CODEWITHSUNDEEP
javaswingbuttongroup
Keith
Keith

Reputation: 133

How to find that item is selected in a button group?

In Java swing, I want to be able to tell what item is selected in a button group. I looked in the Button Group API and didn't see anything that would achieve this. Is there some method that any of you have discovered to do this?

Upvotes: 1

Views: 9450

Answers (2)

DavidPostill
DavidPostill

Reputation: 7921

Reference ButtonGroup: getSelection()

The following example shows how to manage the selection of an item in a button group:

import java.awt.Container;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;

import javax.swing.AbstractButton;
import javax.swing.ButtonGroup;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JRadioButton;

public class MainClass {
  public static void main(String[] args) {
    JRadioButton dem = new JRadioButton("Bill", false);
    dem.setActionCommand("Bill");
    JRadioButton rep = new JRadioButton("Bob", false);
    rep.setActionCommand("Bob");
    JRadioButton ind = new JRadioButton("Ross", false);
    ind.setActionCommand("Ross");

    final ButtonGroup group = new ButtonGroup();
    group.add(dem);
    group.add(rep);
    group.add(ind);

    class VoteActionListener implements ActionListener {
      public void actionPerformed(ActionEvent ex) {
        String choice = group.getSelection().getActionCommand();
        System.out.println("ACTION Candidate Selected: " + choice);
      }
    }

    class VoteItemListener implements ItemListener {
      public void itemStateChanged(ItemEvent ex) {
        String item = ((AbstractButton) ex.getItemSelectable()).getActionCommand();
        boolean selected = (ex.getStateChange() == ItemEvent.SELECTED);
        System.out.println("ITEM Candidate Selected: " + selected + " Selection: " + item);
      }
    }

    ActionListener al = new VoteActionListener();
    dem.addActionListener(al);
    rep.addActionListener(al);
    ind.addActionListener(al);

    ItemListener il = new VoteItemListener();
    dem.addItemListener(il);
    rep.addItemListener(il);
    ind.addItemListener(il);

    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container c = frame.getContentPane();
    c.setLayout(new GridLayout(4, 1));
    c.add(new JLabel("Please Cast Your Vote"));
    c.add(dem);
    c.add(rep);
    c.add(ind);
    frame.pack();
    frame.setVisible(true);
  }
}

See the Java Tutorial How to Use the ButtonGroup Component for more information.

Upvotes: 1

Batuhan Tasdoven
Batuhan Tasdoven

Reputation: 798

I would just loop through your JRadioButtons and call isSelected(). If you really want to go from the ButtonGroup you can only get to the models. You could match the models to the buttons, but then if you have access to the buttons, why not use them directly?

quoted from here

If you are using actions at the end, it would also be helpful to set an action for each button then:

buttonGroup = new ButtonGroup();
...
...
button1.setActionCommand("Java");
...
buttonGroup.add(button1);
...

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

Upvotes: 0

Related Questions