Programming Flex 3

Using XML

XML is a standard protocol for transferring, storing, and reading data for several purposes, including application initialization parameters, data sets, and remote procedure calls. Flex applications work with XML by using Flash Player’s native support.

Flash Player 9 supports two mechanisms for working with XML: a legacy XMLDocument class and the new XML class that implements the ECMAScript for XML (E4X) standard. All XML examples in this book use E4X unless otherwise noted.

Creating XML Objects

There are two ways to create XML objects in ActionScript: using XML literals or with the XML constructor. XML literals are useful when you want to define the XML data directly in the code and you know the exact XML data you want to use. The following example defines an XML literal and assigns it to a variable:

var xml:XML = <books>
              <book>
                <title>Programming Flex 3</title>
                <authors>
                  <author first="Chafic" last="Kazoun" />
                  <author first="Joey" last="Lott" />
                </authors>
              </book>
              <book>
                <title>ActionScript 3.0 Cookbook</title>
                <authors>
                  <author first="Joey" last="Lott" />
                  <author first="Keith" last="Peters" />
                  <author first="Darron" last="Schall" />
                </authors>
              </book>
            </books>;

Note

We’ll assume that this is the XML object referenced by the remainder of the XML examples in this chapter.

If you aren’t able to define the XML data directly in ActionScript, you can load the data as a string and pass it to the XML constructor. In the following example, loadedXMLData is a variable containing XML ...