AccessibleControlListener


1   /*******************************************************************************
2    * Copyright (c) 2000, 2006 IBM Corporation and others.
3    * All rights reserved. This program and the accompanying materials
4    * are made available under the terms of the Eclipse Public License v1.0
5    * which accompanies this distribution, and is available at
6    * http://www.eclipse.org/legal/epl-v10.html
7    *
8    * Contributors:
9    *     IBM Corporation - initial API and implementation
10   *******************************************************************************/
11  package org.eclipse.swt.accessibility;
12  
13  
14  import org.eclipse.swt.internal.SWTEventListener;
15  
16  /**
17   * Classes that implement this interface provide methods
18   * that deal with the events that are generated when an
19   * accessibility client sends a message to a control.
20   * <p>
21   * After creating an instance of a class that implements
22   * this interface it can be added to a control using the
23   * <code>addAccessibleControlListener</code> method and removed
24   * using the <code>removeAccessibleControlListener</code> method.
25   * When a client requests information the appropriate method
26   * will be invoked.
27   * </p><p>
28   * Note: Accessibility clients use child identifiers to specify
29   * whether they want information about a control or one of its children.
30   * Child identifiers are increasing integers beginning with 0.
31   * The identifier CHILDID_SELF represents the control itself.
32   * </p><p>
33   * Note: This interface is typically used by implementors of
34   * a custom control to provide very detailed information about
35   * the control instance to accessibility clients.
36   * </p>
37   *
38   * @see AccessibleControlAdapter
39   * @see AccessibleControlEvent
40   * 
41   * @since 2.0
42   */
43  public interface AccessibleControlListener extends SWTEventListener {
44  
45      /**
46       * Sent when an accessibility client requests the identifier
47       * of the control child at the specified display coordinates.
48       * <p>
49       * Return the identifier of the child at display point (x, y)
50       * in the <code>childID</code> field of the event object.
51       * Return CHILDID_SELF if point (x, y) is in the control itself
52       * and not in any child. Return CHILDID_NONE if point (x, y)
53       * is not contained in either the control or any of its children.
54       * </p>
55       *
56       * @param e an event object containing the following fields:<ul>
57       *    <li>x, y [IN] - the specified point in display coordinates</li>
58       *    <li>childID [Typical OUT] - the ID of the child at point, or CHILDID_SELF, or CHILDID_NONE</li>
59       *    <li>accessible [Optional OUT] - the accessible object for the control or child may be returned instead of the childID</li>
60       * </ul>
61       */
62      public void getChildAtPoint(AccessibleControlEvent e);
63  
64      /**
65       * Sent when an accessibility client requests the location
66       * of the control, or the location of a child of the control.
67       * <p>
68       * Return a rectangle describing the location of the specified
69       * control or child in the <code>x, y, width, and height</code>
70       * fields of the event object.
71       * </p>
72       *
73       * @param e an event object containing the following fields:<ul>
74       *    <li>childID [IN] - an identifier specifying the control or one of its children</li>
75       *    <li>x, y, width, height [OUT] - the control or child location in display coordinates</li>
76       * </ul>
77       */
78      public void getLocation(AccessibleControlEvent e);
79      
80      /**
81       * Sent when an accessibility client requests the accessible object
82       * for a child of the control.
83       * <p>
84       * Return an <code>Accessible</code> for the specified control or
85       * child in the <code>accessible</code> field of the event object.
86       * Return null if the specified child does not have its own
87       * <code>Accessible</code>.
88       * </p>
89       *
90       * @param e an event object containing the following fields:<ul>
91       *    <li>childID [IN] - an identifier specifying a child of the control</li>
92       *    <li>accessible [OUT] - an Accessible for the specified childID, or null if one does not exist</li>
93       * </ul>
94       */
95      public void getChild(AccessibleControlEvent e);
96      
97      /**
98       * Sent when an accessibility client requests the number of
99       * children in the control.
100      * <p>
101      * Return the number of child items in the <code>detail</code>
102      * field of the event object.
103      * </p>
104      *
105      * @param e an event object containing the following fields:<ul>
106      *    <li>detail [OUT] - the number of child items in this control</li>
107      * </ul>
108      */
109     public void getChildCount(AccessibleControlEvent e);
110     
111     /**
112      * Sent when an accessibility client requests the default action
113      * of the control, or the default action of a child of the control.
114      * <p>
115      * This string is typically a verb describing what the user does to it.
116      * For example, a Push Button's default action is "Press", a Check Button's
117      * is "Check" or "UnCheck", and List items have the default action "Double Click".
118      * </p><p>
119      * Return a string describing the default action of the specified
120      * control or child in the <code>result</code> field of the event object.
121      * Returning null tells the client to use the platform default action string.
122      * </p>
123      *
124      * @param e an event object containing the following fields:<ul>
125      *    <li>childID [IN] - an identifier specifying the control or one of its children</li>
126      *    <li>result [OUT] - the requested default action string, or null</li>
127      * </ul>
128      */
129     public void getDefaultAction(AccessibleControlEvent e);
130     
131     /**
132      * Sent when an accessibility client requests the identity of
133      * the child or control that has keyboard focus.
134      * <p>
135      * Return the identifier of the child that has focus in the
136      * <code>childID</code> field of the event object.
137      * Return CHILDID_SELF if the control itself has keyboard focus.
138      * Return CHILDID_NONE if neither the control nor any of its children has focus.
139      * </p>
140      *
141      * @param e an event object containing the following fields:<ul>
142      *    <li>childID [Typical OUT] - the ID of the child with focus, or CHILDID_SELF, or CHILDID_NONE</li>
143      *    <li>accessible [Optional OUT] - the accessible object for a child may be returned instead of its childID</li>
144      * </ul>
145      */
146     public void getFocus(AccessibleControlEvent e);
147     
148     /**
149      * Sent when an accessibility client requests the role
150      * of the control, or the role of a child of the control.
151      * <p>
152      * Return a role constant (constant defined in ACC beginning with ROLE_)
153      * that describes the role of the specified control or child in the
154      * <code>detail</code> field of the event object.
155      * </p>
156      *
157      * @param e an event object containing the following fields:<ul>
158      *    <li>childID [IN] - an identifier specifying the control or one of its children</li>
159      *    <li>detail [OUT] - a role constant describing the role of the control or child</li>
160      * </ul>
161      */
162     public void getRole(AccessibleControlEvent e);
163     
164     /**
165      * Sent when an accessibility client requests the identity of
166      * the child or control that is currently selected.
167      * <p>
168      * Return the identifier of the selected child in the
169      * <code>childID</code> field of the event object.
170      * Return CHILDID_SELF if the control itself is selected.
171      * Return CHILDID_MULTIPLE if multiple children are selected, and return an array of childIDs in the <code>children</code> field.
172      * Return CHILDID_NONE if neither the control nor any of its children are selected.
173      * </p>
174      *
175      * @param e an event object containing the following fields:<ul>
176      *    <li>childID [Typical OUT] - the ID of the selected child, or CHILDID_SELF, or CHILDID_MULTIPLE, or CHILDID_NONE</li>
177      *    <li>accessible [Optional OUT] - the accessible object for the control or child may be returned instead of the childID</li>
178      * </ul>
179      */
180     public void getSelection(AccessibleControlEvent e);
181     
182     /**
183      * Sent when an accessibility client requests the state
184      * of the control, or the state of a child of the control.
185      * <p>
186      * Return a state mask (mask bit constants defined in ACC beginning with STATE_)
187      * that describes the current state of the specified control or child in the
188      * <code>detail</code> field of the event object.
189      * </p>
190      *
191      * @param e an event object containing the following fields:<ul>
192      *    <li>childID [IN] - an identifier specifying the control or one of its children</li>
193      *    <li>detail [OUT] - a state mask describing the current state of the control or child</li>
194      * </ul>
195      */
196     public void getState(AccessibleControlEvent e);
197     
198     /**
199      * Sent when an accessibility client requests the value
200      * of the control, or the value of a child of the control.
201      * <p>
202      * Many controls do not return a value. Examples of controls
203      * that do are: Combo returns the text string, Text returns
204      * its contents, ProgressBar returns a string representing a
205      * percentage, and Tree items return a string representing
206      * their level in the tree.
207      * </p><p>
208      * Return a string describing the value of the specified control
209      * or child in the <code>result</code> field of the event object.
210      * Returning null tells the client to use the platform value string.
211      * </p>
212      *
213      * @param e an event object containing the following fields:<ul>
214      *    <li>childID [IN] - an identifier specifying the control or one of its children</li>
215      *    <li>result [OUT] - the requested value string, or null</li>
216      * </ul>
217      */
218     public void getValue(AccessibleControlEvent e);
219     
220     /**
221      * Sent when an accessibility client requests the children of the control.
222      * <p>
223      * Return the children as an array of childIDs in the <code>children</code>
224      * field of the event object.
225      * </p>
226      *
227      * @param e an event object containing the following fields:<ul>
228      *    <li>children [Typical OUT] - an array of childIDs</li>
229      *    <li>children [Optional OUT] - an array of accessible objects for the children may be returned instead of the childIDs</li>
230      * </ul>
231      */
232     public void getChildren(AccessibleControlEvent e);
233 }
234
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