按钮监听事件

<?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"
creationComplete="applicationCreationCompleteHandler(event)" minWidth="955" minHeight="600">
<fx:Script>
<![CDATA[
import mx.collections.ArrayCollection;
import mx.controls.Alert;
import mx.events.FlexEvent;

public function applicationCreationCompleteHandler(event:FlexEvent):void
{
this.bu.addEventListener(MouseEvent.CLICK, onClick);
var ar:ArrayCollection = new ArrayCollection([{"label":"dog", "name":"gou"}, {"label":"cat", "name":"mao"}]);
this.ddl.dataProvider = ar;
var len:int = this.ddl.dataProvider.length;
}
private function onClick(event:MouseEvent):void {
var obj:Object = this.ddl.selectedItem;
Alert.show("|" + obj + "|");
Alert.show(obj.label, "prompt");
}
]]>
</fx:Script>
<fx:Declarations>
<!-- Place non-visual elements (e.g., services, value objects) here -->
</fx:Declarations>
<s:VGroup>
<s:ComboBox id="ddl"/>
<s:Button id="bu" label="Press it"/>
</s:VGroup>
</s:Application>