To find out when the contents of the list model change,
you can register a ListDataListener with the model.
ListDataEvent Type Constants
Type Constant | Method |
CONTENTS_CHANGED | contentsChanged() |
INTERVAL_ADDED | intervalAdded() |
INTERVAL_REMOVED | intervalRemoved() |
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JScrollPane;
import javax.swing.event.ListDataEvent;
import javax.swing.event.ListDataListener;
public class ModifyModelSampleListDataListener {
static String labels[] = { "A", "B", "C", "D", "E", "F", "G" };
public static void main(String args[]) {
JFrame frame = new JFrame("Modifying Model");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Fill model
final DefaultListModel model = new DefaultListModel();
for (int i = 0, n = labels.length; i < n; i++) {
model.addElement(labels[i]);
}
JList jlist = new JList(model);
JScrollPane scrollPane1 = new JScrollPane(jlist);
frame.add(scrollPane1, BorderLayout.CENTER);
ListDataListener listDataListener = new ListDataListener() {
public void contentsChanged(ListDataEvent listDataEvent) {
appendEvent(listDataEvent);
}
public void intervalAdded(ListDataEvent listDataEvent) {
appendEvent(listDataEvent);
}
public void intervalRemoved(ListDataEvent listDataEvent) {
appendEvent(listDataEvent);
}
private void appendEvent(ListDataEvent listDataEvent) {
switch (listDataEvent.getType()) {
case ListDataEvent.CONTENTS_CHANGED:
System.out.println("Type: Contents Changed");
break;
case ListDataEvent.INTERVAL_ADDED:
System.out.println("Type: Interval Added");
break;
case ListDataEvent.INTERVAL_REMOVED:
System.out.println("Type: Interval Removed");
break;
}
System.out.println(", Index0: " + listDataEvent.getIndex0());
System.out.println(", Index1: " + listDataEvent.getIndex1());
DefaultListModel theModel = (DefaultListModel) listDataEvent.getSource();
System.out.println(theModel);
}
};
model.addListDataListener(listDataListener);
JButton jb = new JButton("add F");
jb.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent actionEvent) {
model.add(0, "First");
}
});
frame.add(jb,BorderLayout.SOUTH);
frame.setSize(640, 300);
frame.setVisible(true);
}
}