Several months ago I had to choose among php, .net, coldfusion, asp and Ruby on Rails. I chose Ruby on Rails because I had seen the famous screencast where the author creates a blog within minutes. I even bought the Agile Web Developement book and then almost any book with Ruby or Rails in its title. To this day I am still learning without much to show off. The question is how I am going to justify so much time spent on this learning. my answer is I find this a lot more fulfilling and promising than I had bargained for.

Would I recommend it to others ?

Here is a better reply given by Michael Slater and Chris Haupt

“Ultimately, the factor that probably keeps more developers away from Rails than any other is the learning curve. If you’ve already been working with one technology, it’s always more time consuming in the short term to switch to a different one. And if you’re only working on simple sites, it may not be worth the investment.

But if you want to advance your skills and become as productive as you can be, you owe it to yourself to learn Ruby on Rails. You’ll need to invest a few months of study and practice to become proficient, but from that point forward you’ll be building better sites more quickly and having more fun doing it.

If you’re a PHP developer, you many wonder whether you can take a short-cut and use a PHP-based MVC framework instead of having to learn Ruby. In the short term, this may save you time. But Ruby is a key enabler of many aspects of Rails, and it just isn’t possible to build a framework that really matches Rails in a language such as PHP. Learning any powerful framework takes a significant effort, whether it’s a PHP framework or a Ruby framework. Learning the basics of Ruby isn’t hard. The payback is that you’ll be working in a more modern, more elegant language, and with a more powerful framework as well.

In future episodes of this podcast, we’ll explore all the key concepts that underlie Ruby on Rails. Ultimately, though, you need to begin building sites with it to really understand it. There’s a variety of good books and online resources available, many of which you’ll find listed in the show notes at learningrails.com.”

Actually this is from the transcript of the podcast . You can view the podcast here

Learning Flex and RoR simultaneously can be a hard Job for anyone especially for those who with years of designing experience but little or no programming experience.

Colin Moock has taken some pains to explain whether ActionScript is hard or not in this article titled ActionScript 3.0: Is It Hard or Not.

Well my opinion is (after reading the article and the ongoing public debate in the shape of comments and counter comments ) that end users never bother to see in which language the application is written.They just want the application to solve their problems and not force them to learn something new just to use it.

Author: Ashwinee Kumar Dash.

Name of the Book: Essential ActionScript 3.0 by Colin Moock

Copyright:
Disclaimer: Anything in quotation marks is a direct quotation from Essential
ActionScript 3.0. All other notes are my own summaries of the concepts
presented in the book.

These notes are for reference purpose only and not intended to replace the book .Therefore I would strongly advise you to read the original book as well as make your own notes wherever necessary.

Send your suggestions and feedbacks to aswhineedash[at]gmail[dot]com or aswhinee2004[at]gamil[dot]com.

Data Type

• Data Type means a set of values.
• Null, void and object are three data types in AS.
• Null has null value
• Void has undefined as its value
• Object includes all the instances of all the classes in ActionScript.
• Each class creates a unique datatype. Its values are the instances of the class itself and its subclasses.
• Any given subtype is compatible with its supertype and likewise a supertype is incompatible with its subtype. That’s because an instance of subclass can be treated as an instance of its superclass.
• A type annotation or type declaration is a suffix that constrains the datatype of a variable parameter or function return value.
• Type declaration is preceded by colon “:”.
• In case of variable or function parameter the data type must be a class or interface.
• In case of return type the data type must be a class, interface or void.
• They can take * as data type which means untyped.
• 3 situations where data type mismatch error is ignored in strict mode until runtime (1) untyped expression assigned to typed variable or parameter or returned from a function with a declared return type (2) any expression assigned to a typed variable or parameter with Boolean datatype or returned from a function with a Boolean return type (3) any numeric type is used where a different numeric type is expected
• To detect reference errors compiler relies on type annotations.
• Compiler checks the method definition in the class or interface which is specified by variable’s type annotation.
• Compiler does not check the actual class of the value.
• To avoid such errors at the compile time cast operation is used.
• Cast operation tells the compiler to treat the expression as a specified type.
• Type (expression).
• At the runtime if the expression resolves to the specified object, it is returned.
• If it does not resolve to a specified object, either it is converted to a primitive datatype or an error is generated.
• Casting an object to its supertype is known as upcast
• Casting an object to its subtype is known as downcast.
• Upcast never generates an error
• Downcast has the potential to generate error
• To check the data type of an object, the ‘is’ operator is used like (expression is type) which returns a true or false value.
• A cast operation can be used to convert any value to a particular primitive type.
• When a variable is declared without a type annotation and without an initial value, its value is set to undefined.
• If a variable is not initialized, it takes the default value of its datatype.
• Both null and undefined means absence of data
• The null value represents the absence of data for variables, parameters and return values with any type annotations except Boolean, int, uint, and number
• Undefined represents absence of data for variables, parameters or return values without any specified type annotations
• Undefined also means complete absence of variable or method on an object whose class is defined as dynamic

After a 3 part video regarding Thermo appeared in youtube many developers got excited about the product and started blogging about it. So FlexNotes also watched the video and read the blog posts with eagerness and anticipation.The author even had an imaginary conversation with a developer (referred to as D) proficient in many technologies as well as managing large scale projects. He also runs his own company.

Disclaimer: The conversation between FL and D that you are going to read is a work of fiction. It does not bear any resembalance to anyone living or dead in real world.Please stop reading further from the point where it starts hurting your feelings, sentiments etc.

FL: Do you know when Thermo is coming?
D(Dev) :No, we don’t.
FL: Have you really tried it out ?
D: No, but I have seen a video on the YouTube.
FL: But you have posted in your blog divdavdev.com that Thermo will generate bad code. How do you know that ?
D: Any such thing that is designer friendly is bound to produce bad code. Just like any WYSIWYG editor.
FL: Do you intend to use it in your organisation for developing RIAs, along with Flex builder?
D: Look, its a designers’ only product that helps a novice to draw a very fanciful image of an application in Photoshop and then import it and convert it into a working Flex project, of course by adding interactivity to it. So its only good for designers who do not know MXML or AS 3.0.But we don’t need it as we are very efficient in writing code in Flex builder to generate what we want.Hence WE do not need it.
FL: May be your designers will need it.
D: We don’t have a full time designer. Whenever we have any design requirements we just ask any freelancer to do it. That’s all.
FL: What do you do when design related change requests come from clients ? Do you send it to the designers again for changes ?
D: We try to do it ourselves. Once the main design has been done, it is easy to make small changes in Photoshop. Then again we always ask the clients to consider bad effects of changing UI such as increase in loading time, decrease in performance which will lead to more development efforts etc.
FL: Do the clients always agree ?
D: Most of the time they do.
FL: What happens if the client does not agree ?
D: We make necessary changes ourselves. Chink our best java developer knows Photoshop a little.We ask to him to make the small changes. He likes it. You should see his some of his photo editing capabilities in flickr.
FL: But RIA without designers does not sound very promising?
D: Actually we are trying very hard find very best designers, but so far we have no luck?
FL: What are your requirements ?
D: Very few. He should know Flex 2 (both MXML and Actionscripting) very well and must have some knowledge in one Server side language and should know one database.While we would be certainly happy if he has some experience in Swing, Hibernate or JSF but that is not mandatory. But he must know about design patterns.
FL: You expect a designer to know all that?
D: We want someone to work in our team with team spirit and all our team members are conversant with that.
FL: Do you think Thermo will introduce new way of developing RIAs?
D: It is difficult to say anything about that right now .
FL: It is being speculated that once Thermo comes out designers would take care of all design, UI and Interactivity related tasks which will leave developers to concern about all logic and database related things. Do you think this is possible ?
D: It is a very difficult thing to achieve because for that Thermo has to produce readable and maintainable code just as we developers do.
FL: And who says if the code is up to the standard ?
D: We.
FL: Are you afraid of the fact that once Thermo comes, some of the RIA market will go to designers or in some cases they will control a considerable portions of any applications to be developed using Flex ?
D: Let me make this very clear. We rule the enterprise application development world. Mere designers armed with Photoshop and Thermo can’t take it away from us. We won’t simply let them have any of it. They can keep learning and publishing nice tutorials in their pretty blogs but that’s it.

Author: Ashwinee Kumar Dash.

Name of the Book: Essential ActionScript 3.0 by Colin Moock

Copyright:
Disclaimer: Anything in quotation marks is a direct quotation from Essential
ActionScript 3.0. All other notes are my own summaries of the concepts
presented in the book.

These notes are for reference purpose only and not intended to replace the book .Therefore I would strongly advise you to read the original book as well as make your own notes wherever necessary.

Send your suggestions and feedbacks to aswhineedash[at]gmail[dot]com or aswhinee2004[at]gamil[dot]com.

Instance Methods

• The keyword this can be omitted as ActionScript automatically searches for the instance variable or method unless there is a local one available matching the search result.
• Usage of the keyword this is legal only in the following cases instance method, constructor method, functions and code in global scope.
• Method can be assigned as value to variable and again can be invoked through that variable. Such methods are known as bound methods.
• This is most used when one section of program wishes to instruct another section of the program to invoke a particular method on a particular object.
• Get method is used to retrieve the value of the private instance property
• To define get method get keyword is used.
• Get methods have a return type as they have the return value
• Similarly set methods are used to modify the values of variables.
• To define a set method set keyword is used.
• Unlike get methods set methods do not have return values.
• To invoke set or get methods “()” is not used.
• In case of set methods a value is assigned rather than any arguments are passed
• To deal with unknown number of parameters ….(rest) can be used where (rest) is the array of arguments. Just like any array arguments can be retrieved using array index.

Author: Ashwinee Kumar Dash.

Name of the Book: Essential ActionScript 3.0 by Colin Moock

Copyright:
Disclaimer: Anything in quotation marks is a direct quotation from Essential
ActionScript 3.0. All other notes are my own summaries of the concepts
presented in the book.

These notes are for reference purpose only and not intended to replace the book .Therefore I would strongly advise you to read the original book as well as make your own notes wherever necessary.

Send your suggestions and feedbacks to aswhineedash[at]gmail[dot]com or aswhinee2004[at]gamil[dot]com.

Static Variables and Methods

• Static variables are class variables, not instance variables. Static variables do not vary from instance to instance
• Static keyword defines the variable to be a class variable
• Four access control modifiers available and they are public, private, internal and protected. These modifiers come before the static keyword.
• Inside the class static variables can be used as regular variables. But otherwise it has to be accessed by using className.variable.
• Inside a class a static variable and an instance variable of same names can coexist.
• Constant is a variable with a value that do not change throughout the program
• It is defined using the keyword const in stead of var
• Like static variables, static methods define functionality that relate to an entire class.
• Static methods cannot use the keyword this.
• Static methods cannot access instance variables and instance methods of the class where it is defined. quite logical.
• When ActionScript creates a class at runtime, it creates a method called class initializer and runs it.
• In the class initializer it places all the static variables and all class level code that is not instance variable or instance method.
• Every class in ActionScript is represented at runtime as an instance of the Class class.
• Class objects are primarily used to access static properties and static methods.
• Like other objects class objects can be used as values for assigning and return type.

Author: Ashwinee Kumar Dash.

Name of the Book: Essential ActionScript 3.0 by Colin Moock

Copyright:
Disclaimer: Anything in quotation marks is a direct quotation from Essential
ActionScript 3.0. All other notes are my own summaries of the concepts
presented in the book.

These notes are for reference purpose only and not intended to replace the book .Therefore I would strongly advise you to read the original book as well as make your own notes wherever necessary.

Send your suggestions and feedbacks to aswhineedash[at]gmail[dot]com or aswhinee2004[at]gamil[dot]com.

Classes

• Classes are the blue prints upon which objects are built.
• Every object that you see in a program has a class of its own.
• Classes written from scratch known as custom classes.
• Built in classes are used to perform some fundamental tasks
• Classes built directly into ActionScript are known as native classes.
• Classes are created by using class keyword.
• class Identifier {

}

• Name of the class should start with capital letter. Class name is known as Indentifier.
• Class files should be saved with .as extension and the file name should match the class name.
• All classes should reside in a package definition. A folder in that name should be created to contain the .as files.
• To avoid a class conflicting with another class having the same name, it is defined within a package.
• Package names start with small letters to distinguish from class names.
• In ActionScript all program instructions are called directives.
• A package definition can span multiple files but a class definition cannot span multiple files
• Class in AS can have 4 attributes public, private, internal and static. The abstract property is not supported.
• The main class must have public as its attribute set.
• Internal is the default attribute.
• If a class is meant to be used outside its package, it must be declared as public.
• Internal means the class can be used inside the package only.
• objects can be created out of classes by calling its constructor methods
• If no constructor is provided, AS creates a default constructor. In this case no initialization takes place on new instances.
• AS considers all constructor methods as public.
• Codes in a given package can access the classes in that package only.
• Code in a given package can refer to the classes in that package by their unqualified name i.e. name without their package name like com. className.
• To use classes in other packages it must be imported first.
• Once the class has been imported, it can be referred by its unqualified name.
• Packages that have no name associated with them are placed in an automated created package Unnamed Package.These classes can be used in any where in the program without import directive.
• Every object is considered as a self contained, single piece of data known as value.
• Other legal values are null and undefined, they represent the concept of no value.
• A variable is an identifier that refers to a value.
• There are four types of variables: local variables, instance variables, dynamic instance variables and static variables
• // Local variables//
• Local variables track information temporarily within the confinement of a constructor method, an instance method, a static method or a function.
• The variable definition starts with var keyword.
• (Note) any directive that do not include a block statement ends with a semicolumn;
• Value to a variable is assigned by using = sign.Both the = sign and value are known as variable initialiser.
• When variable initialiser is missing actionscript assigns a default value.
• The local variable expires once the function or the method that contains its definition is finished executing.
• // Instance Variable//
• Each object has got some characteristics that describe some aspect of that object. To keep track of an object’s characteristics, instance variables are used.
• Instance variables are created using var keyword directly inside the class body. Once declared, it is directly attached to the instances automatically.
• Instance variables can be and commonly set outside the class.
• Four types of access control modifiers are available for instance variables. They are: public, internal, protected and private.
• Instance variables having public attributes can be accessed both inside and outside of the package.
• Instance variable declared internal can be accessed inside the package only. Internal is the default one.
• Protected instance variables and private instance variables can be accessed by those classes where they have been defined. But the difference lies in subclasses accessing protected ones.
• // constructor parameter //
• Constructor parameters are variables that are declared and used as part of the construction method.
• Assigning values to constructor parameters is known as passing values to variables.
• Required parameter is the parameter whose value has not been initialized
• At the instantiation of the class the required parameters must be passed.
• An expression that contains variable’s name only is known as identifier expression
• Within the body of the constructor method, this refers to the object created i.e. itself.
• // Copies and references//
• When the source variable is an instance of String, Boolean, int, uint, Number, ActionScript makes a copy of that variable and assigns the copy to the destination variable. In other cases it only refers to the original value.
• Instance methods are functions that defines the actions of the object
• Call expression is used to make the object perform the action.
• Like instance variables, instance methods also got access control modifiers. They are public, private, protected and internal
• As usual internal is the default one and it will be assigned unless anything else is specified. Internal is for package use only.
• Public means it can be used outside the package.
• Protected instance methods can be used inside the class and its subclasses only
• Methods accepts values through their parameters
• Methods also return values.
• Method signatures include each parameter’s datatype and return type.

I would like to thank Colin for allowing me to publish my own notes that I had jotted down while studying his (essential) book aptly titled Essential ActionScript 3.0.

In my opinion it is the best book currently available to learn Object Oriented Programming using Actionscript 3.0. The following three categories of readers can benefit from the book

• those who are new to OOP and AS 3.0 ( they will find it most useful).
• those wishing to upgrade from AS 2.0 to AS 3.0 will need this book to understand concepts like e4x, display architecture, Flash player security and events and event handling etc.
• C# or C++ or java developers wishing to use AS 3.0 in their Flex projects won’t find such in depth knowledge and coverage of AS3.0 in any other book.

The importance of AS 3.0 has increased in these days due to quick adoption of Flex and to use Flex to its fullest extent one must know AS 3.0 inside out . When it comes to ActionScript, nobody teaches you the better than Colin Moock.

I, like countless others have learnt a lot about ActionScript and Flash just by reading his books. I hope he continues to write more about ActionScript, a popular language destined to become.

Currently it is not posssible to create a screen capture application using AS 3.0 and AIR Beta 1.

I built a demo screen capture application to test the fact.

Here is the screenshot of the application:

Image created and saved by the application:

Here is the code of the application I built to test the fact.

//code begin//
<?xml version=”1.0″ encoding=”utf-8″?>
<mx:Application xmlns:mx=”http://www.adobe.com/2006/mxml” layout=”absolute” applicationComplete=”init();”>
<mx:Style>
Application
{
background-color: “”;
background-image: “”;
margin-top: 0;
margin-right: 0;
margin-bottom: 0;
margin-left: 0;
}
</mx:Style>

<mx:Script>
<![CDATA[

import mx.controls.Alert;

import flash.display.Bitmap;
import com.adobe.images.JPGEncoder;
import flash.filesystem.*;

private var bitmapData:BitmapData;
private var newImage:File;
private var fileStream:FileStream;

private function init():void {
fileStream = new FileStream();
stage.window.width = 500;
stage.window.height = 500;

}
private function snagPic():void {
bitmapData = new BitmapData(this.width,this.height,false,0x00000000);
bitmapData.draw(this,new Matrix());
var bitmap : Bitmap = new Bitmap(bitmapData);
var jpg:JPGEncoder = new JPGEncoder();
var ba:ByteArray = jpg.encode(bitmapData);
newImage = File.applicationStorageDirectory.resolve("Images/" + fileName.text + ".jpg");
fileStream = new FileStream();
fileStream.open(newImage, FileMode.UPDATE);
fileStream.writeBytes(ba);
}
private function onClose(evt:MouseEvent):void
{
stage.window.close();
}

]]>
</mx:Script>
<mx:Panel x=”50″ y=”37″ width=”250″ height=”200″ layout=”absolute”>
<mx:TextInput x=”35″ y=”87″ id=”fileName” text=”MyNewFile”/>
</mx:Panel>
<mx:Button x=”83″ y=”284″ label=”snap” click=”snagPic()”/>
<mx:Button x=”207.5″ y=”284″ label=”Close” click=”onClose(event)”/>

</mx:Application>

//code ends//

Note : Make the application transparent.

The application tries to save the image of the stage along with all the display object on it in the runtime.The stage is set to transparent.so while running the application we only see the display objects and not the stage.

But when the image is drawn on a BitmapData object the background color is set to white when transparent property is set to true in case of the property being set to false, the background color turns black.

Colin Moock also discussed about screen captures in Essential Actionscript 3.0 book. Here is an excerpt from the book:
“26.7.1.2. No arbitrary screen captures
Note that it is not possible to take a screen capture of an arbitrary rectangular region of the
screen via ActionScript. ActionScript can only copy display objects to bitmap format.
ActionScript’s closest analog to screen capturing the display area is to use the Stage instance
as draw()’s source parameter, as in:
var canvas:BitmapData = new BitmapData(100, 100, false, 0xFFFFFFFF);
canvas.draw(someDisplayObject.stage);
where someDisplayObject is a DisplayObject instance on the display list. The preceding
code will produce a bitmap containing every object currently on the display list, with the
following caveats:
• The .swf file’s background color is not copied to the bitmap.
• If any objects on the display list are inaccessible due to security restrictions, they are not copied to the bitmap and a SecurityError exception is thrown.”

Lets hope that building such an application will be possible the release of AIR version 1.

Sorry for being away for a while.

It is a simple example to play .flv files from the local system. Earlier in my Jukebox tutorials I had used a fileOpen component. As the component is no more available for download, I thought of showing this alternative way to access files from local system rather than rewriting the juke box tutorials again.

I hope readers would be ablw to use this concept while building their own mp3 players.

In case there is a problem, just send me a mail (no spam, please) .

Just create a new AIR project in Flex Builder 3 and use the following code . Then click Run to see the application.

<?xml version=”1.0″ encoding=”utf-8″?>
<mx:WindowedApplication xmlns:mx=”http://www.adobe.com/2006/mxml” layout=”absolute” backgroundGradientAlphas=”[1.0, 1.0]” backgroundGradientColors=”[#FBFAFC, #F3F3F4]“>
<mx:Script>
<![CDATA[
import flash.filesystem.File;
import mx.events.FileEvent;

/*****************************
Create a file object and point it to documentsDirectory.
It is the My Documents directory in case of Windows and
Documents subdirectory of the user directory in case of Mac OS.
******************************/

private var file:File = File.documentsDirectory;

/*****************************
browseForOpen method opens up a browse directory dialog
box to open a file from My Documents directory
(Documents directory in case of Mac OS) for file browsing
and upon selection of a file onSelect method is called.
******************************/

private function fileOpen():void {
file.browseForOpen("Select a file");
file.addEventListener(Event.SELECT, onSelect);
}
/**********************************
onSelect method assigns the url property of the file object to the
variable vUrl and the name property to the variable vName as a string.

**********************************/
[Bindable]
private var vUrl:String;
[Bindable]
private var vName:String;
private function onSelect(event:Event):void {
vUrl = file.url;
vName = file.name;
myVideo.play();
timer.visible=true
}

private function closeVid():void {
myVideo.stop();
timer.visible=false;
vidName.visible=false;
}

]]>
</mx:Script>
<mx:VideoDisplay x=”70″ y=”26″ width=”379″ height=”234″ id=”myVideo” source=”{vUrl}”/>
<mx:Button click=”fileOpen()” label=”Open” x=”70″ y=”289″/>
<mx:Button x=”134″ y=”289″ label=”Close” click=”closeVid()”/>
<mx:Label x=”90″ y=”10″ text=”{vName}” id=”vidName” fontSize=”10″ fontWeight=”bold” color=”#0E5B87″/>
<mx:Label x=”210″ y=”291″ id=”timer” text=”{myVideo.playheadTime}/{myVideo.totalTime}” visible=”false”/>
</mx:WindowedApplication>
If everything is OK and the application works, then start packaging for distribution.

With release of next version of Flash Player, You will be able to create your own media player . Future seems so bright.

Imtiyaz.m.s has compiled a comparison between Java 5.0 and ActionScript 3.0 in his blog. Here is the link http://msimtiyaz.wordpress.com/flex/java-and-actionscript/

And don’t forget to view the comments here http://msimtiyaz.wordpress.com/2007/08/05/mfug-2/

Update

Detailed comparison can be found in the book Rich Internet Applications with Adobe Flex and Java .

This book is written by Yakov Fain, Dr. Victor Rasputnis, Anatole Tartakovsky.