Demonstrating the ItemListener
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.GridLayout;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import javax.swing.ButtonGroup;
import javax.swing.JComboBox;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
public class ItemTest {
public static void main(String args[]) {
JFrame frame = new JFrame();
Container contentPane = frame.getContentPane();
ItemListener listener = new ItemListener() {
public void itemStateChanged(ItemEvent e) {
System.out.println("Source: " + name(e.getSource()));
System.out.println("Item: " + name(e.getItem()));
int state = e.getStateChange();
System.out.println("State: "
+ ((state == ItemEvent.SELECTED) ? "Selected"
: "Deselected"));
}
private String name(Object o) {
if (o instanceof JComponent) {
JComponent comp = (JComponent) o;
return comp.getName();
} else {
return o.toString();
}
}
};
JPanel panel = new JPanel(new GridLayout(0, 1));
ButtonGroup group = new ButtonGroup();
JRadioButton option = new JRadioButton("French Fries", true);
option.setName(option.getText());
option.addItemListener(listener);
group.add(option);
panel.add(option);
option = new JRadioButton("Onion Rings", false);
option.setName(option.getText());
option.addItemListener(listener);
group.add(option);
panel.add(option);
option = new JRadioButton("Ice Cream", false);
option.setName(option.getText());
option.addItemListener(listener);
group.add(option);
panel.add(option);
contentPane.add(panel, BorderLayout.NORTH);
String flavors[] = { "Item 1", "Item 2", "Item 3"};
JComboBox jc = new JComboBox(flavors);
jc.setName("Combo");
jc.addItemListener(listener);
jc.setMaximumRowCount(4);
contentPane.add(jc, BorderLayout.SOUTH);
frame.pack();
frame.show();
}
}
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