Android音乐播放器-播放列表之兑现

Android音乐播放器--播放列表之实现
  经过一上午的时间，播放列表算是初步搞定了，不过一定还有很多Bug要慢慢解决，下面是代码，希望大家指出不足和错误。。（我没有用到mediaStore多媒体数据库，算是最大的不足，只是用自己建的数据库，来保存歌曲的地址）

public class DBService {public static void save(String name,Context context){          //把歌曲添加到数据库MusicDBOpenHelper helper=new MusicDBOpenHelper(context);SQLiteDatabase db=helper.getReadableDatabase();db.execSQL("insert into music(music_name)values(?)",new Object[]{name});db.close();} public static List<Music> findAll(Context context){            //查找出数据库中的所有列表List<Music> musics =new ArrayList<Music>();MusicDBOpenHelper helper=new MusicDBOpenHelper(context);SQLiteDatabase db=helper.getReadableDatabase();Cursor  cursor=db.rawQuery("select * from music", null);while(cursor.moveToNext()){Music music=new Music();music.setId(cursor.getInt(0));music.setMusicName(cursor.getString(1));musics.add(music);}return musics;} }

public class MusicDBOpenHelper extends SQLiteOpenHelper {private static final String name="musics";private static final int version=1;public MusicDBOpenHelper(Context context) {super(context, name, null, version);// TODO Auto-generated constructor stub}@Overridepublic void onCreate(SQLiteDatabase db) {// TODO Auto-generated method stubdb.execSQL("create table IF NOT EXISTS  music (id integer primary key autoincrement,music_name char(20))");}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {// TODO Auto-generated method stubdb.execSQL("drop table IF EXISTS  student");onCreate(db);}}

 public void addList()                      //把数据库中的音乐信息加入播放列表。  {  List<Music> musics =new ArrayList<Music>();  musics=DBService.findAll(MusicPalyerActivity.this);  List<HashMap<String,String>> data=new ArrayList<HashMap<String,String>>();    for(Music music:musics){  HashMap<String,String> map=new HashMap<String,String>();  map.put("id",String.valueOf(music.getId()));          map.put("music_name", music.getMusicName());          data.add(map);  }    SimpleAdapter adapter=new SimpleAdapter(MusicPalyerActivity.this, data, R.layout.music_items, new String[]{"id","music_name"}, new int[]{R.id.musicId,R.id.musicName});     listView.setAdapter(adapter);      listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {@Overridepublic void onItemClick(AdapterView<?> parent, View view,int position, long id) {ListView listView=(ListView)parent;HashMap<String,String>  map=(HashMap<String,String>)listView.getItemAtPosition(position);playMusic(map.get("music_name"));           //播放单击选择的歌曲}        });    }