initialize,creationComplete,applicationComplete

<?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"
      initialize="application1_initializeHandler(event)"
      creationComplete="application1_creationCompleteHandler(event)"
      applicationComplete="application1_applicationCompleteHandler(event)">
 <fx:Declarations>
  <!-- 将非可视元素（例如服务、值对象）放在此处 -->
 </fx:Declarations>
 <fx:Script>
  <![CDATA[
   import mx.controls.Alert;
   import mx.events.FlexEvent;
   
   protected function application1_initializeHandler(event:FlexEvent):void{
    Alert.show("initialize");
   }
   
   protected function application1_creationCompleteHandler(event:FlexEvent):void{
    Alert.show("creationComplete");
   }
   
   protected function application1_applicationCompleteHandler(event:FlexEvent):void{
    Alert.show("applicationcomplete");
   }
  ]]>
 </fx:Script>
 <s:Panel title="Hello, flex!" width="600" horizontalCenter="0" verticalCenter="0">
  <s:Button label="Click Me" click="Alert.show('Hello flex, I am coming!', 'Hello, flex!');" horizontalCenter="0" verticalCenter="0" />
 </s:Panel>
</s:Application>

参考：

http://wangjianwei866.blog.163.com/blog/static/92958232010112391257934/

http://blog.csdn.net/sjz168/article/details/7244374