User Guide

140 Creating Simple Visual Components in ActionScript

You can use your custom component in the following Flex application:

<?xml version="1.0"?>

<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"

xmlns:MyComps="myComponents.*">

<MyComps:MyPanelComponent id="myP"/>

<mx:Button label="Copy" click="myP.xfer();"/>

</mx:Application>

If the value of the id property of a TextInput control does not match an inherited property

name, Flex creates a property of the component, where the

id property defines the name of

the new property.

To support initialization from MXML, an inherited property must have the following

characteristics:

■ The inherited property must be public.

If you try to initialize a non-public inherited property, the Flex compiler issues an error.

■ The inherited property must be writable.

If you try to initialize a constant, or a property defined by a getter method without a

corresponding setter method, the Flex compiler issues an error.

■ The data type of the value that you specify to the inherited property must by compatible

with the data type of the property.

If you try to initialize a property with a value of an incompatible data type, the Flex

compiler issues an error.

Defining events in ActionScript

components

Flex components dispatch their own events and listen to other events. An object that wants to

know about another object’s events registers as a listener with that object. When an event

occurs, the object dispatches the event to all registered listeners.

The core class of the Flex architecture, mx.core.UIComponent, defines core events, such as

updateComplete, resize, move, creationComplete, and others that are fundamental to all

components. Subclasses of these classes inherit and dispatch these events.