User Guide

32 Getting Started with ActionScript

The Greeter class now has a number of new features:

■ The validNames array lists valid user names. The array is initialized to a list of three

names when the Greeter class is loaded.

■ The sayHello() method now accepts a user name and changes the greeting based on

some conditions. If the

userName is an empty string (""), the greeting property is set

to prompt the user for a name. If the user name is valid, the greeting becomes

"Hello,

userName.”

Finally, if either of those two conditions are not met, the greeting

variable is set to

"Sorry, userName, you are not on the list."

■ The validName() method returns true if the inputName is found in the validNames

array, and

false if it is not found. The statement validNames.indexOf(inputName)

checks each of the strings in the

validNames array against the inputName string. The

Array.indexOf() method returns the index position of the first instance of an object

in an array, or the value -1 if the object is not found in the array.

Next you will edit the Flash or Flex file that references this ActionScript class.

To modify the application using Flex Builder:

1. Open the HelloWorld.mxml file.

2. Next modify the <mx:TextArea> tag to indicate to the user that is is for display only, by

changing the background color to a light gray and preventing the user from editing the

displayed text:

<mx:TextArea id = "mainTxt" width="400" backgroundColor="#DDDDDD"

editable="false" />

Now add the following lines right after the <mx:TextArea> closing tag. These lines create

a new TextInput field that lets the user enter a user name value:

<mx:HBox width="400">

<mx:Label text="User Name:"/>

<mx:TextInput id="userNameTxt" width="100%" enter="mainTxt.text =

myGreeter.sayHello(userNameTxt.text);" />

</mx:HBox>

The enter attribute specifies that when the user presses the Enter key in the userNameTxt

field, the text in the field will be passed to the

Greeter.sayHello() method, and the

greeting displayed in the

mainTxt field will change accordingly.

The final contents of the HelloWorld.mxml file should look like this:

<?xml version="1.0" encoding="utf-8"?>

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

layout="vertical"

creationComplete = "initApp()" >

<mx:Script>

<![CDATA[