this is an new question in reference this this post: Nullpointer on sql query with android
Quick History: - Main.Class - Main_fragment.Class
in Fragment this code:
    private void showList() {
    ArrayList<ContactListItems> contactList = new ArrayList<ContactListItems>();
    contactList.clear();
    String query = "SELECT * FROM "+SqlDbHelper.DATABASE_TABLE;
    Cursor c1 = sqlHandler.selectQuery(query);
    if (c1 != null && c1.getCount() != 0) {
        if (c1.moveToFirst()) {
            do {
                ContactListItems contactListItems = new ContactListItems();
                contactListItems.setID(c1.getString(c1.getColumnIndex("id")));
                contactListItems.setFirstName(c1.getString(c1.getColumnIndex("first name")));
                contactListItems.setSecondName(c1.getString(c1.getColumnIndex("secondname")));
                contactListItems.setBDAY(c1.getString(c1.getColumnIndex("bday")));
                contactList.add(contactListItems);
            } while (c1.moveToNext());
        }
    }
    c1.close();
    ContactListAdapter contactListAdapter = new ContactListAdapter(getActivity(), contactList);
    lvCustomList.setAdapter(contactListAdapter);
}
on the last line i get an null pointer.
lvCustomList.setAdapter(contactListAdapter);
This is my ContactListAdapter.class:
public class ContactListAdapter extends BaseAdapter {
Context context;
ArrayList<ContactListItems> contactList;
public ContactListAdapter(Context context, ArrayList<ContactListItems> list) {
    this.context = context;
    contactList = list;
}
@Override
public int getCount() {
    return contactList.size();
}
@Override
public Object getItem(int position) {
    return contactList.get(position);
}
@Override
public long getItemId(int position) {
    return position;
}
@Override
public View getView(int position, View convertView, ViewGroup arg2) {
    ContactListItems contactListItems = contactList.get(position);
    if (convertView == null) {
        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = inflater.inflate(R.layout.custom_listview_item, null);
    }
    TextView tvfirstname = (TextView) convertView.findViewById(R.id.txtViewFirstNamee);
    tvName.setText(contactListItems.getFirstname());
    TextView tvsecondname = (TextView) convertView.findViewById(R.id.txtViewSecondName);
    tvPhone.setText(contactListItems.getSecondName());
    TextView tvbday = (TextView) convertView.findViewById(R.id.txtViewBDAY);
    tvbday.setText(contactListItems.getBDAY());
    return convertView;
}
Any ideas? :/
 
     
    