我有一个旧的Java NetBenas项目，其中包含从JPanel派生的UI类。在这些类中，代码编辑器不包含Design按钮。 Design按钮仅出现在新创建的JPanel fom中。可以以某种方式告诉NetBeans以Design模式打开旧表格吗？
无法在Design模式下打开的表单：
public class About extends javax.swing.JPanel /*JFrame*/ {
private ClassLoader cl = getClass().getClassLoader();
public ImageIcon logo = new ImageIcon(
cl.getResource("icons/logo.gif"));
public ImageIcon ball = new ImageIcon(
cl.getResource("icons/ball.gif"));
private JPanel centerPanel;
private JPanel topPanel;
private JLabel productName = new JLabel("<html><font face=\"verdana\" size=10>"+
"SocketTest",logo,JLabel.CENTER);
private JTextArea readme = new JTextArea();
private JScrollPane jsp;
String html="<html><font face=\"verdana\" size=\"2\">";
private JLabel versionText = new JLabel(html+"Version",ball,JLabel.LEFT);
private JLabel version = new JLabel(html+": 3.0.0", JLabel.LEFT);
private JLabel licenceText = new JLabel(html+"Licence",ball,JLabel.LEFT);
private JLabel licence = new JLabel(html+": GNU Lesser General Public License", JLabel.LEFT);
private JLabel authorText = new JLabel(html+"Author",ball,JLabel.LEFT);
private JLabel author = new JLabel(html+": Akshathkumar Shetty", JLabel.LEFT);
private JLabel copyrightText = new JLabel(html+"Copyright © 2003-2008 Akshathkumar Shetty",ball,JLabel.LEFT);
private JLabel websiteText = new JLabel(html+"Website",ball,JLabel.LEFT);
private JLabel website = new JLabel(html+": http://sockettest.sourceforge.net/", JLabel.LEFT);
private JLabel readmeText = new JLabel(html+"ReadMe",ball,JLabel.LEFT);
private GridBagConstraints gbc = new GridBagConstraints();
/** Creates a new instance of About */
public About() {
//Container cp = getContentPane();
Container cp = this;
topPanel = new JPanel();
topPanel.setLayout(new GridBagLayout());
gbc.insets = new Insets( 2, 2, 2, 2 );
gbc.weighty = 0.0;
gbc.weightx = 0.0;
gbc.gridx = 0;
gbc.gridy = 0;
gbc.gridheight = 1;
gbc.gridwidth = 3;
gbc.anchor = GridBagConstraints.CENTER;
gbc.fill = GridBagConstraints.NONE;
topPanel.add(productName, gbc);
gbc.anchor = GridBagConstraints.WEST;
gbc.fill = GridBagConstraints.HORIZONTAL;
gbc.gridy = 1;
gbc.gridx = 0;
gbc.weightx = 0.0;
topPanel.add(versionText, gbc);
gbc.gridx = 1;
topPanel.add(version, gbc);
gbc.gridx = 2;
gbc.weightx = 1.0;
gbc.fill = GridBagConstraints.HORIZONTAL;
topPanel.add(Box.createHorizontalGlue(), gbc);
gbc.gridy = 2;
gbc.gridx = 0;
gbc.weightx = 0.0;
topPanel.add(licenceText, gbc);
gbc.gridx = 1;
topPanel.add(licence, gbc);
gbc.gridx = 2;
gbc.weightx = 1.0;//1.0
gbc.fill = GridBagConstraints.HORIZONTAL;
topPanel.add(new JLabel(), gbc);
gbc.gridy = 3;
gbc.gridx = 0;
gbc.weightx = 0.0;
topPanel.add(authorText, gbc);
gbc.gridx = 1;
topPanel.add(author, gbc);
gbc.gridx = 2;
gbc.weightx = 1.0;
gbc.fill = GridBagConstraints.HORIZONTAL;
topPanel.add(Box.createHorizontalGlue(), gbc);
gbc.gridy = 4;
gbc.gridx = 0;
gbc.weightx = 0.0;
topPanel.add(websiteText, gbc);
gbc.gridx = 1;
topPanel.add(website, gbc);
gbc.gridx = 2;
gbc.weightx = 1.0;
gbc.fill = GridBagConstraints.HORIZONTAL;
topPanel.add(Box.createHorizontalGlue(), gbc);
gbc.gridy = 5;
gbc.gridx = 0;
gbc.weightx = 0.0;
gbc.gridwidth = 2;
topPanel.add(copyrightText, gbc);
gbc.gridwidth = 1;
gbc.gridx = 2;
gbc.weightx = 1.0;
gbc.fill = GridBagConstraints.HORIZONTAL;
topPanel.add(Box.createHorizontalGlue(), gbc);
gbc.gridy = 6;
gbc.gridx = 0;
gbc.weightx = 0.0;
gbc.gridwidth = 1;
topPanel.add(readmeText, gbc);
gbc.gridx = 1;
topPanel.add(new JLabel(" "), gbc);
gbc.gridx = 2;
gbc.weightx = 1.0;
gbc.fill = GridBagConstraints.HORIZONTAL;
topPanel.add(Box.createHorizontalGlue(), gbc);
centerPanel = new JPanel();
readme.setText("Loading... readme");
try {
String cont = Util.readFile("readme.txt",(Object)About.this);
readme.setText(cont);
} catch (IOException e){
System.err.println("Error reading readme.txt "+e);
readme.append("\r\nFailed : "+e.getMessage());
}
readme.setEditable(false);
readme.setLineWrap(true);
readme.setWrapStyleWord(true);
jsp = new JScrollPane(readme);
centerPanel.setLayout(new BorderLayout());
centerPanel.add(jsp);
centerPanel.setBorder(BorderFactory.createEmptyBorder(0,9,0,9));
cp.setLayout(new BorderLayout(0,10));
cp.add(topPanel,BorderLayout.NORTH);
cp.add(centerPanel,BorderLayout.CENTER);
setBorder(BorderFactory.createEmptyBorder(10,10,10,10));
}
}