网上有下过其它人的实现的样例。可是样式不好改。还有就是不能初始化选中，还有三态效果那个半选中状态也是不清楚。所以自己依据Itemrender搞了一个，还凑合
效果如图：全选和半选状态，Checkbox的flex3的样式用的图片
TreeCheckboxItemRender.mxml
<?xml version="1.0" encoding="utf-8"?> <s:MXTreeItemRenderer xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/mx" initialize="mxtreeitemrenderer1_initializeHandler(event)"> <fx:Metadata> [Event(name="checkBoxClick",type="CustomEvent")] </fx:Metadata> <fx:Style> @namespace s "library://ns.adobe.com/flex/spark"; @namespace mx "library://ns.adobe.com/flex/mx"; .halfSelected{ upIcon:Embed(source='1.png'); overIcon:Embed(source='1.png'); downIcon:Embed(source='1.png'); disabledIcon:Embed(source='1.png'); } .selected{ upIcon:Embed(source='4.png'); overIcon:Embed(source='4.png'); downIcon:Embed(source='4.png'); disabledIcon:Embed(source='4.png'); } .unSelected{ upIcon:Embed(source='2.png'); overIcon:Embed(source='3.png'); downIcon:Embed(source='3.png'); disabledIcon:Embed(source='2.png'); } </fx:Style> <fx:Script> <![CDATA[ import mx.controls.Tree; import mx.events.FlexEvent; [Bindable] [Embed(source="1.png")] public static var HARFSELECT_CLASS:Class; [Bindable] [Embed(source="2.png")] public static var UNSELECT_CLASS:Class; [Bindable] [Embed(source="3.png")] public static var UNSELECT_OVER_CLASS:Class; [Bindable] [Embed(source="4.png")] public static var SELECT_CLASS:Class; override protected function commitProperties():void { super.commitProperties(); if(data != null && data.@selected != ""){ if(data.children().length() == 0){ if(data.@selected == "true"){ checkBox.selected = true; } else{ checkBox.selected = false; } return; } recursion(data); } else{ checkBox.selected = false; } } private function recursion(dataItem:Object):void{ //遍历全部子节点。假设子节点下还有子节点则递归 for(var i:int = 0; i < dataItem.children().length(); i++){ var child:XML = dataItem.children()[i]; if(child.children().length() > 0){ recursion(child); } } //查询该节点下的选中的子节点 var selectedChild:XMLList = dataItem..node.(@pid == dataItem.@id && @selected == "true"); var selectElement:XMLList = dataItem..node.(@selected == "true"); //假设该节点的子节点数等于该节点下选中的子节点数，则该节点选中 if(dataItem.children().length() == selectedChild.length()){ checkBox.selected = true; dataItem.@selected = "true"; fillCheckBox(false); } else{ checkBox.selected = false; fillCheckBox(false); if(selectElement.length() > 0){ fillCheckBox(true); } } } protected function checkBox_changeHandler(event:Event):void { if(data.@selected != ""){ toggleChildrens(data); toggleParents(data, Tree(this.owner)); } } private function toggleChildrens(item:Object):void{ item.@selected = checkBox.selected; for(var i:int = 0; i < item.children().length(); i++){ item.children()[i].@selected = checkBox.selected; toggleChildrens(item.children()[i]); } } /** * // TODO : 递归设置父项目的状态 * @param item 项目 * @param tree 树对象 * @param state 目标状态 * */ private function toggleParents(item:Object, tree:Tree):void { if (item == null) return ; else { var parentItem:Object=tree.getParentItem(item); if(parentItem != null){ if(item.@selected == "false"){ parentItem.@selected = "false"; }else{ var flag:int = 0; for(var i:int = 0; i < parentItem.children().length(); i++){ if(parentItem.children()[i].@selected == "true"){ flag++; } } if(flag == parentItem.children().length()){ parentItem.@selected = "true"; } } toggleParents(parentItem, tree); } } } protected function fillCheckBox(isFill:Boolean):void { checkBox.graphics.clear(); if (isFill) { var myRect:Rectangle=checkBox.getBounds(checkBox); checkBox.graphics.beginFill(0xff0000, 1) checkBox.graphics.drawRoundRect(myRect.x+3, myRect.y+3, checkBox.width/2, checkBox.height/2, 1, 1); checkBox.graphics.endFill(); checkBox.styleName = "halfSelected"; } else{ if(checkBox.selected){ checkBox.styleName = "selected"; } else{ checkBox.styleName = "unSelected"; } } } protected function mxtreeitemrenderer1_initializeHandler(event:FlexEvent):void { // TODO Auto-generated method stub //Tree(this.owner) } protected function checkBox_clickHandler(event:MouseEvent):void { // TODO Auto-generated method stub Tree(this.owner).dispatchEvent(new CustomEvent(CustomEvent.CHECKBOX_CLICK, {"selected":checkBox.selected})); } ]]> </fx:Script> <s:states> <s:State name="normal" /> <s:State name="hovered" /> <s:State name="selected" /> </s:states> <s:HGroup left="0" right="0" top="0" bottom="0" verticalAlign="middle"> <s:Rect id="indentationSpacer" width="{treeListData.indent}" percentHeight="100" alpha="0"> <s:fill> <s:SolidColor color="0xFFFFFF" /> </s:fill> </s:Rect> <s:Group id="disclosureGroup"> <s:BitmapImage source="{treeListData.disclosureIcon}" visible="{treeListData.hasChildren}" /> </s:Group> <mx:CheckBox id="checkBox" change="checkBox_changeHandler(event)" click="checkBox_clickHandler(event)" styleName="unSelected" selectedDownIcon="{SELECT_CLASS}" selectedUpIcon="{SELECT_CLASS}" selectedOverIcon="{SELECT_CLASS}"/> <s:BitmapImage source="{treeListData.icon}" /> <s:RichEditableText id="labelField" editable="false" text="{treeListData.label}" paddingTop="2"/> </s:HGroup> </s:MXTreeItemRenderer>
主文件
<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600" xmlns:components="com.pricklythistle.common.components.*">
<fx:Declarations>
<!-- 将非可视元素（比如服务、值对象）放在此处 -->
<fx:XML xmlns="" id="xmlData">
<node id="0" pid="-1" label="厦门" openedId="-1" type="-1" cid="0" selected="false" isBranch="true">
<node id="110" pid="0" selected="false" cid="0" isBranch="true" type="2" updateStatus="1" label="软件园演示点2" createTime="1404267128253" updateTime="1404267128253" icon="">
<node id="362" pid="110" selected="false" cid="110" label="望海路（720P－变码率）" isBranch="false" updateStatus="1" channelValue="1" isOffLine="false" isPlaying="false" channelStatus="0" xCoordinate="0.0" yCoordinate="0.0" overdueStatus="1" createTime="1404268448260" updateTime="1404268514558" icon=""/>
<node id="360" pid="110" selected="false" cid="110" label="电梯间（720P－变码率）" isBranch="false" updateStatus="1" channelValue="1" isOffLine="false" isPlaying="false" channelStatus="1" xCoordinate="0.0" yCoordinate="0.0" overdueStatus="1" createTime="1404268305648" updateTime="1404268724984" icon=""/>
<node id="359" pid="110" selected="false" cid="110" label="办公室（720P－变码率）" isBranch="false" updateStatus="1" channelValue="1" isOffLine="false" isPlaying="false" channelStatus="0" xCoordinate="0.0" yCoordinate="0.0" overdueStatus="1" createTime="1404268247553" updateTime="1404268725016" icon=""/>
<node id="361" pid="110" selected="false" cid="110" label="停车场（720P－变码率）" isBranch="false" updateStatus="1" channelValue="1" isOffLine="false" isPlaying="false" channelStatus="0" xCoordinate="0.0" yCoordinate="0.0" overdueStatus="1" createTime="1404268394947" updateTime="1410789105184" icon=""/>
</node>
<node id="101" pid="0" cid="0" selected="false" isBranch="true" type="2" updateStatus="1" label="软件园演示点（户外）" createTime="1404121845986" updateTime="1408623064915" icon="">
<node id="357" pid="101" selected="false" cid="101" label="三叉路口（720P-均衡）" isBranch="false" updateStatus="1" channelValue="1" isOffLine="false" isPlaying="false" channelStatus="0" xCoordinate="0.0" yCoordinate="0.0" overdueStatus="1" createTime="1404131355779" updateTime="1410773639789" icon=""/>
<node id="356" pid="101" selected="false" cid="101" label="停车场（720P-高清）" isBranch="false" updateStatus="1" channelValue="1" isOffLine="false" isPlaying="false" channelStatus="0" xCoordinate="0.0" yCoordinate="0.0" overdueStatus="1" createTime="1404131355717" updateTime="1410773658118" icon=""/>
<node id="358" pid="101" selected="false" cid="101" label="办公室（720P-流畅）" isBranch="false" updateStatus="1" channelValue="1" isOffLine="false" isPlaying="false" channelStatus="0" xCoordinate="0.0" yCoordinate="0.0" overdueStatus="1" createTime="1404182528941" updateTime="1410773894041" icon=""/>
<node id="355" pid="101" selected="false" cid="101" label="球机（720P-可云台控制）" isBranch="false" updateStatus="1" channelValue="1" isOffLine="false" isPlaying="false" channelStatus="0" xCoordinate="0.0" yCoordinate="0.0" overdueStatus="1" createTime="1404131355654" updateTime="1410779974117" icon=""/>
<node id="354" pid="101" selected="false" cid="101" label="望海路（720P-流畅）" isBranch="false" updateStatus="1" channelValue="1" isOffLine="false" isPlaying="false" channelStatus="0" xCoordinate="0.0" yCoordinate="0.0" overdueStatus="1" createTime="1404131355592" updateTime="1410787537718" icon=""/>
<node id="222" pid="101" cid="0" selected="false" isBranch="true" type="2" updateStatus="1" label="软件园二期演示点（户外）" createTime="1404121845986" updateTime="1408623064915" icon="">
<node id="200" pid="222" selected="false" cid="222" label="观日路" isBranch="false" updateStatus="1" channelValue="1" isOffLine="false" isPlaying="false" channelStatus="0" xCoordinate="0.0" yCoordinate="0.0" overdueStatus="1" createTime="1404131355779" updateTime="1410773639789" icon=""/>
<node id="201" pid="222" selected="false" cid="222" label="公厕" isBranch="false" updateStatus="1" channelValue="1" isOffLine="false" isPlaying="false" channelStatus="0" xCoordinate="0.0" yCoordinate="0.0" overdueStatus="1" createTime="1404131355779" updateTime="1410773639789" icon=""/>
<node id="202" pid="222" selected="false" cid="222" label="景观湖" isBranch="false" updateStatus="1" channelValue="1" isOffLine="false" isPlaying="false" channelStatus="0" xCoordinate="0.0" yCoordinate="0.0" overdueStatus="1" createTime="1404131355779" updateTime="1410773639789" icon=""/>
</node>
<node id="333" pid="101" cid="0" selected="false" isBranch="true" type="2" updateStatus="1" label="软件园一期演示点（户外）" createTime="1404121845986" updateTime="1408623064915" icon="">
<node id="210" pid="333" selected="false" cid="222" label="十字路口" isBranch="false" updateStatus="1" channelValue="1" isOffLine="false" isPlaying="false" channelStatus="0" xCoordinate="0.0" yCoordinate="0.0" overdueStatus="1" createTime="1404131355779" updateTime="1410773639789" icon=""/>
</node>
</node>
</node>
</fx:XML>
</fx:Declarations>
<fx:Script>
<![CDATA[
]]>
</fx:Script>
<mx:Tree id="tree" dataProvider="{xmlData}" styleName="treeStyle" horizontalCenter="0" width="270" height="100%"
itemRenderer="TreeCheckboxItemRender" labelField="@label"/>
</s:Application>
说明：在xml文件里基本的两个属性就是pid和selected属性，pid就是父ID，selected代表是否选中，假设为true初始化的时候就选中，我在Itemrender中是用这两个属性来推断这三个状态的