import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.ComboBoxModel;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Main extends JPanel implements ActionListener{
JComboBox<String> combo1 = new JComboBox<>(new String[] { "Course 1",
"Course 2", "Course 3" });
JComboBox<String> combo2 = new JComboBox<>();
ComboBoxModel<String>[] models = new ComboBoxModel[3];
public Main() {
models[0] = new DefaultComboBoxModel<>(new String[] { "A1", "A2" });
models[1] = new DefaultComboBoxModel<>(new String[] { "B1", "B2", "B3",
"B4" });
models[2] = new DefaultComboBoxModel<>(new String[] { "C1", "C2" });
combo2.setModel(models[0]);
this.add(combo1);
this.add(combo2);
combo1.addActionListener(this);
}
@Override
public void actionPerformed(ActionEvent e) {
int i = combo1.getSelectedIndex();
combo2.setModel(models[i]);
}
public static void main(String[] args) {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(new Main());
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
}
【jcombobox】
