DropDownListBaseAccImpl

套件	spark.accessibility
類別	public class DropDownListBaseAccImpl
繼承	DropDownListBaseAccImpl ListBaseAccImpl AccImpl AccessibilityImplementation Object
子類別	ComboBoxAccImpl

語言版本:

ActionScript 3.0

產品版本:

Flex 4

執行階段版本:

Flash Player 10, AIR 1.5

DropDownListAccImpl is the accessibility implementation class for spark.components.supportClasses.DropDownListBase.

Although ComboBox has its own accessibility implementation subclass, DropDownList simply uses the one for DropDownListBase. Therefore, the rest of this description refers to the commonly-used DropDownList component rather than the DropDownListBase base class.

When a Spark DropDownList is created, its accessibilityImplementation property is set to an instance of this class. The Flash Player then uses this class to allow MSAA clients such as screen readers to see and manipulate the DropDownList. See the mx.accessibility.AccImpl and flash.accessibility.AccessibilityImplementation classes for background information about accessibility implementation classes and MSAA.

Children

The MSAA children of a DropDownList are its list items. The number of children is the number of items in the dataProvider not just the number of visible renderers.

As described below, the accessibility of the list items is managed by the DropDownList; the accessibilityImplementation and accessibilityProperties of the item renderers are ignored by the Flash Player.

Role

The MSAA Role of a DropDownList is ROLE_SYSTEM_COMBOBOX.

The Role of each list item is ROLE_SYSTEM_LISTITEM.

Name

The MSAA Name of a DropDownList is, by default, an empty string. When wrapped in a FormItem element, the Name is the FormItem's label. To override this behavior, set the DropDownList's accessibilityName property.

The Name of each list item is determined by the DropDownList's itemToLabel() method.

When the Name of the DropDownList or one of its items changes, a DropDownList dispatches the MSAA event EVENT_OBJECT_NAMECHANGE with the proper childID for a list item or 0 for itself.

Description

The MSAA Description of a DropDownList is, by default, an empty string, but you can set the DropDownList's accessibilityDescription property.

The Description of each list item is the empty string.

State

The MSAA State of a DropDownList is a combination of:

STATE_SYSTEM_UNAVAILABLE (when enabled is false)
STATE_SYSTEM_FOCUSABLE (when enabled is true)
STATE_SYSTEM_FOCUSED (when enabled is true and the DropDownList has focus)
STATE_SYSTEM_EXPANDED (when it is open)
STATE_SYSTEM_COLLAPSED (when it is closed)

The State of a list item is a combination of:

STATE_SYSTEM_FOCUSABLE
STATE_SYSTEM_FOCUSED (when it has focus)
STATE_SYSTEM_SELECTABLE
STATE_SYSTEM_SELECTED (when it is selected)

When the State of the DropDownList or one of its list items changes, a DropDownList dispatches the MSAA event EVENT_OBJECT_STATECHANGE with the proper childID for the list item or 0 for itself.

Value

The MSAA Value of a DropDownList is the MSAA Name of the currently selected list item.

The Value of each list item is the empty string.

When the Value of the DropDownList changes, it dispatches the MSAA event EVENT_OBJECT_VALUECHANGE.

Location

The MSAA Location of a DropDownList or a list item is its bounding rectangle.

Default Action

A DropDownList does not have an MSAA DefaultAction

The DefaultAction of a list item is "Double click".

Focus

The DropDownList itself can receive focus, as well as its list items (either while the DropDownList is collapsed or expanded). The EVENT_OBJECT_FOCUS is fired when this happens.

Selection

The DropDownList allows a single item to be selected, in which case an EVENT_OBJECT_SELECTION event is fired.

公用屬性

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	屬性		定義自
		constructor : Object 類別物件的參照或是特定物件實體的建構函數。	Object
		errno : uint 指出錯誤碼。	AccessibilityImplementation
		stub : Boolean 用於建立組件輔助功能虛設常式。	AccessibilityImplementation

保護屬性

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	屬性		定義自
		eventsToHandle : Array [唯讀] All subclasses must override this function by returning an array of strings of the events to listen for.	AccImpl
		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

公用方法

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	方法		定義自
		DropDownListBaseAccImpl(master:UIComponent) Constructor.	DropDownListBaseAccImpl
		accDoDefaultAction(childID:uint):void IAccessible 方法會執行與組件關聯的預設動作，而該組件是由此 AccessibilityImplementation 或其子元素之一所代表。	AccessibilityImplementation
		accLocation(childID:uint):* MSAA 方法適用於傳回 DisplayObject 或 Rectangle，以便在 AccessibilityImplementation 中指定子系元素的範圍框。	AccessibilityImplementation
		accSelect(operation:uint, childID:uint):void 用於改變組件中之選擇的 IAccessible 方法，該組件是由此 AccessibilityImplementation 所代表。	AccessibilityImplementation
		enableAccessibility():void [靜態] Enables accessibility in the DropDownListBase class.	DropDownListBaseAccImpl
		get_accDefaultAction(childID:uint):String 傳回組件預設動作的 MSAA 方法，該組件是由此 AccessibilityImplementation 或其子元素之一所代表。	AccessibilityImplementation
		get_accFocus():uint 傳回子元素 (如果有的話) 無正負號整數 ID 的 MSAA 方法，該子元素在組件中具有子元素焦點。	AccessibilityImplementation
		get_accName(childID:uint):String 傳回組件名稱的 MSAA 方法，該組件是由此 AccessibilityImplementation 或其子元素之一所代表。	AccessibilityImplementation
		get_accRole(childID:uint):uint 傳回組件系統角色的 MSAA 方法，該組件是由此 AccessibilityImplementation 或其子元素之一所代表。	AccessibilityImplementation
		get_accSelection():Array 傳回陣列的 MSAA 方法，該陣列包含所有選取子元素的 ID。	AccessibilityImplementation
		get_accState(childID:uint):uint 傳回組件目前執行階段狀態的 IAccessible 方法，該組件是由此 AccessibilityImplementation 或其子元素之一所代表。	AccessibilityImplementation
		get_accValue(childID:uint):String 傳回組件執行階段值的 MSAA 方法，該組件是由此 AccessibilityImplementation 或其子元素之一所代表。	AccessibilityImplementation
		get_selectionActiveIndex():*	AccessibilityImplementation
		get_selectionAnchorIndex():*	AccessibilityImplementation
		getChildIDArray():Array 傳回陣列，其中包含 AccessibilityImplementation 所有子元素的無正負號整數 ID。	AccessibilityImplementation
		getFormName(component:UIComponent):String [靜態] Method for supporting Form Accessibility.	AccImpl
		hasOwnProperty(name:String):Boolean 指出物件是否有已定義的指定屬性。	Object
		isAncestorDisabled(component:UIComponent):Boolean [靜態] Returns true if an ancestor of the component has enabled set to false.	AccImpl
		isLabeledBy(labelBounds:Rectangle):Boolean 傳回 true 或 false，以指出具有由 x、y、width 與 height 所指定之範圍框的文字物件，是否應該被視為此 AccessibilityImplementation 所代表之組件的標籤。	AccessibilityImplementation
		isPrototypeOf(theClass:Object):Boolean 指出 Object 類別的實體是否位於指定為參數的物件原型鏈中。	Object
		propertyIsEnumerable(name:String):Boolean 指出指定的屬性是否存在，以及是否可列舉。	Object
		setPropertyIsEnumerable(name:String, isEnum:Boolean = true):void 為迴圈作業設定動態屬性的可用性。	Object
		toLocaleString():String 傳回代表此物件的字串，根據地區特定慣例進行格式化。	Object
		toString():String 會傳回指定之物件的字串形式。	Object
		valueOf():Object 會傳回指定之物件的基本值。	Object

保護方法

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	方法		定義自
		eventHandler(event:Event):void Generic event handler.	AccImpl
		getName(childID:uint):String Returns the name of the accessible component.	AccImpl
		getState(childID:uint):uint Utility method to determine state of the accessible component.	AccImpl

建構函式詳細資料

()

建構函式

public function DropDownListBaseAccImpl(master:UIComponent)

語言版本:

ActionScript 3.0

產品版本:

Flex 4

執行階段版本:

Flash Player 10, AIR 1.5

Constructor.

參數

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

方法詳細資訊

enableAccessibility

()

方法

public static function enableAccessibility():void

語言版本:

ActionScript 3.0

產品版本:

Flex 4

執行階段版本:

Flash Player 10, AIR 1.5

Enables accessibility in the DropDownListBase class.

This method is called by application startup code that is autogenerated by the MXML compiler. Afterwards, when instances of DropDownListBase are initialized, their accessibilityImplementation property will be set to an instance of this class.

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DropDownListBaseAccImpl - AS3 Flex

類別 x

DropDownListBaseAccImpl

enableAccessibility