public ArrayList<Contact> getAllContacts() {

    ArrayList<Contact> contactList = new ArrayList<Contact>();

    String selectQuery = "SELECT  * FROM " + TABLE_DETAILS;

    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);

    if (cursor.moveToFirst()) { // if (cursor != null)
      do {
        Contact contact = new Contact();
        contact.setName(cursor.getString(1));
        contact.setAddress(cursor.getString(4));
        contact.setPhone(cursor.getString(5));

        String interest = getInterest(cursor.getInt(0));
        contact.setInterest(interest);

        contactList.add(contact);

      } while (cursor.moveToNext());
    }
    return contactList;
  }
  public ArrayList<Contact> getCustomizedContacts(String interest, String city, String area) {

    ArrayList<Contact> contactList = new ArrayList<Contact>();

    boolean flag = true;

    String selectQuery =
        "select * from " + TABLE_DETAILS + " as a" + " natural join " + TABLE_INTEREST + " as b ";

    if (interest.compareTo("ALL") != 0) {
      if (flag) {
        selectQuery += " where ";
        flag = false;
      } else selectQuery += " and ";

      selectQuery += " a.Sr = b.sr and b.Interest = '" + interest + "'";
    }

    if (city.compareTo("ALL") != 0) {
      if (flag) {
        selectQuery += " where ";
        flag = false;
      } else selectQuery += " and ";

      selectQuery += " a.City = '" + city + "'";
    }

    if (area.compareTo("ALL") != 0) {
      if (flag) {
        selectQuery += " where ";
        flag = false;
      } else selectQuery += " and ";

      selectQuery += " a.Area = '" + area + "'";
    }

    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);

    if (cursor.moveToFirst()) { // if (cursor != null)
      do {
        Contact contact = new Contact();
        contact.setName(cursor.getString(1));
        contact.setAddress(cursor.getString(4));
        contact.setPhone(cursor.getString(5));
        contact.setInterest(cursor.getString(6));

        contactList.add(contact);

      } while (cursor.moveToNext());
    }
    return contactList;
  }