Displaying the List of music files Stored in SD card and playing music in the background

The foolowing example used to list all the music files stored in SDcard and you can play the music
in the backgroung by selecting the file from list.

main.xml
--------
<?xml version="1.0" encoding="utf-8"?>
< LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:orientation="vertical" android:layout_width="fill_parent"
      android:layout_height="fill_parent">
      < ListView
            android:id="@+id/PhoneMusicList"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"/>
</LinearLayout>

MusicActivity.java
-------------------
package sample.music;

import android.app.Activity;
import android.content.Context;
import android.database.Cursor;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.AdapterView.OnItemClickListener;

public class MusicActivity extends Activity {
      ListView musiclist;
      Cursor musiccursor;
      int music_column_index;
      int count;
      MediaPlayer mMediaPlayer;

      /** Called when the activity is first created. */
      @Override
      public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);
            init_phone_music_grid();
      }

      private void init_phone_music_grid() {
            System.gc();
            String[] proj = { MediaStore.Audio.Media._ID,
MediaStore.Audio.Media.DATA,
MediaStore.Audio.Media.DISPLAY_NAME,
MediaStore.Video.Media.SIZE };
            musiccursor = managedQuery(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
proj, null, null, null);
            count = musiccursor.getCount();
            musiclist = (ListView) findViewById(R.id.PhoneMusicList);
            musiclist.setAdapter(new MusicAdapter(getApplicationContext()));

            musiclist.setOnItemClickListener(musicgridlistener);
            mMediaPlayer = new MediaPlayer();
      }

      private OnItemClickListener musicgridlistener = new OnItemClickListener() {
            public void onItemClick(AdapterView parent, View v, int position,
long id) {
                  System.gc();
                  music_column_index = musiccursor
.getColumnIndexOrThrow(MediaStore.Audio.Media.DATA);
                  musiccursor.moveToPosition(position);
                  String filename = musiccursor.getString(music_column_index);

                  try {
                        if (mMediaPlayer.isPlaying()) {
                              mMediaPlayer.reset();
                        }
                        mMediaPlayer.setDataSource(filename);
                        mMediaPlayer.prepare();
                        mMediaPlayer.start();
                  } catch (Exception e) {

                  }
            }
      };

      public class MusicAdapter extends BaseAdapter {
            private Context mContext;

            public MusicAdapter(Context c) {
                  mContext = c;
            }

            public int getCount() {
                  return count;
            }

            public Object getItem(int position) {
                  return position;
            }

            public long getItemId(int position) {
                  return position;
            }

            public View getView(int position, View convertView, ViewGroup parent) {
                  System.gc();
                  TextView tv = new TextView(mContext.getApplicationContext());
                  String id = null;
                  if (convertView == null) {
                        music_column_index = musiccursor
.getColumnIndexOrThrow(MediaStore.Audio.Media.DISPLAY_NAME);
                        musiccursor.moveToPosition(position);
                        id = musiccursor.getString(music_column_index);
                        music_column_index = musiccursor
.getColumnIndexOrThrow(MediaStore.Audio.Media.SIZE);
                        musiccursor.moveToPosition(position);
                        id += " Size(KB):" + musiccursor.getString(music_column_index);
                        tv.setText(id);
                  } else
                        tv = (TextView) convertView;
                  return tv;
            }
      }
}