import java.awt.GridBagLayout;
import java.util.Random;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Main {
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setVisible(true);
}
}
class TestPane extends JPanel {
JComboBox comboBox;
JButton update;
public TestPane() {
setLayout(new GridBagLayout());
update = new JButton("Update");
comboBox = new JComboBox();
update.addActionListener(e ->updateCombo());
updateCombo();
add(comboBox);
add(update);
}
void updateCombo() {
DefaultComboBoxModel model = new DefaultComboBoxModel();
Random rnd = new Random();
for (int index = 0; index < 10 + rnd.nextInt(90); index++) {
model.addElement(rnd.nextInt(1000));
}
comboBox.setModel(model);
}
}