Macromedia flex 2 Manual

174

Creating Advanced Visual Components in ActionScript

However, if a child component dispatches an event, and you want that opportunity to handle 
the event outside of the component, you must add logic to your custom component to 
propagate the event. Notice that the event listener for the 

change

 event for the TextArea 

control propagates the event. This lets you handle the event in your application, as the 
following example shows:

<?xml version="1.0"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" 

xmlns:MyComp="myComponents.*">

<mx:Script>

<![CDATA[

import flash.events.Event;

function handleText(eventObj:Event)
{

...

}

]]>

</mx:Script>

<MyComp:ModalText changed="handleText(event);"/>

</mx:Application>

Creating the ModalText component

The following code example implements the class definition for the ModalText component. 
The ModalText component is a composite component that contains a 

Button

 control and a 

TextArea

 control. The following image shows this control:

This control has the following attributes:

■

You cannot edit the TextArea control by default.

■

You click the Button control to toggle editing of the TextArea control.

■

You use the 

textPlacement

 property of the control to make the TextArea appear on the 

right side or the left side of the control.

■

Editing the 

textPlacement

 property of the control dispatches the 

placementChanged

 

event. 

■

You use the 

text

 property to programmatically write content to the TextArea control. 

■

Editing the 

text

 property of the control dispatches the 

textChanged

 event. 

■

Editing the text in the TextArea control dispatches the 

change

 event.