自考 课后题 第六章6

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Exec65 extends JFrame implements ItemListener{

JComboBox box;
JTextField text;
static String[] lessons = {"语文","数学","化学","物理"};
public static void main(String[] args) {
new Exec65();

}
public Exec65(){
this.setTitle("Test");
this.setSize(500,500);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLocationRelativeTo(null);

box = new JComboBox(lessons);
box.setEditable(true);
box.addItemListener(this);
text = new JTextField(10);

add(box,BorderLayout.NORTH);
add(text,BorderLayout.CENTER);

this.setVisible(true);
pack();
}
@Override
public void itemStateChanged(ItemEvent e) {
text.setText(((JComboBox)(e.getSource())).getSelectedItem().toString());

}

}