EXTRA_PRESELECTED_CONTACTS NOT WORKING

[C-Spydo]

I can't get the contact picker to retain contacts I have selected before.
I've collected all the selected contacts id into a serializable arraylist like this:

private ArrayListpreSelectedContacts;
preSelectedContacts=new ArrayList();
preSelectedContacts.add(cp.getString(cp.getColumnIndex(ContactsContract.CommonDataKinds.Phone.CONTACT_ID)));

What can I do?