Flex - DropDownList Control
Introduction
The DropDownList control contains a drop-down list from which the user can select a single value similar to that of the SELECT form element in HTML.
Class Declaration
Following is the declaration for spark.components.DropDownList class:
public class DropDownList extends DropDownListBase
Public properties
| S.N. | Property & Description |
|---|---|
| 1 | prompt : String The prompt for the DropDownList control. |
| 2 | typicalItem : Object [override] Layouts use the preferred size of the typicalItem when fixed row or column sizes are required, but a specific rowHeight or columnWidth value is not set. |
Public methods
| S.N. | Method & Description |
|---|---|
| 1 | DropDownList() Constructor. |
Methods inherited
This class inherits methods from the following classes:
spark.components.supportClasses.DropDownListBase
spark.components.List
spark.components.supportClasses.ListBase
spark.components.SkinnableDataContainer
spark.components.supportClasses.SkinnableContainerBase
spark.components.supportClasses.SkinnableComponent
mx.core.UIComponent
mx.core.FlexSprite
flash.display.Sprite
flash.display.DisplayObjectContainer
flash.display.InteractiveObject
flash.display.DisplayObject
flash.events.EventDispatcher
Object
Flex DropDownList Control Example
Let us follow the following steps to check usage of DropDownList control in a Flex application by creating a test application:
| Step | Description |
|---|---|
| 1 | Create a project with a name HelloWorld under a package com.tutorialspoint.client as explained in the Flex - Create Application chapter. |
| 2 | Modify HelloWorld.mxml as explained below. Keep rest of the files unchanged. |
| 3 | Compile and run the application to make sure business logic is working as per the requirements. |
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[
import mx.collections.ArrayCollection;
import spark.events.IndexChangeEvent;
[Bindable]
public var data:ArrayCollection = new ArrayCollection(
[
{value:"France", code:"FR"},
{value:"Japan", code:"JP"},
{value:"India", code:"IN"},
{value:"Russia", code:"RS"},
{value:"United States", code:"US"}
]
);
protected function dropDownList_changeHandler
(event:IndexChangeEvent):void
{
ddlIndex.text=dropDownList.selectedIndex.toString();
ddlSelectedItem.text=dropDownList.selectedItem.value;
ddlCode.text=dropDownList.selectedItem.code;
}
]]>
</fx:Script>
<s:BorderContainer width="550" height="400" id="mainContainer"
styleName="container">
<s:VGroup width="100%" height="100%" gap="50" horizontalAlign="center"
verticalAlign="middle">
<s:Label id="lblHeader" text="Form Controls Demonstration"
fontSize="40" color="0x777777" styleName="heading" />
<s:Panel id="dropDownListPanel" title="Using DropDownList"
width="420" height="200">
<s:layout>
<s:VerticalLayout gap="10" verticalAlign="middle"
horizontalAlign="center" />
</s:layout>
<s:HGroup>
<s:Label text="Index :" />
<s:Label id="ddlIndex" fontWeight="bold" />
<s:Label text="Value :" />
<s:Label id="ddlSelectedItem"
text="{dropDownList.selectedItem.value}" fontWeight="bold" />
<s:Label text="Code :" />
<s:Label id="ddlCode"
text="{dropDownList.selectedItem.code}" fontWeight="bold" />
</s:HGroup>
<s:DropDownList id="dropDownList" dataProvider="{data}"
width="150" change="dropDownList_changeHandler(event)"
selectedIndex="0" labelField="value" />
</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, this will produce following result:
