Loading animated gif from JAR file into ImageIcon

问题:

I'm trying to create a ImageIcon from a animated gif stored in a jar file.

ImageIcon imageIcon = new ImageIcon(ImageIO.read(MyClass.class.getClassLoader().getResourceAsStream("animated.gif")));

The image loads, but only the first frame of the animated gif. The animation does not play.

If I load the animated gif from a file on the filesystem, everything works as expected. The animation plays through all the of frames. So this works:

ImageIcon imageIcon = new ImageIcon("/path/on/filesystem/animated.gif");

How can I load an animated gif into an ImageIcon from a jar file?

EDIT: Here is a complete test case, why doesn't this display the animation?

import javax.imageio.ImageIO;
import javax.swing.*;

public class AnimationTest extends JFrame {

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                AnimationTest test = new AnimationTest();
                test.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                test.setVisible(true);
            }
        });
    }

    public AnimationTest() {
        super();
        try {
            JLabel label = new JLabel();
            ImageIcon imageIcon = new ImageIcon(ImageIO.read(AnimationTest.class.getClassLoader().getResourceAsStream("animated.gif")));
            label.setIcon(imageIcon);
            imageIcon.setImageObserver(label);
            add(label);
            pack();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

回答1:

This reads gif animation from inputStream

InputStream in = ...;
Image image = Toolkit.getDefaultToolkit().createImage(org.apache.commons.io.IOUtils.toByteArray(in));

回答2:

You have to use getClass().getResource(imgName); to get a URL to the image file. Check out this tutorial from Real's HowTo.

EDIT: Once the image is loaded you have to set the ImageObserver property to get the animation to run.

回答3:

Since this thread was just linked from a more current thread that had little to do with animated GIFs but got dragged OT, I thought I'd add this trivial source that 'works for me'.

import javax.swing.*;
import java.net.URL;

class AnimatedGifInLabel {

    public static void main(String[] args) throws Exception {
        final URL url = new URL("http://i.stack.imgur.com/OtTIY.gif");
        Runnable r = new Runnable() {
            public void run() {
                ImageIcon ii = new ImageIcon(url);
                JLabel label = new JLabel(ii);
                JOptionPane.showMessageDialog(null, label);
            }
        };
        SwingUtilities.invokeLater(r);
    }
}

回答4:

Hopefully it's not too late for this.

I managed to get the animated gif inside my JPanel this way:

private JPanel loadingPanel() {
    JPanel panel = new JPanel();
    BoxLayout layoutMgr = new BoxLayout(panel, BoxLayout.PAGE_AXIS);
    panel.setLayout(layoutMgr);

    ClassLoader cldr = this.getClass().getClassLoader();
    java.net.URL imageURL   = cldr.getResource("img/spinner.gif");
    ImageIcon imageIcon = new ImageIcon(imageURL);
    JLabel iconLabel = new JLabel();
    iconLabel.setIcon(imageIcon);
    imageIcon.setImageObserver(iconLabel);

    JLabel label = new JLabel("Loading...");
    panel.add(iconLabel);
    panel.add(label);
    return panel;
}

Some points of this approach:
1. The image file is within the jar;
2. ImageIO.read() returns a BufferedImage, which doesn't update the ImageObserver;
3. Another alternative to find images that are bundled in the jar file is to ask the Java class loader, the code that loaded your program, to get the files. It knows where things are.

So by doing this I was able to get my animated gif inside my JPanel and it worked like a charm.