Java tutorial
/* * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.swing; import java.beans.JavaBean; import java.beans.BeanProperty; import javax.swing.plaf.*; import javax.accessibility.*; import java.io.ObjectOutputStream; import java.io.IOException; /** * An implementation of a radio button -- an item that can be selected or * deselected, and which displays its state to the user. * Used with a {@link ButtonGroup} object to create a group of buttons * in which only one button at a time can be selected. (Create a ButtonGroup * object and use its <code>add</code> method to include the JRadioButton objects * in the group.) * <blockquote> * <strong>Note:</strong> * The ButtonGroup object is a logical grouping -- not a physical grouping. * To create a button panel, you should still create a {@link JPanel} or similar * container-object and add a {@link javax.swing.border.Border} to it to set it off from surrounding * components. * </blockquote> * <p> * Buttons can be configured, and to some degree controlled, by * <code><a href="Action.html">Action</a></code>s. Using an * <code>Action</code> with a button has many benefits beyond directly * configuring a button. Refer to <a href="Action.html#buttonActions"> * Swing Components Supporting <code>Action</code></a> for more * details, and you can find more information in <a * href="https://docs.oracle.com/javase/tutorial/uiswing/misc/action.html">How * to Use Actions</a>, a section in <em>The Java Tutorial</em>. * <p> * See <a href="https://docs.oracle.com/javase/tutorial/uiswing/components/button.html">How to Use Buttons, Check Boxes, and Radio Buttons</a> * in <em>The Java Tutorial</em> * for further documentation. * <p> * <strong>Warning:</strong> Swing is not thread safe. For more * information see <a * href="package-summary.html#threading">Swing's Threading * Policy</a>. * <p> * <strong>Warning:</strong> * Serialized objects of this class will not be compatible with * future Swing releases. The current serialization support is * appropriate for short term storage or RMI between applications running * the same version of Swing. As of 1.4, support for long term storage * of all JavaBeans™ * has been added to the <code>java.beans</code> package. * Please see {@link java.beans.XMLEncoder}. * * @see ButtonGroup * @see JCheckBox * @author Jeff Dinkins * @since 1.2 */ @JavaBean(description = "A component which can display it's state as selected or deselected.") @SwingContainer(false) @SuppressWarnings("serial") // Same-version serialization only public class JRadioButton extends JToggleButton implements Accessible { /** * @see #getUIClassID * @see #readObject */ private static final String uiClassID = "RadioButtonUI"; /** * Creates an initially unselected radio button * with no set text. */ public JRadioButton() { this(null, null, false); } /** * Creates an initially unselected radio button * with the specified image but no text. * * @param icon the image that the button should display */ public JRadioButton(Icon icon) { this(null, icon, false); } /** * Creates a radiobutton where properties are taken from the * Action supplied. * * @param a an {@code Action} * @since 1.3 */ public JRadioButton(Action a) { this(); setAction(a); } /** * Creates a radio button with the specified image * and selection state, but no text. * * @param icon the image that the button should display * @param selected if true, the button is initially selected; * otherwise, the button is initially unselected */ public JRadioButton(Icon icon, boolean selected) { this(null, icon, selected); } /** * Creates an unselected radio button with the specified text. * * @param text the string displayed on the radio button */ public JRadioButton(String text) { this(text, null, false); } /** * Creates a radio button with the specified text * and selection state. * * @param text the string displayed on the radio button * @param selected if true, the button is initially selected; * otherwise, the button is initially unselected */ public JRadioButton(String text, boolean selected) { this(text, null, selected); } /** * Creates a radio button that has the specified text and image, * and that is initially unselected. * * @param text the string displayed on the radio button * @param icon the image that the button should display */ public JRadioButton(String text, Icon icon) { this(text, icon, false); } /** * Creates a radio button that has the specified text, image, * and selection state. * * @param text the string displayed on the radio button * @param icon the image that the button should display * @param selected if {@code true}, the button is initially selected * otherwise, the button is initially unselected */ public JRadioButton(String text, Icon icon, boolean selected) { super(text, icon, selected); setBorderPainted(false); setHorizontalAlignment(LEADING); } /** * Resets the UI property to a value from the current look and feel. * * @see JComponent#updateUI */ public void updateUI() { setUI((ButtonUI) UIManager.getUI(this)); } /** * Returns the name of the L&F class * that renders this component. * * @return the string "RadioButtonUI" * @see JComponent#getUIClassID * @see UIDefaults#getUI */ @BeanProperty(bound = false, expert = true, description = "A string that specifies the name of the L&F class.") public String getUIClassID() { return uiClassID; } /** * The icon for radio buttons comes from the look and feel, * not the Action. */ void setIconFromAction(Action a) { } /** * See readObject() and writeObject() in JComponent for more * information about serialization in Swing. */ private void writeObject(ObjectOutputStream s) throws IOException { s.defaultWriteObject(); if (getUIClassID().equals(uiClassID)) { byte count = JComponent.getWriteObjCounter(this); JComponent.setWriteObjCounter(this, --count); if (count == 0 && ui != null) { ui.installUI(this); } } } /** * Returns a string representation of this JRadioButton. This method * is intended to be used only for debugging purposes, and the * content and format of the returned string may vary between * implementations. The returned string may be empty but may not * be <code>null</code>. * * @return a string representation of this JRadioButton. */ protected String paramString() { return super.paramString(); } ///////////////// // Accessibility support //////////////// /** * Gets the AccessibleContext associated with this JRadioButton. * For JRadioButtons, the AccessibleContext takes the form of an * AccessibleJRadioButton. * A new AccessibleJRadioButton instance is created if necessary. * * @return an AccessibleJRadioButton that serves as the * AccessibleContext of this JRadioButton */ @BeanProperty(bound = false, expert = true, description = "The AccessibleContext associated with this Button") public AccessibleContext getAccessibleContext() { if (accessibleContext == null) { accessibleContext = new AccessibleJRadioButton(); } return accessibleContext; } /** * This class implements accessibility support for the * <code>JRadioButton</code> class. It provides an implementation of the * Java Accessibility API appropriate to radio button * user-interface elements. * <p> * <strong>Warning:</strong> * Serialized objects of this class will not be compatible with * future Swing releases. The current serialization support is * appropriate for short term storage or RMI between applications running * the same version of Swing. As of 1.4, support for long term storage * of all JavaBeans™ * has been added to the <code>java.beans</code> package. * Please see {@link java.beans.XMLEncoder}. */ @SuppressWarnings("serial") // Same-version serialization only protected class AccessibleJRadioButton extends AccessibleJToggleButton { /** * Get the role of this object. * * @return an instance of AccessibleRole describing the role of the object * @see AccessibleRole */ public AccessibleRole getAccessibleRole() { return AccessibleRole.RADIO_BUTTON; } } // inner class AccessibleJRadioButton }