/* * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * *   - Redistributions of source code must retain the above copyright *     notice, this list of conditions and the following disclaimer. * *   - Redistributions in binary form must reproduce the above copyright *     notice, this list of conditions and the following disclaimer in the *     documentation and/or other materials provided with the distribution. * *   - Neither the name of Sun Microsystems nor the names of its *     contributors may be used to endorse or promote products derived *     from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ package events;/* * FocusEventDemo.java * */import java.util.Vector;import java.awt.*;import java.awt.event.*;import javax.swing.*;public class FocusEventDemo extends JFrame        implements FocusListener {    final static String newline = "\n";    JTextArea display;        public FocusEventDemo(String name) {        super(name);    }        public void addComponentsToPane(final Container pane) {        GridBagLayout gridbag = new GridBagLayout();        pane.setLayout(gridbag);                GridBagConstraints c = new GridBagConstraints();                c.fill = GridBagConstraints.HORIZONTAL;        c.weightx = 1.0;  //Make column as wide as possible.        JTextField textField = new JTextField("A TextField");        textField.setMargin(new Insets(0,2,0,2));        textField.addFocusListener(this);        gridbag.setConstraints(textField, c);        add(textField);                c.weightx = 0.1;  //Widen every other column a bit, when possible.        c.fill = GridBagConstraints.NONE;        JLabel label = new JLabel("A Label");        label.setBorder(BorderFactory.createEmptyBorder(0,5,0,5));        label.addFocusListener(this);        gridbag.setConstraints(label, c);        add(label);                String comboPrefix = "ComboBox Item #";        final int numItems = 15;        Vector<String> vector = new Vector<String>(numItems);        for (int i = 0; i < numItems; i++) {            vector.addElement(comboPrefix + i);        }        JComboBox comboBox = new JComboBox(vector);        comboBox.addFocusListener(this);        gridbag.setConstraints(comboBox, c);        add(comboBox);                c.gridwidth = GridBagConstraints.REMAINDER;        JButton button = new JButton("A Button");        button.addFocusListener(this);        gridbag.setConstraints(button, c);        add(button);                c.weightx = 0.0;        c.weighty = 0.1;        c.fill = GridBagConstraints.BOTH;        String listPrefix = "List Item #";        Vector<String> listVector = new Vector<String>(numItems);        for (int i = 0; i < numItems; i++) {            listVector.addElement(listPrefix + i);        }        JList list = new JList(listVector);        list.setSelectedIndex(1); //It's easier to see the focus change        //if an item is selected.        list.addFocusListener(this);        JScrollPane listScrollPane = new JScrollPane(list);                gridbag.setConstraints(listScrollPane, c);        add(listScrollPane);                c.weighty = 1.0; //Make this row as tall as possible.        c.gridheight = GridBagConstraints.REMAINDER;        //Set up the area that reports focus-gained and focus-lost events.        display = new JTextArea();        display.setEditable(false);        //The setRequestFocusEnabled method prevents a        //component from being clickable, but it can still        //get the focus through the keyboard - this ensures        //user accessibility.        display.setRequestFocusEnabled(false);        display.addFocusListener(this);        JScrollPane displayScrollPane = new JScrollPane(display);                gridbag.setConstraints(displayScrollPane, c);        add(displayScrollPane);        setPreferredSize(new Dimension(450, 450));        ((JPanel)pane).setBorder(BorderFactory.createEmptyBorder(20,20,20,20));    }        public void focusGained(FocusEvent e) {        displayMessage("Focus gained", e);    }        public void focusLost(FocusEvent e) {        displayMessage("Focus lost", e);    }        void displayMessage(String prefix, FocusEvent e) {        display.append(prefix                + (e.isTemporary() ? " (temporary):" : ":")                + e.getComponent().getClass().getName()                + "; Opposite component: "                + (e.getOppositeComponent() != null ?                    e.getOppositeComponent().getClass().getName() : "null")                    + newline);        display.setCaretPosition(display.getDocument().getLength());    }        /**     * Create the GUI and show it.  For thread safety,     * this method should be invoked from the     * event dispatch thread.     */    private static void createAndShowGUI() {        //Create and set up the window.        FocusEventDemo frame = new FocusEventDemo("FocusEventDemo");        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);                //Set up the content pane.        frame.addComponentsToPane(frame.getContentPane());                //Display the window.        frame.pack();        frame.setVisible(true);    }        public static void main(String[] args) {        /* Use an appropriate Look and Feel */        try {            //UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");            UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");        } catch (UnsupportedLookAndFeelException ex) {            ex.printStackTrace();        } catch (IllegalAccessException ex) {            ex.printStackTrace();        } catch (InstantiationException ex) {            ex.printStackTrace();        } catch (ClassNotFoundException ex) {            ex.printStackTrace();        }                /* Turn off metal's use of bold fonts */        UIManager.put("swing.boldMetal", Boolean.FALSE);        //Schedule a job for the event dispatch thread:        //creating and showing this application's GUI.        javax.swing.SwingUtilities.invokeLater(new Runnable() {            public void run() {                createAndShowGUI();            }        });    }}