Q:

Call fnRowCallback on table redraw in datatable

I am doing some post processing in datatable in fnRowCallback. But they are not being called when the table is redrawn. (i.e, when some event like changing the number of displayed rows are called from UI, the table is redrawn)
      $(document).ready(function () {
            var oTable = $('#data').dataTable({
                "bJQueryUI": true,
                "bProcessing": true,
                "bServerSide": true,
                "bSort": false,
                "sAjaxSource": "query.php",
                "sPaginationType": "full_numbers",
                "aoColumns": [
                    null,
                    null,
                    null,
                ],
                "fnRowCallback": function (nRow, aData, iDisplayIndex) {
                    $(nRow).attr("id", aData[4]);
                    return nRow;
                },
               "fnDrawCallback": function( oSettings ) {
                // How do I call fnRowCallback here? 
               // losing post processing because it is not being called after a redraw
                }
    });

A:

I think your attempt to look up the actual row via jquery in $(nRow) does not work. nRow contains the whole row. You should just is as namespace for the jquery selector (second parameter) to restrict it to this particular row.
Like so: 

$("selector",nRow).jqueryaction()

This works for me:
Html:
  <tr>
    <td>a</td>
    <td class="boldmetight">b</td>
  </tr>
  <tr>
    <td class="boldmetight">c</td>
    <td>d</td>
  </tr>.. etc

And the table definition with a rowcallback that bolds every cell with a specific class (just for example):
  var otable = $("#datatable").dataTable({
    "fnRowCallback": function(nRow, aData, iDisplayIndex) {
      $('.boldmetight', nRow).html('<b>' +  $('.boldmetight', nRow).text() + '</b>');
    }
  });

Look at this working Plunker

