java简单应用----下拉条的 应用

package zuoye0517;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class XIA extends JFrame{
	private JComboBox lst;
	private JLabel lbl;
	private Object cities[]={"","叫哥哥","叫爸爸"};
	public XIA(){
		super("dadadadad");
		Container c=getContentPane();
		c.setLayout(new FlowLayout());
		lst=new JComboBox(cities);
		lst.setMaximumRowCount(4);
		lbl=new JLabel("请从组合框中选择");
		c.add(lst);
		c.add(lbl);
		lst.addItemListener(new Handler1());
		setSize(300,150);
		setVisible(true);
	}
	public static void main(String args[]){
		XIA app=new XIA();
		app.addWindowListener( new Handler2());
	}
	class Handler1 implements ItemListener{
		public void itemStateChanged(ItemEvent e){
			lbl.setText("你选中了："+lst.getSelectedItem());
		}
	}
	static class Handler2 extends WindowAdapter{
		public void windowClosing(WindowEvent e){
			System.exit(0);
		}
	}
	

}

一个简单而容易理解的例子  ，需要注意的是监听设置。