Transfer focus from button to button with help of arrows keys. : JButton « Swing « Java Tutorial






/*
 * Copyright 2006 Sun Microsystems, Inc., 4150 Network Circle,
 * Santa Clara, California 95054, U.S.A. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */


import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Container;
import java.awt.FocusTraversalPolicy;
import java.awt.GridLayout;
import java.awt.KeyboardFocusManager;
import java.awt.LayoutManager;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.InputEvent;
import java.awt.event.KeyEvent;

import javax.swing.AbstractButton;
import javax.swing.BorderFactory;
import javax.swing.ButtonGroup;
import javax.swing.ButtonModel;
import javax.swing.DefaultButtonModel;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.KeyStroke;
import javax.swing.LayoutFocusTraversalPolicy;
import javax.swing.SwingUtilities;
import javax.swing.border.TitledBorder;

/**
 * This is a JPanel subclass which provides a special functionality
 * for its children buttons components.
 * It makes it possible to transfer focus from button to button
 * with help of arrows keys.
 * <p>The following example shows how to enable cyclic focus transfer 
 * <pre>
 * import org.jdesktop.swinghelper.buttonpanel.*; 
 * import javax.swing.*;
 *
 * public class SimpleDemo {
 *     public static void main(String[] args) throws Exception {
 *         SwingUtilities.invokeLater(new Runnable() {
 *             public void run() {
 *                 final JFrame frame = new JFrame();
 *                 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 *       
 *                 JXButtonPanel panel = new JXButtonPanel();
 *                 panel.setCyclic(true);
 *       
 *                 panel.add(new JButton("One"));
 *                 panel.add(new JButton("Two"));
 *                 panel.add(new JButton("Three"));
 *       
 *                 frame.add(panel);
 *                 frame.setSize(200, 200);
 *                 frame.setLocationRelativeTo(null);
 *                 frame.setVisible(true);
 *             }
 *         });
 *     }
 * }
 * </pre> 
 *  
 * If your buttons inside JXButtonPanel are added to one ButtonGroup
 * arrow keys will transfer selection between them as well as they do it for focus<p>
 * Note: you can control this behaviour with setGroupSelectionFollowFocus(boolean) 
 * <pre>
 * import org.jdesktop.swinghelper.buttonpanel.*;
 * import javax.swing.*;
 *
 * public class RadioButtonDemo {
 *     public static void main(String[] args) throws Exception {
 *         SwingUtilities.invokeLater(new Runnable() {
 *             public void run() {
 *                 final JFrame frame = new JFrame();
 *                 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 * 
 *                 JXButtonPanel panel = new JXButtonPanel();
 *                 ButtonGroup group = new ButtonGroup();
 * 
 *                 JRadioButton rb1 = new JRadioButton("One");
 *                 panel.add(rb1);
 *                 group.add(rb1);
 *                 JRadioButton rb2 = new JRadioButton("Two");
 *                 panel.add(rb2);
 *                 group.add(rb2);
 *                 JRadioButton rb3 = new JRadioButton("Three");
 *                 panel.add(rb3);
 *                 group.add(rb3);
 * 
 *                 rb1.setSelected(true);
 *                 frame.add(panel);
 * 
 *                 frame.setSize(200, 200);
 *                 frame.setLocationRelativeTo(null);
 *                 frame.setVisible(true);
 *             }
 *         });
 *     }
 * }
 * </pre> 
 * 
 * @author Alexander Potochkin
 * 
 * https://swinghelper.dev.java.net/
 * http://weblogs.java.net/blog/alexfromsun/ 
 */
public class JXButtonPanel extends JPanel {
    private boolean isCyclic;
    private boolean isGroupSelectionFollowFocus;

    /**
     * {@inheritDoc}
     */
    public JXButtonPanel() {
        super();
        init();
    }

    /**
     * {@inheritDoc}
     */
    public JXButtonPanel(LayoutManager layout) {
        super(layout);
        init();
    }

    /**
     * {@inheritDoc}    
     */
    public JXButtonPanel(boolean isDoubleBuffered) {
        super(isDoubleBuffered);
        init();
    }

    /**
     * {@inheritDoc}
     */
    public JXButtonPanel(LayoutManager layout, boolean isDoubleBuffered) {
        super(layout, isDoubleBuffered);
        init();
    }

    private void init() {
        setFocusTraversalPolicyProvider(true);
        setFocusTraversalPolicy(new JXButtonPanelFocusTraversalPolicy());
        ActionListener actionHandler = new ActionHandler();
        registerKeyboardAction(actionHandler, ActionHandler.FORWARD,
                KeyStroke.getKeyStroke(KeyEvent.VK_RIGHT, 0),
                JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
        registerKeyboardAction(actionHandler, ActionHandler.FORWARD,
                KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0),
                JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
        registerKeyboardAction(actionHandler, ActionHandler.BACKWARD,
                KeyStroke.getKeyStroke(KeyEvent.VK_LEFT, 0),
                JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
        registerKeyboardAction(actionHandler, ActionHandler.BACKWARD,
                KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0),
                JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
        setGroupSelectionFollowFocus(true);
    }

    /**
     * Returns whether arrow keys should support
     * cyclic focus traversal ordering for for this JXButtonPanel.   
     */
    public boolean isCyclic() {
        return isCyclic;
    }

    /**
     * Sets whether arrow keys should support
     * cyclic focus traversal ordering for this JXButtonPanel.
     */
    public void setCyclic(boolean isCyclic) {
        this.isCyclic = isCyclic;
    }

    /**
     * Returns whether arrow keys should transfer button's 
     * selection as well as focus for this JXButtonPanel.<p>
     * 
     * Note: this property affects buttons which are added to a ButtonGroup 
     */
    public boolean isGroupSelectionFollowFocus() {
        return isGroupSelectionFollowFocus;
    }

    /**
     * Sets whether arrow keys should transfer button's
     * selection as well as focus for this JXButtonPanel.<p>
     * 
     * Note: this property affects buttons which are added to a ButtonGroup 
     */
    public void setGroupSelectionFollowFocus(boolean groupSelectionFollowFocus) {
        isGroupSelectionFollowFocus = groupSelectionFollowFocus;
    }

    private static ButtonGroup getButtonGroup(AbstractButton button) {
        ButtonModel model = button.getModel();
        if (model instanceof DefaultButtonModel) {
            return ((DefaultButtonModel) model).getGroup();
        }
        return null;
    }

    private class ActionHandler implements ActionListener {
        private static final String FORWARD = "moveSelectionForward";
        private static final String BACKWARD = "moveSelectionBackward";

        public void actionPerformed(ActionEvent e) {
            FocusTraversalPolicy ftp = JXButtonPanel.this.getFocusTraversalPolicy();

            if (ftp instanceof JXButtonPanelFocusTraversalPolicy) {
                JXButtonPanelFocusTraversalPolicy xftp =
                        (JXButtonPanelFocusTraversalPolicy) ftp;

                String actionCommand = e.getActionCommand();
                Component fo =
                        KeyboardFocusManager.getCurrentKeyboardFocusManager().getFocusOwner();
                Component next;

                xftp.setAlternativeFocusMode(true);

                if (FORWARD.equals(actionCommand)) {
                    next = xftp.getComponentAfter(JXButtonPanel.this, fo);
                } else if (BACKWARD.equals(actionCommand)) {
                    next = xftp.getComponentBefore(JXButtonPanel.this, fo);
                } else {
                    throw new AssertionError("Unexpected action command: " + actionCommand);
                }

                xftp.setAlternativeFocusMode(false);

                if (fo instanceof AbstractButton) {
                    AbstractButton b = (AbstractButton) fo;
                    b.getModel().setPressed(false);
                }
                if (next != null) {
                    if (fo instanceof AbstractButton && next instanceof AbstractButton) {
                        ButtonGroup group = getButtonGroup((AbstractButton) fo);
                        AbstractButton nextButton = (AbstractButton) next;
                        if (group != getButtonGroup(nextButton)) {
                            return;
                        }
                        if (isGroupSelectionFollowFocus() && group != null && 
                                group.getSelection() != null && !nextButton.isSelected()) {
                            nextButton.setSelected(true);
                        }
                        next.requestFocusInWindow();
                    }
                }
            }
        }
    }

    private class JXButtonPanelFocusTraversalPolicy extends LayoutFocusTraversalPolicy {
        private boolean isAlternativeFocusMode;

        public boolean isAlternativeFocusMode() {
            return isAlternativeFocusMode;
        }

        public void setAlternativeFocusMode(boolean alternativeFocusMode) {
            isAlternativeFocusMode = alternativeFocusMode;
        }

        protected boolean accept(Component c) {
            if (!isAlternativeFocusMode() && c instanceof AbstractButton) {
                AbstractButton button = (AbstractButton) c;
                ButtonGroup group = JXButtonPanel.getButtonGroup(button);
                if (group != null && group.getSelection() != null
                        && !button.isSelected()) {
                    return false;
                }
            }
            return super.accept(c);
        }

        public Component getComponentAfter(Container aContainer, Component aComponent) {
            Component componentAfter = super.getComponentAfter(aContainer, aComponent);
            if (!isAlternativeFocusMode()) {
                return componentAfter;
            }
            if (JXButtonPanel.this.isCyclic()) {
                return componentAfter == null ?
                        getFirstComponent(aContainer) : componentAfter;
            }
            if (aComponent == getLastComponent(aContainer)) {
                return aComponent;
            }
            return componentAfter;
        }

        public Component getComponentBefore(Container aContainer, Component aComponent) {
            Component componentBefore = super.getComponentBefore(aContainer, aComponent);
            if (!isAlternativeFocusMode()) {
                return componentBefore;
            }
            if (JXButtonPanel.this.isCyclic()) {
                return componentBefore == null ?
                        getLastComponent(aContainer) : componentBefore;
            }
            if (aComponent == getFirstComponent(aContainer)) {
                return aComponent;
            }
            return componentBefore;
        }
    }
}




/**
 * @author Alexander Potochkin
 * 
 * https://swinghelper.dev.java.net/
 * http://weblogs.java.net/blog/alexfromsun/ 
 */
class JXButtonPanelDemo extends JFrame {
    private ButtonGroup radioGroup = new ButtonGroup();

    public JXButtonPanelDemo() {
        super("JXButtonPanel demo");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setResizable(false);
        JPanel topPanel = new JPanel(new GridLayout(1, 0));
        
        final JXButtonPanel radioGroupPanel = createRadioJXButtonPanel();
        topPanel.add(radioGroupPanel);
        
        final JXButtonPanel checkBoxPanel = createCheckBoxJXButtonPanel();
        topPanel.add(checkBoxPanel);

        add(topPanel);
        add(createButtonJXButtonPanel(), BorderLayout.SOUTH);
        pack();

        JMenuBar bar = new JMenuBar();
        JMenu menu = new JMenu("Options");
        JMenuItem item = new JMenuItem("Unselect radioButtons");
        item.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_C, InputEvent.ALT_MASK));
        item.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                // hack for 1.5 
                // in 1.6 ButtonGroup.clearSelection added
                JRadioButton b = new JRadioButton();
                radioGroup.add(b);
                b.setSelected(true);
                radioGroup.remove(b);
            }
        });
        menu.add(item);
        bar.add(menu);
        setJMenuBar(bar);

        setSize(300, 300);
        setLocationRelativeTo(null);
    }

    private JXButtonPanel createRadioJXButtonPanel() {
        JXButtonPanel panel = new JXButtonPanel();
        panel.setLayout(new GridLayout(0, 1));
        JRadioButton one = new JRadioButton("One");
        panel.add(one);
        radioGroup.add(one);
        JRadioButton two = new JRadioButton("Two");
        panel.add(two);
        radioGroup.add(two);
        JRadioButton three = new JRadioButton("Three");
        panel.add(three);
        radioGroup.add(three);
        JRadioButton four = new JRadioButton("Four");
        panel.add(four);
        radioGroup.add(four);
        one.setSelected(true);
        panel.setBorder(BorderFactory.createTitledBorder("JXButtonPanel"));
        return panel;
    }

    private JXButtonPanel createCheckBoxJXButtonPanel() {
        JXButtonPanel panel = new JXButtonPanel();
        panel.setLayout(new GridLayout(0, 1));
        JCheckBox one = new JCheckBox("One");
        panel.add(one);
        JCheckBox two = new JCheckBox("Two");
        panel.add(two);
        JCheckBox three = new JCheckBox("Three");
        panel.add(three);
        JCheckBox four = new JCheckBox("Four");
        panel.add(four);
        panel.setBorder(BorderFactory.createTitledBorder("JXButtonPanel"));
        return panel;
    }

    private JPanel createButtonJXButtonPanel() {
        JPanel ret = new JPanel(new BorderLayout());
        JLabel label = new JLabel("Does JXButtonPanel support arrow keys ?");
        label.setBorder(BorderFactory.createEmptyBorder(0, 0, 10, 0));
        JPanel temp = new JPanel();
        temp.add(label);
        ret.add(temp);
        
        JXButtonPanel panel = new JXButtonPanel();
        panel.setCyclic(true);
        panel.add(new JButton("Yes"));
        panel.add(new JButton("Sure"));
        panel.add(new JButton("Absolutely !"));
        panel.setBorder(BorderFactory.createTitledBorder(null, 
                "JXButtonPanel.setCyclic(true)",
                TitledBorder.CENTER, TitledBorder.BOTTOM));
        ret.setBorder(BorderFactory.createEmptyBorder(10, 0, 10, 0));

        ret.add(panel, BorderLayout.SOUTH);
        return ret;
    }

    public static void main(String[] args) throws Exception {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new JXButtonPanelDemo().setVisible(true);
            }
        });         
    }
}








14.5.JButton
14.5.1.Creating a JButton
14.5.2.Creating a JButton from an Action objectCreating a JButton from an Action object
14.5.3.Using MnemonicsUsing Mnemonics
14.5.4.Displaying Mnemonics in Button textDisplaying Mnemonics in Button text
14.5.5.Adding Icon to JButtonAdding Icon to JButton
14.5.6.Adding a Rollover and Pressed Icon to a JButton Component
14.5.7.Adding a Disabled Icon to a JButton Component
14.5.8.Set pressed icon
14.5.9.Setting the Gap Size Between the Label and Icon in a JButton Component
14.5.10.Change button Horizontal Text Position
14.5.11.Set Rollover Icon and set Rollover Enabled
14.5.12.Button with user-draw Image iconButton with user-draw Image icon
14.5.13.Button icons, a default button, HTML in a button,and button mnemonics.
14.5.14.Placing Text and Icon togetherPlacing Text and Icon together
14.5.15.Displaying HTML on JButtonDisplaying HTML on JButton
14.5.16.Creating a Multiline Label for a JButton Component
14.5.17.Lines are left justified. This label text will center the lines
14.5.18.Label text italicizes the second line
14.5.19.Register two event listeners to JButtonRegister two event listeners to JButton
14.5.20.Setting the default buttonSetting the default button
14.5.21.Set tooltip for buttonSet tooltip for button
14.5.22.Call button doClick method to simulate a click action
14.5.23.Dynamically update the appearance of a component
14.5.24.Customizing a JButton Look and Feel
14.5.25.Buttons used in toolbars.
14.5.26.Transfer focus from button to button with help of arrows keys.
14.5.27.Arrow Button