ScrollView模拟上拉刷新

本篇介绍ScrollView实现上拉刷新的功能，也可以实现下拉刷新。

数据来自Data.json文件

首先显示3条数据，在ScrollView滚动到底部回弹时再显示新数据。

local MainScene = class("MainScene",cc.load("mvc").ViewBase)

function MainScene:ctor()
    self:enableNodeEvents()
    self.localData = {}
    self.index = 0
end

function MainScene:onEnter()
    self:createUI()
end

function MainScene:createUI()
    local path = "res/Data.json"
    if cc.FileUtils:getInstance():isFileExist(path) then
        local fs = cc.FileUtils:getInstance():getStringFromFile(path)
        local t = json.decode(fs)
        for i = 1,#t.data do
            table.insert(self.localData,t.data[i])
        end
        self.index = self.index + #self.localData
    end

    self:setScroll()
end

function MainScene:setScroll()
    self.hT = {}
    local h = 40 + (#self.localData-1) * 20

    self.sv = ccui.ScrollView:create()
    self.sv:setContentSize(600,560)
    self.sv:setBounceEnabled(true)
    self.sv:setDirection(ccui.ScrollViewDir.vertical)
    self.sv:setClippingEnabled(true)
    self.sv:setAnchorPoint(0,0)
    self.sv:setPosition(180,50)
    self:addChild(self.sv)

    local total = 0
    if self.index > 3 then
        total = 3
    else
        total = self.index
    end
    self.index = self.index - total
    for i=1,total do
        local label = self.getWhiteLabel(self.localData[i],20,{width = 600,height = 0},cc.TEXT_ALIGNMENT_LEFT,cc.VERTICAL_TEXT_ALIGNMENT_CENTER)
        if i%2 == 0 then
            label:setTextColor(cc.c4f(0,186,255,255))
        end
        h = h + label:getContentSize().height
        table.insert(self.hT,h-40-(#self.localData-1) * 20)
        self.sv:addChild(label)
    end 
    self.sv:setInnerContainerSize(cc.size(self.sv:getContentSize().width,h))
    local chs = self.sv:getChildren()
    for i=1,#chs do
        local label = chs[i]
        label:setAnchorPoint(0,0)
        local y = h - 20 - self.hT[i] - (i-1) * 20
        label:setPosition(0,y)
    end

    self.sv:addEventListener(function(sender,event)
        if event == ccui.ScrollviewEventType.bounceBottom then
            if self.index > 0 then
                self:showMessage("Loading........")
                self:beginLoad(total)
            else
                self:showMessage("no more message")
            end 
        end
    end)
end

function MainScene:showMessage(str)
    local label = self.getRedLabel(str,28)
    local size = cc.Director:getInstance():getWinSize()
    self:addChild(label)
    label:setPosition(size.width/2,size.height/2)

    local moveTo = cc.MoveTo:create(3,cc.p(size.width/2,size.height*1.2))
    label:runAction(cc.Sequence:create(moveTo,cc.RemoveSelf:create()))
end

function MainScene:beginLoad(total)
    local h = self.sv:getInnerContainerSize().height
    for i = 1,self.index do
        local label = self.getWhiteLabel(self.localData[total+i],cc.VERTICAL_TEXT_ALIGNMENT_CENTER)
        if (total+i)%2 == 0 then
            label:setTextColor(cc.c4f(0,h-40-(#self.localData-1) * 20)
        self.sv:addChild(label)
    end
    self.sv:setInnerContainerSize(cc.size(self.sv:getContentSize().width,h))
    self:reloadData()
end

function MainScene:reloadData()
    local chs = self.sv:getChildren()
    local h = self.sv:getInnerContainerSize().height
    for i=1,y)
    end
    self:finishLoad()
end

function MainScene:finishLoad()
    self.sv:scrollToPercentVertical(80,0.5,true)
    self.index = 0
end

function MainScene.getWhiteLabel(text,fontSize,dimensions,hAlignment,vAlignment,mb)
    return MainScene.getTextLabel(text,fontSize,cc.c4f(255,255),dimensions,hAlignment,vAlignment,mb)
end

function MainScene.getBlueLabel(text,fontsize,fontsize,cc.c4f(0,mb)
end

function MainScene.getRedLabel(text,0,84,mb)
end

function MainScene.getTextLabel(text,color,mb)
    local ttfConfig = {}
    ttfConfig.fontFilePath = "res/fonts/DFYUANW7-GB2312.ttf"
    ttfConfig.fontSize     = fontsize
    ttfConfig.glyphs       = cc.GLYPHCOLLECTION_DYNAMIC
    ttfConfig.customGlyphs = true
    ttfConfig.distanceFieldEnabled = false 

    local textLabel = cc.Label:createWithTTF(ttfConfig,text)
    textLabel:setLineBreakWithoutSpace(true) 
    if color then textLabel:setTextColor(color) end 
    if dimensions then textLabel:setDimensions(dimensions.width,dimensions.height) end
    if hAlignment then textLabel:setAlignment(hAlignment) end
    if vAlignment then textLabel:setVerticalAlignment(vAlignment) end
    -- 描边
    if not mb then textLabel:enableOutline(cc.c4b(0,2) end
    return textLabel 
end

return MainScene

运行效果：