在JPanel中添加ActionListener

Question

I have a JPanel that has two Jbuttons. The purpose is that as soon as I push the first Jbutton ("Do you have predicted value ...."), another JPanel pop up and I can see other created Jbuttons. The problem is that when I run the code, I can see the first panel, but when I click on the button, nothing happens. It would be great if you can help me.

public class Main {

    private static Component frame;
    private static JFileChooser inputFile;
    private static JFileChooser outputFile;
    private static String fullpath;
    private static String fullpath1;
    private static String fullpath2;
    private static String fullpath3;

    public static void main(String args[]) throws FileNotFoundException, IOException {

        try {

            GridBagConstraints gbc = new GridBagConstraints();
            gbc.insets = new Insets(5, 5, 5, 5);

            JButton nextPanel = new JButton("Do you have predicted values or residual errors?");
            JButton inputButton = new JButton("Browse predictor dataset");

            JPanel myPanel = new JPanel(new GridBagLayout()); //new panel

            gbc.gridwidth = 1;
            gbc.gridheight = 1;
            gbc.gridx = 0;
            gbc.gridy = 1;
            gbc.anchor = (0 == 0) ? GridBagConstraints.WEST : GridBagConstraints.EAST;
            gbc.fill = (0 == 0) ? GridBagConstraints.BOTH
                : GridBagConstraints.HORIZONTAL;
            gbc.weightx = (0 == 0) ? 0.1 : 0.1;
            gbc.weighty = 1.0;
            myPanel.add(nextPanel, gbc);

            final JPanel myPanel1 = new JPanel(new GridBagLayout());
            myPanel.add(myPanel1);    

            nextPanel.addActionListener(new ActionListener(){
                public void actionPerformed(ActionEvent e){

                    GridBagConstraints gbc1 = new GridBagConstraints();
            gbc1.insets = new Insets(5, 5, 5, 5);
            JButton errorButton = new JButton("Browse residual error associated to each instance");
            JButton predictedButton = new JButton("Browse predicted value associated to each instance");
            gbc1.gridwidth = 1;
            gbc1.gridheight = 1;
            gbc1.gridx = 0;
            gbc1.gridy = 1;
            gbc1.anchor = (0 == 0) ? GridBagConstraints.WEST : GridBagConstraints.EAST;
            gbc1.fill = (0 == 0) ? GridBagConstraints.BOTH
                : GridBagConstraints.HORIZONTAL;
            gbc1.weightx = (0 == 0) ? 0.1 : 0.1;
            gbc1.weighty = 1.0;
            myPanel1.add(errorButton, gbc1);
                }
            });

            gbc.gridwidth = 1;
            gbc.gridheight = 1;
            gbc.gridx = 0;
            gbc.gridy = 9;
            gbc.anchor = (0 == 0) ? GridBagConstraints.WEST : GridBagConstraints.EAST;
            gbc.fill = (0 == 0) ? GridBagConstraints.BOTH
                : GridBagConstraints.HORIZONTAL;
            gbc.weightx = (0 == 0) ? 0.1 : 0.1;
            gbc.weighty = 1.0;
            myPanel.add(inputButton, gbc);

            inputButton.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e) {
                    JFileChooser inputFile = new JFileChooser();
                    inputFile.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);
                    if (inputFile.showOpenDialog(null) == JFileChooser.APPROVE_OPTION) {
                        File file1 = inputFile.getSelectedFile();
                        String fullpathTemp = (String) file1.getAbsolutePath();
                        fullpath = fullpathTemp;
                    }
                 }
            });

             int result = JOptionPane.showConfirmDialog(null, myPanel, "CPM Program", JOptionPane.OK_CANCEL_OPTION);


 } catch (Exception e) {
             System.err.println("Error: " + e.getMessage());
         } finally {
         }
    }
}

Answer 1

You have two problems. Firstly, you should use a JDialog frame in order to display mypanel1--I don't think you can just display JPanel by itself.

So, , when the option is clicked, create a new JDialog and add your second JPanel to it. Be sure to call the setVisible method on the JDialog box.

Now, you will have another problem. The first frame that you created(the showConfirm message) is going to get all the actionEvents,and your JDialog will get none . And, since you passed in null as the parent frame for your JOption box, your new JDialog will not be able to "requestFocus" and thus, won't receive any actionEvents.

So, you will need to refactor your code in order to make sure that any new JDialogBox that is spawned can request focus.