Updating the view is pretty easy but the problems start when you click on a pager link or try the filter form after the view is updated. The Javascript functionality of the view is lost and the URL used by the pager is now the URL of the original AJAX request.

After a lot of debugging I found out that in order to properly update a view using AJAX you will need to take care of two small things:

1. Override the view’s path before you generate its content
2. In the page, call Drupal.attachBehaviors after you replace the content of the view. This will initialize the javascript functionality of the view.

There are a lot of tutorials on the net about embedding and updating a view if you want more details on that, so I’ll just post a small example in order to clarify the context of the two points presented above.

In your module:

// Define the URL for the AJAX call (http://api.drupal.org//api/function/hook_menu/6)
function MODULE_menu() {
  $items = array();

  $items['ACTION_URL'] = array(
    'title' => 'Some title',
    'page callback' => 'MODULE_process_ajax_call',
    // Let's assume you will need two arguments in the processing function
    'page arguments' => array(1, 2),
    'access callback' => 'MODULE_check_access',
    'type' => MENU_CALLBACK,
  );

  return $items;
}

// Access callback, for this example allow anyone to access the 'ACTION_URL'
function MODULE_check_access() {
  return TRUE;
}

// AJAX callback function
function MODULE_process_ajax_call($arg1, $arg2) {
  //do the work here and then render the view

  $view = views_get_view('VIEW_NAME');
  $view->set_display('default');
  // set the view arguments here, if needed
  //$view->set_arguments( array( 'VIEW', 'ARGUMENTS') );

  // Override the view path, otherwise the path will be 'ACTION_URL'
  $view->override_path = 'views/ajax';
  $output = $view->preview();

  return drupal_json(array('view_output' => $output));
}

In the page:

<div id='view-container'>
  <?php print views_embed_view('VIEW_NAME', 'default'); ?>
</div>

<script type='text/javascript'>
if(Drupal.jsEnabled) {
  var ajax_result_callback = function(data) {
    var result = Drupal.parseJson(data);
    jQuery('#view-container').html(result.view_output);
    Drupal.attachBehaviors('#view-container'); //Don't forget this !!!
  }

  function do_ajax_call(arg1, arg2) {
    jQuery.get('<?php print $base_url?>/ACTION_URL/'+arg1+'/'+arg2, 
                null, ajax_result_callback);
    // preventing entire page from reloading
    return false;
  }
}
</script>

When the exposed form is reloaded, the value for the date field is incorrectly set as a string instead of an array.

The solution I used to fix this error was to override the filter value just before submit, using hook_form_alter inside my own module.

function MODULE_form_alter(&$form, &$form_state, $form_id) {
  switch ($form_id) {
    case 'views_exposed_form':
      if($form_state['view']->name == 'YOUR_VIEW_NAME') {
        $value = $form_state['input']['YOUR_DATE_FILTER']['value'];
        if(is_string($value)) {
           $regexp = '/^([0-9]{4})-([0-9]{2})-([0-9]{2})\s([0-9]{2}):([0-9]{2}):([0-9]{2})$/';
           if(preg_match($regexp, $value, $matches)) {
            $form_state['input']['YOUR_DATE_FILTER']['value'] =
                array('year' => $matches[1],
                         'month' => intval($matches[2]),
                         'day' => intval($matches[3]),
                         'hour' => intval($matches[4]),
                         'minute' => intval($matches[5]),
                         'second' => intval($matches[6]));
           }
        }
    }
    break;

    default:
    break;
}

I think “Common Lisp: A Gentle Introduction to Symbolic Computation” is a good book to start with. It is available for free here.

I’ll post some notes, to help me review what I’ve learned.