/* * Swing version */import javax.swing.*;import java.awt.Dimension;import java.awt.BorderLayout;import java.awt.event.*;public class ComponentEventDemo extends JApplet                                implements ComponentListener,                                           ActionListener {    JTextArea display;    JFrame aFrame;    public boolean showIt = false;    final static String SHOW = "show";    final static String CLEAR = "clear";    String newline = "\n";    public void init() {        display = new JTextArea();        display.setEditable(false);        JScrollPane scrollPane = new JScrollPane(display);        scrollPane.setPreferredSize(new Dimension(200, 75));        getContentPane().add(scrollPane, BorderLayout.CENTER);        JButton b1 = new JButton("Start playing...");        b1.setActionCommand(SHOW);        b1.addActionListener(this);        getContentPane().add(b1, BorderLayout.NORTH);        JButton b2 = new JButton("Clear");        b2.setActionCommand(CLEAR);        b2.addActionListener(this);        getContentPane().add(b2, BorderLayout.SOUTH);        aFrame = new JFrame("A Frame");        ComponentPanel p = new ComponentPanel(this);        aFrame.addComponentListener(this);        p.addComponentListener(this);        aFrame.getContentPane().add(p, BorderLayout.CENTER);        aFrame.pack();        aFrame.addWindowListener(new WindowAdapter() {            // This event handler is executed before the            // default close operation (hide) is applied.            public void windowClosing(WindowEvent e) {                showIt = false;            }        });    }    public void actionPerformed(ActionEvent e) {        if (e.getActionCommand() == SHOW) {            showIt = true;            aFrame.setVisible(true);        } else { //CLEAR            display.setText("");        }    }    public void stop() {        SwingUtilities.invokeLater(new Runnable() {            public void run() {                aFrame.setVisible(false);            }        });    }    public void start() {        SwingUtilities.invokeLater(new Runnable() {            public void run() {                if (showIt) {                    aFrame.setVisible(true);                }            }        });    }    protected void displayMessage(String message) {        display.append(message + newline);    }    public void componentHidden(ComponentEvent e) {        displayMessage("componentHidden event from "                       + e.getComponent().getClass().getName());    }    public void componentMoved(ComponentEvent e) {        displayMessage("componentMoved event from "                       + e.getComponent().getClass().getName());    }    public void componentResized(ComponentEvent e) {        displayMessage("componentResized event from "                       + e.getComponent().getClass().getName());    }    public void componentShown(ComponentEvent e) {        displayMessage("componentShown event from "                       + e.getComponent().getClass().getName());    }}class ComponentPanel extends JPanel                      implements ItemListener {    JLabel label;    JCheckBox checkbox;    ComponentPanel(ComponentEventDemo listener) {        super(new BorderLayout());        label = new JLabel("This is a Label", JLabel.CENTER);        add(label, BorderLayout.CENTER);        checkbox = new JCheckBox("Label visible", true);        checkbox.addItemListener(this);        add(checkbox, BorderLayout.SOUTH);        label.addComponentListener(listener);        checkbox.addComponentListener(listener);    }    public void itemStateChanged(ItemEvent e) {        if (e.getStateChange() == ItemEvent.SELECTED) {            label.setVisible(true);            //Need to revalidate and repaint, or else the label            //will probably be drawn in the wrong place.            label.revalidate();            label.repaint();        } else {            label.setVisible(false);        }    }}