3G手机Android应用开发第四天课程2.从网络获取xml格式的视频资讯，我的解析xml出现错误

Question

按照视频中的例子做，出现如下错误：
web项目运行正常，如访问：http://localhost:8088/videoweb/video/list.do
返回的xml为：
<?xml version="1.0" encoding="UTF-8" ?>

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  这些短横线不知道是什么东东。
  android项目是想解析这个xml文件，解析器的代码如下：
  public class VideoService {
  public static List getLastVideos() throws Exception{
  String path = "http://192.168.1.100:8088/videoweb/video/list.do";
  URL url = new URL(path);
  HttpURLConnection conn = (HttpURLConnection)url.openConnection();
  conn.setReadTimeout(5*1000);
  conn.setRequestMethod("GET");
  InputStream inStream = conn.getInputStream();
  byte[] buffer = new byte[1024];
  int len = 0;
  ByteArrayOutputStream bos = new ByteArrayOutputStream();
  while((len=inStream.read(buffer))!=-1){
  bos.write(buffer, 0, len);
  }
  return parseXML(inStream);
  }

  private static List parseXML(InputStream inStream) throws Exception{
  List videos = null;
  Video video = null;
  XmlPullParser parser = Xml.newPullParser();
  parser.setInput(inStream, "UTF-8");
  int eventType = parser.getEventType();//产生第一个事件
  while(eventType!=XmlPullParser.END_DOCUMENT){//只要不是文档结束事件
  switch (eventType) {
  case XmlPullParser.START_DOCUMENT:
  videos = new ArrayList();
  break;

      case XmlPullParser.START_TAG:
          String name = parser.getName();//获取解析器当前指向的元素的名称
          if("video".equals(name)){
              video = new Video();
              video.setId(new Integer(parser.getAttributeValue(0)));
          }
          if(video!=null){
              if("title".equals(name)){
                  video.setTitle(parser.nextText());//获取解析器当前指向元素的下一个文本节点的值
              }
              if("timelength".equals(name)){
                  video.setTime(new Integer(parser.nextText()));
              }
          }
          break;
      case XmlPullParser.END_TAG:
          if("video".equals(parser.getName())){
              videos.add(video);
              video = null;
          }
          break;
      }
      eventType = parser.next();
  }
  return videos;
  

  }
  
  }
  而activity代码如下：
  public class VideoClientActivity extends Activity {
  private ListView listView;
  @Override
  public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);

  listView = (ListView)this.findViewById(R.id.listView);
  try {
      List<Video> videos = VideoService.getLastVideos();
      List<HashMap<String, Object>> data = new ArrayList<HashMap<String,Object>>();
      for(Video video : videos){
          HashMap<String, Object> item = new HashMap<String, Object>();
          item.put("id", video.getId());
          item.put("title", video.getTitle());
          item.put("timelength", "时长:"+ video.getTime());
          data.add(item);
      }
      Log.i("size", videos.size()+"");
      SimpleAdapter adapter = new SimpleAdapter(this, data, R.layout.item, 
              new String[]{"title", "timelength"}, new int[]{R.id.title, R.id.timelength});
      listView.setAdapter(adapter);
  } catch (Exception e) {
      Toast.makeText(VideoClientActivity.this, "获取最新视频资讯失败", 1).show();
      Log.e("VideoClientActivity", e.toString());
  } 
  

  }
  }
  在LogCat中添加一个过滤器：VideoClientActivity，出现的错误是：
  [color=red]11-13 08:14:21.303: ERROR/VideoClientActivity(365): org.xmlpull.v1.XmlPullParserException: Premature end of document. (position:line

-1, column -1) caused by: org.apache.harmony.xml.ExpatParser$ParseException: At line 1, column 0: no element found[/color]
请各位大侠解救。 :(

Answer 1

像<?xml version="1.0" encoding="UTF-8" ?> 这个是版本号和编码格式，xml的编写有一定的格式要求。还有web打开的xml会自动查看你的标签，然后每个小标签出现那种横线。你再仔细看下视频吧，应该介绍得很清楚，不行的话自己多打输出语句，自己调错。