You have to use callback function for this.. for example
$crud->add_action('Smileys', '','','' array($this,'_just_a_test'));
'just_a_test' is callback function.. so i create a function in the same controller like this..
function _just_a_test($primary_key , $row)
{
return $row->id;
}
you can select any field from your $crud->columns params to replace my $row->id e.g $row->country
OR
you can edit existing column like this..
$crud->callback_column('smiley', array($this,'_just_a_test2'));
and the callback function
function _just_a_test2($primary_key , $row)
{
return '<a href="controller/method/'.$row->id.'"><img src="http://www.grocerycrud.com/assets/uploads/general/smiley.png"></a>';
}
dont forget to add 'smiley' in $crud->columns
$crud->columns('city','country','phone','smiley');
hope u find this useful.