关于安卓开发音乐播放器

[工控小码农zzz]

public void getSongs() {
songs=new ArrayList<Song>();

Cursor cursor=getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
null,null,null,MediaStore.Audio.Media.DEFAULT_SORT_ORDER);

for(i=0;i<cursor.getCount();i++){
Song song=new Song();
cursor.moveToNext();
song.setFilename(cursor.getLong(cursor.getColumnIndex(MediaStore.Audio.Media._ID)));//歌曲ID
song.setTitle(cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.TITLE)));//歌曲名称
song.setFileurl(cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.DATA)));//歌曲路径
song.setTime(cursor.getLong(cursor.getColumnIndex(MediaStore.Audio.Media.DURATION)));//歌曲时长
song.setSize(cursor.getLong(cursor.getColumnIndex(MediaStore.Audio.Media.SIZE)));//歌曲大小
songs.add(song);

}
}
public void show(){
List<HashMap<String,String>> musiclist=new ArrayList<HashMap<String,String>>();
Iterator<Song> iterator=songs.iterator();
while (iterator.hasNext()) {
Song song=iterator.next();
HashMap<String,String> map=new HashMap<String,String>();
map.put("title", song.getTitle());
map.put("singer",song.getSinger());
map.put("fileurl",song.getFileurl());
map.put("time", String.valueOf(song.getTime()));
map.put("size", String.valueOf(song.getSize()));
musiclist.add(map);
}
SimpleAdapter mAdapter=new SimpleAdapter(this, musiclist,R.layout.list_view,new String[]{"title","singer","time"},
new int[]{R.id.musictitle,R.id.musicsinger,R.id.musictime});
musicView.setAdapter(mAdapter);
}
}
为什么这样写 我的安卓虚拟机找不到我导入的音乐文件