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RadioButtonGroup

Package | mx.controls
Class | public class RadioButtonGroup
Inheritance | RadioButtonGroup flash.events.EventDispatcher
Implements | IMXMLObject

Language Version : | ActionScript 3.0

Product Version : | Flex 3

Runtime Versions : | Flash Player 9, AIR 1.1

| Starting with Flex 4.0, Apache recommends that you use the spark.components.RadioButtonGroup class as an alternative to this class.

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.

MXML Syntax Show MXML Syntax
Hide MXML Syntax

The `<mx:RadioButtonGroup>` tag inherits all of the tag attributes of its superclass, and adds the following tag attributes:

      <mx:RadioButtonGroup
        Properties
        enabled="true|false"
        id="No default"
        labelPlacement="right|left|top|bottom"
         Events
        change="No default"
        itemClick="No default"
      />

View the examples

See also

mx.controls.RadioButton

Public Properties

| Property | Defined By
--- | --- | ---
|  | enabled : Boolean Determines whether selection is allowed. | RadioButtonGroup
|  | labelPlacement : String Position of the RadioButton label relative to the RadioButton icon for each control in the group. | RadioButtonGroup
|  | numRadioButtons : int [read-only] The number of RadioButtons that belong to this RadioButtonGroup. | RadioButtonGroup
|  | selectedValue : Object 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). | RadioButtonGroup
|  | selection : RadioButton Contains a reference to the currently selected RadioButton control in the group. | RadioButtonGroup

Public Methods

| Method | Defined By
--- | --- | ---
|  | RadioButtonGroup(document:IFlexDisplayObject = null) Constructor. | RadioButtonGroup
|  | getRadioButtonAt(index:int):RadioButton Returns the RadioButton control at the specified index. | RadioButtonGroup
|  | initialized(document:Object, id:String):void Implementation of the IMXMLObject.initialized() method to support deferred instantiation. | RadioButtonGroup

Events

| Event | Summary | Defined By
--- | --- | --- | ---
|  | change | Dispatched when the value of the selected RadioButton control in this group changes. | RadioButtonGroup
|  | itemClick | 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`

selection | property |

`selection:RadioButton`

Language Version : | ActionScript 3.0

Product Version : | Flex 3

Runtime Versions : | Flash Player 9, AIR 1.1

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`
Constructor Detail

RadioButtonGroup | () | Constructor

`public function RadioButtonGroup(document:IFlexDisplayObject = null)`

Language Version : | ActionScript 3.0

Product Version : | Flex 3

Runtime Versions : | Flash Player 9, AIR 1.1

Constructor.

Parameters

| `document:IFlexDisplayObject` (default = `null`)`` — In simple cases where a class extends EventDispatcher, the `document` parameter should not be used.

See also

flash.events.EventDispatcher
Method Detail

getRadioButtonAt | () | method

`public function getRadioButtonAt(index:int):RadioButton`

Language Version : | ActionScript 3.0

Product Version : | Flex 3

Runtime Versions : | Flash Player 9, AIR 1.1

Returns the RadioButton control at the specified index.

Parameters

| `index:int` — The index of the RadioButton control in the RadioButtonGroup control, where the index of the first control is 0.

Returns

| `RadioButton` — The specified RadioButton control.

initialized | () | method |

`public function initialized(document:Object, id:String):void`

Language Version : | ActionScript 3.0

Product Version : | Flex 3

Runtime Versions : | Flash Player 9, AIR 1.1

Implementation of the `IMXMLObject.initialized()` method to support deferred instantiation.

Parameters

| `document:Object` — The MXML document that created this object.
| `id:String` — The identifier used by document to refer to this object. If the object is a deep property on document, `id` is null.

See also

mx.core.IMXMLObject
Event Detail

change | Event

Event Object Type: `flash.events.Event`
Event.type property = `flash.events.Event.CHANGE`

Language Version : | ActionScript 3.0

Product Version : | Flex 3

Runtime Versions : | Flash Player 9, AIR 1.1

Dispatched when the value of the selected RadioButton control in this group changes.

itemClick | Event |

Event Object Type: `mx.events.ItemClickEvent`
ItemClickEvent.type property = `mx.events.ItemClickEvent.ITEM_CLICK`

Language Version : | ActionScript 3.0

Product Version : | Flex 3

Runtime Versions : | Flash Player 9, AIR 1.1

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>

Sun Mar 5 2017, 03:42 PM +11:00