Gif 没有在 JFrame 中播放

Question

您好，我在 JFrame 中有一个 gif。一切都很好，只是第一次冻结 gif 就好像它是 jpeg 或 png。

此外，stackoverflow 告诉我我需要添加更多详细信息，即使我已经添加了陈述我的问题所需的所有详细信息，所以请随意忽略这一点。

代码如下：

import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.io.*;
import javax.imageio.*;
import javax.swing.*;

 public class LoadImageApp extends Component {

BufferedImage img;

public void paint(Graphics g) {
    g.drawImage(img, 0, 0, this);
}

public LoadImageApp() {
    try {
       img = ImageIO.read(new File("spooky.gif"));
   } catch (IOException e) {
   }

}

public Dimension getPreferredSize() {
    if (img == null) {
         return new Dimension(100,100);
    } else {
       return new Dimension(img.getWidth(null), img.getHeight(null));
   }
}

public static void main(String[] args) {

    JFrame f = new JFrame("Load Image Sample");

    f.addWindowListener(new WindowAdapter(){
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });

    f.add(new LoadImageApp());
    f.pack();
    f.setVisible(true);
}

}

Answer 1

我很确定 ImageIO 在动画 gif 方面存在一些问题。

尝试使用JLabel 和图标，如下所示：

Icon icon = new ImageIcon(filename);
JLabel gif = new JLabel(icon);

JFrame f = new JFrame("Load Image Sample");

f.addWindowListener(new WindowAdapter(){
        public void windowClosing(WindowEvent e) {
            System.exit(0);
        }
    });

f.getContentPane().add(gif);
f.pack();
f.setVisible(true);

Answer 2

如前所述，ImageIO 不会正确加载动画 GIF 的所有帧。但是Toolkit 方法之一会。例如

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

// Ach AWT!
//public class LoadImageApp extends Component {
public class LoadImageApp extends JPanel {

    Image img;

    // should be paintComponent for a JComponent
    //public void paint(Graphics g) {
    public void paintComponent(Graphics g) {
        super.paintComponent(g); // call super method first
        g.drawImage(img, 0, 0, this);
    }

    public LoadImageApp() {
        setBackground(Color.BLUE.darker().darker());
        try {
            URL url = new URL("http://i.stack.imgur.com/OtTIY.gif");
            // as mentioned, ImageIO will not load animated GIFs correctly.
            //img = ImageIO.read(url));
            // but the toolkit method will, OTOH..
            img = Toolkit.getDefaultToolkit().createImage(url);
            // ..we need a MediaTracker
            MediaTracker mt = new MediaTracker(this);
            mt.addImage(img, 0);
            mt.waitForAll();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public Dimension getPreferredSize() {
        if (img == null) {
            return new Dimension(100, 100);
        } else {
            return new Dimension(img.getWidth(this), img.getHeight(this));
        }
    }

    public static void main(String[] args) {
        // should be donw on the EDT - BNI
        JFrame f = new JFrame("Load Image Sample");
        f.add(new LoadImageApp());
        f.pack();
        f.setVisible(true);
        f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
    }
}

如需进一步讨论，请参阅Show an animated BG in Swing。