1 /* 2 * Copyright (c) 1997, 2014, 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://docs.oracle.com/javase/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://docs.oracle.com/javase/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™ 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 @SuppressWarnings("serial") // Same-version serialization only 90 public class JRadioButton extends JToggleButton implements Accessible { 91 92 /** 93 * @see #getUIClassID 94 * @see #readObject 95 */ 96 private static final String uiClassID = "RadioButtonUI"; 97 98 99 /** 100 * Creates an initially unselected radio button 101 * with no set text. 102 */ 103 public JRadioButton () { 104 this(null, null, false); 105 } 106 107 /** 108 * Creates an initially unselected radio button 109 * with the specified image but no text. 110 * 111 * @param icon the image that the button should display 112 */ 113 public JRadioButton(Icon icon) { 114 this(null, icon, false); 115 } 116 117 /** 118 * Creates a radiobutton where properties are taken from the 119 * Action supplied. 120 * 121 * @since 1.3 122 */ 123 public JRadioButton(Action a) { 124 this(); 125 setAction(a); 126 } 127 128 /** 129 * Creates a radio button with the specified image 130 * and selection state, but no text. 131 * 132 * @param icon the image that the button should display 133 * @param selected if true, the button is initially selected; 134 * otherwise, the button is initially unselected 135 */ 136 public JRadioButton(Icon icon, boolean selected) { 137 this(null, icon, selected); 138 } 139 140 /** 141 * Creates an unselected radio button with the specified text. 142 * 143 * @param text the string displayed on the radio button 144 */ 145 public JRadioButton (String text) { 146 this(text, null, false); 147 } 148 149 /** 150 * Creates a radio button with the specified text 151 * and selection state. 152 * 153 * @param text the string displayed on the radio button 154 * @param selected if true, the button is initially selected; 155 * otherwise, the button is initially unselected 156 */ 157 public JRadioButton (String text, boolean selected) { 158 this(text, null, selected); 159 } 160 161 /** 162 * Creates a radio button that has the specified text and image, 163 * and that is initially unselected. 164 * 165 * @param text the string displayed on the radio button 166 * @param icon the image that the button should display 167 */ 168 public JRadioButton(String text, Icon icon) { 169 this(text, icon, false); 170 } 171 172 /** 173 * Creates a radio button that has the specified text, image, 174 * and selection state. 175 * 176 * @param text the string displayed on the radio button 177 * @param icon the image that the button should display 178 */ 179 public JRadioButton (String text, Icon icon, boolean selected) { 180 super(text, icon, selected); 181 setBorderPainted(false); 182 setHorizontalAlignment(LEADING); 183 } 184 185 186 /** 187 * Resets the UI property to a value from the current look and feel. 188 * 189 * @see JComponent#updateUI 190 */ 191 public void updateUI() { 192 setUI((ButtonUI)UIManager.getUI(this)); 193 } 194 195 196 /** 197 * Returns the name of the L&F class 198 * that renders this component. 199 * 200 * @return String "RadioButtonUI" 201 * @see JComponent#getUIClassID 202 * @see UIDefaults#getUI 203 * @beaninfo 204 * expert: true 205 * description: A string that specifies the name of the L&F class. 206 */ 207 public String getUIClassID() { 208 return uiClassID; 209 } 210 211 212 /** 213 * The icon for radio buttons comes from the look and feel, 214 * not the Action. 215 */ 216 void setIconFromAction(Action a) { 217 } 218 219 /** 220 * See readObject() and writeObject() in JComponent for more 221 * information about serialization in Swing. 222 */ 223 private void writeObject(ObjectOutputStream s) throws IOException { 224 s.defaultWriteObject(); 225 if (getUIClassID().equals(uiClassID)) { 226 byte count = JComponent.getWriteObjCounter(this); 227 JComponent.setWriteObjCounter(this, --count); 228 if (count == 0 && ui != null) { 229 ui.installUI(this); 230 } 231 } 232 } 233 234 235 /** 236 * Returns a string representation of this JRadioButton. This method 237 * is intended to be used only for debugging purposes, and the 238 * content and format of the returned string may vary between 239 * implementations. The returned string may be empty but may not 240 * be <code>null</code>. 241 * 242 * @return a string representation of this JRadioButton. 243 */ 244 protected String paramString() { 245 return super.paramString(); 246 } 247 248 249 ///////////////// 250 // Accessibility support 251 //////////////// 252 253 254 /** 255 * Gets the AccessibleContext associated with this JRadioButton. 256 * For JRadioButtons, the AccessibleContext takes the form of an 257 * AccessibleJRadioButton. 258 * A new AccessibleJRadioButton instance is created if necessary. 259 * 260 * @return an AccessibleJRadioButton that serves as the 261 * AccessibleContext of this JRadioButton 262 * @beaninfo 263 * expert: true 264 * description: The AccessibleContext associated with this Button 265 */ 266 public AccessibleContext getAccessibleContext() { 267 if (accessibleContext == null) { 268 accessibleContext = new AccessibleJRadioButton(); 269 } 270 return accessibleContext; 271 } 272 273 /** 274 * This class implements accessibility support for the 275 * <code>JRadioButton</code> class. It provides an implementation of the 276 * Java Accessibility API appropriate to radio button 277 * user-interface elements. 278 * <p> 279 * <strong>Warning:</strong> 280 * Serialized objects of this class will not be compatible with 281 * future Swing releases. The current serialization support is 282 * appropriate for short term storage or RMI between applications running 283 * the same version of Swing. As of 1.4, support for long term storage 284 * of all JavaBeans™ 285 * has been added to the <code>java.beans</code> package. 286 * Please see {@link java.beans.XMLEncoder}. 287 */ 288 @SuppressWarnings("serial") // Same-version serialization only 289 protected class AccessibleJRadioButton extends AccessibleJToggleButton { 290 291 /** 292 * Get the role of this object. 293 * 294 * @return an instance of AccessibleRole describing the role of the object 295 * @see AccessibleRole 296 */ 297 public AccessibleRole getAccessibleRole() { 298 return AccessibleRole.RADIO_BUTTON; 299 } 300 301 } // inner class AccessibleJRadioButton 302 }