mx.accessibility.ComboBaseAccImpl

Package	mx.accessibility
Class	public class ComboBaseAccImpl
Inheritance	ComboBaseAccImpl AccImpl AccessibilityImplementation
Subclasses	ColorPickerAccImpl, ComboBoxAccImpl

Review Needed

The ComboBaseAccImpl class, also called the ComboBase Accessibility Implementation class, is used to make a ComboBase component accessible.

Since ComboBox inherits from ComboBase, this class is inherited by ComboBoxAccImpl.

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

A ComboBase reports the role ROLE_SYSTEM_COMBOBOX (0x2E) to a screen reader. Items of a ComboBase report the role ROLE_SYSTEM_LISTITEM (0x22).

A ComboBase 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)

Additionally, items of a ComboBase report the following states:

STATE_SYSTEM_SELECTED (0x00000002)
STATE_SYSTEM_SELECTABLE (0x00200000)

A ComboBase dispatches the following events to a screen reader:

EVENT_OBJECT_SELECTION (0x8006)
EVENT_OBJECT_STATECHANGE (0x800A)
EVENT_OBJECT_NAMECHANGE (0x800C)
EVENT_OBJECT_VALUECHANGE (0x800E)

	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 [read-only] 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.	ComboBaseAccImpl
		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

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Show Inherited Public Methods

	Method		Defined by
		ComboBaseAccImpl(master:UIComponent) Creates a new ComboBaseAccImpl instance for the specified ComboBase component.	ComboBaseAccImpl
		accDoDefaultAction(childID:uint):void IAccessible method that performs the default action associated with the component that this AccessibilityImplementation represents or of one of its child elements.	AccessibilityImplementation
		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.	ComboBaseAccImpl
		get_accDefaultAction(childID:uint):String IAccessible method for returning the default action of the component that this AccessibilityImplementation represents or of one of its child elements.	AccessibilityImplementation
		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 system role for the component.	ComboBaseAccImpl
		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 ComboBase (basically to remove 'not selected').	ComboBaseAccImpl
		get_accValue(childID:uint):String IAccessible method for returning the value of the ComboBase, which would be the text of the item selected.	ComboBaseAccImpl
		getChildIDArray():Array Method to return an array of childIDs.	ComboBaseAccImpl

	Method	Defined by
		eventHandler(event:Event):void Override the generic event handler.	ComboBaseAccImpl
		getName(childID:uint):String Method for returning the name of the ComboBase or one of its child items.	ComboBaseAccImpl
		getState(childID:uint):uint Returns the state of the accessible component.	AccImpl

Property detail

eventsToHandle

property

eventsToHandle:Array [read-only]

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.

Implementation
protected function get eventsToHandle():Array

Constructor detail

ComboBaseAccImpl

()

constructor

public function ComboBaseAccImpl(master:UIComponent)

Creates a new ComboBaseAccImpl instance for the specified ComboBase 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 ComboBaseAccImpl 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.controls.ComboBase component.

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

eventHandler

()

method

protected override function eventHandler(event:Event):void

Override the generic event handler. Each AccImpl subclass must implement this method to listen for events from its master component.

Parameters

event:Event — The event object.

get_accRole

()

method

public override function get_accRole(childID:uint):uint

IAccessible method for returning system role for the component. System roles are predefined for all the components in MSAA.

A ComboBase component, ( childID == 0 ), reports the role ROLE_SYSTEM_COMBOBOX (0x2E). Items of a ComboBase component ( childID >= 1 ) report the role ROLE_SYSTEM_LISTITEM (0x22).

Parameters

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

Returns

uint — Role associated with the component.

get_accState

()

method

public override function get_accState(childID:uint):uint

IAccessible method for returning the state of the ComboBase (basically to remove 'not selected'). States are predefined for all the components in MSAA. Values are assigned to each state. Depending upon the listItem being Selected, Selectable, Invisible, Offscreen, a value is returned.

Parameters

childID:uint — uint

Returns

uint — State uint

get_accValue

()

method

public override function get_accValue(childID:uint):String

IAccessible method for returning the value of the ComboBase, which would be the text of the item selected. The ComboBase should return the content of the TextField as the value.

Parameters

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

Returns

String — Value String

getChildIDArray

()

method

public override function getChildIDArray():Array

Method to return an array of childIDs.

Returns

Array — An array of unsigned integer IDs, one for each listItem defined in the ComboBase component's dataProvider.

getName

()

method

protected override function getName(childID:uint):String

Method for returning the name of the ComboBase or one of its child items. For child items, it adds an "m of n" string to the name.

Parameters

childID:uint — uint

Returns

String — Name String

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