网络请求xml PULL解析

package com.example.administrator.litong20160905;

import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.Toast;
import com.example.administrator.litong20160905.adapter.MyAdapter;
import com.example.administrator.litong20160905.bean.Listxinxi;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlPullParserFactory;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private LinearLayout ll;
    private ListView lv;
    private Listxinxi xinxi;
    private MyAdapter myadapter;
    private String url="http://172.17.29.120/localuser/loupengfei/kaoshi/student.XML";
    private Handler handler=new Handler(){
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what){
                case 0:
                    List<Listxinxi> listxin= (List<Listxinxi>) msg.obj;
                    //Toast.makeText(MainActivity.this,listxin.toString(),Toast.LENGTH_SHORT).show();
                    myadapter=new MyAdapter(listxin,MainActivity.this);
                    lv.setAdapter(myadapter);
                    myadapter.notifyDataSetChanged();
                    break;
                default:
                    break;
            }
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        /*ll= (LinearLayout) findViewById(R.id.ll);
        Yuan yuan=new Yuan(MainActivity.this);
        ll.addView(yuan);*/
        getid(url);
        lv= (ListView) findViewById(R.id.lv);
    }
    private void getid(final String urll) {
        new Thread(){
            @Override
            public void run() {
                try {
                    URL url=new URL(urll);
                    HttpURLConnection connection= (HttpURLConnection) url.openConnection();
                    connection.setReadTimeout(5000);
                    connection.setConnectTimeout(5000);
                    connection.setRequestMethod("GET");
                    int code=connection.getResponseCode();
                    if(code==200){
                        InputStream is=connection.getInputStream();
                        List<Listxinxi> listxin=tojson(is);
                        Message message=new Message();
                        message.what=0;
                        message.obj=listxin;
                        handler.sendMessage(message);
                    }
                } catch (MalformedURLException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }.start();
    }

    private List<Listxinxi> tojson(InputStream str){
        List<Listxinxi> listxinxis = null;
        try {
            XmlPullParserFactory factory =XmlPullParserFactory.newInstance();
            XmlPullParser parser = factory.newPullParser();
            parser.setInput(str,"utf-8");
            //类型判断
            int eventType = parser.getEventType();
            while(eventType!=XmlPullParser.END_DOCUMENT){
                String name = parser.getName();
                switch (eventType){
                    case XmlPullParser.START_DOCUMENT:
                        listxinxis=new ArrayList<>();
                        break;
                    case XmlPullParser.START_TAG:
                        if("student".equals(name)){
                            xinxi=new Listxinxi();
                            xinxi.setXuehao(parser.getAttributeValue(0));
                        }else if("name".equals(name)){
                            xinxi.setName(parser.nextText());
                        }else if("address".equals(name)){
                            xinxi.setAddress(parser.nextText());
                        }else if("phone".equals(name)){
                            xinxi.setPhone(parser.nextText());
                        }else if("tel".equals(name)){
                            xinxi.setTel(parser.nextText());
                        }
                        break;
                    case XmlPullParser.END_TAG:
                        if(name.equals("student")) {
                            listxinxis.add(xinxi);
                        }
                        break;
                }
                eventType=parser.next();
            }
        } catch (XmlPullParserException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return listxinxis;
    }
}