Flex - Quick Guide

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Flex - Overview

What is Flex?

Flex is a powerful, open source application framework that allows you to build traditional applications for browser, mobile and desktop using the same programming model, tool, and codebase.

Flex provides FLEX SDK consisting of the Flex class library (ActionScript classes), the Flex compilers, the debugger, the MXML and ActionScript programming languages, and other utilities to build expressive and interactive rich internet applications (RIA)

Flex takes care of the user interface (UI) or the client-side functionality of a web application. Server-side functionality is dependent on server-side components written in a traditional scripting language (Java/ PHP etc.)

A Flex based application actually delivered as a SWF file and it closely resembles the HTML / JavaScript portion of a traditional web application.

Flex application is deployed as SWF file(s) plus an HTML wrapper, the CSS file(s) and any server-side script files (i.e. Java, .CFM, .PHP, etc.) to the server. Like traditional web applications.

These resources are delivered from a server to the client’s browser using the customary HTTP request / response fashion and Flash Player which runs the application in a browser.

Advantages of Flex

• Flex applications are usually Flash Player based which can access device capabilities like GPS, camera, local database, graphics accelerometer.

• Flex applications can run on Android, BlackBerry Tablet OS, and iOS devices.

• Flex applications can run on Browsers as well as on Desktop.

• Flex applications are platform independent. UI can be native to platform or can be made same on each platform.

• Flex applications can interact with server with all major server side technologies like Java, Spring, Hibernate, PHP, Ruby, .NET, Adobe ColdFusion, and SAP using industry standards such as REST, SOAP, JSON, JMS, and AMF.

• Flex Applications assures rich user experience through intuitive interaction with the application and presenting information in a visually richer interface.

• Flex application is a single page application where states can transition from one state to other state without having to fetch a new page from the server or to refresh the browser.

• Flex application reduces the load on the server to great extent because it is only required to return the application once, rather than a new page every time when the user changes views.

Disadvantages of Flex

• Flex applications are single threaded applications but Flex provides an asynchronous programming model to mitigate this concern.

• Flex is ActionScript and XML based. Learning of these two is a must to work in Flex.

Flex - Environment Setup

This tutorial will guide you on how to prepare a development environment to start your work with Adobe Flex Framework. This tutorial will also teach you how to setup JDK and Adobe Flash Builder on your machine before you setup Flex Framework.

System Requirement

FLEX requires JDK 1.4 or higher, so the very first requirement is to have JDK installed in your machine.

Follow the given steps to setup your environment to start with Flex application development.

Step 1 - Verify Java installation on your machine

Now open the console and execute the following java command.

Let's verify the output for all the operating systems −

Step 2 - Setup Java Development Kit (JDK)

If you do not have Java installed, then you can install the Java Software Development Kit (SDK) from Oracle's Java site Java SE Downloads. You will find instructions for installing JDK in downloaded files, then follow the given instructions to install and configure the setup. Finally set PATH and JAVA_HOME environment variables to refer to the directory that contains java and javac, typically java_install_dir/bin and java_install_dir respectively.

Set the JAVA_HOME environment variable to point to the base directory location where Java is installed on your machine. For example −

Append the Java compiler location to the System Path.

Step 3 - Setup Adobe Flash Builder 4.5

All the examples in this tutorial has been written using Adobe Flash Builder 4.5 Profession IDE Trial Version. Hence, suggest you to have latest version of Adobe Flash Builder installed on your machine. Also, check compatibility of operating system.

To install Adobe Flash Builder IDE, download the latest Adobe Flash Builder binaries from https://www.adobe.com/in/products/flash-builder.html. Once you downloaded the installation, unpack the binary distribution into a convenient location. For example, in C:\flash-builder on windows, or /usr/local/flash-builder on Linux/Unix and finally set PATH variable appropriately.

Flash Builder will start, when you execute the following commands on windows machine, or when you can simply double click on FlashBuilder.exe

%C:\flash-builder\FlashBuilder.exe

Flash Builder can be started by executing the following commands on Unix (Solaris, Linux, etc.) machine −

$/usr/local/flash-builder/FlashBuilder

Adobe Flash Builder Trial Version can be used for 60 days. Just accept the terms and conditions, and skip the initial registration steps to continue with the IDE. For our understanding, we’re using the trial version for teaching purpose.

After a successful startup, if everything is fine then it should display the following result −

Adobe Flash Builder comes pre-configured with FLEX SDKs. We're using FLEX SDK 4.5 in our examples which come bundled with Adobe Flash Builder 4.5.

Step 4 – Setup Apache Tomcat

You can download the latest version of Tomcat from https://tomcat.apache.org/. Once, you downloaded the installation, unpack the binary distribution into a convenient location. For example, in C:\apache-tomcat-6.0.33 on windows, or /usr/local/apache-tomcat-6.0.33 on Linux/Unix and set CATALINA_HOME environment variable pointing to the installation locations.

Tomcat can be started by executing the following commands on windows machine, or you can simply double click on startup.bat

%CATALINA_HOME%\bin\startup.bat 
or 
C:\apache-tomcat-6.0.33\bin\startup.bat 

Tomcat can be started by executing the following commands on UNIX (Solaris, Linux, etc.) machine −

$CATALINA_HOME/bin/startup.sh 
Or 
/usr/local/apache-tomcat-6.0.33/bin/startup.sh

After a successful startup, the default web applications included with Tomcat will be available by visiting http://localhost:8080/. If everything is fine, then it should display the following result −

Further information about configuring and running Tomcat can be found in the documentation included here, as well as on the Tomcat web site: http://tomcat.apache.org

Tomcat can be stopped by executing the following commands on windows machine −

%CATALINA_HOME%\bin\shutdown
Or
C:\apache-tomcat-5.5.29\bin\shutdown

Tomcat can be stopped by executing the following commands on UNIX (Solaris, Linux, etc.) machine −

$CATALINA_HOME/bin/shutdown.sh
Or
/usr/local/apache-tomcat-5.5.29/bin/shutdown.sh

Flex - Applications

Before we start creating actual “HelloWorld” application using Flash Builder, let us see what the actual parts of a Flex application are −

A Flex application consists of the following four important parts, out of which last part is optional but first three parts are mandatory.

• Flex Framework Libraries
• Client-side code
• Public Resources (HTML/JS/CSS)
• Server-side code

Sample locations of different parts of a typical Flex application like HelloWord will be as shown below −

Application Build Process

To start with, Flex application requires Flex framework libraries. Later, Flash Builder automatically adds the libraries to build path.

When we build our code using Flash builder, Flash builder will do the following tasks −

• Compiles the source code to HelloWorld.swf file.

• Compiles a HelloWorld.html (a wrapper file for swf file) from a file index.template.html stored in html-template folder

• Copies HelloWorld.swf and HelloWorld.html files in target folder, bin-debug.

• Copies swfobject.js, a JavaScript code responsible to load swf file dynamically in HelloWorld.html in target folder, bin-debug

• Copies framework libraries in form of swf file named frameworks_xxx.swf in target folder, bin-debug

• Copies other flex modules (.swf files such as sparkskins_xxx.swf, textLayout_xxx.swf) in target folder.

Application Launch Process

• Open the HelloWorld.html file available in \HelloWorld\bin-debug folder in any web-browser.

• HelloWorld.swf will load automatically and application will start running.

Flex Framework Libraries

Following is the brief detail about few important framework libraries. Please note that, Flex libraries are denoted using .swc notation

Client-side Code

Flex application code can be written in MXML as well as ActionScript.

In Flex, we can mix ActionScript and MXML, to do the following −

• Layout user interface components using MXML tags

• Use MXML to declaratively define nonvisual aspects of an application, such as access to data sources on the server

• Use MXML to create data bindings between user interface components and data sources on the server.

• Use ActionScript to define event listeners inside MXML event attributes.

• Add script blocks using the tag.

• Include external ActionScript files.

• Import ActionScript classes.

• Create ActionScript components.

Public Resources

These are help files referenced by Flex application, such as Host HTML page, CSS or images located under html-template folder. It contains following files −

HelloWorld.mxml

This is the actual MXML/AS (ActionScript) code written implementing the business logic of the application and that the Flex compiler translates into SWF file which will be executed by flash player in the browser.

A sample HelloWorld Entry class will be as follows −

<?xml version = "1.0" encoding = "utf-8"?>
<s:Application xmlns:fx = "http://ns.adobe.com/mxml/2009" 
   xmlns:s = "library://ns.adobe.com/flex/spark" 
   xmlns:mx = "library://ns.adobe.com/flex/mx"
   width = "100%" height = "100%"
   minWidth = "500" minHeight = "500" 
   initialize = "application_initializeHandler(event)">

   <fx:Script>
      <![CDATA[
         import mx.controls.Alert;
         import mx.events.FlexEvent;
         protected function btnClickMe_clickHandler(event:MouseEvent):void {
            Alert.show("Hello World!");				
         }

         protected function application_initializeHandler(event:FlexEvent):void {
            lblHeader.text = "My Hello World Application";				
         }
      ]]>
   </fx:Script>
   
   <s:VGroup horizontalAlign = "center" width = "100%" height = "100%" 
      paddingTop = "100" gap = "50">
      <s:Label id = "lblHeader" fontSize = "40" color = "0x777777" />
      <s:Button label = "Click Me!" id = "btnClickMe" 
         click = "btnClickMe_clickHandler(event)" />
   </s:VGroup>	
</s:Application>

Following table gives the description of all the tags used in the above code script.

Server-side code

This is the server side part of your application and it’s very much optional. If you are not doing any backend processing within your application, then you do not need this part but if there is some processing required at backend and your clientside application interacts with the server, then you will have to develop these components.

In the next chapter, we will use all the above-mentioned concepts to create a HelloWorld application using Flash Builder.

Flex - Create Application

We'll use Flash Builder 4.5 to create Flex Applications. Let's start with a simple HelloWorld application.

Step 1 – Create Project

The first step is to create a simple Flex Project using Flash Builder IDE. Launch project wizard using the option File > New > Flex Project. Now name your project as HelloWorld using the wizard window as follows −

Select Application Type Web (runs in Adobe Flash Player). However, if this is not selected, then leave other default values as such and click Finish Button. Once your project is created successfully, then you will have the following content in your Project Explorer −

Here is a brief description of all the important folders −

Step 2 – Create External CSS File

Create a CSS file styles.css for Wrapper HTML page in html-template folder.

html, body { 
   height:100%;
}

body { 
   margin:0; 
   padding:0; 
   overflow:auto; 
   text-align:center;		
}   

object:focus { 
   outline:none; 
}

#flashContent { 
   display:none;	
}

.pluginHeader {
   font-family:Arial, Helvetica, sans-serif;
   font-size:14px;
   color:#9b1204;
   text-decoration:none;
   font-weight:bold;
}

.pluginInstallText {
   font-family:Arial, Helvetica, sans-serif;
   font-size:12px;
   color:#000000;
   line-height:18px;
   font-style:normal;
}

.pluginText { 
   font-family:Arial, Helvetica, sans-serif;
   font-size:12px;
   color:#000000;
   line-height:18px;
   font-style:normal;
}

Step 3 – Modify Wrapper HTML page template

Modify Wrapper HTML page template index.template.html in htmltemplate folder. Flash Builder will create a default Wrapper HTML page template html-template/index.template.html, which will be compiled to HelloWorld.html.

This file contains placeholders which Flash Builder replaces during the compilation process. For example, flash player version, application name, etc.

Let us modify this file to display custom messages in case flash plugin is not installed.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns = "http://www.w3.org/1999/xhtml" lang = "en" xml:lang = "en">
   
   <head>
      <title>${title}</title>
      <meta name = "google" value = "notranslate" />
      <meta http-equiv = "Content-Type" content = "text/html; charset = utf-8" />
      <link rel = "stylesheet" href = "styles.css" type = "text/css"></link>
      <link rel = "stylesheet" type = "text/css" href = "history/history.css" />
      <script type = "text/javascript" table table-bordered = "history/history.js">
      </script>
      <script type = "text/javascript" table table-bordered = "swfobject.js"></script>
      
      <script type = "text/javascript">
         // For version detection, set to min. required Flash Player version,
         //or 0 (or 0.0.0), for no version detection.
         var swfVersionStr = "${version_major}.${version_minor}.${version_revision}";

         // To use express install, set to playerProductInstall.swf,
         //otherwise the empty string.
         var xiSwfUrlStr = "${expressInstallSwf}";
         var flashvars = {};
         var params = {};
         params.quality = "high";
         params.bgcolor = "${bgcolor}";
         params.allowscriptaccess = "sameDomain";
         params.allowfullscreen = "true";
         
         var attributes = {};
         attributes.id = "${application}";
         attributes.name = "${application}";
         attributes.align = "middle";
         swfobject.embedSWF (
            "${swf}.swf", "flashContent",
            "${width}", "${height}",
            swfVersionStr, xiSwfUrlStr,
            flashvars, params, attributes);

         // JavaScript enabled so display the flashContent div in case
         //it is not replaced with a swf object.
         swfobject.createCSS("#flashContent", "display:block;text-align:left;");
      </script>
   </head>
   
   <body>
      <div id = "flashContent">
         <p style = "margin:100px;">

            <table width = "700" cellpadding = "10" cellspacing = "2" border = "0">
               <tr>
                  <td class = "pluginHeader">Flash Player Required</td>
               </tr>
               
               <tr>
                  <td class = "pluginText">The Adobe Flash Player version
                     10.2.0 or greater is required.</td>
               </tr>
               
               <tr>
                  <td class = "pluginInstallText" align = "left">
               
                  <table border = "0" width = "100%">
                     <tr class = "pluginInstallText" >
                        <td>Click here to download and install Adobe Flash Player:</td>
                        <td> </td>
                        <td align = "right">
                           <script type = "text/javascript">
                              var pageHost
                                 = ((document.location.protocol == "https:") ? "https://" : "http://");
                              document.write("<a target = '_blank'"
                                 +" href = 'http://get.adobe.com/flashplayer/'><"
                                 +"img style = 'border-style: none' table table-bordered = '"
                                 +pageHost
                                 +"www.adobe.com/images/shared/download_buttons/get_flash_player.gif'"
                                 +" alt = 'Get Adobe Flash player' /></a>" );
                           </script>
                        </td>
                     </tr>
                  </table>
               </tr>
            </table>
         </p>
      </div>
      
      <noscript>
         <object classid = "clsid:D27CDB6E-AE6D-11cf-96B8-444553540000"
            width = "${width}" height = "${height}" id = "${application}">
            <param name = "movie" value = "${swf}.swf" />
            <param name = "quality" value = "high" />
            <param name = "bgcolor" value = "${bgcolor}" />
            <param name = "allowScriptAccess" value = "sameDomain" />
            <param name = "allowFullScreen" value = "true" />
         
            <!--[if !IE]>-->
            <object type = "application/x-shockwave-flash" data = "${swf}.swf"
               width = "${width}" height = "${height}">
               <param name = "quality" value = "high" />
               <param name = "bgcolor" value = "${bgcolor}" />
               <param name = "allowScriptAccess" value = "sameDomain" />
               <param name = "allowFullScreen" value = "true" />
            <!--<![endif]-->
         
            <!--[if gte IE 6]>-->
               <p>
                  <p style = "margin:100px;">
                     <table width = "700" cellpadding = "10" cellspacing = "2" 
                        border = "0">
                        <tr>
                           <td class = "pluginHeader">Flash Player Required</td>
                        </tr>
                        
                        <tr>
                           <td class = "pluginText">The Adobe Flash Player version
                           10.2.0 or greater is required.</td>
                        </tr>
                        
                        <tr>
                           <td class = "pluginInstallText" align = "left">

                           <table border = "0" width = "100%">
                              <tr class = "pluginInstallText" >
                                 <td>Click here to download and install Adobe Flash 
                                    Player:</td>
                                 <td> </td>
                                 <td align = "right">
                                    <script type = "text/javascript">
                                       var pageHost
                                          = ((document.location.protocol == "https:") ? "https://" : "http://");
                                       document.write("<a target = '_blank'"
                                          +" href = 'http://get.adobe.com/flashplayer/'><"
                                          +"img style = 'border-style: none' table table-bordered = '"
                                          +pageHost
                                          +"www.adobe.com/images/shared/download_buttons/get_flash_player.gif'"
                                          +" alt = 'Get Adobe Flash player' /></a>" );
                                    </script>
                                 </td>
                              </tr>
                           </table>
                        </tr>
                     </table>
                  </p>
               </p>
            <!--<![endif]-->
         
            <p style = "margin:100px;">
               <table width = "700" cellpadding = "10" cellspacing = "2" border = "0">
                  <tr><td class = "pluginHeader">Flash Player Required</td></tr>
                  <tr><td class = "pluginText">The Adobe Flash Player version
                     10.2.0 or greater is required.</td></tr>
                  <tr>
                     <td class = "pluginInstallText" align = "left">
                        <table border = "0" width = "100%">
                           <tr class = "pluginInstallText" >
                              <td>Click here to download and install Adobe Flash 
                                 Player:</td>
                              <td> </td>
                              <td align = "right">
                                 <script type = "text/javascript">
                                    var pageHost
                                       = ((document.location.protocol == "https:") ? "https://" : "http://");
                                    document.write("<a target = '_blank'"
                                       +" href = 'http://get.adobe.com/flashplayer/'><"
                                       +"img style = 'border-style: none' table table-bordered = '"
                                       +pageHost
                                       +"www.adobe.com/images/shared/download_buttons/get_flash_player.gif'"
                                       +" alt = 'Get Adobe Flash player' /></a>" );
                                 </script>
                              </td>
                           </tr>
                        </table>
                     </td>
                  </tr>
               </table>
            </p>
         <!--[if !IE]>-->
         </object>
         <!--<![endif]-->
         </object>
      </noscript>
   </body>
</html>

Step 4 – Create Internal CSS file

Create a CSS file Style.css for HelloWorld.mxml in table tablebordered/com/tutorialspoint folder. Flex provides similar css styles for its UI Controls as there are css styles for HTML UI controls.

/* CSS file */
@namespace s "library://ns.adobe.com/flex/spark";
@namespace mx "library://ns.adobe.com/flex/mx";

.heading {
   fontFamily: Arial, Helvetica, sans-serif;
   fontSize: 17px;
   color: #9b1204;
   textDecoration:none;
   fontWeight:normal;
}

.button {
   fontWeight: bold;			
}

.container {
   cornerRadius :10;
   horizontalCenter :0;	
   borderColor: #777777;
   verticalCenter:0;
   backgroundColor: #efefef;
}

Step 5 – Modify Entry Level Class

Flash Builder will create a default mxml file table tablebordered/com.tutorialspoint/HelloWorld.mxml, which is having root tag <application> container for the application. Let us modify this file to display "Hello,World!" −

<?xml version = "1.0" encoding = "utf-8"?>
<s:Application xmlns:fx = "http://ns.adobe.com/mxml/2009"
   xmlns:s = "library://ns.adobe.com/flex/spark"
   xmlns:mx = "library://ns.adobe.com/flex/mx
   width = "100%" height = "100%"
      minWidth = "500" minHeight = "500"
      initialize = "application_initializeHandler(event)">
   
   <fx:Style source = "/com/tutorialspoint/client/Style.css" />
   <fx:Script>
      <![CDATA[
         import mx.controls.Alert;
         import mx.events.FlexEvent;
         protected function btnClickMe_clickHandler(event:MouseEvent):void {
            Alert.show("Hello World!");
         }

         protected function application_initializeHandler(event:FlexEvent):void {
            lblHeader.text = "My Hello World Application";
         }
      ]]>
   </fx:Script>
   
   <s:BorderContainer width = "500" height = "500" id = "mainContainer"
      styleName = "container">
      <s:VGroup width = "100%" height = "100%" gap = "50" horizontalAlign = "center"
         verticalAlign = "middle">
         <s:Label id = "lblHeader" fontSize = "40" color = "0x777777"
            styleName = "heading" />
         <s:Button label = "Click Me!" id = "btnClickMe"
            click = "btnClickMe_clickHandler(event)" styleName = "button" />
      </s:VGroup>
   </s:BorderContainer>
</s:Application>

You can create more mxml or actionscript files in the same source directory to define either new applications or to define helper routines.

Step 6 – Build Application

Flash Builder has Build Automatically by default checked. Just check the Problems View if there is any error. Once you are done with the changes, you will not see any errors.

Step 7 – Run Application

Now click on Run application menu and select HelloWorld application to run the application.

If everything is fine, you must see browser pop up, application up, and running. If everything is fine with your application, it will produce the following result: [ Try it online ]

Because, you are running your application in flash player, then it will need to install Flash Player plugin for your browser. Simply follow the onscreen instructions to install the plugin. If you already have Flash Player plugin set for your browser, then you should be able to see the following output −

Congratulations! You have implemented your first application using Flex.

Flex - Deploy Application

This tutorial will explain you how to create an application war file and how to deploy that in Apache Tomcat Web server root.

If you understood this simple example then you will also be able to deploy a complex Flex application following the same steps.

Let us follow the following steps to create a Flex application −

Follow the steps given below to create a release build of a Flex application and then deploy it to tomcat server −

The first step is to create a release build using Flash Builder IDE. Launch release build wizard using the option File > Export > Flash Builder > Release Build.

Select project as HelloWorld using the wizard window as follows

Leave other default values as such and click Finish Button. Now, Flash Builder will create a bin-release folder containing the project's release build.

Now our release build is ready, let us follow the following steps to deploy a Flex application −

Following is the content of the modified mxml file table table-bordered/com.tutorialspoint/HelloWorld.mxml.

<?xml version = "1.0" encoding = "utf-8"?>
<s:Application xmlns:fx = "http://ns.adobe.com/mxml/2009" 
   xmlns:s = "library://ns.adobe.com/flex/spark" 
   xmlns:mx = "library://ns.adobe.com/flex/mx"
   width = "100%" height = "100%"
   minWidth = "500" minHeight = "500" 
   initialize = "application_initializeHandler(event)">
   
   <fx:Style source = "/com/tutorialspoint/client/Style.css" />
   <fx:Script>
      <![CDATA[
         import mx.controls.Alert;
         import mx.events.FlexEvent;
         protected function btnClickMe_clickHandler(event:MouseEvent):void {
            Alert.show("Hello World!");				
         }

         protected function application_initializeHandler(event:FlexEvent):void {
            lblHeader.text = "My Hello World Application";				
         }
      ]]>
   </fx:Script>
   
   <s:BorderContainer width = "500" height = "500" id = "mainContainer" 
      styleName = "container">
      <s:VGroup width = "100%" height = "100%" gap = "50" horizontalAlign = "center" 
         verticalAlign = "middle">
         <s:Label id = "lblHeader" fontSize = "40" color = "0x777777" 
            styleName = "heading" />
         <s:Button label = "Click Me!" id = "btnClickMe" 
            click = "btnClickMe_clickHandler(event)" styleName = "button" />
      </s:VGroup>	
   </s:BorderContainer>	
</s:Application>

Once you are ready with all the changes done, let us compile and run the application in normal mode as we did in Flex - Create Application chapter. If everything is fine with your application, then it will produce the following result: [ Try it online ]

Create WAR File

Now our application is working fine and we are ready to export it as a war file. Follow the following steps −

• Go into your project's bin-release directory C:\workspace\HelloWorld\binrelease

• Select all the files & folders available inside bin-release directory.

• Zip all the selected files & folders in a file called HelloWorld.zip.

• Rename HelloWorld.zip to HelloWorld.war.

Deploy WAR file

Stop the tomcat server.

• Copy the HelloWorld.war file to tomcat installation directory > webapps folder.

• Start the tomcat server.

• Look inside webapps directory, there should be a folder HelloWorld got created.

• Now HelloWorld.war is successfully deployed in Tomcat Webserver root.

Run Application

Enter a URL in web browser −

http://localhost:8080/HelloWorld/HelloWorld.html to launch the application.

Server name (localhost) and port (8080) may vary as per your tomcat configuration.

Flex - Life Cycle Phases

Life Cycle of Flex Application

Although, you can build Flex applications without understanding the life cycle phases of an application, it is good to know the basic mechanism; the order in which things occur. It will help you to configure features such as loading other Flex applications at runtime, and manage the process of loading and unloading class libraries and assets at runtime.

A good understanding of the Flex application life cycle will enable you to build better applications and optimize them because you will know where to optimally run code. For example, if you need to ensure that some code runs during a preloader, you need to know where to place the code for that event.

When we load flex application in a browser, the following events occurs during the lifecycle of flex application.

Following is the brief detail about different Flex Life cycle events.

Flex Life Cycle Example

Let us follow the steps to understand test life cycle of a Flex application by creating a test application −

Following is the content of the modified mxml file src/com.tutorialspoint/HelloWorld.mxml.

<?xml version = "1.0" encoding = "utf-8"?>
<s:Application xmlns:fx = "http://ns.adobe.com/mxml/2009"
   xmlns:s = "library://ns.adobe.com/flex/spark"
   xmlns:mx = "library://ns.adobe.com/flex/mx"
   width = "100%" height = "100%" minWidth = "500" minHeight = "500"
   initialize = "reportEvent(event)"
   preinitialize = "reportEvent(event)"
   creationComplete = "reportEvent(event)"
   applicationComplete = "reportEvent(event)">	
   
   <fx:Style source = "/com/tutorialspoint/client/Style.css" />
   <fx:Script>
      <![CDATA[
         import mx.controls.Alert;
         import mx.events.FlexEvent;
   
         [Bindable]
         private var report:String = "";

         private function reportEvent(event:FlexEvent):void {
            report += "\n" + (event.type + " event occured at: " 
            + getTimer() + " ms" + "\n");
         }
      ]]>
   </fx:Script>
   
   <s:BorderContainer width = "500" height = "500" id = "mainContainer" 
      styleName = "container">
      <s:VGroup width = "100%" height = "100%" gap = "50" 
         horizontalAlign = "center" verticalAlign = "middle">
         <s:Label textAlign = "center" width="100%" id = "lblHeader"
         fontSize = "40" color = "0x777777" styleName = "heading" 
         text = "Life Cycle Events Demonstration" />
         <s:TextArea id = "reportText" text = "{report}" editable = "false" 
         width = "300" height = "200">				
         </s:TextArea>			
      </s:VGroup>	
   </s:BorderContainer>	
</s:Application>

Once you are ready with all the changes done, let us compile and run the application in normal mode as we did in Flex - Create Application chapter. If everything is fine with your application, it will produce the following result: [ Try it online ]

Flex - Style with CSS

Flex supports the use of CSS syntax and styles to apply to its UI controls in the same way as CSS to HTML components.

Way # 1: Using External Style Sheet File

You can refer to a style sheet available in the class path of the application. For example consider Style.css file in com/tutorialspoint/client folder where HelloWorld.mxml file also lies.

/* CSS file */
@namespace s "library://ns.adobe.com/flex/spark";
@namespace mx "library://ns.adobe.com/flex/mx";
...
.container {
   cornerRadius :10;
   horizontalCenter :0;	
   borderColor: #777777;
   verticalCenter:0;
   backgroundColor: #efefef;
}

Then css file can be referred by following code snippet

<fx:Style source = "/com/tutorialspoint/client/Style.css" />

Assign styles to UI component using styleName property

<s:BorderContainer width = "500" height = "500" id = "mainContainer" 
   styleName = "container"> 
   ...
</s:BorderContainer>		  

Way # 2: Using Styles Within Ui Container Component

You can define styles within UI container component using <fx:Style> tag

Class Level Selector

<fx:Style>
   @namespace s "library://ns.adobe.com/flex/spark";
   @namespace mx "library://ns.adobe.com/flex/mx";

   /* class level selector  */
   .errorLabel {
      color: red;
   }		
</fx:Style>

Assign styles to UI component using styleName property.

<s:Label id = "errorMsg" text = "This is an error message" styleName = "errorLabel" />

Id Level Selector

Style UI component using id selector.

<fx:Style> 
   /* id level selector  */ 
   #msgLabel { 
      color: gray; 
   } 
</fx:Style>

<s:Label id = "msgLabel" text = "This is a normal message" /> 

Type Level Selector

Style one type of UI Component in one GO.

<fx:Style> 
   /* style applied on all buttons  */ 
   s|Button {  
      fontSize: 15; 
      color: #9933FF; 
   } 
</fx:Style>

<s:Button label = "Click Me!" id = "btnClickMe"
   click = "btnClickMe_clickHandler(event)" />

Flex Style with CSS Example

Let us follow the steps to check CSS styling of a Flex application by creating a test application −

Following is the content of the modified CSS file src/com.tutorialspoint/Style.css.

/* CSS file */
@namespace s "library://ns.adobe.com/flex/spark";
@namespace mx "library://ns.adobe.com/flex/mx";

.heading
{
   fontFamily: Arial, Helvetica, sans-serif;
   fontSize: 17px;
   color: #9b1204;
   textDecoration:none;
   fontWeight:normal;
}

.button {
   fontWeight: bold;			
}

.container {
   cornerRadius :10;
   horizontalCenter :0;	
   borderColor: #777777;
   verticalCenter:0;
   backgroundColor: #efefef;
}

Following is the content of the modified mxml file src/com.tutorialspoint/HelloWorld.mxml.

<?xml version = "1.0" encoding = "utf-8"?>
<s:Application xmlns:fx = "http://ns.adobe.com/mxml/2009"
   xmlns:s = "library://ns.adobe.com/flex/spark"
   xmlns:mx = "library://ns.adobe.com/flex/mx"
   width = "100%" height = "100%" minWidth = "500" minHeight = "500"
   initialize = "application_initializeHandler(event)">
   
   <!--Add reference to style sheet -->
   <fx:Style source = "/com/tutorialspoint/client/Style.css" />

   <!--Using styles within mxml file -->
   <fx:Style>
      @namespace s "library://ns.adobe.com/flex/spark";
      @namespace mx "library://ns.adobe.com/flex/mx";

      /* class level selector  */
      .errorLabel {
         color: red;
      }

      /* id level selector  */
      #msgLabel {
         color: gray;
      }

      /* style applied on all buttons  */
      s|Button {
         fontSize: 15;
         color: #9933FF;
      }
   </fx:Style>

   <fx:Script>
      <![CDATA[
         import mx.controls.Alert;
         import mx.events.FlexEvent;
         protected function btnClickMe_clickHandler(event:MouseEvent):void {
            Alert.show("Hello World!");
         }

         protected function application_initializeHandler(event:FlexEvent):void {
            lblHeader.text = "CSS Demonstrating Application";
         }
      ]]>
   </fx:Script>
   
   <s:BorderContainer width = "560" height = "500" id = "mainContainer"
      styleName = "container">
      <s:VGroup width = "100%" height = "100%" gap = "50"
         horizontalAlign = "center" verticalAlign = "middle">
         <s:Label width = "100%" id = "lblHeader" fontSize = "40"
            color = "0x777777" styleName = "heading" />
         <s:Button label = "Click Me!" id = "btnClickMe"
            click = "btnClickMe_clickHandler(event)"  />
         <s:Label id = "errorMsg"
            text = "This is an error message" styleName = "errorLabel" />
         <s:Label id = "msgLabel" text = "This is a normal message" />
      </s:VGroup>
   </s:BorderContainer>
</s:Application>

Once you are ready with all the changes done, let us compile and run the application in normal mode as we did in Flex - Create Application chapter. If everything is fine with your application, this will produce following result: [ Try it online ]

Flex - Style with Skin

What is Skinning?

• Skinning in Flex, is a process of customizing look and feel of a UI Component completely.

• A Skin can define text, image, filters, transitions and states of a component.

• A Skin can be created as a separate mxml or ActionScript component.

• Using skin, we can control all visual aspects of a UI component.

• The process of defining skin is same for all the UI component.

Step 1 – Create a Skin

Launch Create MXML Skin wizard using the option File > New > MXML Skin.

Enter Package as com.tutorialspoint.skin, name as GradientBackgroundSkin and choose host component as existing flex BorderContainer controlspark.component.BorderContainer.

Now you've created a skin for a BorderContainer. Modify content of the mxml skin file src/com.tutorialspoint/skin/GradientBackgroundSkin.mxml.

Update fill layer as follows −

<!-- fill -->
<s:Rect id = "backgroundRect" left = "0" right = "0" height = "100%" top = "0">
   <s:fill>
      <s:LinearGradient rotation = "90">
         <s:GradientEntry color = "0x888888" ratio = "0.2" />
         <s:GradientEntry color = "0x111111" ratio = "1" />
      </s:LinearGradient>
   </s:fill>
</s:Rect>	

Step 2: Apply Skin

You can apply skin over a component in two ways −

Apply skin in MXML script (statically)

Apply GradientBackgroundSkin to a BorderContainer with id mainContainer using its skinClass attribute.

<s:BorderContainer width = "560" height = "500" id = "mainContainer" 
   styleName = "container">
   <s:VGroup width = "100%" height = "100%" gap = "50" 
      horizontalAlign = "center" verticalAlign = "middle" 
      skinClass = "com.tutorialspoint.skin.GradientBackgroundSkin">

Apply skin in ActionScript (dynamically)

Apply GradientBackgroundSkin to a BorderContainer with id mainContainer using its skinClass property.

protected function gradientBackground_clickHandler(event:MouseEvent):void {
   mainContainer.setStyle("skinClass", GradientBackgroundSkin);
}

Flex Style with Skin Example

Let us follow the following steps to see skinning in action in a Flex application by creating a test application −

Following is the content of the GradientBackgroundSkin.mxml file src/com/tutorialspoint/skin/GradientBackg roundSkin.mxml.

<?xml version = "1.0" encoding = "utf-8"?>
<s:Skin xmlns:fx = "http://ns.adobe.com/mxml/2009" 
   xmlns:s = "library://ns.adobe.com/flex/spark" 
   xmlns:mx = "library://ns.adobe.com/flex/mx">
   
   <!-- host component -->
   <fx:Metadata>
      [HostComponent("spark.components.BorderContainer")]
   </fx:Metadata> 

   <!-- states -->
   <s:states>
      <s:State name = "disabled" />
      <s:State name = "disabled" />
      <s:State name = "normal" />
   </s:states>

   <!-- SkinParts
   name = contentGroup, type = spark.components.Group, required = false
   -->
   
   <!-- fill -->
   <s:Rect id = "backgroundRect" left = "0" right = "0" height = "100%" top = "0">
      <s:fill>
         <s:LinearGradient rotation = "90">
            <s:GradientEntry color = "0x111111" ratio = "0.2" />
            <s:GradientEntry color = "0x888888" ratio = "1" />
         </s:LinearGradient>
      </s:fill>
   </s:Rect>	
   
   <!-- must specify this for the host component --> 
   <s:Group id = "contentGroup" left = "0" right = "0" top = "0" bottom = "0" />
</s:Skin>

Following is the content of the modified HelloWorld.mxml filesrc/com/tutorialspoint/client/HelloWorld.mxml.

<?xml version = "1.0" encoding = "utf-8"?>
<s:Application xmlns:fx = "http://ns.adobe.com/mxml/2009"
   xmlns:s = "library://ns.adobe.com/flex/spark"
   xmlns:mx = "library://ns.adobe.com/flex/mx"
   width = "100%" height = "100%" minWidth = "500" minHeight = "500"
   initialize = "application_initializeHandler(event)">

   <fx:Style source = "/com/tutorialspoint/client/Style.css" />
   <fx:Script>
      <![CDATA[
         import com.tutorialspoint.skin.GradientBackgroundSkin;
         import mx.controls.Alert;
         import mx.events.FlexEvent;
         import spark.skins.spark.BorderContainerSkin;			

         protected function btnClickMe_clickHandler(event:MouseEvent):void {
            Alert.show("Hello World!");				
         }

         protected function application_initializeHandler(event:FlexEvent):void {
            lblHeader.text = "My Hello World Application";				
         }

         protected function gradientBackground_clickHandler(event:MouseEvent):void {
            mainContainer.setStyle("skinClass", GradientBackgroundSkin );
         }

         protected function standardBackground_clickHandler(event:MouseEvent):void {
            mainContainer.setStyle("skinClass", BorderContainerSkin );
         }
      ]]>
   </fx:Script>
   
   <fx:Declarations>
      <s:RadioButtonGroup id = "selectorGroup" />
   </fx:Declarations>
   
   <s:BorderContainer width = "500" height = "500" id = "mainContainer"
      skinClass = "spark.skins.spark.BorderContainerSkin" 
      horizontalCenter = "0" verticalCenter = "0" cornerRadius = "10">
      
      <s:VGroup width = "100%" height = "100%" gap = "50" horizontalAlign = "center"
         verticalAlign = "middle">
         <s:Label id = "lblHeader" fontSize = "40" color = "green" 
            styleName = "heading" />
         <s:Button label = "Click Me!" id = "btnClickMe" 
            click = "btnClickMe_clickHandler(event)" />
         <s:RadioButton color = "gray" fontWeight = "bold" 
            group = "{selectorGroup}" label = "Standard Background" 
            click = "standardBackground_clickHandler(event)" selected = "true" />
         <s:RadioButton color = "gray" fontWeight = "bold" 
            group = "{selectorGroup}" label = "Gradient Background" 
            click = "gradientBackground_clickHandler(event)" />			
      </s:VGroup>			
   </s:BorderContainer>	
</s:Application>

Once you are ready with all the changes done, let us compile and run the application in normal mode as we did in Flex - Create Application chapter. If everything is fine with your application, it will produce the following result: [ Try it online ]

Flex - Data Binding

What is Data Binding?

Data Binding is a process in which data of one object is tied to another object. It requires a source property, a destination property and a triggering event which indicates, when to copy the data from source to destination.

Flex provides three ways to do Data Binding as below

• Curly brace syntax in MXML Script ({})
• <fx:binding> tag in MXML
• BindingUtils in ActionScript

Data Binding – Using Curly Braces in MXML

The following example demonstrates how to use curly braces to specify data binding of a source to destination.

<s:TextInput id = "txtInput1" />
<s:TextInput id = "txtInput2" text = "{txtInput1.text}" />

Data Binding – Using <fx:Binding> tag in MXML

The following example demonstrates how to use tag to specify data binding of a source to destination.

<fx:Binding source = "txtInput1.text" destination = "txtInput2.text" />
<s:TextInput id = "txtInput1" />
<s:TextInput id = "txtInput2" />

Data Binding – Using BindingUtils in ActionScript

The following example demonstrates how to use BindingUtils to specify data binding of a source to destination.

<fx:Script>
   <![CDATA[
      import mx.binding.utils.BindingUtils;
      import mx.events.FlexEvent;

      protected function txtInput2_preinitializeHandler(event:FlexEvent):void {
         BindingUtils.bindProperty(txtInput2,"text",txtInput1, "text");
      }      
   ]]>
</fx:Script>

<s:TextInput id = "txtInput1" />
<s:TextInput id = "txtInput2" 
   preinitialize = "txtInput2_preinitializeHandler(event)" />

Flex Data Binding Example

Let us follow the steps given below to see skinning in action in a Flex application by creating a test application −

Following is the content of the modified HelloWorld.mxml filesrc/com/tutorialspoint/client/HelloWorld.mxml.

<?xml version = "1.0" encoding = "utf-8"?>
<s:Application xmlns:fx = "http://ns.adobe.com/mxml/2009"
   xmlns:s = "library://ns.adobe.com/flex/spark"
   xmlns:mx = "library://ns.adobe.com/flex/mx
   width = "100%" height = "100%" minWidth = "500" minHeight = "500">
   
   <fx:Style source = "/com/tutorialspoint/client/Style.css" />
   <fx:Script>
      <![CDATA[
         import mx.binding.utils.BindingUtils;   
         import mx.events.FlexEvent;

         protected function txtInput6_preinitializeHandler(event:FlexEvent):void {
            BindingUtils.bindProperty(txtInput6,"text",txtInput5, "text");
         }
      ]]>
   </fx:Script>
   
   <fx:Binding source = "txtInput3.text" destination = "txtInput4.text" />
   <s:BorderContainer width = "500" height = "550" id = "mainContainer" 
      styleName = "container">
      <s:VGroup width = "100%" height = "100%" gap = "50" horizontalAlign = "center" 
         verticalAlign = "middle">
         <s:Label id = "lblHeader" text = "Data Binding Demonstration"
            fontSize = "40" color = "0x777777" styleName = "heading" />
         <s:Panel title = "Example #1 (Using Curly Braces,\{\})" width = "400" 
            height = "100" >
            <s:layout>
               <s:VerticalLayout paddingTop = "10" paddingLeft = "10" />
            </s:layout>
            
            <s:HGroup >
               <s:Label text = "Type here: " width = "100" paddingTop = "6" />
               <s:TextInput id = "txtInput1" />	
            </s:HGroup>
            
            <s:HGroup >
               <s:Label text = "Copied text: " width = "100" paddingTop = "6" />
               <s:TextInput id = "txtInput2" text = "{txtInput1.text}" />
            </s:HGroup>						
         </s:Panel>
         
         <s:Panel title = "Example #2 (Using &lt;fx:Binding&gt;)" width = "400" 
            height = "100" >
            <s:layout>
               <s:VerticalLayout paddingTop = "10" paddingLeft = "10" />
            </s:layout>
            
            <s:HGroup >
               <s:Label text = "Type here: " width = "100" paddingTop = "6" />
               <s:TextInput id = "txtInput3" />	
            </s:HGroup>
            
            <s:HGroup >
               <s:Label text = "Copied text: " width = "100" paddingTop = "6" />
               <s:Label id = "txtInput4" />
            </s:HGroup>						
         </s:Panel>
         
         <s:Panel title = "Example #3 (Using BindingUtils)" width = "400" 
            height = "100" >
            <s:layout>
               <s:VerticalLayout paddingTop = "10" paddingLeft = "10" />
            </s:layout>
            
            <s:HGroup >
               <s:Label text = "Type here: " width = "100" paddingTop = "6" />
               <s:TextInput id = "txtInput5" />	
            </s:HGroup>
            
            <s:HGroup >
               <s:Label text = "Copied text: " width = "100" paddingTop = "6" />
               <s:TextInput enabled = "false" id = "txtInput6" 
                  preinitialize = "txtInput6_preinitializeHandler(event)" />
            </s:HGroup>						
         </s:Panel>
      </s:VGroup>	 
   </s:BorderContainer>	
</s:Application>

Once you are ready with all the changes done, let us compile and run the application in normal mode as we did in Flex - Create Application chapter. If everything is fine with your application, it will produce the following result: [ Try it online ]

Flex - Basic Controls

Every user interface considers the following three main aspects −

• UI Elements − These are the core visual elements the user eventually sees and interacts with. Flex provides a huge list of widely used and common elements varying from basic to complex which we will cover in this tutorial.

• Layouts − They define how UI elements should be organized on the screen and provide a final look and feel to the GUI (Graphical User Interface). This part will be covered in Layout chapter.

• Behavior − These events occur when the user interacts with UI elements. This part will be covered in Event Handling chapter.

Flex UI Elements

The Flex UI library provides classes in a well-defined class hierarchy to create complex web-based user interfaces. All classes in this component hierarchy have been derived from the EventDispatcher base class as shown below −

Every Basic UI control inherits properties from UI Component class which in turn inherits properties from EventDispatcher and other top level classes.

Basic Controls

Following are the few important Basic Controls −

Flex - Form Controls

Form controls allow the users to input data and provides them interaction capability with the application. Every Form UI controls and inherits properties from UIComponent class which in turn inherits properties from EventDispatcher and other top level classes.

Form Controls

Following are few important Form Controls −

Flex - Complex Controls

Complex controls provide users with advanced capabilities to deal with large amount of data in an easier way and provides them interaction capability with the application. Every Complex UI control inherits properties from UIComponent class which in turn inherits properties from EventDispatcher and other top level classes.

Complex Controls

Following are the few important Complex Controls −

Flex - Layout Panels

Layout panel controls provides users to organize UI controls on the page. Every Layout control inherits properties from UIComponent class which in turn inherits properties from EventDispatcher and other top level classes.

Layout Panels

Following are few important Layout Panels −

Flex - Visual Effects

We can add behavior to flex application using the concept of Effects. For example, when a text box gets focus, we can make its text become bolder and make its size slight bigger.

Every effect inherits properties from Effect class which in turn inherits properties from EventDispatcher and other top level classes.

Basic Effects

Following are the few important Basic Visual Effects −

Flex - Event Handling

Flex uses concept of event to pass data from one object to another depending upon the state or user interaction within the application.

ActionScript has a generic Event class which defines much of the functionality needed to work with events. Every time an event occurs within a Flex application, three types of objects from the Event class hierarchy are created.

Event has the following three key properties

Event Flow Phases

An event goes through three phases looking for event handlers.

Consider the following application code −

<?xml version = "1.0" encoding = "utf-8"?>
<s:Application xmlns:fx = "http://ns.adobe.com/mxml/2009" 
   xmlns:s = "library://ns.adobe.com/flex/spark" 
   xmlns:mx = "library://ns.adobe.com/flex/mx
   width = "100%" height = "100%" minWidth = "500" minHeight = "500" >
   
   <s:Panel>
      <s:Button id = "clickMeButton" label = "Click Me!" click = "doAction( );" />
   </s:Panel>   
</s:Application>

When the user clicks the Button, he or she has also clicks the Panel and the Application.

The event goes through three phases looking for event-handler assignments.

Let us follow the steps below to test event handing in a Flex application −

Following is the content of the modified mxml file src/com.tutorialspoint/HelloWorld.mxml.

<?xml version = "1.0" encoding = "utf-8"?>
<s:Application xmlns:fx = "http://ns.adobe.com/mxml/2009"
   xmlns:s = "library://ns.adobe.com/flex/spark"
   xmlns:mx = "library://ns.adobe.com/flex/mx
   width = "100%" height = "100%" minWidth = "500" minHeight = "500">
   
   <fx:Style source = "/com/tutorialspoint/client/Style.css" />
   <fx:Script>
      <![CDATA[
         protected function reportEvent(event:MouseEvent):void {
            var target:String = event.target.id;
            var currentTarget:String = event.target.id;
            var eventPhase: String;

            if(event.target is Button) {
               var button:Button = event.target as Button;
               target = button.label + " Button";
            } else if(event.target is HGroup) {
               var hGroup:HGroup = event.target as HGroup;
               target = hGroup.id + " HGroup";
            } else if(event.target is Panel) {
               var panel:Panel = event.target as Panel;
               target = panel.id + " Panel";
            }

            if(event.currentTarget is Button) {
               var button1:Button = event.currentTarget as Button;
               currentTarget = button1.label + " Button";
            } else if(event.currentTarget is HGroup) {
               var hGroup1:HGroup = event.currentTarget as HGroup;
               currentTarget = hGroup1.id + " HGroup";
            } else if(event.currentTarget is Panel) {
               var panel1:Panel = event.currentTarget as Panel;
               currentTarget = panel1.id + " Panel";
            }

            var eventPhaseInt:uint = event.eventPhase;

            if(eventPhaseInt == EventPhase.AT_TARGET) {
               eventPhase = "Target";
            } else if(eventPhaseInt == EventPhase.BUBBLING_PHASE) {
               eventPhase = "Bubbling";
            } else if(eventPhaseInt == EventPhase.CAPTURING_PHASE) {
               eventPhase = "Capturing";
            }
            
            reports.text += " Target: " + target + "\n currentTarget: " +
               currentTarget + "\n Phase: " + eventPhase + "\n----------\n";
         }
      ]]>
   </fx:Script>
   
   <s:BorderContainer width = "630" height = "480" id = "mainContainer"
      styleName = "container">
      <s:VGroup width = "100%" height = "100%" gap = "10"
         horizontalAlign = "center" verticalAlign = "middle">
         <s:Label id = "lblHeader" text = "Event Handling Demonstration"
            fontSize = "40" color = "0x777777" styleName = "heading" />

         <s:Panel id = "parentPanel" title = "Main Parent"
            click = "reportEvent(event)" width = "500"
            height = "100" includeInLayout = "true" visible = "true">
            <s:layout>
               <s:VerticalLayout  gap = "10" verticalAlign = "middle"
                  horizontalAlign = "center" />
            </s:layout>
            
            <s:HGroup id = "mainHGroup" click = "reportEvent(event)">
               <s:Button label = "Click Me" click = "reportEvent(event)" />
            </s:HGroup>
         </s:Panel>

         <s:Panel id = "reportPanel" title = "Events" width = "500" height = "230">
            <mx:Text id = "reports" />
         </s:Panel>
      </s:VGroup>
   </s:BorderContainer>
</s:Application>

Once you are ready with all the changes done, let us compile and run the application in normal mode as we did in Flex - Create Application chapter. If everything is fine with your application, it will produce the following result: [ Try it online ]

Flex - Custom Controls

Flex provides two ways to create custom components.

• Using ActionScript
• Using MXML

Using ActionScript

You can create a component by extending existing component. To create a component using Flash Builder, Click on File > New > ActionScript Class.

Enter the details as shown below −

Flash Builder will create the following CustomButton.as file.

package com.tutorialspoint.client {
   import spark.components.Button;

   public class CustomButton extends Button {
      public function CustomButton() {
         super();
      }
   }
}

Using MXML

You can create a component by extending existing component. To create a component using Flash Builder, Click on File > New > MXML Component.

Enter the details as shown below.

Flash Builder will create the following CustomLogin.mxml file.

<?xml version = "1.0" encoding = "utf-8"?>
<s:Group xmlns:fx = "http://ns.adobe.com/mxml/2009" 
   xmlns:s = "library://ns.adobe.com/flex/spark" 
   xmlns:mx = "library://ns.adobe.com/flex/mx" 
   width = "400" height = "300">
</s:Group>

Let us follow the following steps to test custom controls in a Flex application −

Following is the content of the modified mxml file src/com.tutorialspoint/client/CustomLogin.mxml.

<?xml version = "1.0" encoding = "utf-8"?>
<s:Group xmlns:fx = "http://ns.adobe.com/mxml/2009" 
   xmlns:s = "library://ns.adobe.com/flex/spark" 
   xmlns:mx = "library://ns.adobe.com/flex/mx" width = "400" height = "300">
   
   <s:Form>
      <s:FormItem label = "UserName:">
         <s:TextInput width = "200" />
      </s:FormItem>
      
      <s:FormItem label = "Password:">
         <s:TextInput width = "200" displayAsPassword = "true" />
      </s:FormItem>
      
      <s:FormItem>
         <s:Button label = "Login" />
      </s:FormItem>		
   </s:Form>
</s:Group>

Following is the content of the modified mxml file src/com.tutorialspoint/client/CustomButton.as.

package com.tutorialspoint.client {
   import spark.components.Button;

   public class CustomButton extends Button {
      
      public function CustomButton() {
         super();
         this.setStyle("color","green");
         this.label = "Submit";
      }
   }
}

Following is the content of the modified mxml file src/com.tutorialspoint/client/HelloWorld.mxml.

<?xml version = "1.0" encoding = "utf-8"?>
<s:Application xmlns:fx = "http://ns.adobe.com/mxml/2009" 
   xmlns:s = "library://ns.adobe.com/flex/spark" 
   xmlns:mx = "library://ns.adobe.com/flex/mx" 
   xmlns:client = "com.tutorialspoint.client.*"
   initialize = "application_initializeHandler(event)">
   
   <fx:Style source = "/com/tutorialspoint/client/Style.css" />
   <fx:Script>
      <![CDATA[
        import mx.events.FlexEvent;

        protected function application_initializeHandler(event:FlexEvent):void {
           //create a new custom button
           var customButton: CustomButton = new CustomButton();
           asPanel.addElement(customButton);
        }

      ]]>
   </fx:Script>
   
   <s:BorderContainer width = "630" height = "480" id = "mainContainer" 
      styleName = "container">
      <s:VGroup width = "100%" height = "100%" gap = "10" 
         horizontalAlign = "center" verticalAlign = "middle">
         <s:Label id = "lblHeader" text = "Custom Controls Demonstration" 
            fontSize = "40" color = "0x777777" styleName = "heading" />

         <s:Panel title = "Using MXML Component" width = "400" height = "200">
            <client:CustomLogin>			
            </client:CustomLogin>		
         </s:Panel>
         
         <s:Panel  title = "Using AS Component" width = "400" height = "100">
            <s:VGroup id = "asPanel" width = "100%" height = "100%" gap = "10" 
               horizontalAlign = "center" verticalAlign = "middle">
            </s:VGroup>
         </s:Panel>
      </s:VGroup>
   </s:BorderContainer>
</s:Application>

Once you are ready with all the changes done, let us compile and run the application in normal mode as we did in Flex - Create Application chapter. If everything is fine with your application, it will produce the following result: [ Try it online ]

Flex - RPC Services

Flex provides RPC services to provide server side data to client side. Flex provides a fair amount of control on to server side data.

• Using Flex RPC services, we can define user actions to be executed on server side.

• Flex RPC Sservices can be integrated with any server side technologies.

• One of Flex RPC Service provide inbuilt support for compressed binary data to be transferred over the wire and is pretty fast.

Flex provides the following three types of RPC Services

We're going to discuss HTTP Service in detail. We'll use an XML source file placed at server and access it at client side via HTTP Service.

Items.xml

<items>
   <item name = "Book" description = "History of France"></item>
   <item name = "Pen" description = "Parker Pen"></item>
   <item name = "Pencil" description = "Stationary"></item>
<items>

HTTPService Declaration

Now declare a HTTPService and pass it url of the above file

<fx:Declarations>
   <mx:HTTPService id = "itemRequest" 
   url = "http://www.tutorialspoint.com/flex/Items.xml" />
</fx:Declarations>

RPC Call

Make a call to itemRequest.send() method and bind values from lastResult object of itemRequest webservice to Flex UI component.

...
itemRequest.send();
...
<mx:DataGrid id = "dgItems" height = "80%" width = "75%" 
   dataProvider = "{itemRequest.lastResult.items.item}">
   <mx:columns>
      <mx:DataGridColumn headerText = "Name" dataField = "name" />
      <mx:DataGridColumn headerText = "Description" dataField = "description" />
   </mx:columns>
</mx:DataGrid>

RPC Service Call Example

Now, Let us follow the steps to test RPC services in a Flex application −

Following is the content of the modified mxml file src/com.tutorialspoint/HelloWorld.mxml.

<?xml version = "1.0" encoding = "utf-8"?>
<s:Application xmlns:fx = "http://ns.adobe.com/mxml/2009" 
   xmlns:s = "library://ns.adobe.com/flex/spark" 
   xmlns:mx = "library://ns.adobe.com/flex/mx" 
   minWidth = "500" minHeight = "500" creationComplete = "init(event)">
   
   <fx:Style source = "/com/tutorialspoint/client/Style.css" />
   <fx:Script>
      <![CDATA[
         import mx.events.FlexEvent;
         import mx.rpc.events.FaultEvent;
         import mx.rpc.events.ResultEvent;

         protected function init(event:FlexEvent):void {
            itemRequest.send();				
         }
      ]]>
   </fx:Script>
   
   <fx:Declarations>
      <mx:HTTPService id = "itemRequest" 
         url = "http://www.tutorialspoint.com/flex/Items.xml" />
   </fx:Declarations>
   
   <s:BorderContainer width = "630" height = "480" id = "mainContainer" 
      styleName = "container">
      <s:VGroup width = "100%" height = "100%" gap = "10" 
         horizontalAlign = "center" verticalAlign = "middle">
         <s:Label id = "lblHeader" text = "RPC Service Demonstration" 
            fontSize = "40" color = "0x777777" styleName = "heading" />
         
         <s:Panel id = "parentPanel" title = "Using RPC Services"  
            width = "500" height = "200" >
            <s:layout>
               <s:VerticalLayout  gap = "10" 
                  verticalAlign = "middle" horizontalAlign = "center" />
            </s:layout>						
            
            <mx:DataGrid id = "dgItems" height = "80%" width = "75%" 
               dataProvider = "{itemRequest.lastResult.items.item}">
               
               <mx:columns>
                  <mx:DataGridColumn headerText = "Name" dataField = "name" />
                  <mx:DataGridColumn headerText = "Description" 
                     dataField = "description" />
               </mx:columns>
            </mx:DataGrid>
         </s:Panel>	
      </s:VGroup>	 
   </s:BorderContainer>	
</s:Application>

Once you are ready with all the changes done, let us compile and run the application in normal mode as we did in Flex - Create Application chapter. If everything is fine with your application, it will produce the following result: [ Try it online ]

Flex - FlexUnit Integration

Flash Builder 4 has an excellent inbuilt support for FlexUnit integration in Flex development Cycle.

Create a Test Case Class

You can create a Test Case Class using Flash Builder Create Test Class wizard. Running test cases is a breeze with Flash Builder as you will see in this article.

To create a test case class using Flash Builder, Click on File > New > Test Case Class. Enter the details as shown below.

Flash Builder will create the following TestClass1.as a file.

package com.tutorialspoint.client {
   public class TestClass1 {		
      [Before]
      public function setUp():void {}

      [After]
      public function tearDown():void {}

      [BeforeClass]
      public static function setUpBeforeClass():void {}

      [AfterClass]
      public static function tearDownAfterClass():void {}	
   }
}

FlexUnit Integration Example

Now, let us follow the steps to test FlexUnit Integration in a Flex application −

Following is the content of the modified as file src/com.tutorialspoint/client/TestClass1.as.

package com.tutorialspoint.client {
   import org.flexunit.asserts.assertEquals;

   public class TestClass1 {		
      private var counter: int = 1;

      [Before]
      public function setUp():void {
         //this code will run before every test case execution
      }

      [After]
      public function tearDown():void {
         //this code will run after every test case execution
      }

      [BeforeClass]
      public static function setUpBeforeClass():void {
         //this code will run once when test cases start execution
      }

      [AfterClass]
      public static function tearDownAfterClass():void {
         //this code will run once when test cases ends execution
      }      

      [Test]  
      public function testCounter():void { 
         assertEquals(counter, 1);
      }
   }
}

Following is the content of the modified mxml file src/com.tutorialspoint/HelloWorld.mxml.

<?xml version = "1.0" encoding = "utf-8"?>
<s:Application xmlns:fx = "http://ns.adobe.com/mxml/2009" 
   xmlns:s = "library://ns.adobe.com/flex/spark" 
   xmlns:mx = "library://ns.adobe.com/flex/mx" 
   minWidth = "500" minHeight = "500">
</s:Application>

Once you are ready with all the changes done, let us compile in normal mode as we did in Flex - Create Application chapter.

Running Test cases

Now Right Click on TestClass1 in package explorer and select Run As > FlexUnit Tests. You'll see the following output in Flash Builder test window.

Flash Builder also shows test results in the browser.

Flex - Debug Application

Flex provides excellent capability of debugging flex code and Flash Builder 4 has an excellent built-in debugger and debugging perspective support.

• During debug mode, Flex Application runs on Flash Player Debugger version built in Flash Builder 4 which supports debugging capability.

• So developers get an easy and inbuilt debugging configuration in Flash Builder

In this article, we'll demonstrate usage of debugging Flex Client code using Flash Builder. We'll do the following tasks

• Set break points in the code and see them in Breakpoint Explorer.
• Step through the code line by line during debugging.
• View the values of variable.
• Inspect the values of all the variables.
• Inspect the value of an expression.
• Display the stack frame for suspended threads.

Debugging Example

Following is the content of the modified mxml file src/com.tutorialspoint/HelloWorld.mxml.

<?xml version = "1.0" encoding = "utf-8"?>
<s:Application xmlns:fx = "http://ns.adobe.com/mxml/2009" 
   xmlns:s = "library://ns.adobe.com/flex/spark" 
   xmlns:mx = "library://ns.adobe.com/flex/mx"
   width = "100%" height = "100%"
   minWidth = "500" minHeight = "500" 
   initialize = "application_initializeHandler(event)">
   
   <fx:Style source = "/com/tutorialspoint/client/Style.css" />
   <fx:Script>
      <![CDATA[
         import mx.controls.Alert;
         import mx.events.FlexEvent;
         protected function btnClickMe_clickHandler(event:MouseEvent):void {
            Alert.show("Hello World!");
         }

         protected function application_initializeHandler(event:FlexEvent):void {
            lblHeader.text = "My Hello World Application";
         }
      ]]>
   </fx:Script>

   <s:BorderContainer width = "500" height = "500" id = "mainContainer"
      styleName = "container">
      <s:VGroup width = "100%" height = "100%" gap = "50" horizontalAlign = "center"
         verticalAlign = "middle">
         <s:Label id = "lblHeader" fontSize = "40" color = "0x777777"
            styleName = "heading" />
         <s:Button label = "Click Me!" id = "btnClickMe"
            click = "btnClickMe_clickHandler(event)" styleName = "button" />
      </s:VGroup>
   </s:BorderContainer>
</s:Application>

Once you are ready with all the changes done, let us compile in normal mode as we did in Flex - Create Application chapter.

Step 1 - Place Breakpoints

Place a breakpoint on the first line of application initialize Handler of HelloWorld.mxml

Step 2 - Debug Application

Now click on Debug application menu and select HelloWorld application to debug the application.

If everything is fine, application will launch in the browser and you will see following debug logs in Flash Builder console.

[SWF] \HelloWorld\bin-debug\HelloWorld.swf 
- 181,509 bytes after decompression
[SWF] \HelloWorld\bin-debug\HelloWorld.swf\[[DYNAMIC]]\1 
- 763,122 bytes after decompression
[SWF] \HelloWorld\bin-debug\HelloWorld.swf\[[DYNAMIC]]\2 
- 1,221,837 bytes after decompression
[SWF] \HelloWorld\bin-debug\HelloWorld.swf\[[DYNAMIC]]\3 
- 1,136,788 bytes after decompression
[SWF] \HelloWorld\bin-debug\HelloWorld.swf\[[DYNAMIC]]\4 
- 2,019,570 bytes after decompression
[SWF] \HelloWorld\bin-debug\HelloWorld.swf\[[DYNAMIC]]\5 
- 318,334 bytes after decompression

As soon as Application launches,you will see the focus on Flash Builder breakpoint as we've placed the breakpoint on first line of application_initialize Handler method.

You can see the stacktrace for suspended threads.

You can see the values for expressions.

You can see the list of breakpoints placed.

Now keep pressing F6 until you reach the last line of application_initializeHandler() method. As reference for function keys, F6 inspects code line by line, F5 steps inside further and F8 will resume the application. Now you can see the list of values of all variables of application_initializeHandler() method.

Now you can see the flex code can be debugged in the same way as a Java Application can be debugged. Place breakpoints to any line and play with debugging capabilities of flex.

Flex - Internationalization

Flex provides two ways to internationalize a Flex application, We'll demonstrate use of Compile time Internationalization being most commonly used among projects.

Workflow of internationalizing a Flex Application

Step 1 – Create folder structure

Create a locale folder under src folder of Flex project.This will be the parent directory for all of the properties files for the locales that the application will support. Inside the locale folder, create subfolders, one for each of the application's locales to be supported. The convention for naming a locale is

{language}_{country code}

For example, en_US represents English of the United States. The locale de_DE represents German. The sample application will support two common languages: English, and German.

Step 2 – Create properties files

Create properties file containing the messages to be used in the application. We've created a HelloWorldMessages.properties file under src > locale > en_US folder in our example.

enterName = Enter your name
clickMe = Click Me
applicationTitle = Application Internationalization Demonstration
greeting = Hello {0}

Create properties files containing translated values specific to locale. We've created a HelloWorldMessages.properties file under src > locale > de_DE folder in our example. This file contains translations in german language. _de specifies the german locale and we're going to support german language in our application.

If you are creating properties file using Flash Builder then change the encoding of the file to UTF-8.Select the file and then right-click in it to open its properties window.Select Text file encoding as Other UTF-8. Apply and Save the change.

enterName = Geben Sie Ihren Namen
clickMe = Klick mich
applicationTitle = Anwendung Internationalisierung Demonstration
greeting = Hallo {0}

Step 3 – Specify Compiler options

• Right-click your project and select Properties.

• Select Flex Compiler, and add the following to the Additional Compiler Arguments settings −

-locale en_US de_DE

• Right-click your project and select Properties.

• Select Flex Build Path, and add the following to the Source Path settings −

src\locale\{locale}

Internalization Example

Now Let us follow the following steps to test Internalization technique in a Flex application −

Following is the content of the modified mxml file src/com.tutorialspoint/HelloWorld.mxml.

<?xml version = "1.0" encoding = "utf-8"?>
   <s:Application xmlns:fx = "http://ns.adobe.com/mxml/2009" 
   xmlns:s = "library://ns.adobe.com/flex/spark" 
   xmlns:mx = "library://ns.adobe.com/flex/mx" 
   minWidth = "500" minHeight = "500">
   
   <fx:Metadata>
      [ResourceBundle("HelloWorldMessages")]
   </fx:Metadata> 
   
   <fx:Style source = "/com/tutorialspoint/client/Style.css" />
   <fx:Script>
      <![CDATA[
         import mx.controls.Alert;
         [Bindable]
         private var locales:Array =  [{label:"English", locale:"en_US"},
            {label:"German", locale:"de_DE"}];

         private function comboChangeHandler():void {
           resourceManager.localeChain = [localeComboBox.selectedItem.locale];
         }

         protected function clickMe_clickHandler(event:MouseEvent):void {
            var name:String = txtName.text;
            var inputArray:Array = new Array();
            inputArray.push(name);
            Alert.show(resourceManager.getString('HelloWorldMessages'
               ,'greeting',inputArray));
         }
      ]]>
   </fx:Script>
   
   <s:BorderContainer width = "500" height = "500" id = "mainContainer" 
      styleName = "container">
      <s:VGroup width = "100%" height = "100%" gap = "50" 
	  horizontalAlign = "center" verticalAlign = "middle">
         
         <s:Label id = "lblHeader" fontSize = "40" 
            color = "0x777777" 
            text  = "{resourceManager.getString('HelloWorldMessages','applicationTitle')}"
            styleName = "heading" width = "90%" height = "150" />
         
         <s:Panel width = "300" height = "150">
            <s:layout>
               <s:VerticalLayout paddingTop = "10" paddingLeft = "10" />
            </s:layout>
            
            <s:HGroup >
               <s:Label text = "{resourceManager.getString('HelloWorldMessages','enterName')}"
                  paddingTop = "2" />			
               <s:TextInput id = "txtName" />
            </s:HGroup>
            
            <s:Button 
               label = "{resourceManager.getString('HelloWorldMessages','clickMe')}" 
               click = "clickMe_clickHandler(event)" right = "10" />	
         </s:Panel>
         
         <mx:ComboBox id = "localeComboBox" dataProvider = "{locales}"
            change = "comboChangeHandler()" />
      </s:VGroup>	
   </s:BorderContainer>	
</s:Application>

Once you are ready with all the changes done, let us compile and run the application in normal mode as we did in Flex - Create Application chapter. If everything is fine with your application, it will produce the following result: [ Try it online ]

Change the language using language drop down and see the result.

Flex - Printing Support

Flex provides a special class FlexPrintJob to print flex objects.

• FlexPrintJob can be used to print one or more Flex objects, such as a Form or VBox container.

• FlexPrintJob prints the object and all objects that it contains.

• The objects can be all or part of the displayed interface.

• The objects can be components that format data specifically for printing.

• The FlexPrintJob class lets you scale the output to fit the page.

• The FlexPrintJob class automatically uses multiple pages to print an object that does not fit on a single page.

• The FlexPrintJob class causes the operating system to display a Print dialog box. You cannot print without some user action.

Prepare and send a print job

You print output by preparing and sending a print job. Let's create an instance of the FlexPrintJob class

var printJob:FlexPrintJob = new FlexPrintJob();

Start the print job

printJob.start(); 

Flex will cause the operating system to display a Print dialog box. Add one or more objects to the print job and specify how to scale them

printJob.addObject(myObject, FlexPrintJobScaleType.MATCH_WIDTH); 

Each object starts on a new page. Send the print job to the printer

printJob.send(); 

Printing Example

Following is the content of the modified mxml file src/com.tutorialspoint/HelloWorld.mxml.

<?xml version = "1.0" encoding = "utf-8"?>
<s:Application xmlns:fx = "http://ns.adobe.com/mxml/2009" 
   xmlns:s = "library://ns.adobe.com/flex/spark" 
   xmlns:mx = "library://ns.adobe.com/flex/mx"
   width = "100%" height = "100%"
   minWidth = "500" minHeight = "500" 
   initialize = "application_initializeHandler(event)">
   
   <fx:Style source = "/com/tutorialspoint/client/Style.css" />
   <fx:Script>
     <![CDATA[
         import mx.controls.Alert;
         import mx.events.FlexEvent;
         import mx.printing.FlexPrintJob;
         import mx.printing.FlexPrintJobScaleType;
         
         protected function btnClickMe_clickHandler(event:MouseEvent):void {
            
            // Create an instance of the FlexPrintJob class.
            var printJob:FlexPrintJob = new FlexPrintJob();
         
            // Start the print job.
            if (printJob.start() != true) return;

            // Add the object to print. Do not scale it.
            printJob.addObject(myDataGrid, FlexPrintJobScaleType.NONE);

            // Send the job to the printer.
            printJob.send();
        }

        protected function application_initializeHandler(event:FlexEvent):void {
            lblHeader.text = "My Hello World Application";				
        }
     ]]>
   </fx:Script>
   
   <s:BorderContainer width = "500" height = "500" id = "mainContainer" 
      styleName = "container">
      <s:VGroup width = "100%" height = "100%" gap = "50"
         horizontalAlign = "center" 
         verticalAlign = "middle">
         <s:Label id = "lblHeader" fontSize = "40" color = "0x777777" 
            styleName = "heading" />
         
         <mx:DataGrid id = "myDataGrid" width = "300">
            <mx:dataProvider>
               <fx:Object Product = "Flex" Code = "1000" />
               <fx:Object Product = "GWT" Code = "2000" />
               <fx:Object Product = "JAVA" Code = "3000" />
               <fx:Object Product = "JUnit" Code = "4000" />
            </mx:dataProvider>
         </mx:DataGrid>
         
         <s:Button label = "Print Me!" id = "btnClickMe" 
            click = "btnClickMe_clickHandler(event)" 
            styleName = "button" />
      </s:VGroup>	
   </s:BorderContainer>	
</s:Application>

Once you are ready with all the changes done, let us compile and run the application in normal mode as we did in Flex - Create Application chapter. If everything is fine with your application, it will produce the following result: [ Try it online ]

Click on print me button and you can see the printout of the data grid shown below.