<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

     @Override

     protected void onListItemClick(ListView l, View v, int position, long id) {

         //根据用户点击列表当中的位置来得到响应的Mp3Info对象

         Mp3Info info = infos.get(position);

         //生成Intent对象

         Intent intent = new Intent();

         //将Mp3Info对象存入到Intent对象当中

         intent.putExtra("mp3Info", info);

         intent.setClass(this, DownloadService.class);

         //启动Service

         startService(intent);

         super.onListItemClick(l, v, position, id);

     }

 package tony.mp3player.service;

 import tony.download.HttpDownloader;

 import tony.model.Mp3Info;

 import android.app.Service;

 import android.content.Intent;

 import android.os.IBinder;

 public class DownloadService extends Service{

     @Override

     public IBinder onBind(Intent intent) {

         return null;

     }

     //每次用户点击ListActivity当中的一个条目时，就会调用该方法

     @Override

     public int onStartCommand(Intent intent, int flags, int startId) {

         //从Intent对象当中将Mp3Info对象取出

         Mp3Info info = (Mp3Info) intent.getSerializableExtra("mp3Info");

         //生成一个下载线程，并将Mp3Info对象作为参数传递到线程对象当中

         DownloadThread thread = new DownloadThread(info);

         //启动新线程

         new Thread(thread).start();

         return super.onStartCommand(intent, flags, startId);

     }

     class DownloadThread implements Runnable {

         private Mp3Info info;

         public DownloadThread(Mp3Info info) {

             super();

             this.info = info;

         }

         @Override

         public void run() {

             //根据MP3文件的名字，生成下载地址

             String urlStr = "http://192.168.1.104:8080/mp3/" + info.getMp3Name();

             HttpDownloader downloader = new HttpDownloader();

             int result = downloader.downFile(urlStr, "mp3", info.getMp3Name());

             String msg = null;

             switch (result) {

             // -1：代表下载文件出错 0：代表下载文件成功 1：代表文件已经存在

             case -1:

                 msg = "下载失败";break;

             case 0:

                 msg = "文件下载成功";break;

             case 1:

                 msg = "文件已经存在，不需要重复下载";break;

             }

             //使用Notification提示客户下载结果

         }

     }

 }