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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.

Resources

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

Miscellaneous

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.

-end-

Questions & Answers

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
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Introduction to xml. OpenStax CNX. Dec 02, 2014 Download for free at https://legacy.cnx.org/content/col11207/1.18
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