3.1 Xml - namespaces - flex 4

Table of contents

• Preface
  • General
    • Viewing tip
      • Figures
      • Listings
  • Supplemental material
• General background information
  • Historical perspective
  • What is Flex?
• Preview
• Discussion and sample code
  • Skeleton mxml code and namespaces
  • The sample program named Namespace02
• Run the program
• Resources
• Miscellaneous

Preface

General

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

A previous lesson in this series titled XML - Namespaces - Flex 3 concentrated on teaching the XML concept of namespaces and illustrated the concept using a program written in Flex version 3.

Differences in namespaces between Flex 3 and Flex 4

Some of the first things that one is likely to notice when comparing Flex version 3 to Flex version 4 are some obvious differences in the use of namespaces. Therefore, this is an opportune place in the series tointroduce Flex version 4 and to explain some of the differences between the two versions.

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 figuresand listings while you are reading about them.

Figures

• Figure 1 . Output from Namespace01.
• Figure 2 . Output from Namespace02.
• Figure 3 . Project treefor the project named Namespace02.

Listings

• Lasting 1 . Skeleton mxml code for a new Flex 3 project.
• Listing 2 . Skeleton mxml code for a new Flex 4 project.
• Listing 3 . The main mxml file forNamespace01.
• Listing 4 . The main mxml file for Namespace02.
• Listing 5 . Contents of the file named Label.mxml.
• Listing 6 . Contents of the file named Button.mxml.

Supplemental material

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

General background information

Historical perspective

Adobe's Flex is an XML-based programming language that is used to create programs that execute in the Adobe Flash Player .

Teaching XML using Flex

In the Spring semester of 2010, I introduced Adobe's Flex version 3 and the Flex Builder 3 IDE into a course named Introduction to XML that I had been teaching for several years at Austin Community College in Austin, TX. The concept of usingFlex as the programming vehicle to teach XML was well received by the students.

During that same semester, Adobe released Flex version 4 and replaced Flex Builder 3 with a new IDE named Flash Builder 4 . The new IDE supports both Flex 3 and Flex 4.

A fortunate circumstance

This is a fortunate circumstance insofar as the concept of using Flex to teach XML is concerned. Flex 4 is similar to, but very different from, andsomewhat more complicated than Flex 3. The availability of the two versions of Flex makes it possible for the students to gain experience with two similar butdifferent flavors of XML, both supported by the same IDE and both supported by similarly formatted documentation.