Question

我是Java的新手。我想编写一个使文件成为弧形的程序我想使用进度条显示压缩的进度有我的代码，但它不起作用工作完成时只显示100％。

        getContentPane().add(progressBar);
    progressBar.setBorder(new CompoundBorder(null, null));
    springLayout.putConstraint(SpringLayout.EAST, progressBar, 0, SpringLayout.EAST, messageLabel);
    springLayout.putConstraint(SpringLayout.WEST, progressBar, 0, SpringLayout.WEST, messageLabel);
    springLayout.putConstraint(SpringLayout.SOUTH, progressBar, 165, SpringLayout.NORTH, getContentPane());
    springLayout.putConstraint(SpringLayout.NORTH, progressBar, 5, SpringLayout.SOUTH, uploadLocalButton);
    progressBar.setValue(0);
    progressBar.setMaximum(100);
    progressBar.setMinimum(0);
    progressBar.setStringPainted(true); 
...
 public void doZip(String filename,String outFilename) 
 {
     try {
        byte[] dataBytes = new byte[1024];
        File file = new File(outFilename);
        file.createNewFile();
        FileOutputStream fos = new FileOutputStream(file);
        ZipOutputStream zos = new ZipOutputStream(fos);
        File fil = new File(filename); //"Users/you/image.jpg"
        long length= fil.length();
        System.out.println(length);
        zos.putNextEntry(new ZipEntry(fil.getName()));//image.jpg
        FileInputStream in = new FileInputStream(filename);
        int current=0;
        int len;

        while ((len = in.read(dataBytes)) > 0) 
        { current += len; 
        messageLabel.setText(Integer.toString(current));
        System.out.println(current);
        final double progres=(((double)current/(double)length)*100);
        progressBar.setValue((int)progres);             
            zos.write(dataBytes, 0, dataBytes.length);
        }

        zos.closeEntry();
        zos.close();
        in.close();
 }catch (IOException e) {
        JOptionPane.showMessageDialog(null,
                "Access denied. File or patch not exist or in currently in use.","Error",
                JOptionPane.ERROR_MESSAGE);
        e.printStackTrace();

    }}

也许有人知道问题出在哪里？

按下按钮，我打电话给 doZip 。我试过这个

 while ((len = in.read(dataBytes)) > 0) 
        { current += len; 
        zos.write(dataBytes, 0, dataBytes.length);
        final double progres=(((double)current/(double)length)*100);
        try{
            SwingUtilities.invokeLater(new Runnable(){
                public void run(){
                progressBar.setValue((int)progres);
                }
            });
            java.lang.Thread.sleep(100);
        }catch(InterruptedException e){;}

但它也有效，只会使拉链操作的过程更长。

Answer 1

我假设您正在从AWT线程中的某个地方调用doZip（例如，由操作处理程序直接调用（in）作为对点击或其他内容的响应）。因此，在操作（压缩）完成之前，UI不会更新，即使您在两者之间相应地设置了进度..

一个解决方案是在一个单独的线程中启动doZip（通常，建议避免AWT线程中的任何代价高昂的操作，但只做基本的“动作处理”并触发长时间运行的操作那里...）

Java文件进度条

1 个答案: