FetchContacts.java

private class FetchContacts extends AsyncTask<Void, Void, ArrayList<Contact>> {

  private final String DISPLAY_NAME = Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB ?
          ContactsContract.Contacts.DISPLAY_NAME_PRIMARY : ContactsContract.Contacts.DISPLAY_NAME;

  private final String FILTER = DISPLAY_NAME + " NOT LIKE '%@%'";

  private final String ORDER = String.format("%1$s COLLATE NOCASE", DISPLAY_NAME);

  @SuppressLint("InlinedApi")
  private final String[] PROJECTION = {
          ContactsContract.Contacts._ID,
          DISPLAY_NAME,
          ContactsContract.Contacts.HAS_PHONE_NUMBER
  };
  @Override
  protected ArrayList<LearnSaveContact> doInBackground(Void... params) {
      try {
          ArrayList<Contact> contacts = new ArrayList<>();

          ContentResolver cr = getContentResolver();
          Cursor cursor = cr.query(ContactsContract.Contacts.CONTENT_URI, PROJECTION, FILTER, null, ORDER);
          if (cursor != null && cursor.moveToFirst()) {

              do {
                  // get the contact's information
                  String id = cursor.getString(cursor.getColumnIndex(ContactsContract.Contacts._ID));
                  String name = cursor.getString(cursor.getColumnIndex(DISPLAY_NAME));
                  Integer hasPhone = cursor.getInt(cursor.getColumnIndex(ContactsContract.Contacts.HAS_PHONE_NUMBER));

                  // get the user's email address
                  String email = null;
                  Cursor ce = cr.query(ContactsContract.CommonDataKinds.Email.CONTENT_URI, null,
                          ContactsContract.CommonDataKinds.Email.CONTACT_ID + " = ?", new String[]{id}, null);
                  if (ce != null && ce.moveToFirst()) {
                      email = ce.getString(ce.getColumnIndex(ContactsContract.CommonDataKinds.Email.DATA));
                      ce.close();
                  }

                  // get the user's phone number
                  String phone = null;
                  if (hasPhone > 0) {
                      Cursor cp = cr.query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null,
                              ContactsContract.CommonDataKinds.Phone.CONTACT_ID + " = ?", new String[]{id}, null);
                      if (cp != null && cp.moveToFirst()) {
                          phone = cp.getString(cp.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
                          cp.close();
                      }
                  }

                  // if the user user has an email or phone then add it to contacts
                  if ((!TextUtils.isEmpty(email) && android.util.Patterns.EMAIL_ADDRESS.matcher(email).matches()
                          && !email.equalsIgnoreCase(name)) || (!TextUtils.isEmpty(phone))) {
                      Contact contact = new Contact();
                      contact.name = name;
                      contact.email = email;
                      contact.phoneNumber = phone;
                      contacts.add(contact);
                  }

              } while (cursor.moveToNext());

              // clean up cursor
              cursor.close();
          }

          return contacts;
      } catch (Exception ex) {
          return null;
      }
  }

  @Override
  protected void onPostExecute(ArrayList<Contact> contacts) {
      if (contacts != null) {
        // success
          mContacts = contacts;
      } else {
         // show failure
         // syncFailed();
      }
  }
}