java - Java 不会显示被覆盖的图像

Question

我有一张在程序开始时从文件夹中读取的图像。程序会从网上下载一张新图片，并覆盖旧图片，相同的文件路径和相同的名称，但显示的图像是旧图像。当我退出并重新加载程序时，会显示新图像。我知道图像没有改变，因为我还尝试从文件路径创建一个新的 ImageIcon 并在下载后在 JDialog 中显示它，它仍然是旧图像。有任何想法吗？

Answer 1

但是只有 jdialog 才能正确显示。即使我调用了 frame.validate()，原始帧仍然显示旧图像；frame.repaint();

将图像读入内存不会导致组件引用新图像。您仍然需要将图标添加到使用旧图像的任何组件中。

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

public class ImageReload extends JFrame implements ActionListener
{
    JLabel timeLabel;
    JLabel imageLabel;
    ImageIcon icon = new ImageIcon("timeLabel.jpg");

    public ImageReload()
    {
        timeLabel = new JLabel( new Date().toString() );
        imageLabel = new JLabel( timeLabel.getText() );
        getContentPane().add(timeLabel, BorderLayout.NORTH);
        getContentPane().add(imageLabel, BorderLayout.SOUTH);

        javax.swing.Timer timer = new javax.swing.Timer(1000, this);
        timer.start();
    }

    public void actionPerformed(ActionEvent e)
    {
        timeLabel.setText( new Date().toString() );

        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                try
                {
                    String imageName = "timeLabel.jpg";
                    BufferedImage image = ScreenImage.createImage(timeLabel);
                    ScreenImage.writeImage(image, imageName);

                    //  This works using ImageIO

//                  imageLabel.setIcon( new ImageIcon(ImageIO.read( new File(imageName) ) ) );

                    //  Or you can flush the image

                    ImageIcon icon = new ImageIcon(imageName);
                    icon.getImage().flush();
                    imageLabel.setIcon( icon );
                }
                catch(Exception e)
                {
                    System.out.println( e );
                }
            }
        });
    }

    public static void main(String[] args)
    {
        ImageReload frame = new ImageReload();
        frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
        frame.pack();
        frame.setVisible(true);
    }
}

Answer 2

最终从框架中删除旧组件，并用新图像读取标签

frame.remove(picLabel);
BufferedImage b = ImageIO.read(new File(attemptedFilePath));
picLabel = new JLabel(new ImageIcon(b));
GridBagConstraints c = new GridBagConstraints();
c.weightx = 0.5;
c.anchor = GridBagConstraints.FIRST_LINE_START;
c.gridx = 0;
c.gridy = 0;
c.fill = GridBagConstraints.NONE;
c.insets = new Insets(10,10,0,0);
c.gridwidth = 15;
c.gridheight = 15;
frame.getContentPane().add(picLabel, c);