placing components in GridBagLayout - swing

Question

I am trying to place the JLabel and JTextfield like this,
First Name Textbox -> First Name is a label named as lblFirstname
Last Name Textbox TextBox is JTextField
tried using GridBagLayout,
the constraints applied are,
lblFirstNameCons.gridx = 0;
lblLastNameCons.gridy = 0;
txtFirstName.gridx = 0;
txtLastNameCons.gridy = 3;
I am getting the output like this,
First NameTextbox -> There is no space and also, the JTextField is almost invisible.

Answer 1

The layout should be something like this. The values in parenthesis are the gridx and gridy (grix, gridy):
First Name (0, 0) Textbox (1, 0)
Last Name (0, 1) Textbox (1, 1)

Answer 2

You should make sure that the fill property of the GridBagConstraint is set to HORIZONTAL for the textfield and make sure that the weightx is set to something greater than 0
Or you can indicate to the textfield the desired number of columns to display (this will eventually influence the preferred size of the textfield).
Here is an example showing that:
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.net.MalformedURLException;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class TestGridBagLayout {
protected void initUI() throws MalformedURLException {
final JFrame frame = new JFrame();
frame.setTitle(TestGridBagLayout.class.getSimpleName());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final JPanel panel = new JPanel(new GridBagLayout());
JLabel firstName = new JLabel("First name:");
JLabel lastName = new JLabel("Last name:");
JTextField firstNameTF = new JTextField();
JTextField lastNameTF = new JTextField();
GridBagConstraints gbc = new GridBagConstraints();
gbc.insets = new Insets(3, 3, 3, 3);
gbc.weightx = 0;
gbc.fill = GridBagConstraints.HORIZONTAL;
gbc.anchor = GridBagConstraints.CENTER;
panel.add(firstName, gbc);
gbc.weightx = 1;
gbc.gridwidth = GridBagConstraints.REMAINDER;
panel.add(firstNameTF, gbc);
gbc.gridwidth = 1;
gbc.weightx = 0;
panel.add(lastName, gbc);
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbc.weightx = 1;
panel.add(lastNameTF, gbc);
frame.add(panel);
frame.setSize(300, 200);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
try {
new TestGridBagLayout().initUI();
} catch (MalformedURLException e) {
e.printStackTrace();
}
}
});
}
}