Java 文件复制和打开新的 jFrame

Question

我正在创建一个程序，其中一个目录的内容被复制到另一个目录。在复制过程开始之前，我试图打开第二个 Jframe 来告诉用户复制正在进行中。问题是在复制进度完成之前，第二个 JFrame 不会完全加载。有谁知道在开始复制之前完全加载第二帧的方法吗？

第一帧代码

public class First {

private JFrame frmFirstFrame;

/**
 * Launch the application.
 */
public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                First window = new First();
                window.frmFirstFrame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

/**
 * Create the application.
 */
public First() {
    initialize();
}

/**
 * Initialize the contents of the frame.
 */
private void initialize() {
    frmFirstFrame = new JFrame();
    frmFirstFrame.setTitle("First Frame");
    frmFirstFrame.setBounds(100, 100, 450, 300);
    frmFirstFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frmFirstFrame.getContentPane().setLayout(null);

    JButton btnCopy = new JButton("Copy");
    btnCopy.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent arg0) {
            String source = "D:\\";
            String destination = "D:\\test\\";

            Second second = new Second();

            second.setVisible(true);

            File s = new File (source);
            File d = new File (destination);

            try {

                FileUtils.copyDirectory(s, d);
                //second.setVisible(false);
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
    });
    btnCopy.setBounds(184, 111, 89, 23);
    frmFirstFrame.getContentPane().add(btnCopy);
}}

第二帧代码

public class Second extends JFrame {

private JPanel contentPane;

/**
 * Launch the application.
 */
public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                Second frame = new Second();
                frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

/**
 * Create the frame.
 */
public Second() {
    setTitle("Second Frame");
    setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
    setBounds(100, 100, 450, 300);
    contentPane = new JPanel();
    contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
    setContentPane(contentPane);
    contentPane.setLayout(null);

    JLabel lblCopyCompleted = new JLabel("Copy in Progress...");
    lblCopyCompleted.setBounds(76, 70, 217, 37);
    contentPane.add(lblCopyCompleted);
    }
}

这是我在复制过程中得到的。

复制时应该是这样的

Answer 1

1. 第二个 JFrame 应该是 JDialog，因为您的应用程序应该只有一个 JFrame(主窗口)。有关更多信息，请参阅:The Use of Multiple JFrames, Good/Bad Practice?
2. 你的问题是你的代码不遵守 Swing 线程规则，通过在 Swing 事件线程上执行长时间运行的任务，你占用了线程，阻止它执行必要的工作，包括绘制到窗口和与用户。
3. 一个好的解决方案是使用后台线程，特别是从 SwingWorker 获得的线程。教程:Lesson: Concurrency in Swing

import java.awt.*;
import java.awt.Dialog.ModalityType;
import java.awt.event.ActionEvent;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.concurrent.ExecutionException;

import javax.swing.*;

@SuppressWarnings("serial")
public class First2 extends JPanel {
    private static final int COLS = 15;
    private JTextField sourceField = new JTextField(COLS);
    private JTextField destField = new JTextField(COLS);
    private JDialog dialog;
    private DialogPanel dialogPanel = new DialogPanel();

    public First2() {
        setLayout(new GridBagLayout());
        add(new JLabel("Source:"), createGbc(0, 0));
        add(sourceField, createGbc(1, 0));

        add(new JLabel("Destination:"), createGbc(0, 1));
        add(destField, createGbc(1, 1));

        add(new JButton(new CopyAction("Copy")), createGbc(1, 2));
    }

    private GridBagConstraints createGbc(int x, int y) {
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.gridx = x;
        gbc.gridy = y;
        gbc.fill = GridBagConstraints.HORIZONTAL;
        gbc.weightx = 1.0;
        gbc.weighty = 1.0;
        gbc.insets = new Insets(4, 4, 4, 4);
        return gbc;
    }

    private class CopyAction extends AbstractAction {
        public CopyAction(String name) {
            super(name);
            int mnemonic = (int) name.charAt(0);
            putValue(MNEMONIC_KEY, mnemonic);
        }

        @Override
        public void actionPerformed(ActionEvent e) {
            String src = sourceField.getText();
            String dest = destField.getText();

            MyWorker myWorker = new MyWorker(src, dest);
            myWorker.addPropertyChangeListener(new WorkerListener());
            myWorker.execute();

            Window window = SwingUtilities.getWindowAncestor(First2.this);
            dialog = new JDialog(window, "File Copy", ModalityType.APPLICATION_MODAL);
            dialog.add(dialogPanel);
            dialog.pack();
            dialog.setLocationRelativeTo(null);
            dialog.setVisible(true);
        }
    }

    private class MyWorker extends SwingWorker<Void, Void> {
        private String src;
        private String dest;

        public MyWorker(String src, String dest) {
            this.src = src;
            this.dest = dest;
        }

        @Override
        protected Void doInBackground() throws Exception {
            FileUtils.copyDirectory(src, dest);
            return null;
        }
    }

    private class WorkerListener implements PropertyChangeListener {
        @Override
        public void propertyChange(PropertyChangeEvent evt) {
            if (evt.getNewValue() == SwingWorker.StateValue.DONE) {
                if (dialog != null && dialog.isVisible()) {
                    dialog.dispose();
                }
                try {
                    ((MyWorker) evt.getSource()).get();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                } catch (ExecutionException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    private static void createAndShowGui() {
        First2 mainPanel = new First2();

        JFrame frame = new JFrame("First2");
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        frame.getContentPane().add(mainPanel);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGui();
            }
        });
    }
}

class DialogPanel extends JPanel {
    private static final int PREF_W = 300;
    private static final int PREF_H = 250;

    public DialogPanel() {
        setLayout(new GridBagLayout());
        add(new JLabel("Copy in Progress..."));
    }

    @Override
    public Dimension getPreferredSize() {
        if (isPreferredSizeSet()) {
            return super.getPreferredSize();
        }
        return new Dimension(PREF_W, PREF_H);
    }
}