Android&读取Sdcard中的歌曲，ListView操作

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout    android:layout_width="fill_parent" 
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    xmlns:android="http://schemas.android.com/apk/res/android">
    <ImageView    android:id="@+id/img"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />
    <LinearLayout    android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical">
            <TextView    android:id="@+id/title"
                android:layout_width="170px"
                android:layout_height="wrap_content"
                />
            <TextView    android:id="@+id/artist"
                android:layout_width="wrap_content"
                android:layout_height="150px"
                />
        <TextView     android:id="@+id/album"
                android:layout_width="wrap_content"
                android:layout_height="150px"
                />
    </LinearLayout>"
</LinearLayout>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity"
    android:orientation="vertical" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="歌曲列表" />
    <ListView    android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/musiclist"/>
</LinearLayout>

package com.zachary.simpleadapter;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.provider.MediaStore;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;

import com.zachary.mediaplayer.MediaPlayerService;

public class MainActivity extends Activity {
    private HashMap<String, MusicInfo> MusicInfos;
    private ListView MusicList;
    final static String TAG = "LOGCAT";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        MusicInfos = new HashMap<String, MusicInfo>();
        MusicList = (ListView)findViewById(R.id.musiclist);
        Log.i(TAG, "begin to showList");
        showList();
        MusicList.setOnItemClickListener(
                new OnItemClickListener() {

                    @Override
                    public void onItemClick(AdapterView<?> arg0, View arg1,
                            int arg2, long arg3) {
                        Log.i(TAG, "MusicList onItemClickListener");
                        String title = ((TextView)arg1.findViewById(R.id.title)).getText().toString();
                        Log.i(TAG, title);
                        MusicInfo nowSong = MusicInfos.get(title);
                        String path = nowSong.getUrl();
                        Log.i(TAG, path);
                            
                        Intent    intent = new Intent(MainActivity.this, MediaPlayerService.class);
                        intent.putExtra("path", path);
                        MainActivity.this.startService(intent);
                    }    
                }
                    
                );
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    
    public void showList(){
        Cursor mAudioCursor = this.getContentResolver().query(
                MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
                null,
                null,
                null,
                MediaStore.Audio.AudioColumns.TITLE);
        List<Map<String,Object>> mListData = new ArrayList<Map<String, Object>>();
        for(int i=0; i<mAudioCursor.getCount(); i++) {
            mAudioCursor.moveToNext();
            MusicInfo mi = new MusicInfo( mAudioCursor.getString(mAudioCursor.getColumnIndex(MediaStore.Audio.AudioColumns.TITLE)),
                    mAudioCursor.getString(mAudioCursor.getColumnIndex(MediaStore.Audio.AudioColumns.ARTIST)),
                    mAudioCursor.getString(mAudioCursor.getColumnIndex(MediaStore.Audio.AudioColumns.ALBUM)),
                    mAudioCursor.getString(mAudioCursor.getColumnIndex(MediaStore.Audio.AudioColumns.DATA))
                    );
            HashMap<String, Object> nowMap = new HashMap<String, Object>();
            nowMap.put("img",R.drawable.ic_launcher );
            nowMap.put("title", mi.getTitle());
            nowMap.put("artist", mi.getArtist());
            nowMap.put("album", mi.getAlbum());
            mListData.add(nowMap);
            MusicInfos.put(mi.getTitle(),mi);
        }
        SimpleAdapter musicSA = new SimpleAdapter(
                this, 
                mListData,
                R.layout.music,
                new String[]{"img", "title", "artist", "album"},
                new int[] {R.id.img, R.id.title, R.id.artist, R.id.album}
                );
        MusicList.setAdapter(musicSA);
    }
}

package com.zachary.simpleadapter;

/**
 * @author Zachary
 *
 */
public class MusicInfo {
    private String title;
    private String artist;
    private String album;
    private String url;
    public MusicInfo(String title,  String artist, String album, String url){
        this.title = title;
        this.artist =artist;
        this.album = album;
        this.url = url;
    }
    
    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }
    
    public String getArtist() {
        return artist;
    }
    public void setArtist(String artist) {
        this.artist = artist;
    }
    public String getAlbum() {
        return album;
    }
    public void setAlbum(String album) {
        this.album = album;
    }
    public String getUrl() {
        return url;
    }
    public void setUrl(String url) {
        this.url = url;
    }
    
    @Override
    public String toString() {
        return "MusicInfo [title=" + title  + ", artist="
                + artist + ", album=" + album +", url=" + url +", getClass()=" + getClass()
                + "]";
    }
    
}

package com.zachary.mediaplayer;

import android.app.Service;
import android.content.Intent;
import android.media.MediaPlayer;
import android.net.Uri;
import android.os.IBinder;
import android.util.Log;
import android.widget.Toast;

public class MediaPlayerService extends Service {

    private static final String TAG = "Media Player Service";
    private MediaPlayer player = null;
    @Override
    public IBinder onBind(Intent arg0) {
        // TODO Auto-generated method stub
        return null;
    }
    
    @Override
    public void onCreate() {
        Toast.makeText(this, "MediaPlayerService Created", Toast.LENGTH_LONG).show();
        Log.i(TAG, "onCreate");
        System.out.println("onCreate");
    }
    
    @Override
    public void onStart(Intent intent, int startId) {
        Toast.makeText(this, "MediaPlayerService Start", Toast.LENGTH_LONG).show();
        
        String path = intent.getStringExtra("path");
    
            Log.i(TAG, "onStart");
            System.out.println("onStart");
            Log.i(TAG, path);
            System.out.println(path);
            Uri playerUri = Uri.parse(path);
            if (player != null) { 
                player.stop(); 
            } 
            player = MediaPlayer.create(MediaPlayerService.this, playerUri);
            player.start();
    }
    
    @Override
    public void onDestroy() {
        super.onDestroy();
        Toast.makeText(this, "MediaPlayerService Stoped", Toast.LENGTH_LONG).show();
        Log.i(TAG, "onDestory");
        System.out.println("onDestory");
        if(player != null) {
        player.release();
        player = null;
        }
    }

}