问题描述

大四安卓学习mars播放器Listview的问题

抱歉麻烦各位了，本人大四狗，目前在看安卓开发，学习mars老师的音乐播放器时遇到了
个问题，就是设置了SimpleAdapter之后仍然无法显示歌名的内容，只显示了个空白的
TEXTVIEW，我研究了无数次依旧没有发现问题在哪，因此来求教各位大神
附上全部代码，没有错误信息，就是显示不出来，每一步调试过确定都有值
代码如下

 package com.example.android_mp3;

import java.io.StringReader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;

import com.download.HttpDownloader;
import com.model.Mp3Info;
import com.xml.Mp3ListContentHandler;

import android.app.ListActivity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ListView;
import android.widget.SimpleAdapter;

public class MainActivity extends ListActivity {

    private static final int UPDATE = 1;
    private static final int ABOUT = 2;
    private List<Mp3Info> mp3Infos = null;

    /*
     * 用户点击menu按钮后调用，可加入自己的按钮控件
     */
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // TODO 自动生成的方法存根
        // 组id，物品id，排序，显示内容
        menu.add(0, UPDATE, 1, R.string.mp3list_update);
        menu.addSubMenu(0, ABOUT, 2, R.string.mp3list_about);
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        new Thread(r).start();
        // updateListView();
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        if (item.getItemId() == UPDATE) {

        }

        else if (item.getItemId() == ABOUT) {
            System.out.println("1");
            // updateListView();

        }
        return super.onOptionsItemSelected(item);
    }

    // public void updateListView() {
    // new Thread(new Runnable() {
    //
    // @Override
    // public void run() {
    // // TODO 自动生成的方法存根
    // String xml = downloadXML("http://192.168.88.100:8080/mp3/resources.xml");
    // System.out.println("XML------>");
    // System.out.println(xml);
    // System.out.println(Thread.currentThread().getName());
    // mp3Infos = parse(xml);
    // Message msg = Message.obtain();
    // msg.sendToTarget();
    // }
    // }) .start();
    // List<HashMap<String, String>> list = new ArrayList<HashMap<String,
    // String>>();
    // for (Iterator iterator = mp3Infos.iterator(); iterator.hasNext();) {
    // Mp3Info mp3Info = (Mp3Info) iterator.next();
    // HashMap<String, String> map = new HashMap<String, String>();
    // map.put("mp3_name", mp3Info.getMp3Name());
    // map.put("mp3_size", mp3Info.getMp3Size());
    // list.add(map);
    // }
    // SimpleAdapter adapter = new SimpleAdapter(this, list,
    // R.layout.mp3info_xml, new String[] { "mp3_name", "mp3_size" },
    // new int[] { R.id.mp3_name, R.id.mp3_size });
    // setListAdapter(adapter);

    // }

    private Handler handler = new Handler() {

        public void handleMessage(Message msg) {
            // 显示列表
            showList();
        }
    };
    Runnable r = new Runnable() {
        public void run() {
            String xml = downloadXML("http://192.168.88.100:8080/mp3/resources.xml");
            System.out.println("XML------>");
            System.out.println(xml);
            // 解析下载的XML文件
            mp3Infos = parse(xml);
            Message msg = handler.obtainMessage();
            msg.sendToTarget();
        }
    };

    public void showList() {
        List<HashMap<String, String>> list = new ArrayList<HashMap<String, String>>();
        for (Iterator iterator = mp3Infos.iterator(); iterator.hasNext();) {
            Mp3Info mp3Info = (Mp3Info) iterator.next();
            HashMap<String, String> map = new HashMap<String, String>();
            map.put("mp3_name", mp3Info.getMp3Name());
            map.put("mp3_size", mp3Info.getMp3Size());
            list.add(map);
        }
        SimpleAdapter simpleAdapter = new SimpleAdapter(MainActivity.this,
                list, R.layout.mp3info_xml,
                new String[] { "mp3Name", "mp3Size" }, new int[] {
                        R.id.mp3_name, R.id.mp3_size });
        setListAdapter(simpleAdapter);
    }

    private String downloadXML(String urlString) {

        HttpDownloader httpDownloader = new HttpDownloader();
        String result = httpDownloader.download(urlString);
        return result;
    }

    private List<Mp3Info> parse(String xmlStr) {
        SAXParserFactory saxParserFactory = SAXParserFactory.newInstance();
        List<Mp3Info> infos = new ArrayList<Mp3Info>();
        try {
            XMLReader xmlReader = saxParserFactory.newSAXParser()
                    .getXMLReader();
            Mp3ListContentHandler mp3ListContentHandler = new Mp3ListContentHandler(
                    infos);
            xmlReader.setContentHandler(mp3ListContentHandler);
            xmlReader.parse(new InputSource(new StringReader(xmlStr)));
            for (Iterator iterator = infos.iterator(); iterator.hasNext();) {
                Mp3Info mp3Info = (Mp3Info) iterator.next();
                System.out.println(mp3Info);
            }

        } catch (SAXException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        } catch (Exception e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
        return infos;
    }

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

//      Mp3Info mp3Info = mp3Infos.get(position);
//      System.out.println("----->mp3info" + mp3Info);
        super.onListItemClick(l, v, position, id);
    }

}

xml的

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:paddingBottom="1dip"
    android:paddingLeft="10dip"
    android:paddingRight="10dip"
    android:paddingTop="1dip">

    <TextView
        android:id="@+id/mp3_name"
        android:layout_width="180dip"
        android:layout_height="30dip"
        android:textSize="10pt"
         />
    <TextView
        android:id="@+id/mp3_size"
        android:layout_width="180dip"
        android:layout_height="30dip"
        android:textSize="10pt"
         />

</LinearLayout>

调试的是有值的
啊啊啊啊啊啊弄了好久啊，谁知道什么问题的帮帮我啊

解决方案

你的代码贴全了吗?

  for (Iterator iterator = mp3Infos.iterator(); iterator.hasNext();

mp3Infos 是什么？是音乐数据的集合吗？把错误贴出来看看

解决方案二：

只用一个引用试试，在上面HashMap map=null;
下面map=new HashMap