How to organize panels?

[King-Chieh Wang]

Hello everybody,
I am brand new in GUI, so bare with my simple questions here:
I am trying to create a GUI that has 3 textFields, for inputting search strings. Then, a "Submit" button below them , to execute the search. Finally, I would like a JTable , either to the right or bottom of the search field/button to display the results. However, although the textfields and the button works correctly, I cannot make JTable to appear coorectly. I am doing BorderLayout_SOUTH / CENTER / etc for my search fields and button. THen, my JTable either overlapps my button (when I give the BorderLayout_South as coordinate again) or it dont even show up when i put parameter as BorderLayout_East. Whats other way to manage these panels? Also, I wont be able to know how big my JTable will be until I hit the "Submit" button...
THanks for helping out!!
Jack

[Craig Wood]

import java.awt.*;
import javax.swing.*;
 
public class GUITest
{
    public static void main(String[] args)
    {
        JTextField
            tf1 = new JTextField(16),
            tf2 = new JTextField(16),
            tf3 = new JTextField(16);
        JButton button = new JButton("Button");
        JPanel northPanel = new JPanel(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.gridwidth = gbc.REMAINDER;
        gbc.insets = new Insets(2,0,2,0);
        northPanel.add(tf1, gbc);
        northPanel.add(tf2, gbc);
        northPanel.add(tf3, gbc);
        northPanel.add(button, gbc);
        DefaultListModel model = new DefaultListModel();
        model.setSize(4);
        JList list = new JList(model);
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(northPanel, "North");
        f.getContentPane().add(new JScrollPane(list));
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
}

[KR Campbell]

Or at a more abstract level; if you are using a BorderLayout you cannot add more than one component in each part of the layout. So if you add a button to BorderLayout.CENTER and then add a JTable to the same section one of them is not going to be visible.
As the previous correspondent has so ably demonstrated, a good solution is to nest panels within each other.
Regards,
Kenny

[Glenn Murray]

Yes, the idea which you seem to be missing is that you can nest
the panels (with their layouts) in one another. Here's a modification
of the example above which shows that more clearly, I think, and
has the further of advantage of not farting around with GridBagLayout
(it's a newbie question for crying out loud). Note that columnPanel
with the GridLayout is nested in northPanel which has the default
FlowLayout---the only purpose being to provide nice padding. You can
experiment by adding columnPanel instead of northPanel in line 25.
Cheers,
Glenn

  
import java.awt.*;
import javax.swing.*;
 
public class GUITest
{
    public static void main(String[] args)
    {
        JTextField
            tf1 = new JTextField(16),
            tf2 = new JTextField(16),
            tf3 = new JTextField(16);
        JButton button = new JButton("Button");
        JPanel northPanel = new JPanel();
        JPanel columnPanel = new JPanel(new GridLayout(4, 1, 10, 10));
        columnPanel.add(tf1);
        columnPanel.add(tf2);
        columnPanel.add(tf3);
        columnPanel.add(button);
        northPanel.add(columnPanel);
        DefaultListModel model = new DefaultListModel();
        model.setSize(4);
        JList list = new JList(model);
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(northPanel, "North");
        f.getContentPane().add(new JScrollPane(list));
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
}