How can I display JTextFields correctly on a JPanel using GridBagLayout?

Question

I had some inputfields on a JPanel using the boxLayout. All was ok. Then I decided to change the panellayout to GridBagLayout. The JLabel fields are displayed correctly but the JTextField aren't. They are at the JPanel but have a size of 0??? So we cannot see what we type in these fields... Even when I put some text in the field before putting it on the panel.
How can I display JTextFields correctly on a JPanel using GridBagLayout?
here is a shortcut of my code:
private Dimension sFieldSize10 = new Dimension(80, 20);
// Create and instantiate Selection Fields
private JLabel lSearchAbrText = new JLabel();
private JTextField searchAbrText = new JTextField();
// Set properties for SelectionFields
lSearchAbrNumber.setText("ABR Number (0-9999999):");
searchAbrNumber.setText("");
searchAbrNumber.createToolTip();
searchAbrNumber.setToolTipText("enter the AbrNumber.");
searchAbrNumber.setPreferredSize(sFieldSize10);
searchAbrNumber.setMaximumSize(sFieldSize10);
public void createViewSubsetPanel() {
pSubset = new JPanel();
// Set layout
pSubset.setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
// Add Fields
gbc.gridy = 0;
gbc.gridx = GridBagConstraints.RELATIVE;
pSubset.add(lSearchAbrNumber, gbc);
// also tried inserting this statement
// searchAbrNumber.setText("0000000");
// without success
pSubset.add(searchAbrNumber,gbc);
pSubset.add(lSearchAbrText, gbc);
pSubset.add(searchAbrText, gbc);
gbc.gridy = 1;
pSubset.add(lSearchClassCode, gbc);
pSubset.add(searchClassCode, gbc);
pSubset.add(butSearch, gbc);
}

Answer 1

import java.awt.*;
import java.awt.event.*;
import javax .swing.*;
public class GridBagDemo {
  public static void main(String[] args) {
    JLabel
      labelOne   = new JLabel("Label One"),
      labelTwo   = new JLabel("Label Two"),
      labelThree = new JLabel("Label Three"),
      labelFour  = new JLabel("Label Four");
    JLabel[] labels = {
      labelOne, labelTwo, labelThree, labelFour
    JTextField
      tfOne   = new JTextField(),
      tfTwo   = new JTextField(),
      tfThree = new JTextField(),
      tfFour  = new JTextField();
    JTextField[] fields = {
      tfOne, tfTwo, tfThree, tfFour
    Dimension
      labelSize = new Dimension(125,20),
      fieldSize = new Dimension(150,20);
    for(int i = 0; i < labels.length; i++) {
      labels.setPreferredSize(labelSize);
labels[i].setHorizontalAlignment(JLabel.RIGHT);
fields[i].setPreferredSize(fieldSize);
GridBagLayout gridbag = new GridBagLayout();
JPanel panel = new JPanel(gridbag);
GridBagConstraints gbc = new GridBagConstraints();
gbc.weightx = 1.0;
gbc.weighty = 1.0;
gbc.insets = new Insets(5,5,5,5);
panel.add(labelOne, gbc);
panel.add(tfOne, gbc);
gbc.gridwidth = gbc.RELATIVE;
panel.add(labelTwo, gbc);
gbc.gridwidth = gbc.REMAINDER;
panel.add(tfTwo, gbc);
gbc.gridwidth = 1;
panel.add(labelThree, gbc);
panel.add(tfThree, gbc);
gbc.gridwidth = gbc.RELATIVE;
panel.add(labelFour, gbc);
gbc.gridwidth = gbc.REMAINDER;
panel.add(tfFour, gbc);
final JButton
smallerButton = new JButton("smaller"),
biggerButton = new JButton("wider");
final JFrame f = new JFrame();
ActionListener l = new ActionListener() {
final int DELTA_X = 25;
int oldWidth, newWidth;
public void actionPerformed(ActionEvent e) {
JButton button = (JButton)e.getSource();
oldWidth = f.getSize().width;
if(button == smallerButton)
newWidth = oldWidth - DELTA_X;
if(button == biggerButton)
newWidth = oldWidth + DELTA_X;
f.setSize(new Dimension(newWidth, f.getSize().height));
f.validate();
smallerButton.addActionListener(l);
biggerButton.addActionListener(l);
JPanel southPanel = new JPanel(gridbag);
gbc.gridwidth = gbc.RELATIVE;
southPanel.add(smallerButton, gbc);
gbc.gridwidth = gbc.REMAINDER;
southPanel.add(biggerButton, gbc);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(panel);
f.getContentPane().add(southPanel, "South");
f.pack();
f.setLocation(200,200);
f.setVisible(true);