GUI Test using Swing

Source Code

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

public class SGUItest extends JApplet implements ActionListener {
    private JButton b1, b2;
    private JLabel lb;
    private JRadioButton cb1, cb2, cb3, cb4;
    private ButtonGroup bg = new ButtonGroup();
    private JTextField tf;
    private JComboBox cb;

    public void init() {
	JPanel p;
	Container cnt = getContentPane();
	String[] str = {"0", "10", "20", "30"};
	ActionListener al = this;

	p = new JPanel();

	cb = new JComboBox(str);
	p.add(cb);
	cb.addActionListener(al);

	cb1 = new JRadioButton("Learning", true);
	cb1.addActionListener(al);
	cb2 = new JRadioButton("Adaptive", false);
	cb2.addActionListener(al);
	cb3 = new JRadioButton("H infty", false);
	cb3.addActionListener(al);
	cb4 = new JRadioButton("Sliding Mode", false);
	cb4.addActionListener(al);
	bg.add(cb1); bg.add(cb2); bg.add(cb3); bg.add(cb4);
	p.add(cb1); p.add(cb2); p.add(cb3); p.add(cb4);
	cnt.add(p, BorderLayout.NORTH);

	lb = new JLabel("Label");
	lb.setHorizontalAlignment(JLabel.CENTER);
	cnt.add(lb, BorderLayout.CENTER);

	p = new JPanel();
	b1 = new JButton("Start");
	b1.setActionCommand("Start");
	b1.addActionListener(al);

	b2 = new JButton("Stop ");
	b2.setActionCommand("Stop");
	b2.addActionListener(al);
	p.add(b1); p.add(b2);

	tf = new JTextField(20);
	tf.addActionListener(al);
	p.add(tf);

	cnt.add(p, BorderLayout.SOUTH);
    }

    public void actionPerformed(ActionEvent evt) {
        if (evt.getSource() == cb) {
	    lb.setText("ComboBox [" + cb.getSelectedItem() + "]");
	}
	else if (evt.getSource() == tf) {
	    lb.setText("Text [" + tf.getText() + "]");
	    tf.selectAll();
	}
	else if (evt.getSource() instanceof JButton) {
	    String command = evt.getActionCommand();
	    lb.setText("Button [" + command + "]");
	}
	else {
	    String command = evt.getActionCommand();
	    lb.setText("CheckBox [" + command + "]");
	}
    }
}