在SwingWorker中实现JScrollPane / JTextArea

使用SwingWorker时，我的JScrollPane / JTextArea遇到了一些麻烦。这是我目前拥有的：

JTextArea txtDirs;
Task task;

//EDT
public void createGUI(){
    txtDirs = new JTextArea();
    txtDirs.setBounds(10, 56, 414, 125);
    txtDirs.setEditable(false);
    contentPane.add(new JScrollPane(txtDirs));

    task = new Task();
    task.execute();
}

class Task extends SwingWorker<Void, Void>{
    @Override
    public void doInBackground(){
        for(file : files){
            txtDirs.append(file.getAbsolutePath);
        }
    }

    @Override
    public void done(){
        closeWindow();
    }
}

这不是确切的代码，但是它应该为您提供要点。无论如何，问题在于尽管doInBackground（）方法中的代码确实运行了，但JScrollPane却根本没有出现。我希望它与txtDirs.append(file.getAbsolutePath())在后台任务中进行更新（）有关。但是，我不确定在这种情况下如何使其工作。该框架出现按预期的方式，但它完全是空白。类中应该有一个“过程”方法Task吗？那个txtDirs.append(file.getAbsolutePath())应该放在“ ”的地方吗？恐怕我对SwingWorkers的使用还很陌生，因此任何帮助将不胜感激。

编辑：

经过一番困惑后，我决定只发布完整的代码。我知道问题出在哪里，我可能误解了评论中提到的一些内容，因此我希望发布此内容可以使某人指出我犯的任何明显错误。

完整代码：

import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowEvent;
import java.io.File;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JButton;
import javax.swing.JProgressBar;
import javax.swing.JLabel;
import javax.swing.SwingWorker;

import org.apache.commons.io.FileUtils;

@SuppressWarnings("serial")
public class BasicCopy extends JFrame {

    private JPanel contentPane;
    private JTextArea txtCopiedDirs;
    private JButton btnCancel;
    private JProgressBar progressBar;
    private JLabel lblCopying;
    private String mainDrive;
    private String backupDrive;
    private String username;
    private String backupDir;
    long totalSize = 0L;        //total size of directories/files
    long currentSize = 0L;      //current size of files counting up to ONE_PERCENT
    long currentPercent = 0L;   //current progress in %
    long ONE_PERCENT;       //totalSize / 100
    Task task;

    public BasicCopy() {
    }

    public BasicCopy(String inDrive, String outDrive, String username, long space){
        mainDrive = inDrive;
        backupDrive = outDrive;
        this.username = username;
        totalSize = space*1048576;
        ONE_PERCENT = totalSize/100;
        createGUI();
    }

    public void createGUI(){
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setTitle("Backup Progress");
        setBounds(100, 100, 450, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(null);

        txtCopiedDirs = new JTextArea(10, 50);
        txtCopiedDirs.setEditable(false);
        contentPane.add(new JScrollPane(txtCopiedDirs));

        btnCancel = new JButton("Cancel");
        btnCancel.setBounds(169, 227, 89, 23);
        btnCancel.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                closeWindow();
            }
        });
        contentPane.add(btnCancel);

        progressBar = new JProgressBar(0, 100);
        progressBar.setBounds(10, 192, 414, 24);
        progressBar.setValue(0);
        contentPane.add(progressBar);

        lblCopying = new JLabel("Now backing up your files....");
        lblCopying.setBounds(10, 11, 157, 34);
        contentPane.add(lblCopying);

        setVisible(true);
        task = new Task();
        task.execute();
    }


    /**
     * Swing Worker class
     */
    class Task extends SwingWorker<Void, String>{
        @Override
        public Void doInBackground(){
            setProgress(0);

            //Create Backup Directory
            Date date = new Date();
            SimpleDateFormat sdf = new SimpleDateFormat("MM-dd-yyyy_HMMSS");
            String timestamp = sdf.format(date);
            backupDir = backupDrive + ":\\" + "Backup_" + timestamp;
            File backupDirectory = new File(backupDir);
            backupDirectory.mkdir();

            //Copy Files
            //Main directories
            String pics = mainDrive + ":\\Users\\" + username + "\\Pictures\\";
            String docs = mainDrive + ":\\Users\\" + username + "\\Documents\\";
            String vids = mainDrive + ":\\Users\\" + username + "\\Videos\\";
            String musc = mainDrive + ":\\Users\\" + username + "\\Music\\";
            //Backup directories
            String bkPics = backupDir + "\\Pictures\\";
            String bkDocs = backupDir + "\\Documents\\";
            String bkVids = backupDir + "\\Documents\\";
            String bkMusc = backupDir + "\\Pictures\\";

            String[] directories = {pics, docs, vids, musc};
            String[] bkDirectories = {bkPics, bkDocs, bkVids, bkMusc};

            //Loop through directories and copy files
            for (int i = 0; i < directories.length; i++){
                File dir = new File(directories[i]);
                File dest = new File(bkDirectories[i]);
                for(File file: dir.listFiles()){
                    try{
                        if(file.isFile()){
                            FileUtils.copyFileToDirectory(file, dest);
                            publish(file.getAbsolutePath() + "\n");
                        } else if (file.isDirectory()){
                            FileUtils.copyDirectoryToDirectory(file, dest);
                            publish(file.getAbsolutePath() + "\n");
                        }
                        if(getDirSize(file) >= ONE_PERCENT){
                            currentPercent = getDirSize(file)/ONE_PERCENT;
                            progressBar.setValue((int)currentPercent);
                            currentSize = 0;
                        } else {
                            currentSize = currentSize + getDirSize(file);
                            if(currentSize >= ONE_PERCENT){
                                currentPercent = currentSize/ONE_PERCENT;
                                currentPercent++;
                                progressBar.setValue((int)currentPercent);
                                currentSize = 0;
                            }
                        }
                    } catch (IOException e){
                        e.printStackTrace();
                    }
                }
            }
            return null;
        }

        @Override
        public void process(List<String> chunks){
            for(String path : chunks){
                txtCopiedDirs.append(path);
            }
        }

        @Override
        public void done(){
            closeWindow();
        }
    }

    public static Long getDirSize(File file) {
        long size = 0L;

        if (file.isFile() && file != null){       
            size += file.isDirectory() ? getDirSize(file) : file.length();
        } else if (file.isDirectory()){
            for (File f : file.listFiles()) {
            size += f.isDirectory() ? getDirSize(f) : file.length();
        }
        }
        return size;
    }

    /* Close current window */
    public void closeWindow() {
        WindowEvent close = new WindowEvent(this, WindowEvent.WINDOW_CLOSING);
        Toolkit.getDefaultToolkit().getSystemEventQueue().postEvent(close);
        System.exit(0);
    }
}

编辑＃2：

我对createGUI（）方法进行了一些更改，以避免contentPane具有空布局：

public void createGUI(){
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setTitle("Backup Progress");
    setBounds(100, 100, 450, 300);
    contentPane = new JPanel(new BorderLayout());
    contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
    setContentPane(contentPane);
    contentPane.setLayout(null);

    txtCopiedDirs = new JTextArea(10, 50);
    txtCopiedDirs.setEditable(false);
    scrollPane = new JScrollPane(txtCopiedDirs);
    contentPane.add(scrollPane, BorderLayout.CENTER);

    btnCancel = new JButton("Cancel");
    btnCancel.setBounds(169, 227, 89, 23);
    btnCancel.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            closeWindow();
        }
    });
    contentPane.add(btnCancel);

    progressBar = new JProgressBar(0, 100);
    progressBar.setBounds(10, 192, 414, 24);
    progressBar.setValue(0);
    contentPane.add(progressBar);

    lblCopying = new JLabel("Now backing up your files....");
    lblCopying.setBounds(10, 11, 157, 34);
    contentPane.add(lblCopying);

    setVisible(true);
    task = new Task();
    task.execute();
}