ItemListener for JRadioButton : ItemListener « Swing Event « Java Tutorial

1. Java Tutorial
2. Swing Event
3. ItemListener

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Container;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;

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

public class Main extends JFrame {
  private JRadioButton small, medium, large;

  private JButton button;

  public Main(String title) {
    super(title);
    this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    Container contentPane = this.getContentPane();
    ButtonGroup group = new ButtonGroup();
    small = new JRadioButton("small");
    medium = new JRadioButton("medium");
    large = new JRadioButton("large");

    group.add(small);
    group.add(medium);
    group.add(large);
    button = new JButton("Click here.");
    button.setBounds(100, 50, 100, 50);
    JPanel center = new JPanel();
    center.setLayout(null);
    center.add(button);
    contentPane.add(center, BorderLayout.CENTER);

    JPanel north = new JPanel();
    north.add(small);
    north.add(medium);
    north.add(large);
    contentPane.add(north, BorderLayout.NORTH);

    ChangeSize listener = new ChangeSize(button);
    small.addItemListener(listener);
    medium.addItemListener(listener);
    large.addItemListener(listener);
  }

  public static void main(String[] args) {
    JFrame f = new Main("JRadioButtonDemo");
    f.setSize(300, 200);
    f.setVisible(true);
  }
}
class ChangeSize implements ItemListener {
  private Component component;

  public ChangeSize(Component c) {
    component = c;
  }

  public void itemStateChanged(ItemEvent e) {
    String size = (String) e.getItem();
    if (size.equals("small")) {
      component.setSize(75, 20);
    } else if (size.equals("medium")) {
      component.setSize(100, 50);
    } else if (size.equals("large")) {
      component.setSize(150, 75);
    }
  }
}

15.20.ItemListener
	15.20.1.	How to Write an Item Listener
	15.20.2.	Toggle button with ItemListener
	15.20.3.	ComboBox with ItemListener
	15.20.4.	Firing Item Events
	15.20.5.	ItemListener for JRadioButton