScrollViewDir.horizontal then
        scroll_view:setDirection(ccui.ScrollViewDir.horizontal)
    else
        scroll_view:setDirection(ccui.ScrollViewDir.vertical)
    end
    
    scroll_view:setTouchEnabled(true)
    scroll_view:setContentSize(cc.size(width, height))
    scroll_view:setInnerContainerSize(scroll_view:getContentSize())
    scroll_view:setPosition(cc.p(x, y))
    if not tolua.isnull(parent_wnd) then
        parent_wnd:addChild(scroll_view)
    end
    return scroll_view
end

svUtil = class("svUtil", function()
    return ccui.Layout:create()
end)

function svUtil:ctor(parent, pos, dir, start_pos, size, setting, ap