GE - ImageViewer.java

/*
 * GE.1 i) The Quit menu item has an action listener, that calls ImageViewer's
 * actionPerformed method (addActionListener(this)). In actionPerformed, a line
 * is printed containing the string "Item: " followed by the name of the command
 * (event) triggering the method, in this case Quit. On clicking the button, the
 * console will print the text "Item: Quit".
 */
package ge;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

/**
 * ImageViewer is the main class of the image viewer application. It builds
 * and displays the application GUI.
 *
 * To start the application, create an object of this class.
 *
 * @author Michael Kolling and David J Barnes
 * @author hypesystem <[email protected]>
 * @version 0.2 modified by hypesystem
 */
public class ImageViewer
    implements ActionListener
{
    private JFrame frame;

    /**
     * Create an ImageViewer show it on screen.
     */
    public ImageViewer()
    {
        makeFrame();
    }

    /**
     * Receive notification of an action. This is deprecated, but would work, if
     * makeFrame set the actionlisteners of items to this
     * (addActionListener(this)).
     * @param event Details of the action.
     */
    @Override
    public void actionPerformed(ActionEvent event)
    {
        System.out.println("Item: " + event.getActionCommand());
        if(event.getActionCommand().equals("Open")) openFile();
        else if(event.getActionCommand().equals("Save")) saveFile();
        else if(event.getActionCommand().equals("Quit")) quit();
        else System.out.println("Item called not known");
    }

    /**
     * part of deprecated actionPerformed logic
     */
    private void openFile() {
        //...
    }

    /**
     * part of deprecated actionPerformed logic
     */
    private void saveFile() {
        //...
    }

    /**
     * part of deprecated actionPerformed logic
     */
    private void quit() {
        frame.dispose();
    }

    // ---- swing stuff to build the frame and all its components ----

    /**
     * Create the Swing frame and its content.
     */
    private void makeFrame()
    {
        frame = new JFrame("ImageViewer");
        makeMenuBar(frame);

        Container contentPane = frame.getContentPane();

        JLabel label = new JLabel("I am a label. I can display some text.");
        contentPane.add(label);

        // building is done - arrange the components and show
        frame.pack();
        frame.setVisible(true);
    }

    /**
     * Create the main frame's menu bar.
     * @param frame   The frame that the menu bar should be added to.
     */
    private void makeMenuBar(JFrame frame)
    {
        JMenuBar menubar = new JMenuBar();
        frame.setJMenuBar(menubar);

        // create the File menu
        JMenu fileMenu = new JMenu("File");
        menubar.add(fileMenu);

        JMenuItem openItem = new JMenuItem("Open");
        openItem.addActionListener(new OpenActionListener());
        fileMenu.add(openItem);

        JMenuItem saveItem = new JMenuItem("Save");
        saveItem.addActionListener(new SaveActionListener());
        fileMenu.add(saveItem);

        // added seperator to seperate the categories of menu items
        fileMenu.add(new JPopupMenu.Separator());

        JMenuItem quitItem = new JMenuItem("Quit");
        quitItem.addActionListener(new QuitActionListener());
        fileMenu.add(quitItem);
    }

    /**
     * ActionListener performing the actions when clicking the open item.
     */
    class OpenActionListener implements ActionListener {
        @Override
        public void actionPerformed(ActionEvent event) {
            //...
        }
    }

    /**
     * ActionListener performing the actions when clicking the save item.
     */
    class SaveActionListener implements ActionListener {
        @Override
        public void actionPerformed(ActionEvent event) {
            //...
        }
    }

    /**
     * ActionListener performing the actions when clicking the quit item.
     */
    class QuitActionListener implements ActionListener {
        @Override
        public void actionPerformed(ActionEvent event) {
            frame.dispose();
        }
    }
}