JToggleButton


1   /*
2    * @(#)JToggleButton.java   1.59 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.awt.*;
10  import java.awt.event.*;
11  
12  import javax.swing.event.*;
13  import javax.swing.plaf.*;
14  import javax.accessibility.*;
15  
16  import java.io.ObjectOutputStream  ;
17  import java.io.ObjectInputStream  ;
18  import java.io.IOException  ;
19  
20  
21  /**
22   * An implementation of a two-state button.  
23   * The <code>JRadioButton</code> and <code>JCheckBox</code> classes
24   * are subclasses of this class.
25   * For information on using them see
26   * <a
27   href="http://java.sun.com/docs/books/tutorial/uiswing/components/button.html">How to Use Buttons, Check Boxes, and Radio Buttons</a>,
28   * a section in <em>The Java Tutorial</em>.
29   * <p>
30   * <strong>Warning:</strong>
31   * Serialized objects of this class will not be compatible with
32   * future Swing releases. The current serialization support is
33   * appropriate for short term storage or RMI between applications running
34   * the same version of Swing.  As of 1.4, support for long term storage
35   * of all JavaBeans<sup><font size="-2">TM</font></sup>
36   * has been added to the <code>java.beans</code> package.
37   * Please see {@link java.beans.XMLEncoder}.
38   *
39   * @beaninfo
40   *   attribute: isContainer false
41   * description: An implementation of a two-state button.
42   * 
43   * @see JRadioButton
44   * @see JCheckBox
45   * @version 1.59 12/19/03
46   * @author Jeff Dinkins
47   */
48  public class JToggleButton extends AbstractButton   implements Accessible {
49  
50      /**
51       * @see #getUIClassID
52       * @see #readObject
53       */
54      private static final String   uiClassID = "ToggleButtonUI";
55  
56      /**
57       * Creates an initially unselected toggle button
58       * without setting the text or image.
59       */
60      public JToggleButton () {
61          this(null, null, false);
62      }
63  
64      /**
65       * Creates an initially unselected toggle button
66       * with the specified image but no text.
67       *
68       * @param icon  the image that the button should display
69       */
70      public JToggleButton(Icon   icon) {
71          this(null, icon, false);
72      }
73      
74      /**
75       * Creates a toggle button with the specified image 
76       * and selection state, but no text.
77       *
78       * @param icon  the image that the button should display
79       * @param selected  if true, the button is initially selected;
80       *                  otherwise, the button is initially unselected
81       */
82      public JToggleButton(Icon   icon, boolean selected) {
83          this(null, icon, selected);
84      }
85      
86      /**
87       * Creates an unselected toggle button with the specified text.
88       *
89       * @param text  the string displayed on the toggle button
90       */
91      public JToggleButton (String   text) {
92          this(text, null, false);
93      }
94  
95      /**
96       * Creates a toggle button with the specified text
97       * and selection state.
98       *
99       * @param text  the string displayed on the toggle button
100      * @param selected  if true, the button is initially selected;
101      *                  otherwise, the button is initially unselected
102      */
103     public JToggleButton (String   text, boolean selected) {
104         this(text, null, selected);
105     }
106 
107     /**
108      * Creates a toggle button where properties are taken from the 
109      * Action supplied.
110      *
111      * @since 1.3
112      */
113     public JToggleButton(Action   a) {
114         this();
115     setAction(a);
116     }
117 
118     /**
119      * Creates a toggle button that has the specified text and image,
120      * and that is initially unselected.
121      *
122      * @param text the string displayed on the button
123      * @param icon  the image that the button should display
124      */
125     public JToggleButton(String   text, Icon   icon) {
126         this(text, icon, false);
127     }
128 
129     /**
130      * Creates a toggle button with the specified text, image, and
131      * selection state.
132      *
133      * @param text the text of the toggle button
134      * @param icon  the image that the button should display
135      * @param selected  if true, the button is initially selected;
136      *                  otherwise, the button is initially unselected
137      */
138     public JToggleButton (String   text, Icon   icon, boolean selected) {
139         // Create the model
140         setModel(new ToggleButtonModel());
141 
142         model.setSelected(selected);
143 
144         // initialize
145         init(text, icon);
146     }
147 
148     /**
149      * Resets the UI property to a value from the current look and feel.
150      *
151      * @see JComponent#updateUI
152      */
153     public void updateUI() {
154         setUI((ButtonUI)UIManager.getUI(this));
155     }
156     
157     /**
158      * Returns a string that specifies the name of the l&f class
159      * that renders this component.
160      *
161      * @return String "ToggleButtonUI"
162      * @see JComponent#getUIClassID
163      * @see UIDefaults#getUI
164      * @beaninfo
165      *  description: A string that specifies the name of the L&F class
166      */
167     public String   getUIClassID() {
168         return uiClassID;
169     }
170 
171 
172     // *********************************************************************
173 
174     /**
175      * The ToggleButton model
176      * <p>
177      * <strong>Warning:</strong>
178      * Serialized objects of this class will not be compatible with
179      * future Swing releases. The current serialization support is
180      * appropriate for short term storage or RMI between applications running
181      * the same version of Swing.  As of 1.4, support for long term storage
182      * of all JavaBeans<sup><font size="-2">TM</font></sup>
183      * has been added to the <code>java.beans</code> package.
184      * Please see {@link java.beans.XMLEncoder}.
185      */
186     public static class ToggleButtonModel extends DefaultButtonModel   {
187 
188         /**
189          * Creates a new ToggleButton Model
190          */
191         public ToggleButtonModel () {
192         }
193 
194         /**
195          * Checks if the button is selected.
196          */
197         public boolean isSelected() {
198 //              if(getGroup() != null) {
199 //                  return getGroup().isSelected(this);
200 //              } else {
201                 return (stateMask & SELECTED) != 0;
202 //              }
203         }
204 
205 
206         /**
207          * Sets the selected state of the button.
208          * @param b true selects the toggle button,
209          *          false deselects the toggle button.
210          */
211         public void setSelected(boolean b) {
212             ButtonGroup   group = getGroup();
213             if (group != null) {
214                 // use the group model instead
215                 group.setSelected(this, b);
216                 b = group.isSelected(this);
217             }
218 
219             if (isSelected() == b) {
220                 return;
221             }
222 
223             if (b) {
224                 stateMask |= SELECTED;
225             } else {
226                 stateMask &= ~SELECTED;
227             }
228 
229             // Send ChangeEvent
230             fireStateChanged();
231 
232             // Send ItemEvent
233             fireItemStateChanged(
234                     new ItemEvent(this,
235                                   ItemEvent.ITEM_STATE_CHANGED,
236                                   this,
237                                   this.isSelected() ?  ItemEvent.SELECTED : ItemEvent.DESELECTED));
238         
239         }
240 
241         /**
242          * Sets the pressed state of the toggle button.
243          */ 
244         public void setPressed(boolean b) {
245             if ((isPressed() == b) || !isEnabled()) {
246                 return;
247             }
248 
249             if (b == false && isArmed()) {
250                 setSelected(!this.isSelected());
251             } 
252 
253             if (b) {
254                 stateMask |= PRESSED;
255             } else {
256                 stateMask &= ~PRESSED;
257             }
258 
259             fireStateChanged();
260 
261             if(!isPressed() && isArmed()) {
262                 int modifiers = 0;
263                 AWTEvent currentEvent = EventQueue.getCurrentEvent();
264                 if (currentEvent instanceof InputEvent) {
265                     modifiers = ((InputEvent)currentEvent).getModifiers();
266                 } else if (currentEvent instanceof ActionEvent) {
267                     modifiers = ((ActionEvent)currentEvent).getModifiers();
268                 }
269                 fireActionPerformed(
270                     new ActionEvent(this, ActionEvent.ACTION_PERFORMED,
271                                     getActionCommand(),
272                                     EventQueue.getMostRecentEventTime(),
273                                     modifiers));
274             }
275 
276         }
277     }
278 
279 
280     /** 
281      * See readObject() and writeObject() in JComponent for more 
282      * information about serialization in Swing.
283      */
284     private void writeObject(ObjectOutputStream   s) throws IOException   {
285         s.defaultWriteObject();
286         if (getUIClassID().equals(uiClassID)) {
287             byte count = JComponent.getWriteObjCounter(this);
288             JComponent.setWriteObjCounter(this, --count);
289             if (count == 0 && ui != null) {
290                 ui.installUI(this);
291             }
292         }
293     }
294 
295 
296     /**
297      * Returns a string representation of this JToggleButton. This method 
298      * is intended to be used only for debugging purposes, and the 
299      * content and format of the returned string may vary between      
300      * implementations. The returned string may be empty but may not 
301      * be <code>null</code>.
302      * 
303      * @return  a string representation of this JToggleButton.
304      */
305     protected String   paramString() {
306         return super.paramString();
307     }
308 
309 
310 /////////////////
311 // Accessibility support
312 ////////////////
313 
314     /**
315      * Gets the AccessibleContext associated with this JToggleButton. 
316      * For toggle buttons, the AccessibleContext takes the form of an 
317      * AccessibleJToggleButton. 
318      * A new AccessibleJToggleButton instance is created if necessary.
319      *
320      * @return an AccessibleJToggleButton that serves as the 
321      *         AccessibleContext of this JToggleButton
322      * @beaninfo
323      *       expert: true
324      *  description: The AccessibleContext associated with this ToggleButton.
325      */
326     public AccessibleContext getAccessibleContext() {
327         if (accessibleContext == null) {
328             accessibleContext = new AccessibleJToggleButton();
329         }
330         return accessibleContext;
331     }
332 
333     /**
334      * This class implements accessibility support for the 
335      * <code>JToggleButton</code> class.  It provides an implementation of the 
336      * Java Accessibility API appropriate to toggle button user-interface 
337      * elements.
338      * <p>
339      * <strong>Warning:</strong>
340      * Serialized objects of this class will not be compatible with
341      * future Swing releases. The current serialization support is
342      * appropriate for short term storage or RMI between applications running
343      * the same version of Swing.  As of 1.4, support for long term storage
344      * of all JavaBeans<sup><font size="-2">TM</font></sup>
345      * has been added to the <code>java.beans</code> package.
346      * Please see {@link java.beans.XMLEncoder}.
347      */
348     protected class AccessibleJToggleButton extends AccessibleAbstractButton
349         implements ItemListener {
350 
351     public AccessibleJToggleButton() {
352         super();
353         JToggleButton.this.addItemListener(this);
354     }
355 
356     /**
357      * Fire accessible property change events when the state of the
358      * toggle button changes.
359      */
360         public void itemStateChanged(ItemEvent e) {
361             JToggleButton   tb = (JToggleButton  ) e.getSource();
362             if (JToggleButton.this.accessibleContext != null) {
363                 if (tb.isSelected()) {
364                     JToggleButton.this.accessibleContext.firePropertyChange(
365                             AccessibleContext.ACCESSIBLE_STATE_PROPERTY,
366                             null, AccessibleState.CHECKED);
367                 } else {
368                     JToggleButton.this.accessibleContext.firePropertyChange(
369                             AccessibleContext.ACCESSIBLE_STATE_PROPERTY,
370                             AccessibleState.CHECKED, null);
371                 }
372             }
373         }
374 
375         /**
376          * Get the role of this object.
377          *
378          * @return an instance of AccessibleRole describing the role of the 
379          * object
380          */
381         public AccessibleRole getAccessibleRole() {
382             return AccessibleRole.TOGGLE_BUTTON;
383         }
384     } // inner class AccessibleJToggleButton
385 }
386   
387
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