Flex4 的PieChart的点击滑动

<?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">
	<s:layout>
		<s:BasicLayout/>
	</s:layout>
	<fx:Script>
		<![CDATA[
			import mx.charts.events.ChartItemEvent;
			import mx.charts.series.items.PieSeriesItem;
			import mx.controls.Alert;
			import mx.effects.easing.Elastic;
			[Bindable]
			private var arr:Array = [
				{id:1,city:'北京',money:1000,pay:300},{id:2,city:'上海',money:1200,pay:500},{id:3,city:'天津',money:80,pay:200},{id:4,city:'常州',money:100,{id:5,city:'海南',money:500,{id:6,city:'昆山',money:600,{id:7,city:'苏州',money:200,pay:200}
			];
			
			private var _selectedRegion:Object;
			
			public function set selectedRegion(item:Object):void
			{
				_selectedRegion = item;
				
				var index:int = -1;
				for (var i:int=0; i < arr.length && index == -1; i++)
				{
					if (arr[i].money == item.money)
						index = i;
				}
				var explodeData:Array = [];
//				if(explodeData[index]==null){
				
					 explodeData[index] = 0.1;
//				}else{
//					explodeData[index] = 0;
//				}
				piechart1.series[0].perWedgeExplodeRadius = explodeData;
				
			}
			
			
	
			
			protected function piechart1_itemClickHandler(event:ChartItemEvent):void
			{
				// TODO Auto-generated method stub
				var item:PieSeriesItem = event.hitData.chartItem as PieSeriesItem;
				var degrees:Number = radiansToDegrees(item.startAngle);
				var arr1:Array = [];
//				if (checkBox.selected) {
				arr1[item.index] = 0.1;
//				}
				pieSeries.perWedgeExplodeRadius = arr1;
				pieSeries.startAngle -= degrees;
				
				//arr.refresh();
			}
			
			private function radiansToDegrees(radians:Number):Number {
				return radians * (180 / Math.PI);
			}
			
		]]>
	</fx:Script>  
	<fx:Declarations>
		<!-- 将非可视元素（例如服务、值对象）放在此处 -->
		<mx:SeriesInterpolate id="interpolate" elementOffset="10" easingFunction="{Elastic.eaSEOut}"/>
	</fx:Declarations>

	<mx:PieChart x="110" y="51" id="piechart1" dataProvider="{arr}"  itemClick="piechart1_itemClickHandler(event)"
				 showAllDataTips="true" selectionMode="single">
		<mx:series>
			<mx:PieSeries id="pieSeries" displayName="Series 1" field="money" labelPosition="callout" 
						  labelField="city" nameField="city">
				
			</mx:PieSeries>	
		</mx:series>
		<!--鼠标移动-->
		<mx:rollOverEffect>
			<s:Fade alphaFrom="0.5" alphaTo="1" duration="1000" />
		</mx:rollOverEffect>
		<mx:rollOutEffect>
			<s:Fade alphaFrom="1" alphaTo="0.5" duration="1000" />
		</mx:rollOutEffect>
	</mx:PieChart>
	<mx:Legend x="13" y="469" dataProvider="{piechart1}" direction="horizontal" labelPlacement="right"/>
</s:Application>