I have the following code through which i am able to retrieve phone numbers. Somehow , i am not able to retrieve email addresses by using android.provider.Contacts.People API. Any ideas?

import android.app.AlertDialog;
import android.app.ExpandableListActivity;
import android.content.ContentUris;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.Contacts.People;
import android.view.View;
import android.widget.ExpandableListAdapter;
import android.widget.SimpleCursorTreeAdapter;
import android.widget.TextView;
import android.widget.ExpandableListView.OnChildClickListener;

public class ShowContacts extends ExpandableListActivity implements OnChildClickListener {
    private int mGroupIdColumnIndex; 

    private String mPhoneNumberProjection[] = new String[] { 
            People.Phones._ID, People.NUMBER // CHANGE HERE 
    }; 


    private ExpandableListAdapter mAdapter; 


    @Override 
    public void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 


        // Query for people 
        Cursor groupCursor = managedQuery(People.CONTENT_URI, 
                new String[] {People._ID, People.NAME}, null, null, null); 

        // Cache the ID column index 
        mGroupIdColumnIndex = groupCursor.getColumnIndexOrThrow(People._ID); 

        // Set up our adapter 
        mAdapter = new MyExpandableListAdapter(groupCursor, 
                this, 
                android.R.layout.simple_expandable_list_item_1, 
                android.R.layout.simple_expandable_list_item_1, 
                new String[] {People.NAME}, // Name for group layouts 
                new int[] {android.R.id.text1}, 
                new String[] {People.NUMBER}, // AND CHANGE HERE 
                new int[] {android.R.id.text1}); 
        setListAdapter(mAdapter); 
    } 

    public class MyExpandableListAdapter extends SimpleCursorTreeAdapter { 

        public MyExpandableListAdapter(Cursor cursor, Context context, int groupLayout, 
                int childLayout, String[] groupFrom, int[] groupTo, String[] childrenFrom,
                int[] childrenTo) { 
            super(context, cursor, groupLayout, groupFrom, groupTo, childLayout, childrenFrom, 
                    childrenTo); 
        } 

        @Override 
        protected Cursor getChildrenCursor(Cursor groupCursor) { 
            // Given the group, we return a cursor for all the children within that group 

            // Return a cursor that points to this contact's phone numbers 
            Uri.Builder builder = People.CONTENT_URI.buildUpon();

            ContentUris.appendId(builder, groupCursor.getLong(mGroupIdColumnIndex)); 
            builder.appendEncodedPath(People.Phones.CONTENT_DIRECTORY); 
            Uri phoneNumbersUri = builder.build(); 

            return managedQuery(phoneNumbersUri, mPhoneNumberProjection, null, null, null); 
        } 
    } 

    @Override 
     public boolean onChildClick(android.widget.ExpandableListView parent, 
               View v, int groupPosition, int childPosition, long id) { 
          AlertDialog dialog = new AlertDialog.Builder(ShowContacts.this) 
                    .setMessage(((TextView) v).getText().toString()) 
                    .setPositiveButton("OK", null).create(); 
          dialog.show(); 
          return true; 
     } 
}