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.ObjectInputStream; import java.io.IOException; /** * An implementation of a check box -- an item that can be selected or * deselected, and which displays its state to the user. * By convention, any number of check boxes in a group can be selected. * 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 examples and information on using check boxes. * <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> * <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 JRadioButton * * @author Jeff Dinkins * @since 1.2 */ @JavaBean(description = "A component which can be selected or deselected.") @SwingContainer(false) @SuppressWarnings("serial") // Same-version serialization only public class JCheckBox extends JToggleButton implements Accessible { /** Identifies a change to the flat property. */ public static final String BORDER_PAINTED_FLAT_CHANGED_PROPERTY = "borderPaintedFlat"; private boolean flat = false; /** * @see #getUIClassID * @see #readObject */ private static final String uiClassID = "CheckBoxUI"; /** * Creates an initially unselected check box button with no text, no icon. */ public JCheckBox() { this(null, null, false); } /** * Creates an initially unselected check box with an icon. * * @param icon the Icon image to display */ public JCheckBox(Icon icon) { this(null, icon, false); } /** * Creates a check box with an icon and specifies whether * or not it is initially selected. * * @param icon the Icon image to display * @param selected a boolean value indicating the initial selection * state. If <code>true</code> the check box is selected */ public JCheckBox(Icon icon, boolean selected) { this(null, icon, selected); } /** * Creates an initially unselected check box with text. * * @param text the text of the check box. */ public JCheckBox(String text) { this(text, null, false); } /** * Creates a check box where properties are taken from the * Action supplied. * * @param a the {@code Action} used to specify the new check box * @since 1.3 */ public JCheckBox(Action a) { this(); setAction(a); } /** * Creates a check box with text and specifies whether * or not it is initially selected. * * @param text the text of the check box. * @param selected a boolean value indicating the initial selection * state. If <code>true</code> the check box is selected */ public JCheckBox(String text, boolean selected) { this(text, null, selected); } /** * Creates an initially unselected check box with * the specified text and icon. * * @param text the text of the check box. * @param icon the Icon image to display */ public JCheckBox(String text, Icon icon) { this(text, icon, false); } /** * Creates a check box with text and icon, * and specifies whether or not it is initially selected. * * @param text the text of the check box. * @param icon the Icon image to display * @param selected a boolean value indicating the initial selection * state. If <code>true</code> the check box is selected */ public JCheckBox(String text, Icon icon, boolean selected) { super(text, icon, selected); setUIProperty("borderPainted", Boolean.FALSE); setHorizontalAlignment(LEADING); } /** * Sets the <code>borderPaintedFlat</code> property, * which gives a hint to the look and feel as to the * appearance of the check box border. * This is usually set to <code>true</code> when a * <code>JCheckBox</code> instance is used as a * renderer in a component such as a <code>JTable</code> or * <code>JTree</code>. The default value for the * <code>borderPaintedFlat</code> property is <code>false</code>. * This method fires a property changed event. * Some look and feels might not implement flat borders; * they will ignore this property. * * @param b <code>true</code> requests that the border be painted flat; * <code>false</code> requests normal borders * @see #isBorderPaintedFlat * @since 1.3 */ @BeanProperty(visualUpdate = true, description = "Whether the border is painted flat.") public void setBorderPaintedFlat(boolean b) { boolean oldValue = flat; flat = b; firePropertyChange(BORDER_PAINTED_FLAT_CHANGED_PROPERTY, oldValue, flat); if (b != oldValue) { revalidate(); repaint(); } } /** * Gets the value of the <code>borderPaintedFlat</code> property. * * @return the value of the <code>borderPaintedFlat</code> property * @see #setBorderPaintedFlat * @since 1.3 */ public boolean isBorderPaintedFlat() { return flat; } /** * 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 a string that specifies the name of the L&F class * that renders this component. * * @return the string "CheckBoxUI" * @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 checkboxs comes from the look and feel, * not the Action; this is overriden to do nothing. */ 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); } } } /** * See JComponent.readObject() for information about serialization * in Swing. */ private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException { s.defaultReadObject(); if (getUIClassID().equals(uiClassID)) { updateUI(); } } /** * Returns a string representation of this JCheckBox. 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>. * specific new aspects of the JFC components. * * @return a string representation of this JCheckBox. */ protected String paramString() { return super.paramString(); } ///////////////// // Accessibility support //////////////// /** * Gets the AccessibleContext associated with this JCheckBox. * For JCheckBoxes, the AccessibleContext takes the form of an * AccessibleJCheckBox. * A new AccessibleJCheckBox instance is created if necessary. * * @return an AccessibleJCheckBox that serves as the * AccessibleContext of this JCheckBox */ @BeanProperty(bound = false, expert = true, description = "The AccessibleContext associated with this CheckBox.") public AccessibleContext getAccessibleContext() { if (accessibleContext == null) { accessibleContext = new AccessibleJCheckBox(); } return accessibleContext; } /** * This class implements accessibility support for the * <code>JCheckBox</code> class. It provides an implementation of the * Java Accessibility API appropriate to check box 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 AccessibleJCheckBox 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.CHECK_BOX; } } // inner class AccessibleJCheckBox }