Muchas gracias!
Activity_Main.xml
Código PHP:
   <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
 
    <ExpandableListView
        android:id="@+id/expandableListView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true" >
    </ExpandableListView>
 
</RelativeLayout> 
    AdpLv.java
Código PHP:
   package com.akiba.ioweu;
 
import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;
 
public class AdpLv extends BaseExpandableListAdapter {
private Context context;
 
String[]parentList={"Diego","Pablo","Juan","Pito","Pete"};
String[][]childList={
        {
            "Diego1"
        },
        {
            "Pablo1"
        },
        {
            "Juan1"
        },
        {
            "Pito1"
        },
        {
            "Pete1"
        },
};
 
 
    public AdpLv(Context context) {
        // TODO Auto-generated constructor stub
        this.context=context;
    }
 
    public Object getChild(int groupPosition, int childPosition) {
        // TODO Auto-generated method stub
        return null;
    }
 
    public long getChildId(int groupPosition, int childPosition) {
        // TODO Auto-generated method stub
        return 0;
    }
 
    public View getChildView(int groupPosition, int childPosition,
            boolean isLastChild, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
        TextView tv = new TextView(context);
        tv.setText(childList[groupPosition][childPosition]);
        return tv;
    }
 
    public int getChildrenCount(int groupPosition) {
        // TODO Auto-generated method stub
        return childList[groupPosition].length;
    }
 
    public Object getGroup(int groupPosition) {
        // TODO Auto-generated method stub
        return groupPosition;
    }
 
    public int getGroupCount() {
        // TODO Auto-generated method stub
        return parentList.length;
    }
 
    public long getGroupId(int groupPosition) {
        // TODO Auto-generated method stub
        return groupPosition;
    }
 
    public View getGroupView(int groupPosition, boolean isExpanded,
            View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
        TextView tv = new TextView(context);
        tv.setText(parentList[groupPosition]);
        return tv;
    }
 
    public boolean hasStableIds() {
        // TODO Auto-generated method stub
        return false;
    }
 
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        // TODO Auto-generated method stub
        return true;
    }
 
} 
    Código PHP:
   package com.akiba.ioweu;
 
import android.os.Bundle;
import android.app.Activity;
import android.app.AlertDialog;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.view.Menu;
import android.widget.ExpandableListView;
 
 
public class MainActivity extends Activity {
    private ExpandableListView lv;
    
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
                
        SQLiteDatabase db = openOrCreateDatabase("iOweU",MODE_PRIVATE,null);
 
        try {
        /*esto hay que sacarlo, lo pongo solamente para ir editando las tablas*/
        db.execSQL("DROP TABLE IF EXISTS People;");
        db.execSQL("DROP TABLE IF EXISTS Loans;");
        
        
            db.execSQL("CREATE TABLE IF NOT EXISTS People (PeopleID  int(5)," +
                    "                                       LastName  varchar, " +
                    "                                       FirstName varchar, " +
                    "                                       Mail      varchar);");
            
            db.execSQL("CREATE TABLE IF NOT EXISTS Loans (PeopleID  int(5)," +
                    "                                      AmountIN  decimal(6,5)," +
                    "                                      AmountOUT decimal(6,5)," +
                    "                                      Interest  decimal(6,5));");
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            AlertDialog alertDialog;
            alertDialog = new AlertDialog.Builder(this).create();
            alertDialog.setTitle("Error al crear las tablas");
            alertDialog.setMessage("Huvo un error al momento de crear las tablas.");
            alertDialog.show();
        }
        
        lv = (ExpandableListView)findViewById(R.id.expandableListView1);
        lv.setAdapter(new AdpLv(this));
        
        db.close();
    }
 
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }
} 
    
 

