Problem handling JFileChooser events...

Question

The problem I have is rather tricky to explain. I feel maybe I'm treading on an area I'm not ready for yet... but here goes:
I have a JInternalFrame with an "open" button which triggers the JFileChooser and underneath a text field to log activity. My goal is simply to have a String array of all the filenames selected ( one at a time, whilst adding to the array ).
All seems well to start with. I have a System.out.println running after each filename is added to the array, and it verifies that they are being added successfully.
The problem comes just after that... When I call for the String array, it appears to be empty!
I'm sure that this will be a foolish mistake on my behalf, but still, I'm yet to spot it!
this is the code where the filenames are added to the array:
public void actionPerformed(ActionEvent e) {
            if (e.getSource() == openButton) {
            int returnVal = fc.showOpenDialog(FileSelector.this);
            if (returnVal == JFileChooser.APPROVE_OPTION) {
            File file = fc.getSelectedFile();
            str[a] = file.getName();
            a++;
               log.append("File: " + file.getName() + " added to list" + newline);
        } else {
               log.append("Open command cancelled by user." + newline);
           log.setCaretPosition(log.getDocument().getLength());
     System.out.println(str);
}I'm not sure what other bits of code are needed, so ill hold fast.
cheers in advance for any help.
John.

Answer 1

The error message says it all:
"java.lang.IllegalArgumentException: cannot add to layout: constraints must be a GridBagConstraint"
You are apparently adding something to a panel that uses a GridBagLayout, but the constraint you are specifying is not a GridBagConstraints.
JPanel pnl = new JPanel(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
pnl.add(new JLabel("correct"), c);
pnl.add(new JLabel("wrong"), BorderLayout.CENTER);The second add in the above code will cause the error you are getting. This would also explain why it works when you are using a BorderLayout.
Here is the relevant code:The code you posted was not the relevant code. The relevant code is what takes place in your button's ActionListener. There you call the method gotoNextSection(), which you did not post.