Flex custom controls

May 25, 2021 Flex

Flex provides two ways to create custom components.

Use ActionScript
Use MXML

Use ActionScript

You can create components by extending existing ones. /b10> To create a component using Flash Builder, click File and New and ActionScript Class. /b13> Enter the details, as shown below.

Flash Builder creates the following CustomButton.as files.

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

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

Use MXML

You can create components by extending existing ones. /b10> To create a component using Flash Builder, click File and New and MXML Component. /b13> 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's test the custom controls in the Flex application by following these steps:

Steps	Describe
1	As described in the Flex - Create Applications section, create a project called HelloWorld under package com.tutorialspoint.client.
2	Modify HelloWorld.mxml, as described below. /b10> Keep the rest of the file unchanged.
4	Follow the instructions above to create customLogin.mxml and CustomButton.as components. /b10> Follow these instructions to modify these files. /b11> Keep the rest of the file unchanged.
3	Compile and run the application to ensure that the business logic works as required.

The following is the contents of the modified mxml file src / com.tutorialspoint / client / Custom Login.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>

The following is the contents of the modified mxml file src / com.tutorialspoint / client / custom Button.as content.

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

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

The following is the contents 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>

When all the changes are ready, let's compile and run the application in normal mode, as in the Flex - Create Application chapter. If all goes well with your application, this will result in the following results:

Flex custom controls

Table of contents

Use ActionScript

Use MXML

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