JRadioButton

The following code produces an applet like this:

The radiobuttons are the circles that can be clicked on. Only one can be clicked at a time. This is different from a JCheckBox because more than one JCheckBox can be checked off.

They have the same life cycle as a button. The following happens in the init method.

However, to control the JRadioButtons, so only one may selected at a time, all of the JRadioButtons need to be put in a ButtonGroup.

Then, in ActionPerformed, you can use the information from which JRadioButton is selected:

The full code:

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

public class timeConvert extends Applet implements ActionListener
{
JRadioButton minsec, minhour;
JTextField mins;
JLabel result;

public void init ()
{
JLabel ins = new JLabel ("Enter the time in minuters: ");
mins = new JTextField (4);
Panel p = new Panel ();
p.add (ins);
p.add (mins);

minsec = new JRadioButton ("Minutes to seconds");
minsec.addActionListener (this);
minsec.setActionCommand ("minsec");
minhour = new JRadioButton ("Minutes to Hour:Minute");
minhour.addActionListener (this);
minhour.setActionCommand ("minhour");

ButtonGroup group = new ButtonGroup ();
group.add (minsec);
group.add (minhour);

Panel p2 = new Panel (new GridLayout (2, 1));
p2.add (minsec);
p2.add (minhour);

result = new JLabel ("The result is: ");
result.setPreferredSize (new Dimension (250, 20));
add (p);
add (p2);
add (result);
}

public void actionPerformed (ActionEvent e)
{
try
{
if (e.getActionCommand ().equals ("minSec"))
{
int minute = Integer.parseInt (mins.getText ());
minute *= 60;
result.setText ("The time in seconds is " + minute);
}
else
{
int minute = Integer.parseInt (mins.getText ());
int hour = minute / 60;
minute = minute % 60;
result.setText ("In hour:minute format it is " + hour + ":" + minute);
}
}
catch (Exception ee)
{
result.setText ("Enter a number first. Re-select radio button.");

}
}
}