This Java tip illustrates a method of modifying horizontal alignment of text field at runtime. Developer may use this code to design the interface at runtime. Using this code develoeper may also change the interface according to an input from user.

import javax.swing.*;
import java.awt.event.*;

public class JTextFieldExample {

  public static void main(String[] args) {

    final JTextField tf = new JTextField("press <enter>", 20);
    tf.setHorizontalAlignment(JTextField.RIGHT);

    tf.addActionListener(new ActionListener() {
  public void actionPerformed(ActionEvent e) {
    int old = tf.getHorizontalAlignment();
    if (old == JTextField.LEFT) tf.setHorizontalAlignment(JTextField.RIGHT);
    if (old == JTextField.RIGHT) tf.setHorizontalAlignment(JTextField.CENTER);
    if (old == JTextField.CENTER) tf.setHorizontalAlignment(JTextField.LEFT);
  }
      });

    JFrame frame = new JFrame("JTextFieldExample");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().setLayout(new java.awt.FlowLayout());
    frame.getContentPane().add(tf);
    frame.setSize(275, 75);
    frame.setVisible(true);
    tf.requestFocus();
  }
}