Xml - namespaces - flex 3

Table of contents

• Preface
  • General
  • Viewing tip
    • Figures
    • Listings
  • Supplemental material
• General background information
• Preview
• Discussion and sample code
• Resources
• Miscellaneous

Preface

General

This tutorial lesson is part of a series dedicated to programming with Adobe Flex.

Flex is a programming language based on XML. Therefore, in order to program with Flex, you must firstunderstand XML. The lessons in this XML series provide a brief introduction to XML.

Viewing tip

I recommend that you open another copy of this document in a separate browser window and use the following links to easily find and view the figures andlistings while you are reading about them.

Figures

• Figure 1 . The directory tree for the project named Namespace01.
• Figure 2 . Program output at startup.
• Figure 3 . Screen output for upgraded Flex project.

Listings

• Listing 1 . Skeleton MXML code for a new Flex project.
• Listing 2 . Upgraded Flex project code.
• Listing 3 . Contents of the file named Label.mxml.
• Listing 4 . Contents of the file named Button.mxml
• Listing 5 . Contents of the file named NameSpace01.mxml.

Supplemental material

I recommend that you also study the other lessons in my extensive collection of online programmingtutorials. You will find a consolidated index at www.DickBaldwin.com .

General background information

XML namespaces make it possible to combine two or more XML documents into a single XML document and todeal with problems that arise when the same name is used for an element in two or more of the XML documents.

Preview

The XML namespace topic is very broad. I won't attempt to cover the topic of namespaces in this lesson. Instead, I will illustrate and explain a somewhat restricted use of namespaces by explaining a Flex project that combinesthree XML documents with conflicting element names.

Before getting into the detailed code, I will show you a couple of images that I will be referring back to later.

The project file structure

When you create a Flex project, you create a directory tree on the disk to contain the files and folders that make up the project. The tree is rooted in afolder that has the same name as the name that you give to the project. In this lesson, I will explain a Flex project named Namespace01.

Figure 1 shows the directory tree for this project. Figure 1 is a snapshot of the Flex Builder 3 Navigator panel.

Figure

The directory tree for the project named namespace01.

Lots of folders and files

The directory tree contains a relatively large number of folders and files. Fortunately, most of the folders and files are generated automatically by FlexBuilder 3. As Flex programmers, we are primarily interested in the folders and files that are children of the folder named src .