how to add event listener in the class ?

I want to seperate the code from the mxml completely . And
here is my attempt but it is not working. I guess my problem is
about adding the event listeners or setting the component id s in
the class file. How should i change the code so that it works ? and
any good practice advises are welcome. Thank you ...



////////////////////////////////// Code
///////////////////////////////////////////////////////



///////////////// MXML FILE
//////////////////////////////////

%26lt;?xml version=''1.0'' encoding=''utf-8''?%26gt;

%26lt;mx:Application xmlns:mx=''
http://www.adobe.com/2006/mxml''


applicationComplete=''init()''%26gt;

%26lt;mx:Script%26gt;

%26lt;![CDATA[

import mx.controls.Alert

import lostchild.DirectoryBrowser

private var lcModel:DirectoryBrowser

private function init():void{

lcModel = new DirectoryBrowser()

Alert.show(''application complete'', ''Flex Debug'')

}

]]%26gt;

%26lt;/mx:Script%26gt;

%26lt;mx:HDividedBox width=''100%'' height=''100%''%26gt;

%26lt;mx:Button id=''btn'' width=''100'' height=''100%''/%26gt;

%26lt;mx:Text id=''txt'' height=''100%'' width=''100%''/%26gt;

%26lt;/mx:HDividedBox%26gt;

%26lt;/mx:Application%26gt;





//////// DirectoryBrowser.as placed in the folder
''lostchild''//////////



package lostchild{

import flash.events.MouseEvent

import mx.controls.Button

import mx.controls.Text

import mx.controls.Alert



public class DirectoryBrowser{

private var btn:Button = new Button()

private var txt:Text = new Text()

public function DirectoryBrowser():void{

setStuff()

Alert.show(''class loaded'',''class debug'')

}

public function callAlert(evt:MouseEvent):void{

Alert.show(''button clicked'',''debugging event handler'')

txt.text = ''working fine''

}

public function setStuff():void{

btn.label = ''just click!''

txt.text = '' i can't get to see this !''

btn.addEventListener(MouseEvent.CLICK,callAlert)

}

}

}



( And why can't i see an attach code option in this message
form ? )