Flex之Tree组件（修改图标，加复选框）

一、效果展示

二、mxml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" 
               >
    <!--
    <fx:Style>
        @namespace s "library://ns.adobe.com/flex/spark";
        @namespace mx "library://ns.adobe.com/flex/mx";
        mx|Tree{
            /*去掉默认文件夹图标*/
            folderClosedIcon: ClassReference(null);
            folderOpenIcon: ClassReference(null);
            /*去掉叶子节点图标*/
            defaultLeafIcon: ClassReference(null);
        }
    </fx:Style>
    -->
    <fx:Script>
        <![CDATA[
            [Bindable]
            private var layerData:XMLList = XMLList(
                '<node label="Inbox" selected="true" icon="parent">' +
                '<node label="Marketing" selected="true" icon="child"/>' +
                '<node label="Product Management" selected="false" icon="child"/>' +
                '<node label="Personal" selected="false" icon="child" />' +
                '</node>' +
                '<node label="Outbox" icon="parent"  selected="false" >' +
                '<node label="Professional" selected="true" icon="child"/>' +
                '<node label="Personal" icon="child" selected="true"/>' +
                '</node>');
            [Embed(source="images/map-service.png")]  
            public var pIcon:Class;  
            [Embed(source="images/layer.png")]  
            public var cIcon:Class; 

            private function SetIcon(item:Object):*{
                var xml:XML = item as XML;  
                if(xml.attribute("icon")=="parent")  
                {  
                    return pIcon;  
                }  
                else 
                {  
                    return cIcon;  
                }    
            }
        ]]>
    </fx:Script>

    <mx:Tree id="myTree" width="100%" height="100%" labelField="@label"
             showRoot="true" 
             dataProvider="{layerData}" 
             itemRenderer="TreeCheckBoxRenderer"
             iconFunction="SetIcon"
             />

</s:Application>           

三、TreeCheckBoxRenderer.as

package 
{
    import flash.events.Event;
    import flash.events.MouseEvent;

    import mx.controls.Alert;
    import mx.controls.CheckBox;
    import mx.controls.Tree;
    import mx.controls.treeClasses.TreeItemRenderer;
    import mx.controls.treeClasses.TreeListData;

    /**
     * 支持CheckBox的TreeItemRenderer
     * @author Montage
     */    
    public class TreeCheckBoxRenderer extends TreeItemRenderer
    {
        public function TreeCheckBoxRenderer()
        {
            super();
        }

        protected var checkBox:CheckBox;

        /**
         * 构建CheckBox
         */        
        override protected function createChildren():void
        {
            super.createChildren();
            checkBox = new CheckBox();
            addChild( checkBox );
            checkBox.addEventListener(Event.CHANGE, changeHandler);
        }

        /**
         * 点击checkbox时,更新dataProvider
         * @param event
         */        
        protected function changeHandler( event:Event ):void
        {
            //var i:int=0;
            if( data.@selected!="" )
            {
                data.@selected = checkBox.selected.toString();

                /**
                 * 如果有需要，在这里处理选中父，全选子节点的方法。
                 * */
                for (var i:int=0;i<data.children().length();i++)
                {
                    data.children()[i].@selected=checkBox.selected.toString();;

                }     

            }    
        } 


        /**
         * 初始化控件时, 给checkbox赋值
         */        
        override protected function commitProperties():void
        {
            super.commitProperties();
            if(data.@selected!="" )
            {
                if(data.@selected=="true"){
                    checkBox.selected=true;
                }else{
                    checkBox.selected=false;
                }
            }
            else
            {
                checkBox.selected = false;
            }

        }


        /**
         * 重置itemRenderer的宽度
         */  
        /*
        override protected function measure():void
        {
            super.measure();
            measuredWidth += checkBox.getExplicitOrMeasuredWidth();
        }
        */
        /**
         * 重新排列位置, 将label后移
         * @param unscaledWidth
         * @param unscaledHeight
         */    

        override protected function updateDisplayList(unscaledWidth:Number, unscaledHeight:Number):void
        {
            super.updateDisplayList(unscaledWidth, unscaledHeight);
            var startx:Number = data ? TreeListData( listData ).indent : 0;

            if (disclosureIcon)
            {
                disclosureIcon.x = startx;

                startx = disclosureIcon.x + disclosureIcon.width;

                disclosureIcon.setActualSize(disclosureIcon.width,
                    disclosureIcon.height);

                disclosureIcon.visible = data ?
                    TreeListData( listData ).hasChildren :
                    false;
            }

            if (icon)
            {
                icon.x = startx+ icon.measuredWidth;
                //startx = icon.x + icon.measuredWidth;
                icon.setActualSize(icon.measuredWidth, icon.measuredHeight);
            }

            checkBox.move(startx, ( unscaledHeight - checkBox.height ) / 2 );

            label.x = startx + checkBox.getExplicitOrMeasuredWidth()+icon.measuredWidth+3;
        }

    }
}