مشکل این کد مدیا پلیر چی هست ؟

 public class Main extends Activity implements View.OnClickListener {

    MediaPlayer mp;
    ListView    lv;
    String[]    items;


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        lv = (ListView) findViewById(R.id.lvPlayList);
        final ArrayList<File> mySongs = findSongs(Environment.getExternalStorageDirectory());
        items = new String[mySongs.size()];
        for (int i = 0; i < mySongs.size(); i++) {
            //Toast.makeText(getApplicationContext(), mySongs.get(i).getName().toString(), Toast.LENGTH_SHORT).show();
            items[i] = mySongs.get(i).getName().toString();
        }
        ArrayAdapter<String> adp = new ArrayAdapter<String>(getApplicationContext(), R.layout.song_layout, R.id.textView1, items);
        lv.setAdapter(adp);
        mp = new MediaPlayer();

        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> arg0, View arg1, int position, long arg3) {
                // Uri u = Uri.parse(mySongs.get(position).toString());
                // mp = MediaPlayer.create(getApplicationContext(), u);
                startActivity(new Intent(getApplicationContext(), player.class).putExtra("pos", position).putExtra("songList", mySongs));
            }
        });

    }


    public ArrayList<File> findSongs(File root) {
        ArrayList<File> al = new ArrayList<File>();
        File[] files = root.listFiles();
        for (File singleFile: files) {
            if (singleFile.isDirectory() && !singleFile.isHidden()) {
                al.addAll(findSongs(singleFile));
            } else {
                if (singleFile.getName().endsWith(".mp3")) {
                    al.add(singleFile);
                }
            }
        }
        return al;
    }


    @Override
    public void onClick(View arg0) {
        // TODO Auto-generated method stub

    }

}

 public class player extends Activity implements View.OnClickListener {

    MediaPlayer     mp;
    ArrayList<File> mySongs;
    SeekBar         sb;
    Button          btPlaye, btFF, btFB, btNext, btPre;
    int             position;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.player);
        btPlaye = (Button) findViewById(R.id.btPlay);
        btFF = (Button) findViewById(R.id.btFF);
        btFB = (Button) findViewById(R.id.btFB);
        btNext = (Button) findViewById(R.id.btNext);
        btPre = (Button) findViewById(R.id.btPre);
        Intent i = getIntent();
        Bundle b = i.getExtras();
        mySongs = (ArrayList) b.getParcelableArrayList("songList");
        position = b.getInt("pos", 0);
        Uri u = Uri.parse(mySongs.get(position).toString());
        mp = MediaPlayer.create(getApplicationContext(), u);

    }


    @Override
    public void onClick(View v) {
        int id = v.getId();
        switch (id) {
            case R.id.btPlay:
                Uri u = Uri.parse(mySongs.get(position).toString());
                mp = MediaPlayer.create(getApplicationContext(), u);
                mp.start();
                break;

        }
    }
}