## wxAccessible

The wxAccessible class allows wxWidgets applications, and wxWidgets itself, to return extended information about user interface elements to client applications such as screen readers. This is the main way in which wxWidgets implements accessibility features.

At present, only Microsoft Active Accessibility is supported by this class.

To use this class, derive from wxAccessible, implement appropriate functions, and associate an object of the class with a window using wxWindow::SetAccessible.

All functions return an indication of success, failure, or not implemented using values of the wxAccStatus enum type.

If you return wxACC_NOT_IMPLEMENTED from any function, the system will try to implement the appropriate functionality. However this will not work with all functions.

Most functions work with an object id, which can be zero to refer to 'this' UI element, or greater than zero to refer to the nth child element. This allows you to specify elements that don't have a corresponding wxWindow or wxAccessible; for example, the sash of a splitter window.

For details on the semantics of functions and types, please refer to the Microsoft Active Accessibility 1.2 documentation.

This class is compiled into wxWidgets only if the wxUSE_ACCESSIBILITY setup symbol is set to 1.

Derived from

wxObject

Include files

<wx/access.h>

Data structures

Functions return a wxAccStatus error code, which may be one of the following:

    typedef enum
    {
        wxACC_FAIL,            // The function failed
        wxACC_FALSE,           // The function returned false
        wxACC_OK,              // The function completed successfully
        wxACC_NOT_IMPLEMENTED, // The function is not implemented
        wxACC_NOT_SUPPORTED    // The function is not supported
    } wxAccStatus

Directions of navigation are represented by the following:

    typedef enum
    {
        wxNAVDIR_DOWN,
        wxNAVDIR_FIRSTCHILD,
        wxNAVDIR_LASTCHILD,
        wxNAVDIR_LEFT,
        wxNAVDIR_NEXT,
        wxNAVDIR_PREVIOUS,
        wxNAVDIR_RIGHT,
        wxNAVDIR_UP
    } wxNavDir

The role of a user interface element is represented by the following type:

    typedef enum {
        wxROLE_NONE,
        wxROLE_SYSTEM_ALERT,
        wxROLE_SYSTEM_ANIMATION,
        wxROLE_SYSTEM_APPLICATION,
        wxROLE_SYSTEM_BORDER,
        wxROLE_SYSTEM_BUTTONDROPDOWN,
        wxROLE_SYSTEM_BUTTONDROPDOWNGRID,
        wxROLE_SYSTEM_BUTTONMENU,
        wxROLE_SYSTEM_CARET,
        wxROLE_SYSTEM_CELL,
        wxROLE_SYSTEM_CHARACTER,
        wxROLE_SYSTEM_CHART,
        wxROLE_SYSTEM_CHECKBUTTON,
        wxROLE_SYSTEM_CLIENT,
        wxROLE_SYSTEM_CLOCK,
        wxROLE_SYSTEM_COLUMN,
        wxROLE_SYSTEM_COLUMNHEADER,
        wxROLE_SYSTEM_COMBOBOX,
        wxROLE_SYSTEM_CURSOR,
        wxROLE_SYSTEM_DIAGRAM,
        wxROLE_SYSTEM_DIAL,
        wxROLE_SYSTEM_DIALOG,
        wxROLE_SYSTEM_DOCUMENT,
        wxROLE_SYSTEM_DROPLIST,
        wxROLE_SYSTEM_EQUATION,
        wxROLE_SYSTEM_GRAPHIC,
        wxROLE_SYSTEM_GRIP,
        wxROLE_SYSTEM_GROUPING,
        wxROLE_SYSTEM_HELPBALLOON,
        wxROLE_SYSTEM_HOTKEYFIELD,
        wxROLE_SYSTEM_INDICATOR,
        wxROLE_SYSTEM_LINK,
        wxROLE_SYSTEM_LIST,
        wxROLE_SYSTEM_LISTITEM,
        wxROLE_SYSTEM_MENUBAR,
        wxROLE_SYSTEM_MENUITEM,
        wxROLE_SYSTEM_MENUPOPUP,
        wxROLE_SYSTEM_OUTLINE,
        wxROLE_SYSTEM_OUTLINEITEM,
        wxROLE_SYSTEM_PAGETAB,
        wxROLE_SYSTEM_PAGETABLIST,
        wxROLE_SYSTEM_PANE,
        wxROLE_SYSTEM_PROGRESSBAR,
        wxROLE_SYSTEM_PROPERTYPAGE,
        wxROLE_SYSTEM_PUSHBUTTON,
        wxROLE_SYSTEM_RADIOBUTTON,
        wxROLE_SYSTEM_ROW,
        wxROLE_SYSTEM_ROWHEADER,
        wxROLE_SYSTEM_SCROLLBAR,
        wxROLE_SYSTEM_SEPARATOR,
        wxROLE_SYSTEM_SLIDER,
        wxROLE_SYSTEM_SOUND,
        wxROLE_SYSTEM_SPINBUTTON,
        wxROLE_SYSTEM_STATICTEXT,
        wxROLE_SYSTEM_STATUSBAR,
        wxROLE_SYSTEM_TABLE,
        wxROLE_SYSTEM_TEXT,
        wxROLE_SYSTEM_TITLEBAR,
        wxROLE_SYSTEM_TOOLBAR,
        wxROLE_SYSTEM_TOOLTIP,
        wxROLE_SYSTEM_WHITESPACE,
        wxROLE_SYSTEM_WINDOW
    } wxAccRole

Objects are represented by the following type:

    typedef enum {
        wxOBJID_WINDOW =    0x00000000,
        wxOBJID_SYSMENU =   0xFFFFFFFF,
        wxOBJID_TITLEBAR =  0xFFFFFFFE,
        wxOBJID_MENU =      0xFFFFFFFD,
        wxOBJID_CLIENT =    0xFFFFFFFC,
        wxOBJID_VSCROLL =   0xFFFFFFFB,
        wxOBJID_HSCROLL =   0xFFFFFFFA,
        wxOBJID_SIZEGRIP =  0xFFFFFFF9,
        wxOBJID_CARET =     0xFFFFFFF8,
        wxOBJID_CURSOR =    0xFFFFFFF7,
        wxOBJID_ALERT =     0xFFFFFFF6,
        wxOBJID_SOUND =     0xFFFFFFF5
    } wxAccObject

Selection actions are identified by this type:

    typedef enum
    {
        wxACC_SEL_NONE            = 0,
        wxACC_SEL_TAKEFOCUS       = 1,
        wxACC_SEL_TAKESELECTION   = 2,
        wxACC_SEL_EXTENDSELECTION = 4,
        wxACC_SEL_ADDSELECTION    = 8,
        wxACC_SEL_REMOVESELECTION = 16
    } wxAccSelectionFlags

States are represented by the following:

    #define wxACC_STATE_SYSTEM_ALERT_HIGH       0x00000001
    #define wxACC_STATE_SYSTEM_ALERT_MEDIUM     0x00000002
    #define wxACC_STATE_SYSTEM_ALERT_LOW        0x00000004
    #define wxACC_STATE_SYSTEM_ANIMATED         0x00000008
    #define wxACC_STATE_SYSTEM_BUSY             0x00000010
    #define wxACC_STATE_SYSTEM_CHECKED          0x00000020
    #define wxACC_STATE_SYSTEM_COLLAPSED        0x00000040
    #define wxACC_STATE_SYSTEM_DEFAULT          0x00000080
    #define wxACC_STATE_SYSTEM_EXPANDED         0x00000100
    #define wxACC_STATE_SYSTEM_EXTSELECTABLE    0x00000200
    #define wxACC_STATE_SYSTEM_FLOATING         0x00000400
    #define wxACC_STATE_SYSTEM_FOCUSABLE        0x00000800
    #define wxACC_STATE_SYSTEM_FOCUSED          0x00001000
    #define wxACC_STATE_SYSTEM_HOTTRACKED       0x00002000
    #define wxACC_STATE_SYSTEM_INVISIBLE        0x00004000
    #define wxACC_STATE_SYSTEM_MARQUEED         0x00008000
    #define wxACC_STATE_SYSTEM_MIXED            0x00010000
    #define wxACC_STATE_SYSTEM_MULTISELECTABLE  0x00020000
    #define wxACC_STATE_SYSTEM_OFFSCREEN        0x00040000
    #define wxACC_STATE_SYSTEM_PRESSED          0x00080000
    #define wxACC_STATE_SYSTEM_PROTECTED        0x00100000
    #define wxACC_STATE_SYSTEM_READONLY         0x00200000
    #define wxACC_STATE_SYSTEM_SELECTABLE       0x00400000
    #define wxACC_STATE_SYSTEM_SELECTED         0x00800000
    #define wxACC_STATE_SYSTEM_SELFVOICING      0x01000000
    #define wxACC_STATE_SYSTEM_UNAVAILABLE      0x02000000

Event identifiers that can be sent via wxAccessible::NotifyEvent are as follows:

    #define wxACC_EVENT_SYSTEM_SOUND              0x0001
    #define wxACC_EVENT_SYSTEM_ALERT              0x0002
    #define wxACC_EVENT_SYSTEM_FOREGROUND         0x0003
    #define wxACC_EVENT_SYSTEM_MENUSTART          0x0004
    #define wxACC_EVENT_SYSTEM_MENUEND            0x0005
    #define wxACC_EVENT_SYSTEM_MENUPOPUPSTART     0x0006
    #define wxACC_EVENT_SYSTEM_MENUPOPUPEND       0x0007
    #define wxACC_EVENT_SYSTEM_CAPTURESTART       0x0008
    #define wxACC_EVENT_SYSTEM_CAPTUREEND         0x0009
    #define wxACC_EVENT_SYSTEM_MOVESIZESTART      0x000A
    #define wxACC_EVENT_SYSTEM_MOVESIZEEND        0x000B
    #define wxACC_EVENT_SYSTEM_CONTEXTHELPSTART   0x000C
    #define wxACC_EVENT_SYSTEM_CONTEXTHELPEND     0x000D
    #define wxACC_EVENT_SYSTEM_DRAGDROPSTART      0x000E
    #define wxACC_EVENT_SYSTEM_DRAGDROPEND        0x000F
    #define wxACC_EVENT_SYSTEM_DIALOGSTART        0x0010
    #define wxACC_EVENT_SYSTEM_DIALOGEND          0x0011
    #define wxACC_EVENT_SYSTEM_SCROLLINGSTART     0x0012
    #define wxACC_EVENT_SYSTEM_SCROLLINGEND       0x0013
    #define wxACC_EVENT_SYSTEM_SWITCHSTART        0x0014
    #define wxACC_EVENT_SYSTEM_SWITCHEND          0x0015
    #define wxACC_EVENT_SYSTEM_MINIMIZESTART      0x0016
    #define wxACC_EVENT_SYSTEM_MINIMIZEEND        0x0017
    #define wxACC_EVENT_OBJECT_CREATE                 0x8000
    #define wxACC_EVENT_OBJECT_DESTROY                0x8001
    #define wxACC_EVENT_OBJECT_SHOW                   0x8002
    #define wxACC_EVENT_OBJECT_HIDE                   0x8003
    #define wxACC_EVENT_OBJECT_REORDER                0x8004
    #define wxACC_EVENT_OBJECT_FOCUS                  0x8005
    #define wxACC_EVENT_OBJECT_SELECTION              0x8006
    #define wxACC_EVENT_OBJECT_SELECTIONADD           0x8007
    #define wxACC_EVENT_OBJECT_SELECTIONREMOVE        0x8008
    #define wxACC_EVENT_OBJECT_SELECTIONWITHIN        0x8009
    #define wxACC_EVENT_OBJECT_STATECHANGE            0x800A
    #define wxACC_EVENT_OBJECT_LOCATIONCHANGE         0x800B
    #define wxACC_EVENT_OBJECT_NAMECHANGE             0x800C
    #define wxACC_EVENT_OBJECT_DESCRIPTIONCHANGE      0x800D
    #define wxACC_EVENT_OBJECT_VALUECHANGE            0x800E
    #define wxACC_EVENT_OBJECT_PARENTCHANGE           0x800F
    #define wxACC_EVENT_OBJECT_HELPCHANGE             0x8010
    #define wxACC_EVENT_OBJECT_DEFACTIONCHANGE        0x8011
    #define wxACC_EVENT_OBJECT_ACCELERATORCHANGE      0x8012

Members

wxAccessible::wxAccessible
wxAccessible::~wxAccessible
wxAccessible::DoDefaultAction
wxAccessible::GetChild
wxAccessible::GetChildCount
wxAccessible::GetDefaultAction
wxAccessible::GetDescription
wxAccessible::GetFocus
wxAccessible::GetHelpText
wxAccessible::GetKeyboardShortcut
wxAccessible::GetLocation
wxAccessible::GetName
wxAccessible::GetParent
wxAccessible::GetRole
wxAccessible::GetSelections
wxAccessible::GetState
wxAccessible::GetValue
wxAccessible::GetWindow
wxAccessible::HitTest
wxAccessible::Navigate
wxAccessible::NotifyEvent
wxAccessible::Select
wxAccessible::SetWindow

### wxAccessible::wxAccessible

wxAccessible(wxWindow* win = NULL)

Constructor, taking an optional window. The object can be associated with a window later.

### wxAccessible::~wxAccessible

~wxAccessible()

Destructor.

### wxAccessible::DoDefaultAction

virtual wxAccStatus DoDefaultAction(int childId)

Performs the default action for the object. childId is 0 (the action for this object) or greater than 0 (the action for a child). Return wxACC_NOT_SUPPORTED if there is no default action for this window (e.g. an edit control).

### wxAccessible::GetChild

virtual wxAccStatus GetChild(int childId, wxAccessible** child)

Gets the specified child (starting from 1). If child is NULL and the return value is wxACC_OK, this means that the child is a simple element and not an accessible object.

### wxAccessible::GetChildCount

virtual wxAccStatus GetChildCount(int* childCount)

Returns the number of children in childCount.

### wxAccessible::GetDefaultAction

virtual wxAccStatus GetDefaultAction(int childId, wxString* actionName)

Gets the default action for this object (0) or a child (greater than 0). Return wxACC_OK even if there is no action. actionName is the action, or the empty string if there is no action. The retrieved string describes the action that is performed on an object, not what the object does as a result. For example, a toolbar button that prints a document has a default action of "Press" rather than "Prints the current document."

### wxAccessible::GetDescription

virtual wxAccStatus GetDescription(int childId, wxString* description)

Returns the description for this object or a child.

### wxAccessible::GetFocus

virtual wxAccStatus GetFocus(int* childId, wxAccessible** child)

Gets the window with the keyboard focus. If childId is 0 and child is NULL, no object in this subhierarchy has the focus. If this object has the focus, child should be 'this'.

### wxAccessible::GetHelpText

virtual wxAccStatus GetHelpText(int childId, wxString* helpText)

Returns help text for this object or a child, similar to tooltip text.

### wxAccessible::GetKeyboardShortcut

virtual wxAccStatus GetKeyboardShortcut(int childId, wxString* shortcut)

Returns the keyboard shortcut for this object or child. Return e.g. ALT+K.

### wxAccessible::GetLocation

virtual wxAccStatus GetLocation(wxRect& rect, int elementId)

Returns the rectangle for this object (id is 0) or a child element (id is greater than 0). rect is in screen coordinates.

### wxAccessible::GetName

virtual wxAccStatus GetName(int childId, wxString* name)

Gets the name of the specified object.

### wxAccessible::GetParent

virtual wxAccStatus GetParent(wxAccessible** parent)

Returns the parent of this object, or NULL.

### wxAccessible::GetRole

virtual wxAccStatus GetRole(int childId, wxAccRole* role)

Returns a role constant describing this object. See wxAccessible for a list of these roles.

### wxAccessible::GetSelections

virtual wxAccStatus GetSelections(wxVariant* selections)

Gets a variant representing the selected children of this object.

Acceptable values are:

- a null variant (IsNull() returns TRUE)
- a list variant (GetType() == wxT("list"))
- an integer representing the selected child element, or 0 if this object is selected (GetType() == wxT("long"))
- a "void*" pointer to a wxAccessible child object

### wxAccessible::GetState

virtual wxAccStatus GetState(int childId, long* state)

Returns a state constant. See wxAccessible for a list of these states.

### wxAccessible::GetValue

virtual wxAccStatus GetValue(int childId, wxString* strValue)

Returns a localized string representing the value for the object or child.

### wxAccessible::GetWindow

wxWindow* GetWindow()

Returns the window associated with this object.

### wxAccessible::HitTest

virtual wxAccStatus HitTest(const wxPoint& pt, int* childId, wxAccessible** childObject)

Returns a status value and object id to indicate whether the given point was on this or a child object. Can return either a child object, or an integer representing the child element, starting from 1.

pt is in screen coordinates.

### wxAccessible::Navigate

virtual wxAccStatus Navigate(wxNavDir navDir, int fromId, int* toId, wxAccessible** toObject)

Navigates from fromId to toId/toObject.

### wxAccessible::NotifyEvent

virtual static void NotifyEvent(int eventType, wxWindow* window, wxAccObject objectType, int objectType)

Allows the application to send an event when something changes in an accessible object.

### wxAccessible::Select

virtual wxAccStatus Select(int childId, wxAccSelectionFlags selectFlags)

Selects the object or child. See wxAccessible for a list of the selection actions.

### wxAccessible::SetWindow

void SetWindow(wxWindow* window)

Sets the window associated with this object.