SWING组件学习6：下拉菜单

package jcombobox;
import javax.swing.*;
public class JComboBoxTest extends JFrame{
 JComboBox c1 = new JComboBox();
 JComboBoxTest(){
  super("请选择喜欢的城市，这回用列表啦！");
  
  this.setSize(300,100);
  this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  String[] items = {"北京","上海","石家庄"};
  for(int i = 0; i < items.length; i++){
   c1.addItem(items[i]);//设置菜单元素，可以是String,也可以是图片ImageIcon,好像JButton不行
  }
  JPanel p = new JPanel();
  p.add(c1);
  this.setContentPane(p);
  this.show();
  
 }
 public static void main(String[] args) {
  JComboBoxTest j = new JComboBoxTest();
  System.out.println((String)j.c1.getSelectedItem());
  
 }
}