The RadioButtonGroup control defines a group of RadioButton controls
that act as a single mutually exclusive control; therefore,
a user can select only one RadioButton control at a time. While grouping
RadioButton instances
in a RadioButtonGroup is optional, a group lets you do things
like set a single event handler on a group of buttons, rather than
on each individual button.
The id property is required when you use the
<mx:RadioButtonGroup> tag to define the name
of the group.
Notice that the RadioButtonGroup control is a subclass of EventDispatcher, not UIComponent,
and implements the IMXMLObject interface.
All other Flex visual components are subclasses of UIComponent, which implements
the IUIComponent interface.
The RadioButtonGroup control has support built into the Flex compiler
that allows you to use the RadioButtonGroup control as a child of a Flex container,
even though it does not implement IUIComponent.
All other container children must implement the IUIComponent interface.
Therefore, if you try to define a visual component as a subclass of
EventDispatcher that implements the IMXMLObject interface,
you will not be able to use it as the child of a container.
The value of the value property of the selected
RadioButton control in the group, if this has been set
to be something other than null (the default value).
Dispatched when a user selects a RadioButton control in the group.
RadioButtonGroup
Property Detail
enabled
property
enabled:Boolean
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 9, AIR 1.1
Determines whether selection is allowed.
The default value is true.
This property can be used as the source for data binding.
Implementation public function get enabled():Boolean public function set enabled(value:Boolean):void
labelPlacement
property
labelPlacement:String
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 9, AIR 1.1
Position of the RadioButton label relative to the RadioButton icon
for each control in the group.
You can override this setting for the individual controls.
Valid values in MXML are "right", "left",
"bottom", and "top".
In ActionScript, you use the following constants to set this property:
ButtonLabelPlacement.RIGHT, ButtonLabelPlacement.LEFT,
ButtonLabelPlacement.BOTTOM, and ButtonLabelPlacement.TOP.
The default value is "right".
This property can be used as the source for data binding.
Implementation public function get labelPlacement():String public function set labelPlacement(value:String):void
numRadioButtons
property
numRadioButtons:int [read-only]
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 9, AIR 1.1
The number of RadioButtons that belong to this RadioButtonGroup.
The default value is "undefined".
This property can be used as the source for data binding.
Implementation public function get numRadioButtons():int
selectedValue
property
selectedValue:Object
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 9, AIR 1.1
The value of the value property of the selected
RadioButton control in the group, if this has been set
to be something other than null (the default value).
Otherwise, selectedValue is the value of the
label property of the selected RadioButton.
If no RadioButton is selected, this property is null.
If you set selectedValue, Flex selects the
RadioButton control whose value or
label property matches this value.
The default value is null.
This property can be used as the source for data binding.
Implementation public function get selectedValue():Object public function set selectedValue(value:Object):void
Contains a reference to the currently selected
RadioButton control in the group.
You can access the property in ActionScript only;
it is not settable in MXML.
Setting this property to null deselects the currently selected RadioButton control.
The default value is null.
This property can be used as the source for data binding.
Implementation public function get selection():RadioButton public function set selection(value:RadioButton):void
Dispatched when a user selects a RadioButton control in the group.
You can also set a handler for individual RadioButton controls.
The ItemClickEvent.ITEM_CLICK constant defines the value of the
type property of the event object for an itemClick event.
The properties of the event object have the following values:
Property
Value
bubbles
false
cancelable
false
currentTarget
The Object that defines the
event listener that handles the event. For example, if you use
myButton.addEventListener() to register an event listener,
myButton is the value of the currentTarget.
index
The index of the navigation item that was clicked.
item
The item in the data provider of the navigation
item that was clicked.
label
The label of the navigation item that was clicked.
relatedObject
The child object that generated the event.
target
The Object that dispatched the event;
it is not always the Object listening for the event.
Use the currentTarget property to always access the
Object listening for the event.
Examples
RadioButtonGroupExample.mxml
<?xml version="1.0" encoding="utf-8"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<!-- Simple example to demonstrate Halo RadioButtonGroup control. -->
<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">
<fx:Script>
<![CDATA[
import mx.controls.Alert;
import mx.events.ItemClickEvent;
// Event handler function to display the selected button
// in a Halo Alert control.
private function handleCard(evt:ItemClickEvent):void {
switch (evt.currentTarget.selectedValue) {
case "AmEx":
Alert.show("You selected American Express");
break;
case "MC":
Alert.show("You selected MasterCard");
break;
case "Visa":
Alert.show("You selected Visa");
break;
}
}
]]>
</fx:Script>
<fx:Declarations>
<mx:RadioButtonGroup id="cardtype" itemClick="handleCard(event);"/>
</fx:Declarations>
<s:Panel title="Halo RadioButtonGroup Control Example"
width="75%" height="75%"
horizontalCenter="0" verticalCenter="0">
<s:VGroup left="10" right="10" top="10" bottom="10">
<s:Label width="100%" color="blue"
text="Select a type of credit card."/>
<mx:RadioButton groupName="cardtype" id="americanExpress" value="AmEx"
label="American Express" width="150" />
<mx:RadioButton groupName="cardtype" id="masterCard" value="MC"
label="MasterCard" width="150" />
<mx:RadioButton groupName="cardtype" id="visa" value="Visa"
label="Visa" width="150" />
</s:VGroup>
</s:Panel>
</s:Application>
flash.events.EventDispatcher
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