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 java.io.ObjectOutputStream; import java.io.IOException; import javax.accessibility.*; /** * An implementation of a radio button menu item. * A <code>JRadioButtonMenuItem</code> is * a menu item that is part of a group of menu items in which only one * item in the group can be selected. The selected item displays its * selected state. Selecting it causes any other selected item to * switch to the unselected state. * To control the selected state of a group of radio button menu items, * use a <code>ButtonGroup</code> object. * <p> * Menu items 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 menu item has many benefits beyond directly * configuring a menu item. 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> * Some menus can have several button groups with radio button menu items. In * this case it is useful that clicking on one radio button menu item does not * close the menu. Such behavior can be controlled either by client * {@link JComponent#putClientProperty} or the Look and Feel * {@link UIManager#put} property named * {@code "RadioButtonMenuItem.doNotCloseOnMouseClick"}. The default value is * {@code false}. Setting the property to {@code true} prevents the menu from * closing when it is clicked by the mouse. If the client property is set its * value is always used; otherwise the {@literal L&F} property is queried. * Note: some {@code L&F}s may ignore this property. All built-in {@code L&F}s * inherit this behaviour. * <p> * For further documentation and examples see * <a href="https://docs.oracle.com/javase/tutorial/uiswing/components/menu.html">How to Use Menus</a>, * a section in <em>The Java Tutorial.</em> * <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}. * * @author Georges Saab * @author David Karlton * @see ButtonGroup * @since 1.2 */ @JavaBean(description = "A component within a group of menu items which can be selected.") @SwingContainer(false) @SuppressWarnings("serial") // Same-version serialization only public class JRadioButtonMenuItem extends JMenuItem implements Accessible { /** * @see #getUIClassID * @see #readObject */ private static final String uiClassID = "RadioButtonMenuItemUI"; /** * Creates a <code>JRadioButtonMenuItem</code> with no set text or icon. */ public JRadioButtonMenuItem() { this(null, null, false); } /** * Creates a <code>JRadioButtonMenuItem</code> with an icon. * * @param icon the <code>Icon</code> to display on the * <code>JRadioButtonMenuItem</code> */ public JRadioButtonMenuItem(Icon icon) { this(null, icon, false); } /** * Creates a <code>JRadioButtonMenuItem</code> with text. * * @param text the text of the <code>JRadioButtonMenuItem</code> */ public JRadioButtonMenuItem(String text) { this(text, null, false); } /** * Creates a radio button menu item whose properties are taken from the * <code>Action</code> supplied. * * @param a the <code>Action</code> on which to base the radio * button menu item * * @since 1.3 */ public JRadioButtonMenuItem(Action a) { this(); setAction(a); } /** * Creates a radio button menu item with the specified text * and <code>Icon</code>. * * @param text the text of the <code>JRadioButtonMenuItem</code> * @param icon the icon to display on the <code>JRadioButtonMenuItem</code> */ public JRadioButtonMenuItem(String text, Icon icon) { this(text, icon, false); } /** * Creates a radio button menu item with the specified text * and selection state. * * @param text the text of the <code>CheckBoxMenuItem</code> * @param selected the selected state of the <code>CheckBoxMenuItem</code> */ public JRadioButtonMenuItem(String text, boolean selected) { this(text); setSelected(selected); } /** * Creates a radio button menu item 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 JRadioButtonMenuItem(Icon icon, boolean selected) { this(null, icon, selected); } /** * Creates a radio button menu item that has the specified * text, image, and selection state. All other constructors * defer to this one. * * @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 JRadioButtonMenuItem(String text, Icon icon, boolean selected) { super(text, icon); setModel(new JToggleButton.ToggleButtonModel()); setSelected(selected); setFocusable(false); } /** * Returns the name of the L&F class that renders this component. * * @return the string "RadioButtonMenuItemUI" * @see JComponent#getUIClassID * @see UIDefaults#getUI */ @BeanProperty(bound = false) public String getUIClassID() { return uiClassID; } /** * See <code>readObject</code> and <code>writeObject</code> in * <code>JComponent</code> 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 * <code>JRadioButtonMenuItem</code>. 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 * <code>JRadioButtonMenuItem</code> */ protected String paramString() { return super.paramString(); } /** * Overriden to return true, JRadioButtonMenuItem supports * the selected state. */ boolean shouldUpdateSelectedStateFromAction() { return true; } ///////////////// // Accessibility support //////////////// /** * Gets the AccessibleContext associated with this JRadioButtonMenuItem. * For JRadioButtonMenuItems, the AccessibleContext takes the form of an * AccessibleJRadioButtonMenuItem. * A new AccessibleJRadioButtonMenuItem instance is created if necessary. * * @return an AccessibleJRadioButtonMenuItem that serves as the * AccessibleContext of this JRadioButtonMenuItem */ @BeanProperty(bound = false) public AccessibleContext getAccessibleContext() { if (accessibleContext == null) { accessibleContext = new AccessibleJRadioButtonMenuItem(); } return accessibleContext; } /** * This class implements accessibility support for the * <code>JRadioButtonMenuItem</code> class. It provides an * implementation of the Java Accessibility API appropriate to * <code>JRadioButtonMenuItem</code> 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 AccessibleJRadioButtonMenuItem extends AccessibleJMenuItem { /** * Get the role of this object. * * @return an instance of AccessibleRole describing the role of the * object */ public AccessibleRole getAccessibleRole() { return AccessibleRole.RADIO_BUTTON; } } // inner class AccessibleJRadioButtonMenuItem }