使用 xlue 实现简单 listbox 控件

基于 XLUE 实现的 listbox 控件
1. 提供增删查接口，将 obj 作为子控件添加到列表；
2. 提供 Attach/Detach 方法，可以将子控件的事件转发出来；
3. 支持滚动条；
4. 支持鼠标滚轮；

实现过程中的注意点：
1. 使用 ItemObjList 表存储 itemObj , ItemObjList 是一个数组，是 listbox 控件的数据模型；
2. 使用 EventCookieMap 表存储事件回调， Attach 时监听所有 itemObj 的事件，通过 Insert 添加的 itemObj，也要通过 EventCookieMap 表来确定需要监听哪些事件；
3. 鼠标滚轮的实现，子控件鼠标滚轮事件 RouteToFather ，滚动条鼠标滚轮事件重定向到 listbox 控件上；
4. 滚动条的实现，调整位置即可

代码：

simplelistbox.xml

<xlue>
<control class="SimpleListBox">
<attr_def>
<attr name="VScrollBarNormalBkgID" type="string" />
<attr name="VScrollBarHoverBkgID" type="string" />
<attr name="VScrollBarDownBkgID" type="string" />
</attr_def>
<method_def>
<AttachEvent file="simplelistbox.xml.lua" func="AttachEvent" />
<DetachEvent file="simplelistbox.xml.lua" func="DetachEvent" />
<InsertItem file="simplelistbox.xml.lua" func="InsertItem" />
<RemoveItem file="simplelistbox.xml.lua" func="RemoveItem" />
<ClearItem file="simplelistbox.xml.lua" func="ClearItem" />
<GetItem file="simplelistbox.xml.lua" func="GetItem" />
<GetItemNum file="simplelistbox.xml.lua" func="GetItemNum" />
</method_def>
<event_def>
</event_def>
<objtemplate>
<children>
<obj id="list.layout" class="LayoutObject">
<attr>
<left>0</left>
<top>0</top>
<width>father.width</width>
<height>father.height</height>
<limitchild>1</limitchild>
</attr>
<children>
<obj id="listbox.layout" class="LayoutObject">
<attr>
<left>0</left>
<top>0</top>
<width>father.width-4</width>
<height>0</height>
</attr>
<eventlist>
<event name="OnMouseWheel" file="simplelistbox.xml.lua" func="ListLayout_OnMouseWheel" />
</eventlist>
</obj>
<obj id="vscrollbar" class="TextureObject">
<attr>
<left>father.width-4</left>
<top>0</top>
<width>4</width>
<height>0</height>
</attr>
<eventlist>
<event name="OnLButtonDown" file="simplelistbox.xml.lua" func="VScrollBar_OnLButtonDown" />
<event name="OnLButtonUp" file="simplelistbox.xml.lua" func="VScrollBar_OnLButtonUp" />
<event name="OnMouseMove" file="simplelistbox.xml.lua" func="VScrollBar_OnMouseMove" />
<event name="OnMouseLeave" file="simplelistbox.xml.lua" func="VScrollBar_OnMouseLeave" />
<event name="OnMouseWheel" file="simplelistbox.xml.lua" func="ListLayout_OnMouseWheel" redirect="father:listbox.layout"/>
</eventlist>
</obj>
</children>
</obj>
</children>
<eventlist>
<event name="OnInitControl" file="simplelistbox.xml.lua" func="OnInitControl" />
<event name="OnDestroy" file="simplelistbox.xml.lua" func="OnDestroy" />
</eventlist>
</objtemplate>
</control>
</xlue>

simplelistbox.xml.lua

------------------ 以下为外部函数 -------------------

function AttachEvent(ctrlObj, eventName, callback)
if type(eventName) ~= "string" or type(callback) ~= "function" then
return
end
local attr = ctrlObj:GetAttribute()
if attr.EventCookieMap[eventName] == nil then
attr.EventCookieMap[eventName] = {}
end
local cookie = table.maxn(attr.EventCookieMap[eventName]) + 1
attr.EventCookieMap[eventName][cookie] = callback

for index,itemObj in ipairs(attr.ItemObjList) do
local itemcookie,bRet = itemObj:AttachListener(eventName, true, function(...)
for cookie,callback in pairs(attr.EventCookieMap[eventName]) do
callback(index, ...)
end
end)
end
return cookie
end

function DetachEvent(ctrlObj, eventName, cookie)
if type(eventName) ~= "string" or type(cookie) ~= "number" then
return
end
local attr = ctrlObj:GetAttribute()
if attr.EventCookieMap[eventName] == nil then
return
end
attr.EventCookieMap[eventName][cookie] = nil
end

function InsertItem(ctrlObj, index, obj)
if type(index) ~= "number" or obj == nil then
return
end
local attr = ctrlObj:GetAttribute()
local listLayout = ctrlObj:GetControlObject("listbox.layout")

-- 插入item，调整位置
listLayout:AddChild(obj)
local l,t,r,b = obj:GetObjPos()
local width,height = r-l,b-t
if index <= 1 or #attr.ItemObjList == 0 then    -- 插入到最前
for i,itemObj in ipairs(attr.ItemObjList) do
local l,t,r,b = itemObj:GetObjPos()
itemObj:SetObjPos(l,t+height,r,b+height)
end
obj:SetObjPos(0,0,width,height)
index = 1
elseif index > #attr.ItemObjList then    -- 插入到最后
local lastObj = attr.ItemObjList[#attr.ItemObjList]
local _,_,_,bottom = lastObj:GetObjPos()
obj:SetObjPos(0,bottom,width,bottom+height)
index = #attr.ItemObjList + 1
else    -- 插入到中间
local preObj = attr.ItemObjList[index-1]
local _,_,_,bottom = preObj:GetObjPos()
for i=index, #attr.ItemObjList do
local itemObj = attr.ItemObjList[i]
local l,t,r,b = itemObj:GetObjPos()
itemObj:SetObjPos(l,t+height,r,b+height)
end
obj:SetObjPos(0,bottom,width,bottom+height)
end
table.insert(attr.ItemObjList, index, obj)

-- 调整 listLayout 大小
local lastObj = attr.ItemObjList[#attr.ItemObjList]
local _,_,_,bottom = lastObj:GetObjPos()
local l,t,r,b = listLayout:GetObjPos()
listLayout:SetObjPos(l,t,r,t+bottom)

-- 调整 VScrollBar 位置
__AdjustVScrollBarPos(ctrlObj)

-- 监听新添加item的事件
for eventName,cookieTable in pairs(attr.EventCookieMap) do
if table.maxn(cookieTable) > 0 then
obj:AttachListener(eventName, true, function(...)
for cookie, callback in pairs(cookieTable) do
callback(index, ...)
end
end)
end
end
-- 监听OnPosChange，当 obj height 改变时要调整其它 itemObj 的位置
obj:AttachListener("OnPosChange", true, function(obj,oldLeft,oldTop,oldRight,oldBottom,newLeft,newTop,newRight,newBottom)
local oldHeight,newHeight = oldBottom-oldTop,newBottom-newTop
if oldHeight == newHeight then
return
end

local index = nil
for i,itemObj in ipairs(attr.ItemObjList) do
if itemObj:GetID() == obj:GetID() and obj:GetID() ~= nil then
index = i
break
end
end
if not index then
return
end
for i=index+1,#attr.ItemObjList do
local itemObj = attr.ItemObjList[i]
local l,t,r,b = itemObj:GetObjPos()
itemObj:SetObjPos(l,t+newHeight-oldHeight,r,b+newHeight-oldHeight)
end
-- 调整 VScrollBar 位置
__AdjustVScrollBarPos(ctrlObj)
end)
-- 监听 OnMouseWheel ，在 itemObj 上的鼠标滚轮事件也要被响应
obj:AttachListener("OnMouseWheel", true, function(obj, x, y, distance, flags)
obj:RouteToFather()
end)
end

function RemoveItem(ctrlObj, index)
if type(index) ~= "number" then
return
end
local attr = ctrlObj:GetAttribute()
local listLayout = ctrlObj:GetControlObject("listbox.layout")
if #attr.ItemObjList == 0 then
return
end

if index <= 1 then
index = 1
elseif index > #attr.ItemObjList then
index = #attr.ItemObjList
end

-- 删除 obj 调整其它 itemObj 位置
local obj = attr.ItemObjList[index]
local l,t,r,b = obj:GetObjPos()
local width,height = r-l,b-t
for i=index+1, #attr.ItemObjList do
local itemObj = attr.ItemObjList[i]
local l,t,r,b = itemObj:GetObjPos()
itemObj:SetObjPos(l,t-height,r,b-height)
end
listLayout:RemoveChild(obj)
table.remove(attr.ItemObjList, index)

-- 调整 listLayout 高度
local bottom = 0
local lastObj = attr.ItemObjList[#attr.ItemObjList]
if lastObj then
_,_,_,bottom = lastObj:GetObjPos()
end
local l,t,r,b = listLayout:GetObjPos()
listLayout:SetObjPos(l,t,r,t+bottom)

-- 调整 VScrollBar 位置
__AdjustVScrollBarPos(ctrlObj)
end

function ClearItem(ctrlObj)
local attr = ctrlObj:GetAttribute()
local listLayout = ctrlObj:GetControlObject("listbox.layout")
listLayout:RemoveAllChild()
attr.ItemObjList = {}
end

function GetItem(ctrlObj, index)
if type(index) ~= "number" then
return
end
local attr = ctrlObj:GetAttribute()
return attr.ItemObjList[index]
end

function GetItemNum(ctrlObj)
local attr = ctrlObj:GetAttribute()
return #attr.ItemObjList
end

----------------- 以下为事件处理函数 ------------------

function OnInitControl(ctrlObj)
local attr = ctrlObj:GetAttribute()
attr.ItemObjList = {}
attr.EventCookieMap = {}

local vsbarObj = ctrlObj:GetControlObject("vscrollbar")
if attr.VScrollBarNormalBkgID then
vsbarObj:SetTextureID(attr.VScrollBarNormalBkgID)
end
end

function OnDestroy(ctrlObj)

end

function ListLayout_OnMouseWheel(obj, x, y, distance, flags)
local ctrlObj = obj:GetOwnerControl()
local listLayout = ctrlObj:GetControlObject("listbox.layout")
local fatherLayout = listLayout:GetParent()
local left,top,right,bottom = listLayout:GetObjPos()
local _,fatherTop,_,fatherBottom = fatherLayout:GetObjPos()
local fatherHeight = fatherBottom-fatherTop

-- distance 为正数时， listLayout 向下移动，反之向上移动
local moveDistance = distance/10
if moveDistance > 0 and top + moveDistance > 0 then    -- 向下移动到顶了
if top < 0 then
listLayout:SetObjPos(left,0,right,bottom-top)
end
elseif moveDistance < 0 and bottom + moveDistance < fatherHeight then    -- 向上移动到底了
if bottom > fatherHeight then
listLayout:SetObjPos(left,fatherHeight-(bottom-top),right,fatherHeight)
end
else
listLayout:SetObjPos(left,top+moveDistance,right,bottom+moveDistance)
end
__AdjustVScrollBarPos(ctrlObj)
end

function VScrollBar_OnLButtonDown(vsbarObj)
vsbarObj:SetCaptureMouse(true)
local ctrlObj = vsbarObj:GetOwnerControl()
local attr = ctrlObj:GetAttribute()
if attr.VScrollBarDownBkgID then
vsbarObj:SetTextureID(attr.VScrollBarDownBkgID)
end
end

function VScrollBar_OnLButtonUp(vsbarObj)
vsbarObj:SetCaptureMouse(false)
local ctrlObj = vsbarObj:GetOwnerControl()
local attr = ctrlObj:GetAttribute()
if attr.VScrollBarNormalBkgID then
vsbarObj:SetTextureID(attr.VScrollBarNormalBkgID)
end
end

function VScrollBar_OnMouseMove(vsbarObj, x, y, flags)
if flags == 1 then    -- 鼠标左键被按下
local listLayout = vsbarObj:GetOwnerControl():GetControlObject("listbox.layout")
local fatherLayout = vsbarObj:GetParent()
local _,listTop,_,listBottom = listLayout:GetObjPos()
local _,fatherTop,_,fatherBottom = fatherLayout:GetObjPos()
local listHeight,fatherHeight = listBottom-listTop,fatherBottom-fatherTop
local _,vsbTop,_,vsbBottom = vsbarObj:GetObjPos()
local vsbHeight = vsbBottom-vsbTop

-- 调整 VScrollBar 的位置
local vsbTop = y
if y < 0 then
vsbTop = 0
elseif y > fatherHeight - vsbHeight then
vsbTop = fatherHeight - vsbHeight
end
local l,t,r,b = vsbarObj:GetObjPos()
if t ~= vsbTop then
vsbarObj:SetObjPos(l,vsbTop,r,vsbTop+vsbHeight)
end

-- 调整 listLayout 的位置
local listTop = 0
listTop = -listHeight * vsbTop/fatherHeight
local l,t,r,b = listLayout:GetObjPos()
if t ~= listTop then
listLayout:SetObjPos(l,listTop,r,listTop+listHeight)
end
end

if flags ~= 1 then
local ctrlObj = vsbarObj:GetOwnerControl()
local attr = ctrlObj:GetAttribute()
if attr.VScrollBarHoverBkgID then
vsbarObj:SetTextureID(attr.VScrollBarHoverBkgID)
end
end
end

function VScrollBar_OnMouseLeave(vsbarObj)
local ctrlObj = vsbarObj:GetOwnerControl()
local attr = ctrlObj:GetAttribute()
if attr.VScrollBarNormalBkgID then
vsbarObj:SetTextureID(attr.VScrollBarNormalBkgID)
end
end

-------------------- 以下为内部函数 -------------------

function __AdjustVScrollBarPos(ctrlObj)
local listLayout = ctrlObj:GetControlObject("listbox.layout")
local fatherLayout = listLayout:GetParent()
local vsbarObj = ctrlObj:GetControlObject("vscrollbar")

local _,listTop,_,listBottom = listLayout:GetObjPos()
local _,fatherTop,_,fatherBottom = fatherLayout:GetObjPos()
local listHeight,fatherHeight = listBottom-listTop,fatherBottom-fatherTop

-- 大小
local vsbHeight = 0
if listHeight > fatherHeight then
vsbHeight = fatherHeight * fatherHeight/listHeight
end
-- 位置
local vsbTop = 0
if listHeight > fatherHeight then
vsbTop = fatherHeight * (-listTop)/listHeight
end

local l,t,r,b = vsbarObj:GetObjPos()
if t ~= vsbTop or b-t ~= vsbHeight then
vsbarObj:SetObjPos(l,vsbTop,r,vsbTop+vsbHeight)
end
end