mx.accessibility.CheckBoxAccImpl

Package	mx.accessibility
Class	public class CheckBoxAccImpl
Inheritance	CheckBoxAccImpl ButtonAccImpl AccImpl AccessibilityImplementation
Subclasses	RadioButtonAccImpl

Review Needed

The CheckBoxAccImpl class, also called the CheckBox Accessibility Implementation class, is used to make a CheckBox component accessible. This class enables communication between a CheckBox component and a screen reader. Screen readers are used to translate screen content into synthesized speech or braille for visually impaired users.

This class inherits from the ButtonAccImpl.

The CheckBoxAccImpl class supports system roles, object-based events, and states.

A CheckBox reports the role ROLE_SYSTEM_CHECKBUTTON (0x2C) to a screen reader.

A CheckBox reports the following states to a screen reader:

STATE_SYSTEM_NORMAL (0x00000000)
STATE_SYSTEM_UNAVAILABLE (0x00000001)
STATE_SYSTEM_FOCUSED (0x00000004)
STATE_SYSTEM_PRESSED (0x00000008)
STATE_SYSTEM_CHECKED (0x00000010)
STATE_SYSTEM_FOCUSABLE (0x00100000)

A CheckBox dispatches the following events to a screen reader:

EVENT_OBJECT_STATECHANGE (0x800A)
EVENT_OBJECT_NAMECHANGE (0x800C)

Screen reader users can activate a Checkbox component with the spacebar or the Enter key.

	Property	Defined by
		errno : uint Errors are indicated out-of-band, rather than in return values.	AccessibilityImplementation
		stub : Boolean If a component is released without an ActionScript accessibility implementation, it is strongly suggested that a component accessibility stub be included.	AccessibilityImplementation

	Property	Defined by
		eventsToHandle : Array All AccImpl subclasses must override this function by returning an array of strings of the events for which the class should listen from its master component.	ButtonAccImpl
		master : UIComponent A reference to the UIComponent instance that this AccImpl instance is making accessible.	AccImpl
		role : uint Accessibility Role of the component being made accessible.	AccImpl

Public Methods

Hide Inherited Public Methods

Show Inherited Public Methods

	Method		Defined by
		CheckBoxAccImpl(master:UIComponent) Creates a new CheckBoxAccImpl instance for the specified CheckBox component.	CheckBoxAccImpl
		accDoDefaultAction(childID:uint):void IAccessible method for performing the default action associated with Button, which is Press.	ButtonAccImpl
		accLocation(childID:uint):* IAccessible method for returning a `DisplayObject` or `Rectangle` specifying the bounding box of a child element in the AccessibilityImplementation.	AccessibilityImplementation
		accSelect(selFlag:uint, childID:uint):void IAccessible method for altering the selection in the component that this AccessibilityImplementation represents.	AccessibilityImplementation
		enableAccessibility():void [static] Method call for enabling accessibility for a component.	CheckBoxAccImpl
		get_accDefaultAction(childID:uint):String IAccessible method for returning the default action of the CheckBox, which is Check or UnCheck depending on the state.	CheckBoxAccImpl
		get_accFocus():uint IAccessible method for returning the unsigned integer ID of the child element, if any, that has child focus within the component.	AccessibilityImplementation
		get_accName(childID:uint):String IAccessible method for returning the name for the component that this AccessibilityImplementation represents or for one of its child elements.	AccImpl
		get_accRole(childID:uint):uint IAccessible method for returning the system role for the component that this AccessibilityImplementation represents or for one of its child elements.	AccImpl
		get_accSelection():Array IAccessible method for returning an array containing the IDs of all child elements that are selected.	AccessibilityImplementation
		get_accState(childID:uint):uint IAccessible method for returning the state of the CheckBox.	CheckBoxAccImpl
		get_accValue(childID:uint):String IAccessible method for returning the runtime value of the component that this AccessibilityImplementation represents or of one of its child elements.	AccessibilityImplementation
		getChildIDArray():Array Returns an array containing the unsigned integer IDs of all child elements in the AccessibilityImplementation.	AccessibilityImplementation

	Method	Defined by
		eventHandler(event:Event):void Override the generic event handler.	ButtonAccImpl
		getName(childID:uint):String Method for returning the name of the Button which is spoken out by the screen reader.	ButtonAccImpl
		getState(childID:uint):uint Returns the state of the accessible component.	AccImpl

Constructor detail

CheckBoxAccImpl

()

constructor

public function CheckBoxAccImpl(master:UIComponent)

Creates a new CheckBoxAccImpl instance for the specified CheckBox component.

Direct calls to the AccImpl subclass constructors are unneccessary. When a Flex project is compiled with Generate accessible SWF file set to true, the compiler instantiates the accessibility implementations for the components used in the project that have them by calling the the static enableAccessibility() method.

Parameters

master:UIComponent — The UIComponent instance that this CheckBoxAccImpl instance is making accessible.

Method detail

enableAccessibility

()

method

public static function enableAccessibility():void

Method call for enabling accessibility for a component. This method is required for the compiler to activate the accessibility classes for a component.

When a Flex project is compiled with the Generate accessible SWF file set to true, the Flex compiler automatically enables accessibility implementations for the components used in the project that have them.

Accessible component classes should include the [AccessibilityClass] meta tag to specify the appropriate AccImpl subclass or accessibility implementation and let the compiler know to call enableAccessibility().

Example
Following is an example showing how the [AccessibilityClass] meta tag specifies the appropriate AccImpl subclass or accessibility implementation for the mx.accessibility.CheckBox component.

[AccessibilityClass(implementation="mx.accessibility.CheckBoxAccImpl")]

get_accDefaultAction

()

method

public override function get_accDefaultAction(childID:uint):String

IAccessible method for returning the default action of the CheckBox, which is Check or UnCheck depending on the state.

Parameters

childID:uint — An unsigned integer corresponding to one of the component's child elements as defined by getChildIDArray().

Returns

String — DefaultAction Check or UnCheck.

get_accState

()

method

public override function get_accState(childID:uint):uint

IAccessible method for returning the state of the CheckBox. States are predefined for all the components in MSAA. Values are assigned to each state. Depending upon whether the CheckBox is checked or unchecked, a value is returned.

Parameters

childID:uint — An unsigned integer corresponding to one of the component's child elements as defined by getChildIDArray().

Returns

uint — State indicating whether the CheckBox is checked or unchecked.

Adobe® Flex™ 3 Language Reference	All Packages \| All Classes \| Index \| Frames No Frames
Class CheckBoxAccImpl	Properties \| Methods