listtest.java

《Java程序设计与应用》-张仕斌-源程序 《Java程序设计与应用》-张仕斌-源程序

//ListTest.java
import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;

public class ListTest extends JFrame implements ListSelectionListener {
	String [] teams = {"德国" , "巴西" , "英格兰" , "法国" , 
										"阿根廷" , "荷兰" , "西班牙", "意大利"};
	JList lstTeams;
	JLabel lblPrompt , lblResult;
	
	public ListTest() {
		super("JList Test");
		
		lstTeams = new JList(teams);  //用数组元素创建列表框
		Container cp = this.getContentPane();
		JScrollPane sp = new JScrollPane(lstTeams);  //把列表框放到滚动面板中
		
		lblPrompt = new JLabel("你认为哪个国家将获得世界杯?");
		lblResult = new JLabel("你还没拿定主意");
		
		cp.add(lblPrompt , BorderLayout.NORTH);  //提示标签加到上面
		cp.add(lblResult , BorderLayout.SOUTH);  //结果标签加到下面
		cp.add(sp , BorderLayout.CENTER);        //列表框在滚动面板上
		
		/*设为单选*/
		lstTeams.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
		lstTeams.addListSelectionListener(this);  //添加监听
	}
	
	/*处理事件事件*/
	public void valueChanged(ListSelectionEvent e) {
		if (lstTeams.getSelectedIndex() != -1){   //选中
			lblResult.setText("你认为是:" + lstTeams.getSelectedValue());
		} else {                                  //未选中
			lblResult.setText("你还没拿定主意.");
		}
	}
	
	public static void main(String[]args) {
		ListTest lt = new ListTest();
		lt.setSize(400,180);
		lt.setDefaultCloseOperation(EXIT_ON_CLOSE);
		lt.setVisible(true);
	}
}