请帮忙看看，pull 方法解析xml文件 为什么打印不出来结果？错在哪了

[MrCG]

package com.example.pullxml;

import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

import org.xmlpull.v1.XmlPullParser;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.util.Xml;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity implements OnClickListener {
  private Button request;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        request=(Button) findViewById(R.id.send_request);
        request.setOnClickListener(this);
    }

	@Override
	public void onClick(View v) {
		// TODO Auto-generated method stub
	if(v.getId()==R.id.send_request){	
		this.sendRequestWithHttpURLConnection();		
	}
	}

	private void sendRequestWithHttpURLConnection(){
		//开启线程发起网络请求
		new Thread(new Runnable(){

			@Override
			public void run() {
				// TODO Auto-generated method stub
				//实例化
				HttpURLConnection connection=null;
				try {
				
					URL url=new URL("http://10.0.2.2/get_data.xml");
					connection=(HttpURLConnection) url.openConnection();//获取开放连接的实例
					connection.connect();// 进行连接，但是实际上get request要在下一句的 connection.getInputStream()函数中才会真正发到  
			        // 服务器  
					connection.setRequestMethod("GET");
					connection.setConnectTimeout(8000);//设置连接超时
					connection.setReadTimeout(8000);//设置读取超时	
					  //发送http GET请求，获取相应码 
	                     InputStream in = connection.getInputStream();  
	                   	 Log.v("tag", "ok");
	                        //使用pull解析器，解析这个流  
	                        parseXMLWithPull(in);  
		           } 
				catch (Exception e) {
						// TODO: handle exception
					e.printStackTrace();
							
				}
				finally{
					if(connection !=null){
						connection.disconnect();//关闭连接
					}
				}
			}			
		}).start();
		}
	private void parseXMLWithPull(InputStream in) {
		XmlPullParser xmlPullParser = Xml.newPullParser();
		
		try {
			xmlPullParser.setInput(in,"utf-8");
			
			 //对节点的事件类型进行判断，就可以知道当前节点是什么节点 
			int eventType = xmlPullParser.getEventType();
			String id = "";
			String name = "";
			String version = "";
			while (eventType != XmlPullParser.END_DOCUMENT) {
				String nodeName = xmlPullParser.getName();
				switch (eventType) {
				// 开始解析某个结点
				case XmlPullParser.START_TAG: {
					
					if ("id".equals(nodeName)) {
						id = xmlPullParser.nextText();
					} else if ("name".equals(nodeName)) {
						name = xmlPullParser.nextText();
					} else if ("version".equals(nodeName)) {
						version = xmlPullParser.nextText();
					}
					break;
				}
				// 完成解析某个结点
				case XmlPullParser.END_TAG: {
					if ("app".equals(nodeName)) {
						 Log.v("tag", "ok");
						Log.d("MainActivity", "id is " + id);
						Log.d("MainActivity", "name is " + name);
						Log.d("MainActivity", "version is " + version);
					}
					break;
				}
				default:
					break;
				}
				eventType = xmlPullParser.next();
			}			
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}