Get selected JRadioButton from ButtonGroup

Ilias TsagklisNovember 11th, 2012Last Updated: April 21st, 2013

0 2,334 1 minute read

With this example we shall show you how to get the selected JRadioButton for a ButtonGroup in a Java Desktop Application. Radio buttons, in general, implement a very user friendly way ton provide input to your application, especially when the user has some specific elements to choose from.

In order to get the selected JRadioButton from a ButtonGroup, one should follow these steps:

Create a class that extends JFrame and implements ActionListener.
Create some JRadioButtons using JRadioButton constructor, with the button’s title as an argument.
Use setActionCommand to set a command for that button and setSelected to set the by default selected button.
Create a new ButtonGroup and use the add method to add the JRadioButtons to it.
Create a new Button and bundle it with the ActionListener
Override the actionPerformed of the ActionListener interface.
Use ButtonGroup.getSelection().getActionCommand() to get the user’s selection.

Let’s take a look a the code snippet that follows:

package com.javacodegeeks.snippets.desktop;

import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JRadioButton;

public class GetSelectedJRadioButtonFromButtonGroup extends JFrame implements ActionListener {

	private static final long serialVersionUID = 1L;

	private JRadioButton java;
	private JRadioButton c;
	private JRadioButton net;
	private JButton button;
	private ButtonGroup buttonGroup;

	public GetSelectedJRadioButtonFromButtonGroup() {

		// set flow layout for the frame
		this.getContentPane().setLayout(new FlowLayout());

		java = new JRadioButton("Java");
		java.setActionCommand("Java");

		c = new JRadioButton("C/C++");
		c.setActionCommand("c");

		net = new JRadioButton(".NET");
		net.setActionCommand("net");

		java.setSelected(true);

		button = new JButton("Check");

		button.addActionListener(this);

		buttonGroup = new ButtonGroup();

		//add radio buttons
		buttonGroup.add(java);
		buttonGroup.add(c);
		buttonGroup.add(net);

		add(java);
		add(c);
		add(net);
		add(button);

	}

	@Override
	public void actionPerformed(ActionEvent e) {
		if (e.getActionCommand().equals("Check")) {
			System.out.println("Selected Radio Button: " + buttonGroup.getSelection().getActionCommand());
		}
	}

	private static void createAndShowGUI() {

  //Create and set up the window.

  JFrame frame = new GetSelectedJRadioButtonFromButtonGroup();

  //Display the window.

  frame.pack();

  frame.setVisible(true);

  frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    }

	public static void main(String[] args) {

  //Schedule a job for the event-dispatching thread:

  //creating and showing this application's GUI.

  javax.swing.SwingUtilities.invokeLater(new Runnable() {

public void run() {

    createAndShowGUI(); 

}

  });
    }

}

This was an example on how to get the selected JRadioButton from ButtonGroup.