Swing Worker Image Loader


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;
  }  
}
Filthy-Rich-Clients-SwingWorkerImageLoader.zip( 291 k)
Related examples in the same category

1.	Swing Worker from JDK 6 SE
2.	Swing worker from org.jdesktop.swingworker
Swing Worker Image Loader : Swing Worker « JDK 6 « Java

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