开始的时候不知道该怎么写自定义事件，怎感觉很麻烦，其实理解就不麻烦了。
（一）首先你要定义一个事件，让这个事件继承event；放在events包下（建一个events包）
package events{
import flash.events.Event;
public class MyEvent extends Event{
public var str:String; //要传的值，也可以是对象
//构造函数改写
public function MyEvent(type:String, str:String){
super(type);
this.str= str;
}
}
}
（二）你可以自定义组件使用这个事件，比如我定义一个两个按钮的组件
<?xml version="1.0" encoding="utf-8"?>
<s:Group 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:Metadata>
[Event(name="aaa", type="events.MyEvent")] //定义元数据也是声明事件
[Event(name="bbb", type="events.MyEvent")] //定义元数据也是声明事件
</fx:Metadata>
<fx:Script>
<![CDATA[
import events.MyEvent;
protected function ok_handelEvent(event:MouseEvent):void{
var okEvent:MyEvent = new MyEvent("aaa","要传的值");
this.dispatchEvent(okEvent);
}
protected function cancel_handelEvent(event:MouseEvent):void{
var cancelEvent:MyEvent = new MyEvent("bbb","取消的值");
this.dispatchEvent(cancelEvent);
}
]]>
</fx:Script>
<s:Button label="确定" click="ok_handelEvent(event)"/>
<s:Button x="132" y="0" label="取消" click="cancel_handelEvent(event)"/>
</s:Group>
（三）使用事件
<?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" minWidth="955" minHeight="600" xmlns:componnet="componnet.*">
<fx:Script>
<![CDATA[
import events.MyEvent;
import mx.controls.Alert;
protected function mybutton1_aaaHandler(event:MyEvent):void{
Alert.show(event.str);
}
protected function mybutton1_bbbHandler(event:MyEvent):void{
Alert.show(event.str);
}
]]>
</fx:Script>
<componnet:MyButton x="360" y="125" aaa="mybutton1_aaaHandler(event)"
bbb="mybutton1_bbbHandler(event)"/>
</s:Application>