Dynamically changing contents of a scrollpane, doesn't display?

[Joe Vahabzadeh]

All,

I've run into something of a problem.

I've got a GUI using the BorderLayout, with the top part showing several buttons, the bottom also showing several buttons, and the center section with a JScrollPane which starts out empty but will be updated depending on other things that are going on.

Here's the relevant code:

public class AdminTab extends JPanel implements ActionListener
{
static JPanel selectPane = new JPanel();
static JPanel controlPane = new JPanel();
 
static TableModel userBatchNums = new TableModel3();
static JTable table = new JTable(userBatchNums);
static JScrollPane scrollPane = new JScrollPane();
 
public AdminTab()
{
super(false);
setLayout(new BorderLayout());
 
// code here adds things to selectPane and controlPane,
// mostly buttons that choose WHICH table to show
 
add(selectPane, BorderLayout.PAGE_START);
add(scrollPane, BorderLayout.CENTER);
add(controlPane, BorderLayout.PAGE_END);
 
scrollPane.add(table);
scrollPane.revalidate();
}
}

However, all I get in the middle section is a blank area.

If I delete the last two lines of code, and change the 5th line to read as follows:

static JScrollPane scrollPane = new JScrollPane(table);

then everything works. However, this isn't suitable for my needs.

What am I doing wrong? Why can't I add a table to the JScrollPane after the display has already been set up and shown?

Thanks in advance.

[Johan Sun]

don't use
scrollPane.add(table);

use
scrollPane.setViewportView(table)
instead, which is same as
scrollPane.getViewport().add(table)

u can add things to JScrollPane, but it's its viewport that's displayed.

//-----------
import javax.swing.*;
public class AdminTab //extends JPanel //implements ActionListener
{

public static void main(String[] args) {
JScrollPane scrollPane = new JScrollPane();
JFrame frame = new JFrame();
frame.add(scrollPane);

*OK scrollPane.setViewportView(new JLabel("haha"));
*NO scrollPane.add(new JLabel("haha"));

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 300);
frame.setVisible(true);
}
}
//-----------------------

[Joe Vahabzadeh]

Thanks!