ImageLoader.java Source code

Introduction

Here is the source code for ImageLoader.java

Source

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.List;
import java.util.ArrayList;
import java.io.File;
import java.io.IOException;
import java.awt.Image;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.imageio.ImageIO;
import org.jdesktop.swingworker.SwingWorker;

public class ImageLoader extends JFrame {
    private JTextArea log;
    private JPanel viewer;

    public ImageLoader() {
        super("Image Loader");

        this.log = new JTextArea(4, 4);
        this.viewer = new JPanel();

        JButton start = new JButton("Start");
        start.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                String[] files = new String[] { "Bodie_small.png", "Carmela_small.png", "Death Valley_small.png",
                        "Lake_small.png" };
                new ImageLoadingWorker(log, viewer, files).execute();
            }
        });

        add(new JScrollPane(log), BorderLayout.NORTH);
        add(new JScrollPane(viewer), BorderLayout.CENTER);
        add(start, BorderLayout.SOUTH);

        setSize(360, 280);
    }

    public static void main(String... args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new ImageLoader().setVisible(true);
            }
        });
    }
}

// Final result is a list of Image
// Intermediate result is a message as a String
class ImageLoadingWorker extends SwingWorker<List<Image>, String> {
    private JTextArea log;
    private JPanel viewer;
    private String[] filenames;

    public ImageLoadingWorker(JTextArea log, JPanel viewer, String... filenames) {
        this.log = log;
        this.viewer = viewer;
        this.filenames = filenames;
    }

    // In the EDT
    @Override
    protected void done() {
        try {
            for (Image image : get()) {
                viewer.add(new JLabel(new ImageIcon(image)));
                viewer.revalidate();
            }
        } catch (Exception e) {
        }
    }

    // In the EDT
    @Override
    protected void process(String... messages) {
        for (String message : messages) {
            log.append(message);
            log.append("\n");
        }
    }

    // In a thread
    @Override
    public List<Image> doInBackground() {
        List<Image> images = new ArrayList<Image>();
        for (String filename : filenames) {
            try {
                images.add(ImageIO.read(new File("./build/" + filename)));
                publish("Loaded " + filename);
            } catch (IOException ioe) {
                publish("Error loading " + filename);
            }
        }
        return images;
    }
}