JCheckBoxMenuItem


1   /*
2    * @(#)JCheckBoxMenuItem.java   1.55 03/12/19
3    *
4    * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7   package javax.swing;
8   
9   import java.util.EventListener  ;
10  
11  import java.awt.*;
12  import java.awt.event.*;
13  import java.awt.image.*;
14  
15  import java.io.ObjectOutputStream  ;
16  import java.io.ObjectInputStream  ;
17  import java.io.IOException  ;
18  
19  import javax.swing.plaf.*;
20  import javax.accessibility.*;
21  
22  
23  /**
24   * A menu item that can be selected or deselected. If selected, the menu
25   * item typically appears with a checkmark next to it. If unselected or
26   * deselected, the menu item appears without a checkmark. Like a regular
27   * menu item, a check box menu item can have either text or a graphic
28   * icon associated with it, or both.
29   * <p>
30   * Either <code>isSelected</code>/<code>setSelected</code> or 
31   * <code>getState</code>/<code>setState</code> can be used
32   * to determine/specify the menu item's selection state. The
33   * preferred methods are <code>isSelected</code> and
34   * <code>setSelected</code>, which work for all menus and buttons.
35   * The <code>getState</code> and <code>setState</code> methods exist for
36   * compatibility with other component sets.
37   * <p>
38   * For further information and examples of using check box menu items,
39   * see <a
40   href="http://java.sun.com/docs/books/tutorial/uiswing/components/menu.html">How to Use Menus</a>,
41   * a section in <em>The Java Tutorial.</em>
42   * <p>
43   * <strong>Warning:</strong>
44   * Serialized objects of this class will not be compatible with
45   * future Swing releases. The current serialization support is
46   * appropriate for short term storage or RMI between applications running
47   * the same version of Swing.  As of 1.4, support for long term storage
48   * of all JavaBeans<sup><font size="-2">TM</font></sup>
49   * has been added to the <code>java.beans</code> package.
50   * Please see {@link java.beans.XMLEncoder}.
51   *
52   * @beaninfo
53   *   attribute: isContainer false
54   * description: A menu item which can be selected or deselected.
55   *
56   * @version 1.55 12/19/03
57   * @author Georges Saab
58   * @author David Karlton
59   */
60  public class JCheckBoxMenuItem extends JMenuItem   implements SwingConstants  ,
61          Accessible 
62  {
63      /**
64       * @see #getUIClassID
65       * @see #readObject
66       */
67      private static final String   uiClassID = "CheckBoxMenuItemUI";
68  
69      /**
70       * Creates an initially unselected check box menu item with no set text or icon.
71       */
72      public JCheckBoxMenuItem() {
73          this(null, null, false);
74      }
75  
76      /**
77       * Creates an initially unselected check box menu item with an icon.
78       *
79       * @param icon the icon of the CheckBoxMenuItem.
80       */
81      public JCheckBoxMenuItem(Icon   icon) {
82          this(null, icon, false);
83      }
84  
85      /**
86       * Creates an initially unselected check box menu item with text.
87       *
88       * @param text the text of the CheckBoxMenuItem
89       */
90      public JCheckBoxMenuItem(String   text) {
91          this(text, null, false);
92      }
93      
94      /**
95       * Creates a menu item whose properties are taken from the 
96       * Action supplied.
97       *
98       * @since 1.3
99       */
100     public JCheckBoxMenuItem(Action   a) {
101         this();
102     setAction(a);
103     }
104 
105     /**
106      * Creates an initially unselected check box menu item with the specified text and icon.
107      *
108      * @param text the text of the CheckBoxMenuItem
109      * @param icon the icon of the CheckBoxMenuItem
110      */
111     public JCheckBoxMenuItem(String   text, Icon   icon) {
112     this(text, icon, false);
113     }
114 
115     /**
116      * Creates a check box menu item with the specified text and selection state.
117      *
118      * @param text the text of the check box menu item.
119      * @param b the selected state of the check box menu item
120      */
121     public JCheckBoxMenuItem(String   text, boolean b) {
122         this(text, null, b);
123     }
124 
125     /**
126      * Creates a check box menu item with the specified text, icon, and selection state.
127      *
128      * @param text the text of the check box menu item
129      * @param icon the icon of the check box menu item
130      * @param b the selected state of the check box menu item
131      */
132     public JCheckBoxMenuItem(String   text, Icon   icon, boolean b) {
133     super(text, icon);
134         setModel(new JToggleButton.ToggleButtonModel  ());
135         setSelected(b);
136     setFocusable(false);
137     }
138 
139     /**
140      * Returns the name of the L&F class
141      * that renders this component.
142      *
143      * @return "CheckBoxMenuItemUI"
144      * @see JComponent#getUIClassID
145      * @see UIDefaults#getUI
146      */
147     public String   getUIClassID() {
148         return uiClassID;
149     }
150             
151      /**
152       * Returns the selected-state of the item. This method
153       * exists for AWT compatibility only.  New code should
154       * use isSelected() instead.
155       *
156       * @return true  if the item is selected
157       */
158     public boolean getState() {
159         return isSelected();
160     }
161             
162     /**
163      * Sets the selected-state of the item. This method
164      * exists for AWT compatibility only.  New code should
165      * use setSelected() instead.
166      *
167      * @param b  a boolean value indicating the item's
168      *           selected-state, where true=selected
169      * @beaninfo
170      * description: The selection state of the check box menu item
171      *      hidden: true
172      */
173     public synchronized void setState(boolean b) {
174         setSelected(b);
175     }
176             
177             
178     /**
179      * Returns an array (length 1) containing the check box menu item 
180      * label or null if the check box is not selected.
181      *
182      * @return an array containing one Object -- the text of the menu item
183      *         -- if the item is selected; otherwise null 
184      */
185     public Object  [] getSelectedObjects() {
186         if (isSelected() == false)
187             return null;
188         Object  [] selectedObjects = new Object  [1];
189         selectedObjects[0] = getText();
190         return selectedObjects;
191     }
192 
193     /** 
194      * See readObject() and writeObject() in JComponent for more 
195      * information about serialization in Swing.
196      */
197     private void writeObject(ObjectOutputStream   s) throws IOException   {
198         s.defaultWriteObject();
199         if (getUIClassID().equals(uiClassID)) {
200             byte count = JComponent.getWriteObjCounter(this);
201             JComponent.setWriteObjCounter(this, --count);
202             if (count == 0 && ui != null) {
203                 ui.installUI(this);
204             }
205         }
206     }
207 
208 
209     /**
210      * Returns a string representation of this JCheckBoxMenuItem. This method 
211      * is intended to be used only for debugging purposes, and the 
212      * content and format of the returned string may vary between      
213      * implementations. The returned string may be empty but may not 
214      * be <code>null</code>.
215      * 
216      * @return  a string representation of this JCheckBoxMenuItem.
217      */
218     protected String   paramString() {
219     return super.paramString();
220     }
221 
222 /////////////////
223 // Accessibility support
224 ////////////////
225 
226     /**
227      * Gets the AccessibleContext associated with this JCheckBoxMenuItem. 
228      * For JCheckBoxMenuItems, the AccessibleContext takes the form of an 
229      * AccessibleJCheckBoxMenuItem. 
230      * A new AccessibleJCheckBoxMenuItem instance is created if necessary.
231      *
232      * @return an AccessibleJCheckBoxMenuItem that serves as the 
233      *         AccessibleContext of this AccessibleJCheckBoxMenuItem
234      */
235     public AccessibleContext getAccessibleContext() {
236         if (accessibleContext == null) {
237             accessibleContext = new AccessibleJCheckBoxMenuItem();
238         }
239         return accessibleContext;
240     }
241 
242     /**
243      * This class implements accessibility support for the 
244      * <code>JCheckBoxMenuItem</code> class.  It provides an implementation 
245      * of the Java Accessibility API appropriate to checkbox menu item 
246      * user-interface elements.
247      * <p>
248      * <strong>Warning:</strong>
249      * Serialized objects of this class will not be compatible with
250      * future Swing releases. The current serialization support is
251      * appropriate for short term storage or RMI between applications running
252      * the same version of Swing.  As of 1.4, support for long term storage
253      * of all JavaBeans<sup><font size="-2">TM</font></sup>
254      * has been added to the <code>java.beans</code> package.
255      * Please see {@link java.beans.XMLEncoder}.
256      */
257     protected class AccessibleJCheckBoxMenuItem extends AccessibleJMenuItem {
258         /**
259          * Get the role of this object.
260          *
261          * @return an instance of AccessibleRole describing the role of the 
262          * object
263          */
264         public AccessibleRole getAccessibleRole() {
265             return AccessibleRole.CHECK_BOX;
266         }
267     } // inner class AccessibleJCheckBoxMenuItem
268 }
269
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags