1 /* 2 * Copyright (c) 1997, 2006, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 package javax.swing; 26 27 import java.awt.*; 28 import java.awt.event.*; 29 import java.beans.*; 30 31 import javax.swing.plaf.*; 32 import javax.accessibility.*; 33 34 import java.io.ObjectOutputStream; 35 import java.io.ObjectInputStream; 36 import java.io.IOException; 37 38 39 /** 40 * An implementation of a radio button -- an item that can be selected or 41 * deselected, and which displays its state to the user. 42 * Used with a {@link ButtonGroup} object to create a group of buttons 43 * in which only one button at a time can be selected. (Create a ButtonGroup 44 * object and use its <code>add</code> method to include the JRadioButton objects 45 * in the group.) 46 * <blockquote> 47 * <strong>Note:</strong> 48 * The ButtonGroup object is a logical grouping -- not a physical grouping. 49 * To create a button panel, you should still create a {@link JPanel} or similar 50 * container-object and add a {@link javax.swing.border.Border} to it to set it off from surrounding 51 * components. 52 * </blockquote> 53 * <p> 54 * Buttons can be configured, and to some degree controlled, by 55 * <code><a href="Action.html">Action</a></code>s. Using an 56 * <code>Action</code> with a button has many benefits beyond directly 57 * configuring a button. Refer to <a href="Action.html#buttonActions"> 58 * Swing Components Supporting <code>Action</code></a> for more 59 * details, and you can find more information in <a 60 * href="http://java.sun.com/docs/books/tutorial/uiswing/misc/action.html">How 61 * to Use Actions</a>, a section in <em>The Java Tutorial</em>. 62 * <p> 63 * See <a href="http://java.sun.com/docs/books/tutorial/uiswing/components/button.html">How to Use Buttons, Check Boxes, and Radio Buttons</a> 64 * in <em>The Java Tutorial</em> 65 * for further documentation. 66 * <p> 67 * <strong>Warning:</strong> Swing is not thread safe. For more 68 * information see <a 69 * href="package-summary.html#threading">Swing's Threading 70 * Policy</a>. 71 * <p> 72 * <strong>Warning:</strong> 73 * Serialized objects of this class will not be compatible with 74 * future Swing releases. The current serialization support is 75 * appropriate for short term storage or RMI between applications running 76 * the same version of Swing. As of 1.4, support for long term storage 77 * of all JavaBeans<sup><font size="-2">TM</font></sup> 78 * has been added to the <code>java.beans</code> package. 79 * Please see {@link java.beans.XMLEncoder}. 80 * 81 * @beaninfo 82 * attribute: isContainer false 83 * description: A component which can display it's state as selected or deselected. 84 * 85 * @see ButtonGroup 86 * @see JCheckBox 87 * @author Jeff Dinkins 88 */ 89 public class JRadioButton extends JToggleButton implements Accessible { 90 91 /** 92 * @see #getUIClassID 93 * @see #readObject 94 */ 95 private static final String uiClassID = "RadioButtonUI"; 96 97 98 /** 99 * Creates an initially unselected radio button 100 * with no set text. 101 */ 102 public JRadioButton () { 103 this(null, null, false); 104 } 105 106 /** 107 * Creates an initially unselected radio button 108 * with the specified image but no text. 109 * 110 * @param icon the image that the button should display 111 */ 112 public JRadioButton(Icon icon) { 113 this(null, icon, false); 114 } 115 116 /** 117 * Creates a radiobutton where properties are taken from the 118 * Action supplied. 119 * 120 * @since 1.3 121 */ 122 public JRadioButton(Action a) { 123 this(); 124 setAction(a); 125 } 126 127 /** 128 * Creates a radio button with the specified image 129 * and selection state, but no text. 130 * 131 * @param icon the image that the button should display 132 * @param selected if true, the button is initially selected; 133 * otherwise, the button is initially unselected 134 */ 135 public JRadioButton(Icon icon, boolean selected) { 136 this(null, icon, selected); 137 } 138 139 /** 140 * Creates an unselected radio button with the specified text. 141 * 142 * @param text the string displayed on the radio button 143 */ 144 public JRadioButton (String text) { 145 this(text, null, false); 146 } 147 148 /** 149 * Creates a radio button with the specified text 150 * and selection state. 151 * 152 * @param text the string displayed on the radio button 153 * @param selected if true, the button is initially selected; 154 * otherwise, the button is initially unselected 155 */ 156 public JRadioButton (String text, boolean selected) { 157 this(text, null, selected); 158 } 159 160 /** 161 * Creates a radio button that has the specified text and image, 162 * and that is initially unselected. 163 * 164 * @param text the string displayed on the radio button 165 * @param icon the image that the button should display 166 */ 167 public JRadioButton(String text, Icon icon) { 168 this(text, icon, false); 169 } 170 171 /** 172 * Creates a radio button that has the specified text, image, 173 * and selection state. 174 * 175 * @param text the string displayed on the radio button 176 * @param icon the image that the button should display 177 */ 178 public JRadioButton (String text, Icon icon, boolean selected) { 179 super(text, icon, selected); 180 setBorderPainted(false); 181 setHorizontalAlignment(LEADING); 182 } 183 184 185 /** 186 * Resets the UI property to a value from the current look and feel. 187 * 188 * @see JComponent#updateUI 189 */ 190 public void updateUI() { 191 setUI((ButtonUI)UIManager.getUI(this)); 192 } 193 194 195 /** 196 * Returns the name of the L&F class 197 * that renders this component. 198 * 199 * @return String "RadioButtonUI" 200 * @see JComponent#getUIClassID 201 * @see UIDefaults#getUI 202 * @beaninfo 203 * expert: true 204 * description: A string that specifies the name of the L&F class. 205 */ 206 public String getUIClassID() { 207 return uiClassID; 208 } 209 210 211 /** 212 * The icon for radio buttons comes from the look and feel, 213 * not the Action. 214 */ 215 void setIconFromAction(Action a) { 216 } 217 218 /** 219 * See readObject() and writeObject() in JComponent for more 220 * information about serialization in Swing. 221 */ 222 private void writeObject(ObjectOutputStream s) throws IOException { 223 s.defaultWriteObject(); 224 if (getUIClassID().equals(uiClassID)) { 225 byte count = JComponent.getWriteObjCounter(this); 226 JComponent.setWriteObjCounter(this, --count); 227 if (count == 0 && ui != null) { 228 ui.installUI(this); 229 } 230 } 231 } 232 233 234 /** 235 * Returns a string representation of this JRadioButton. This method 236 * is intended to be used only for debugging purposes, and the 237 * content and format of the returned string may vary between 238 * implementations. The returned string may be empty but may not 239 * be <code>null</code>. 240 * 241 * @return a string representation of this JRadioButton. 242 */ 243 protected String paramString() { 244 return super.paramString(); 245 } 246 247 248 ///////////////// 249 // Accessibility support 250 //////////////// 251 252 253 /** 254 * Gets the AccessibleContext associated with this JRadioButton. 255 * For JRadioButtons, the AccessibleContext takes the form of an 256 * AccessibleJRadioButton. 257 * A new AccessibleJRadioButton instance is created if necessary. 258 * 259 * @return an AccessibleJRadioButton that serves as the 260 * AccessibleContext of this JRadioButton 261 * @beaninfo 262 * expert: true 263 * description: The AccessibleContext associated with this Button 264 */ 265 public AccessibleContext getAccessibleContext() { 266 if (accessibleContext == null) { 267 accessibleContext = new AccessibleJRadioButton(); 268 } 269 return accessibleContext; 270 } 271 272 /** 273 * This class implements accessibility support for the 274 * <code>JRadioButton</code> class. It provides an implementation of the 275 * Java Accessibility API appropriate to radio button 276 * user-interface elements. 277 * <p> 278 * <strong>Warning:</strong> 279 * Serialized objects of this class will not be compatible with 280 * future Swing releases. The current serialization support is 281 * appropriate for short term storage or RMI between applications running 282 * the same version of Swing. As of 1.4, support for long term storage 283 * of all JavaBeans<sup><font size="-2">TM</font></sup> 284 * has been added to the <code>java.beans</code> package. 285 * Please see {@link java.beans.XMLEncoder}. 286 */ 287 protected class AccessibleJRadioButton extends AccessibleJToggleButton { 288 289 /** 290 * Get the role of this object. 291 * 292 * @return an instance of AccessibleRole describing the role of the object 293 * @see AccessibleRole 294 */ 295 public AccessibleRole getAccessibleRole() { 296 return AccessibleRole.RADIO_BUTTON; 297 } 298 299 } // inner class AccessibleJRadioButton 300 }