import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;
class JListDemo extends JFrame{
	private JTextArea textArea;
	private JList list;
	private JPanel panel;
	public JListDemo(){
		super("列表框范例");
		Container c=getContentPane();
		c.setLayout(new FlowLayout());
		//創建文本框
		textArea=new JTextArea("你選擇的是：\n",4,15);
		JScrollPane scrollPane1=new JScrollPane(textArea);
		c.add(scrollPane1);
		//創建列表框
		String major[]={"計算機軟件","商務英語","工商管理","建筑工程","國際金融","法律"};
		list=new JList(major);
		list.setVisibleRowCount(4);//設置列表顯示的行數
		JScrollPane scrollPane2=new JScrollPane(list);
		list.addListSelectionListener(new MajorListener());
	    c.add(scrollPane2);
	}
	class MajorListener implements ListSelectionListener{
		public void valueChanged(ListSelectionEvent e){
			int indexMajor=list.getSelectedIndex();//獲取選中條目的索引
			Object majorSelect=list.getSelectedValue();//獲取選中的條目
			String str1=new String(indexMajor+".");
			String str2=(String)majorSelect;
			textArea.setText("你選擇的是：\n"+str1+str2+"\n");
	    }
	}
	public static void main(String args[]){
		JFrame frame=new JListDemo();
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setSize(250,200);
		frame.setVisible(true);
 	}
}