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Lots of comments

As you can see, I included lots of comments in Listing 4 in an attempt to make it as self-explanatory as possible.

In this lesson, I will concentrate on the differences between this Flex 4 project and the Flex 3 project named Namespace01 that arise from creating the two projects using different versions of Flex.

Order of attributes is not important

Let me begin by explaining that in XML, the order in which you write the attributesfor an element doesn't matter so long as they are all there with the correct syntax, the correct names, and the correct values.

More and different namespace attributes

As I explained earlier, a Flex 4 project often has three required namespace attributes and almost always has two. (Because I didn't use any mx components in this program, I could have removed the namespace attribute named mx from Listing 4.)

Other than the namespace attributes, the application element in Listing 4 has the same attribute names and values as the application element in Listing 3.

No VBox element in Namespace02

The next thing to notice is that there is no mx:VBox element in Listing 4. Instead, there is an s:Group element (a Flex 4 Spark component) that replaces the mx:VBox element and serves as a container for the labels and the buttons.

No backgroundColor attribute

The s:Group element has two positioning attributes that cause it to appear in the center of the Flash Playerwindow, but it does not have an attribute named backgroundColor . Like many of the Spark components, and unlike many of the mx components, the s:Group element does not have built-in attributes that are used to control its appearance. Instead, other ways must be found to control theappearance of many Spark components.

A red rectangle

In this case, Listing 4 causes the s:Group element to appear to have a red background by causing it to contain a red rectangle of exactly the right dimensions to completely fillthe s:Group element. This produces the red background color in the upper portion of Figure 2.

As with Figure 1, the lower portion of Figure 2 also has a red background color, but it is covered by another smaller rectangle with an opaque cyan color.

Add an s:VGroup container

Then Listing 4 adds a Spark s:VGroup container to serve essentially the same purpose as the mx:VBox container in Listing 3 (except that it doesn't control the red background color) . The following elements are added tothe s:VGroup element in Listing 4 In a manner very similar to Listing 3:

  • s:Label
  • s:Button
  • MyComps:Label
  • MyComps:Button

The first two elements in the above list are Spark elements having similar characteristics to the mx elements having the same names.

The last two elements in the above list are custom components having similar characteristicsto the custom components having the same names in the earlier program.

Contents of the file named Label.mxml

The contents of the custom component file named Label.mxml are shown in Listing 5.

Contents of the file named label.mxml.

<?xml version="1.0" encoding="utf-8"?><!--Create a custom label by putting a Spark Label in a Spark Group--><s:Group xmlns:MyComps="customComps.*" xmlns:fx="http://ns.adobe.com/mxml/2009"xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/mx"><s:Label text="Custom Label"color="#FFFF00" fontSize="12"fontWeight="bold"/></s:Group>

Contents of the file named Button.mxml

The contents of the custom component file named Button.mxml are shown in Listing 6.

Contents of the file named button.mxml.

<?xml version="1.0" encoding="utf-8"?><!--Create a custom component by putting a Spark Label and a Spark Button in a Spark VGroup inside of a SparkGroup with a Cyan background color.--><s:Group xmlns:MyComps="customComps.*" xmlns:fx="http://ns.adobe.com/mxml/2009"xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/mx"><!--Fill the entire group with a cyan rectangle--><s:Rect width="100%" height="100%"><s:fill><s:SolidColor color="0x00FFFF" /></s:fill></s:Rect><!--Put a Spark VGroup in the Group and put a Spark Label and a Spark Button in the VGroup--><s:VGroup><s:Label text="Custom Component."color="#000000" fontSize="12" fontWeight="bold"/><s:Button label="Button"/></s:VGroup></s:Group>

No further explanation needed

Assuming that you understand the contents of the files named Label.mxml and Button.mxml in the Flex 3 program in the earlier lesson, and assuming that you understood the explanation of thedifferences between the two main mxml files given above, the comments in Listing 5 and Listing 6 should serve as a sufficient explanation of the code in Listing5 and Listing 6.

Run the program

I encourage you to run this program from the web. Then copy the code from Listing 4 through Listing 6. Use that code tocreate your own projects. Compile and run the projects. Experiment with the code, making changes, and observing the results of your changes. Makecertain that you can explain why your changes behave as they do.


I will publish a list containing links to Flex resources as a separate document. Search for Flex Resources in theConnexions search box.


This section contains a variety of miscellaneous materials.

Housekeeping material
  • Module name: XML - Namespaces - Flex 4
  • Files:
    • Flex0086a\Connexions\FlexXhtml0086a.htm
PDF disclaimer: Although the Connexions site makes it possible for you to download a PDF file for thismodule at no charge, and also makes it possible for you to purchase a pre-printed version of the PDF file, you should beaware that some of the HTML elements in this module may not translate well into PDF.


Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
nanocopper obvius
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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