How to Load Images Asynchronously in Java Swing to Prevent GUI Freezing?

Loading an Image Asynchronously

In the provided code, the image loading process may freeze the GUI, particularly when the image is large or the network connection is slow. To prevent this issue and keep the GUI responsive, we can utilize a background thread to load the image. This technique is referred to as asynchronous image loading.

Using SwingWorker for Asynchronous Loading

Java's javax.swing.SwingWorker class provides a convenient way to perform background tasks and update the GUI when they are complete. Here's how we can use it to asynchronously load an image:

import javax.swing.SwingWorker;
import java.awt.image.BufferedImage;
import javax.swing.JLabel;

public class ImageLoader extends SwingWorker<BufferedImage, Void> {

    private final String imageUrl;
    private final JLabel label;

    public ImageLoader(String imageUrl, JLabel label) {
        this.imageUrl = imageUrl;
        this.label = label;
    }

    @Override
    protected BufferedImage doInBackground() throws Exception {
        // Load the image in the background
        BufferedImage image = ImageIO.read(new URL(imageUrl));
        return image;
    }

    @Override
    protected void done() {
        try {
            BufferedImage image = get();
            // Update the GUI with the loaded image in the EDT
            label.setIcon(new ImageIcon(image));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Integrating with Your Code

To integrate this solution with your code:

1. In the client_trackedbus class, create an instance of ImageLoader and execute it in the constructor:

   public client_trackedbus( ... ) {
       // ...
       ImageLoader imageLoader = new ImageLoader("http://www.huddletogether.com/projects/lightbox2/images/image-2.jpg", label);
       imageLoader.execute();
       // ...
   }

2. In the displayMap method, remove the image loading code and simply set the label's visibility to true:

   private void displayMap(...) {
       // ...
       label.setVisible(true);
       // ...
   }

By following these steps, the image loading process will be performed asynchronously, allowing the GUI to remain responsive while the image is being fetched.

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