Animating a Flex PieChart control’s rotation when a user clicks on an item

In the following example, we look at how to add a nice animation effect with some easing to make the effect a bit more smooth

<?xml version="1.0" encoding="utf-8"?>

<!-- http://blog.flexexamples.com/2007/11/22/animating-a-flex-piechart-controls-rotation-when-a-user-clicks-on-an-item/ -->

<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"

        layout="vertical"

        verticalAlign="middle"

        backgroundColor="white">

    <mx:Script>

        <![CDATA[

            import mx.effects.easing.*;

            import mx.charts.series.items.PieSeriesItem;

            import mx.charts.events.ChartItemEvent;

            private function pieChart_itemClick(evt:ChartItemEvent):void {

                var item:PieSeriesItem = evt.hitData.chartItem as PieSeriesItem;

                var degrees:Number = radiansToDegrees(item.startAngle);

                var arr:Array = [];

                if (checkBox.selected) {

                    arr[item.index] = 0.2;

                }

                pieSeries.perWedgeExplodeRadius = arr;

                pieSeries.startAngle -= degrees;

                dp.refresh();

            }

            private function radiansToDegrees(radians:Number):Number {

                return radians * (180 / Math.PI);

        ]]>

    </mx:Script>

    <mx:XMLListCollection id="dp">

        <mx:source>

            <mx:XMLList>

                <product label="Product 1" data="3" />

                <product label="Product 2" data="1" />

                <product label="Product 3" data="4" />

                <product label="Product 4" data="1" />

                <product label="Product 5" data="5" />

                <product label="Product 6" data="9" />

            </mx:XMLList>

        </mx:source>

    </mx:XMLListCollection>

    <mx:ApplicationControlBar dock="true">

        <mx:CheckBox id="checkBox"

                label="Use perWedgeExplodeRadius:"

                labelPlacement="left"

                selected="true" />

    </mx:ApplicationControlBar>

    <mx:PieChart id="pieChart"

            dataProvider="{dp}"

            showDataTips="true"

            itemClick="pieChart_itemClick(event);"

            height="100%"

            width="100%">

        <mx:series>

            <mx:PieSeries id="pieSeries"

                    field="@data"

                    nameField="@label">

                <mx:showDataEffect>

                    <mx:SeriesInterpolate duration="1500"

                            easingFunction="{Elastic.easeOut}" />

                </mx:showDataEffect>

                <mx:filters>

                    <mx:DropShadowFilter />

                </mx:filters>

            </mx:PieSeries>

        </mx:series>

    </mx:PieChart>

    <mx:Legend dataProvider="{pieChart}" direction="horizontal" />

</mx:Application>

    本文转自 OldHawk  博客园博客，原文链接：http://www.cnblogs.com/taobataoma/archive/2008/01/13/1037047.html，如需转载请自行联系原作者