Package org.eclipse.swt.accessibility

Class Accessible

  • public class Accessible
extends Object
    Instances of this class provide a bridge between application code and assistive technology clients. Many platforms provide default accessible behavior for most widgets, and this class allows that default behavior to be overridden. Applications can get the default Accessible object for a control by sending it getAccessible, and then add an accessible listener to override simple items like the name and help string, or they can add an accessible control listener to override complex items. As a rule of thumb, an application would only want to use the accessible control listener to implement accessibility for a custom control.
    Since:
    2.0
    See Also:
    Control.getAccessible(), AccessibleListener, AccessibleEvent, AccessibleControlListener, AccessibleControlEvent, Accessibility snippets, Sample code and further information

    • Constructor Detail

      • Accessible

        @Deprecated
protected Accessible()
        Deprecated.
        Since:
        3.5

    • Method Detail

      • internal_new_Accessible

        public static Accessible internal_new_Accessible​(Control control)
        Invokes platform specific functionality to allocate a new accessible object.

        IMPORTANT: This method is not part of the public API for Accessible. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms, and should never be called from application code.

        Parameters:
        control - the control to get the accessible object for
        Returns:
        the platform specific accessible object
        Restriction:
        This method is not intended to be referenced by clients.

      • addAccessibleListener

        public void addAccessibleListener​(AccessibleListener listener)
        Adds the listener to the collection of listeners who will be notified when an accessible client asks for certain strings, such as name, description, help, or keyboard shortcut. The listener is notified by sending it one of the messages defined in the AccessibleListener interface.
        Parameters:
        listener - the listener that should be notified when the receiver is asked for a name, description, help, or keyboard shortcut string
        Throws:
        IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the listener is null
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver's control has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver's control
        See Also:
        AccessibleListener, removeAccessibleListener(org.eclipse.swt.accessibility.AccessibleListener)

      • addAccessibleControlListener

        public void addAccessibleControlListener​(AccessibleControlListener listener)
        Adds the listener to the collection of listeners who will be notified when an accessible client asks for custom control specific information. The listener is notified by sending it one of the messages defined in the AccessibleControlListener interface.
        Parameters:
        listener - the listener that should be notified when the receiver is asked for custom control specific information
        Throws:
        IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the listener is null
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver's control has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver's control
        See Also:
        AccessibleControlListener, removeAccessibleControlListener(org.eclipse.swt.accessibility.AccessibleControlListener)

      • addRelation

        public void addRelation​(int type,
                        Accessible target)
        Adds a relation with the specified type and target to the receiver's set of relations.
        Parameters:
        type - an ACC constant beginning with RELATION_* indicating the type of relation
        target - the accessible that is the target for this relation
        Throws:
        IllegalArgumentException - ERROR_NULL_ARGUMENT - if the Accessible target is null
        Since:
        3.6

      • dispose

        public void dispose()
        Disposes of the operating system resources associated with the receiver, and removes the receiver from its parent's list of children.

        This method should be called when an accessible that was created with the public constructor Accessible(Accessible parent) is no longer needed. You do not need to call this when the receiver's control is disposed, because all Accessible instances associated with a control are released when the control is disposed. It is also not necessary to call this for instances of Accessible that were retrieved with Control.getAccessible().

        Since:
        3.6

      • getControl

        public Control getControl()
        Returns the control for this Accessible object.
        Returns:
        the receiver's control
        Since:
        3.0

      • internal_dispose_Accessible

        public void internal_dispose_Accessible()
        Invokes platform specific functionality to dispose an accessible object.

        IMPORTANT: This method is not part of the public API for Accessible. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms, and should never be called from application code.

        Restriction:
        This method is not intended to be referenced by clients.

      • internal_WM_GETOBJECT

        public long internal_WM_GETOBJECT​(long wParam,
                                  long lParam)
        Invokes platform specific functionality to handle a window message.

        IMPORTANT: This method is not part of the public API for Accessible. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms, and should never be called from application code.

        Restriction:
        This method is not intended to be referenced by clients.

      • removeAccessibleListener

        public void removeAccessibleListener​(AccessibleListener listener)
        Removes the listener from the collection of listeners who will be notified when an accessible client asks for certain strings, such as name, description, help, or keyboard shortcut.
        Parameters:
        listener - the listener that should no longer be notified when the receiver is asked for a name, description, help, or keyboard shortcut string
        Throws:
        IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the listener is null
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver's control has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver's control
        See Also:
        AccessibleListener, addAccessibleListener(org.eclipse.swt.accessibility.AccessibleListener)

      • removeAccessibleActionListener

        public void removeAccessibleActionListener​(AccessibleActionListener listener)
        Removes the listener from the collection of listeners that will be notified when an accessible client asks for any of the properties defined in the AccessibleActionListener interface.
        Parameters:
        listener - the listener that should no longer be notified when the receiver is asked for AccessibleActionListener interface properties
        Throws:
        IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the listener is null
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver's control has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver's control
        Since:
        3.6
        See Also:
        AccessibleActionListener, addAccessibleActionListener(org.eclipse.swt.accessibility.AccessibleActionListener)

      • removeAccessibleTableListener

        public void removeAccessibleTableListener​(AccessibleTableListener listener)
        Removes the listener from the collection of listeners that will be notified when an accessible client asks for any of the properties defined in the AccessibleTableListener interface.
        Parameters:
        listener - the listener that should no longer be notified when the receiver is asked for AccessibleTableListener interface properties
        Throws:
        IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the listener is null
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver's control has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver's control
        Since:
        3.6
        See Also:
        AccessibleTableListener, addAccessibleTableListener(org.eclipse.swt.accessibility.AccessibleTableListener)

      • removeAccessibleValueListener

        public void removeAccessibleValueListener​(AccessibleValueListener listener)
        Removes the listener from the collection of listeners that will be notified when an accessible client asks for any of the properties defined in the AccessibleValueListener interface.
        Parameters:
        listener - the listener that should no longer be notified when the receiver is asked for AccessibleValueListener interface properties
        Throws:
        IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the listener is null
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver's control has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver's control
        Since:
        3.6
        See Also:
        AccessibleValueListener, addAccessibleValueListener(org.eclipse.swt.accessibility.AccessibleValueListener)

      • removeRelation

        public void removeRelation​(int type,
                           Accessible target)
        Removes the relation with the specified type and target from the receiver's set of relations.
        Parameters:
        type - an ACC constant beginning with RELATION_* indicating the type of relation
        target - the accessible that is the target for this relation
        Throws:
        IllegalArgumentException - ERROR_NULL_ARGUMENT - if the Accessible target is null
        Since:
        3.6

      • sendEvent

        public void sendEvent​(int event,
                      Object eventData,
                      int childID)
        Sends a message with event-specific data and a childID to accessible clients, indicating that something has changed within a custom control. NOTE: This API is intended for applications that are still using childIDs. Moving forward, applications should use accessible objects instead of childIDs.
        Parameters:
        event - an ACC constant beginning with EVENT_* indicating the message to send
        eventData - an object containing event-specific data, or null if there is no event-specific data (eventData is specified in the documentation for individual ACC.EVENT_* constants)
        childID - an identifier specifying a child of the control
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver's control has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver's control
        Since:
        3.8
        See Also:
        ACC.EVENT_DESCRIPTION_CHANGED, ACC.EVENT_LOCATION_CHANGED, ACC.EVENT_NAME_CHANGED, ACC.EVENT_SELECTION_CHANGED, ACC.EVENT_STATE_CHANGED, ACC.EVENT_TEXT_SELECTION_CHANGED, ACC.EVENT_VALUE_CHANGED

      • selectionChanged

        public void selectionChanged()
        Sends a message to accessible clients that the child selection within a custom container control has changed.
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver's control has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver's control
        Since:
        3.0

      • setFocus

        public void setFocus​(int childID)
        Sends a message to accessible clients indicating that the focus has changed within a custom control.
        Parameters:
        childID - an identifier specifying a child of the control
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver's control has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver's control

      • textCaretMoved

        public void textCaretMoved​(int index)
        Sends a message to accessible clients that the text caret has moved within a custom control.
        Parameters:
        index - the new caret index within the control
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver's control has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver's control
        Since:
        3.0

      • textChanged

        public void textChanged​(int type,
                        int startIndex,
                        int length)
        Sends a message to accessible clients that the text within a custom control has changed.
        Parameters:
        type - the type of change, one of ACC.TEXT_INSERT or ACC.TEXT_DELETE
        startIndex - the text index within the control where the insertion or deletion begins
        length - the non-negative length in characters of the insertion or deletion
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver's control has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver's control
        Since:
        3.0
        See Also:
        ACC.TEXT_INSERT, ACC.TEXT_DELETE

      • textSelectionChanged

        public void textSelectionChanged()
        Sends a message to accessible clients that the text selection has changed within a custom control.
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver's control has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver's control
        Since:
        3.0