java glasspane不会更新

Question

我的代码中有一点问题。单击udpate按钮后，它应该显示玻璃板。但它没有，我不知道为什么。如果我将setVisibility（true）设置为构造函数中的glasspane，它就可以工作。有人可以帮我吗？这是我的代码

public class ViewClientSettings extends JFrame {

private static final long serialVersionUID = 8498637682155215375L;
private JTextField [] fields;
private JLabel [] label;
private JButton update;
private JComponent glass;

private static final String IPADDRESS_PATTERN = 
        "^([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\." +
                "([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\." +
                "([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\." +
                "([01]?\\d\\d?|2[0-4]\\d|25[0-5])$";

public ViewClientSettings(String s){
    super(s);
    this.setLayout(null);
    this.setSize(210, 150);
    JPanel panel = new JPanel(new GridLayout(2,2,0,15));
    panel.setBounds(0, 0, 210, 80);
    fields = new JTextField[2];
    label = new JLabel[2];
    label[0] = new JLabel("server ip");
    panel.add(label[0]);
    fields[0] = new JTextField(ClientSettings.getServerIP());
    panel.add(fields[0]);
    label[1] = new JLabel("server port");
    panel.add(label[1]);
    fields[1] = new JTextField(ClientSettings.getServerPort()+"");
    panel.add(fields[1]);
    add(panel);

    update = new JButton("update");
    update.setBounds(50, 85, 100, 25);
    update.addActionListener(new Listener());
    add(update);

    this.setVisible(false);
    this.setDefaultCloseOperation(HIDE_ON_CLOSE);
    this.setLocation(280, 310);
    this.setResizable(false);

    setGlassPane(glass = new Glass());
    lock();
}

public void lock() {
    glass.setVisible(true);
}

public void unlock() {
    glass.setVisible(false);
}


@SuppressWarnings("serial")
private class Glass extends JComponent{
    private String message = "checking";
    private ImageIcon icon = new ImageIcon("gif/test.gif");

    public Glass() {
        this.setBackground(Color.WHITE);
        this.setFont(new Font("Default", Font.BOLD, 10));
    }

    @Override
    protected void paintComponent(Graphics g) {
        // enables anti-aliasing
        Graphics2D g2 = (Graphics2D) g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                RenderingHints.VALUE_ANTIALIAS_ON);

        // gets the current clipping area
        Rectangle clip = g.getClipBounds();

        // sets a 65% translucent composite
        AlphaComposite alpha = AlphaComposite.SrcOver.derive(0.65f);
        Composite composite = g2.getComposite();
        g2.setComposite(alpha);

        // fills the background
        g2.setColor(getBackground());
        g2.fillRect(clip.x, clip.y, clip.width, clip.height);

        // draw gif
        icon.paintIcon(this,g2,75,25);

        // draws the text
        g2.setColor(Color.BLACK);
        g2.drawString(message, 85, 60);

        // draws the content of the progress bar
        Paint paint = g2.getPaint();

        g2.setPaint(paint);
        g2.setComposite(composite);
    }
}

private class Listener implements ActionListener{

    @Override
    public void actionPerformed(ActionEvent e) {
        lock();
        glass.repaint();
        repaint();
        if(fields[0].getText().trim().compareTo("") !=  0 && fields[1].getText().trim().compareTo("") != 0){
            if(fields[0].getText().trim().matches(IPADDRESS_PATTERN) && fields[1].getText().trim().matches("^\\d+$")){
                String ip = fields[0].getText().trim();
                int port = Integer.valueOf(fields[1].getText());

                try {
                    InetAddress connectionAddress = InetAddress.getByName(ip);
                    Socket mySocket = new Socket(connectionAddress, port);
                    System.out.println("connected to address " + ip);
                    mySocket.close();
                }
                catch (IOException en) {
                    System.out.println("unable to connect to host " +ip);
                    JOptionPane.showMessageDialog(ViewClientSettings.this, "No connection to this server","Warning",JOptionPane.WARNING_MESSAGE);
                    return;
                } 
                ClientSettings.setServerIP(fields[0].getText().trim());
                ClientSettings.setServerPort(Integer.valueOf(fields[1].getText().trim()));
                JOptionPane.showMessageDialog(ViewClientSettings.this, "Settings updated","Success",JOptionPane.INFORMATION_MESSAGE);
                setVisible(false);
                unlock();
            }
            else
                JOptionPane.showMessageDialog(ViewClientSettings.this, "False Settings","Warning",JOptionPane.WARNING_MESSAGE);
        }
        else
            JOptionPane.showMessageDialog(ViewClientSettings.this, "Fill all settings","Warning",JOptionPane.WARNING_MESSAGE);
    }       
}   

}

提前谢谢