Cursor positioning problem

LogCat is experiencing a problem with NullPointerException , but I can not identify it. In my point of view, that's right. I know that there is a problem in lines 34 and 39 of ContactRegister that lead to condition if(moveToFirst()) in ContactRepository , but I can not understand what the error is. Could it be a cursor positioning problem?

 E/AndroidRuntime(914): FATAL EXCEPTION: main
 E/AndroidRuntime(914): Process: br.com.contactsmanager, PID: 914
 E/AndroidRuntime(914): java.lang.RuntimeException: Unable to start activity ComponentInfo{br.com.contactsmanager/br.com.contactsmanager.ContactRegister}: java.lang.NullPointerException
 E/AndroidRuntime(914): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2176)
 E/AndroidRuntime(914): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2226)
 E/AndroidRuntime(914): at android.app.ActivityThread.access$700(ActivityThread.java:135)
 E/AndroidRuntime(914): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1397)
 E/AndroidRuntime(914): at android.os.Handler.dispatchMessage(Handler.java:102)
 E/AndroidRuntime(914): at android.os.Looper.loop(Looper.java:137)
 E/AndroidRuntime(914): at android.app.ActivityThread.main(ActivityThread.java:4998)
 E/AndroidRuntime(914): at java.lang.reflect.Method.invokeNative(Native Method)
 E/AndroidRuntime(914): at java.lang.reflect.Method.invoke(Method.java:515)
 E/AndroidRuntime(914): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
 E/AndroidRuntime(914): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593)
 E/AndroidRuntime(914): at dalvik.system.NativeStart.main(Native Method)
 E/AndroidRuntime(914): Caused by: java.lang.NullPointerException
 E/AndroidRuntime(914): at br.com.contactsmanager.ContactRepository.listContacts(ContactRepository.java:175)
 E/AndroidRuntime(914): at br.com.contactsmanager.ContactRegister.updateList(ContactRegister.java:39)
 E/AndroidRuntime(914): at br.com.contactsmanager.ContactRegister.onCreate(ContactRegister.java:34)
 E/AndroidRuntime(914): at android.app.Activity.performCreate(Activity.java:5243)
 E/AndroidRuntime(914): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
 E/AndroidRuntime(914): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2140)
 E/AndroidRuntime(914):     ... 11 more

Finally, they follow the ContactRepository and ContactRegister codes.

The project is a calendar of contacts synchronized with that of Android, which will serve as the basis for an application to be developed. I'm new to object-oriented programming.

ContactRepository.java

package br.com.contactsmanager;

import java.util.ArrayList;
import java.util.List;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteQueryBuilder;
import android.util.Log;
import br.com.contactsmanager.Contact.Contacts;

public class ContactRepository {

    private static final String CATEGORY = "data";

    private static final String DB_NAME = "android_data";

    public static final String TABLE_NAME = "contact";

    protected SQLiteDatabase db;

    public ContactRepository(Context ctx) 
    {

        db = ctx.openOrCreateDatabase(DB_NAME, Context.MODE_PRIVATE, null);

    }

    protected ContactRepository() 
    {

    }

    public long save(Contact contact) 
    {
        long id = contact.id1;

        if (id != 0) {
            update(contact);
        }
        else
        {

            id = insert(contact);
        }

        return id;
    }

    // Insere uma nova pessoa   
    public long insert(Contact contact)
    {
        ContentValues values = new ContentValues();
        values.put(Contacts.NAME, contact.name1);
        values.put(Contacts.LASTNAME, contact.name2);
        values.put(Contacts.PHONE, contact.phone1);

        long id = insert(values);
        return id;
    }

    // Insere uma nova pessoa
    public long insert(ContentValues values)
    {
        long id = db.insert(TABLE_NAME, "", values);
        return id;
    }

    // Atualiza a pessoa no banco. O id da pessoa é utilizado.
    public int update(Contact contact) 
    {
        ContentValues values = new ContentValues();
        values.put(Contacts.NAME, contact.name1);
        values.put(Contacts.LASTNAME, contact.name2);
        values.put(Contacts.PHONE, contact.phone1);

        String _id = String.valueOf(contact.id1);

        String where = Contacts._ID + "=?";
        String[] whereArgs = new String[] { _id };

        int count = update(values, where, whereArgs);

        return count;

    }

    // Atualiza a pessoa com os valores abaixo
    // A cláusula where é utilizada para identificar a pessoa a ser atualizado
    public int update(ContentValues values, String where, String[] whereArgs) 
    {
        int count = db.update(TABLE_NAME, values, where, whereArgs);
        Log.i(CATEGORY, "Updated [" + count + "] registers");
        return count;
    }

    // Deleta a pessoa com o id fornecido
    public int delete(long id) {
        String where = Contacts._ID + "=?";

        String _id = String.valueOf(id);
        String[] whereArgs = new String[] { _id };

        int count = delete(where, whereArgs);

        return count;
    }

    // Deleta a pessoa com os argumentos fornecidos
    public int delete(String where, String[] whereArgs) {
        int count = db.delete(TABLE_NAME, where, whereArgs);
        Log.i(CATEGORY, "Has deleted [" + count + "] registers");
        return count;
    }

    // Busca a pessoa pelo id
    public Contact searchContact(long id) 
    {
        // select * from pessoa where _id=?
        Cursor c = db.query(true, TABLE_NAME, Contact.columns, Contacts._ID + "=" + id, null, null, null, null, null);

        c.moveToFirst ();

        if (c.getCount() > 0) {

            // Posiciona no primeiro elemento do cursor
            //c.moveToFirst ();

            Contact contact = new Contact();

            // Lê os dados
            contact.id1 = c.getLong(0);
            contact.name1 = c.getString(1);
            contact.name2 = c.getString(2);
            contact.phone1 = c.getInt(3);

            return contact;
        }

        return null;
    }

    // Retorna um cursor com todas as pessoas
    public Cursor getCursor() 
    {
        try {
            // select * from pessoas
            return db.query(TABLE_NAME, Contact.columns, Contacts.NAME, null, null, null, null, null); 
        } 
        catch (SQLException e)
        {
            Log.e(CATEGORY, "Error while searching contacts: " + e.toString());
            e.printStackTrace();
            return null;
        }
    }

    // Retorna uma lista com todas as pessoas
    public List<Contact> listContacts() 
        {
        Cursor c = getCursor();

        List<Contact> contacts = new ArrayList<Contact>();

        if ( c.moveToFirst() )
        {

            // Recupera os índices das colunas
            int idxId = c.getColumnIndex(Contacts._ID);
            int idxFirstName = c.getColumnIndex(Contacts.NAME);
            int idxLastName = c.getColumnIndex(Contacts.LASTNAME);
            int idxPhone = c.getColumnIndex(Contacts.PHONE);

            // Loop até o final
            do 
            {
                Contact contact = new Contact();
                contacts.add(contact);

                // recupera os atributos da pessoa
                contact.id1 = c.getLong(idxId);
                contact.name1 = c.getString(idxFirstName);
                contact.name2 = c.getString(idxLastName);
                contact.phone1 = c.getInt(idxPhone);

            } 
            while ( c.moveToNext() );
        }

        return contacts;
    }

    // Busca a pessoa pelo nome "select * from pessoa where nome=?"
    public Contact searchContactByName(String name1) {
        Contact contact = null;

        try {
            // Idem a: SELECT _id,nome,cpf,idade from pessoa where nome = ?
            Cursor c = db.query(TABLE_NAME, Contact.columns, Contacts.NAME + "='" + name1 + "'", null, null, null, null);

            // Se encontrou...
            if (c.moveToNext()) {

                contact = new Contact();

                // utiliza os métodos getLong(), getString(), getInt(), etc para recuperar os valores
                contact.id1 = c.getLong(0);
                contact.name1 = c.getString(1);
                contact.name2 = c.getString(2);
                contact.phone1 = c.getInt(3);
            }
        } catch (SQLException e) {
            Log.e(CATEGORY, "Error while searching person by name: " + e.toString());
            return null;
        }

        return contact;
    }

    // Busca uma pessoa utilizando as configurações definidas no
    // SQLiteQueryBuilder
    // Utilizado pelo Content Provider de pessoa
    public Cursor query(SQLiteQueryBuilder queryBuilder, String[] projection, String selection, String[] selectionArgs,
            String groupBy, String having, String orderBy) 
    {
        Cursor c = queryBuilder.query(this.db, projection, selection, selectionArgs, groupBy, having, orderBy);
        return c;
    }

    // Fecha o banco
    public void close() 
    {
        // fecha o banco de dados
        if (db != null) 
        {
            db.close();
        }
    }

}

----------------------

ContactRegister.java

package br.com.contactsmanager;

import java.util.List;

import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ListView;
import br.com.contactsmanager.Contact.Contacts;

public class ContactRegister extends ListActivity {
    protected static final int INSERT_EDIT = 1;
    protected static final int SEARCH = 2;

    public static ContactRepositoryScript repository;


    private List<Contact> contacts;

    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        repository = new ContactRepositoryScript(this);
        updateList();
    }

    protected void updateList() 
    {
        contacts = repository.listContacts();

        setListAdapter(new ContactListAdapter(this, contacts));
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        super.onCreateOptionsMenu(menu);
        menu.add(0, INSERT_EDIT, 0, "Insert new").setIcon(R.drawable.newcontact);
        menu.add(0, SEARCH, 0, "Search").setIcon(R.drawable.search);
        return true;
    }

    @Override
    public boolean onMenuItemSelected(int featureId, MenuItem item) {

        switch (item.getItemId()) {
        case INSERT_EDIT:

            startActivityForResult(new Intent(this, EditContact.class), INSERT_EDIT);
            break;
        case SEARCH:

            startActivity(new Intent(this, SearchContact.class));
            break;
        }
        return true;
    }

    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        super.onListItemClick(l, v, position, id);
        editContact(position);
    }

    protected void editContact(int position) 
    {
        Contact contact = contacts.get(position);

        Intent it = new Intent(this, EditContact.class);

        it.putExtra(Contacts._ID, contact.id1);

        startActivityForResult(it, INSERT_EDIT);
    }

    @Override
    protected void onActivityResult(int code, int returnCode, Intent it) {
        super.onActivityResult(code, returnCode, it);

        if (returnCode == RESULT_OK) 
        {
            updateList();
        }
    }

    @Override
    protected void onDestroy()
    {
        super.onDestroy();

        repository.close();
    }

}