使用JDialog,参照Windows记事本编写一个“字体”对话框

好的，我可以通过以下代码实现：

import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;

public class FontDialog extends JDialog implements ActionListener, ListSelectionListener {
    private static final long serialVersionUID = 1L;
    private JTextField tfFont;
    private JTextField tfSize;
    private JList<String> listFontNames;
    private JList<Integer> listSizes;
    private JButton btnOK;
    private JButton btnCancel;
    private Font selectedFont;

    public FontDialog(JFrame parentFrame) {
        super(parentFrame, "Font", true);
        setResizable(false);
        setSize(400, 300);
        setLocationRelativeTo(parentFrame);

        JPanel panelMain = new JPanel();
        panelMain.setLayout(new BorderLayout(10, 10));
        JPanel panelFont = new JPanel(new GridLayout(2, 2, 10, 10));
        JPanel panelSize = new JPanel();

        tfFont = new JTextField("Arial", 20);
        tfSize = new JTextField("12", 5);

        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        String[] fontNames = ge.getAvailableFontFamilyNames();
        listFontNames = new JList<String>(fontNames);
        listFontNames.setSelectedValue("Arial", true);
        listFontNames.addListSelectionListener(this);

        Integer[] sizes = { 8, 9, 10, 11, 12, 14, 16, 18, 20, 22, 24, 26, 28, 36, 48, 72 };
        listSizes = new JList<Integer>(sizes);
        listSizes.setSelectedValue(12, true);
        listSizes.addListSelectionListener(this);

        JScrollPane scrollFontNames = new JScrollPane(listFontNames);
        JScrollPane scrollSizes = new JScrollPane(listSizes);
        scrollFontNames.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
        scrollSizes.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);

        panelFont.add(new JLabel("Font: "));
        panelFont.add(tfFont);
        panelFont.add(new JLabel("Size: "));
        panelFont.add(tfSize);

        panelSize.setLayout(new BorderLayout());
        panelSize.add(new JLabel("Size: "), BorderLayout.NORTH);
        panelSize.add(scrollSizes, BorderLayout.CENTER);

        panelMain.add(panelFont, BorderLayout.NORTH);
        panelMain.add(scrollFontNames, BorderLayout.CENTER);
        panelMain.add(panelSize, BorderLayout.EAST);

        JPanel panelButtons = new JPanel();
        btnOK = new JButton("OK");
        btnCancel = new JButton("Cancel");
        btnOK.addActionListener(this);
        btnCancel.addActionListener(this);

        panelButtons.add(btnOK);
        panelButtons.add(btnCancel);
        panelMain.add(panelButtons, BorderLayout.SOUTH);

        setContentPane(panelMain);
    }

    public Font showDialog() {
        setVisible(true);
        return selectedFont;
    }

    public void actionPerformed(ActionEvent e) {
        Object source = e.getSource();
        if (source == btnOK) {
            String fontName = tfFont.getText();
            int size = Integer.parseInt(tfSize.getText());
            selectedFont = new Font(fontName, Font.PLAIN, size);
            dispose();
        } else if (source == btnCancel) {
            selectedFont = null;
            dispose();
        }
    }

    public void valueChanged(ListSelectionEvent e) {
        Object source = e.getSource();
        if (!e.getValueIsAdjusting()) {
            if (source == listFontNames) {
                String fontName = listFontNames.getSelectedValue();
                tfFont.setText(fontName);
                tfFont.setFont(new Font(fontName, Font.PLAIN, 12));
            } else if (source == listSizes) {
                Integer size = listSizes.getSelectedValue();
                tfSize.setText(size.toString());
                tfSize.setFont(new Font(tfSize.getFont().getFamily(), Font.PLAIN, size));
            }
        }
    }
}

然后在主程序中调用该对话框即可：

import javax.swing.*;

public class Main {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Sample");
        frame.setSize(400, 300);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);

        FontDialog fontDialog = new FontDialog(frame);
        Font font = fontDialog.showDialog();
        if (font != null) {
            JOptionPane.showMessageDialog(frame, "Selected font: " + font.getName() + " " + font.getSize());
            // Do something with selected font
        }
    }
}

这样就可以弹出一个“字体”对话框，用户可以选择想要的字体和字号。