/* * LunarPhases.java is a 1.4 example that requires * the following files: *    images/image0.jpg *    images/image1.jpg *    images/image2.jpg *    images/image3.jpg *    images/image4.jpg *    images/image5.jpg *    images/image6.jpg *    images/image7.jpg */import java.awt.*;import java.awt.event.*;import javax.swing.*;import java.net.URL;public class LunarPhases implements ActionListener {    final static int NUM_IMAGES = 8;    final static int START_INDEX = 3;    ImageIcon[] images = new ImageIcon[NUM_IMAGES];    JPanel mainPanel, selectPanel, displayPanel;    JComboBox phaseChoices = null;    JLabel phaseIconLabel = null;    public LunarPhases() {        //Create the phase selection and display panels.        selectPanel = new JPanel();        displayPanel = new JPanel();        //Add various widgets to the sub panels.        addWidgets();        //Create the main panel to contain the two sub panels.        mainPanel = new JPanel();        mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.PAGE_AXIS));        mainPanel.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));        //Add the select and display panels to the main panel.        mainPanel.add(selectPanel);        mainPanel.add(displayPanel);    }    /*     * Get the images and set up the widgets.     */    private void addWidgets() {        //Get the images and put them into an array of ImageIcons.        for (int i = 0; i < NUM_IMAGES; i++) {            images[i] = createImageIcon("/images/image" + i + ".jpg");        }        /*         * Create a label for displaying the moon phase images and         * put a border around it.         */        phaseIconLabel = new JLabel();        phaseIconLabel.setHorizontalAlignment(JLabel.CENTER);        phaseIconLabel.setVerticalAlignment(JLabel.CENTER);        phaseIconLabel.setVerticalTextPosition(JLabel.CENTER);        phaseIconLabel.setHorizontalTextPosition(JLabel.CENTER);        phaseIconLabel.setBorder(BorderFactory.createCompoundBorder(            BorderFactory.createLoweredBevelBorder(),            BorderFactory.createEmptyBorder(5,5,5,5)));        phaseIconLabel.setBorder(BorderFactory.createCompoundBorder(            BorderFactory.createEmptyBorder(0,0,10,0),            phaseIconLabel.getBorder()));        //Create a combo box with lunar phase choices.        String[] phases = { "New", "Waxing Crescent", "First Quarter",                             "Waxing Gibbous", "Full", "Waning Gibbous",                             "Third Quarter", "Waning Crescent" };        phaseChoices = new JComboBox(phases);        phaseChoices.setSelectedIndex(START_INDEX);        //Display the first image.        phaseIconLabel.setIcon(images[START_INDEX]);        phaseIconLabel.setText("");        //Add a border around the select panel.        selectPanel.setBorder(BorderFactory.createCompoundBorder(            BorderFactory.createTitledBorder("Select Phase"),             BorderFactory.createEmptyBorder(5,5,5,5)));        //Add a border around the display panel.        displayPanel.setBorder(BorderFactory.createCompoundBorder(            BorderFactory.createTitledBorder("Display Phase"),             BorderFactory.createEmptyBorder(5,5,5,5)));        //Add moon phases combo box to select panel and image label.        displayPanel.add(phaseIconLabel);        selectPanel.add(phaseChoices);        //Listen to events from the combo box.        phaseChoices.addActionListener(this);    }    public void actionPerformed(ActionEvent event) {        if ("comboBoxChanged".equals(event.getActionCommand())) {            //Update the icon to display the new phase.            phaseIconLabel.setIcon(images[phaseChoices.getSelectedIndex()]);        }    }    /** Returns an ImageIcon, or null if the path was invalid. */    protected static ImageIcon createImageIcon(String path) {        java.net.URL imageURL = LunarPhases.class.getResource(path);        if (imageURL == null) {            System.err.println("Resource not found: "                               + path);            return null;        } else {            return new ImageIcon(imageURL);        }    }    /**     * Create the GUI and show it.  For thread safety,     * this method should be invoked from the     * event-dispatching thread.     */    private static void createAndShowGUI() {        //Make sure we have nice window decorations.        JFrame.setDefaultLookAndFeelDecorated(true);        //Create a new instance of LunarPhases.        LunarPhases phases = new LunarPhases();        //Create and set up the window.        JFrame lunarPhasesFrame = new JFrame("Lunar Phases");        lunarPhasesFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);         lunarPhasesFrame.setContentPane(phases.mainPanel);        //Display the window.        lunarPhasesFrame.pack();        lunarPhasesFrame.setVisible(true);    }    public static void main(String[] args) {        //Schedule a job for the event-dispatching thread:        //creating and showing this application's GUI.        javax.swing.SwingUtilities.invokeLater(new Runnable() {            public void run() {                createAndShowGUI();            }        });    }}