How to programmatically create an exposed filter?

Question

Is there a way to create programmatically exposed filters in Drupal 7?

I searched a lot but I found only topics related remove or alter exposed filters already available in a view.

By instance my view doesn't provide any exposed filter. I must create it through the code in my module. I have a view but I can't change it via Views administration interface. I must achieve the result by implementing hook_views_pre_view() and add_item().

Unfortunately add_item is not very well documented or, at least, not the part concerning the $options array structure.

Given 'field_status' a "select list" with 3 items defined in the field configuration, and the following piece of code:

 function hook_views_pre_view(&$view, &$display_id, &$args) {
   $field = field_info_field('field_status');
   if (!empty($field)) {
    $filter = array(
     'identifier' => 'field_status',
     'exposed' => TRUE,
     'is_grouped' => FALSE,
     'table' => 'field_data_field_status',
     'type' => 'list_text',
     'expose' => array(
       'operator_id' => 'field_status_value',
       'label' => 'Status',
     )
   );
   $view->add_item($view->current_display, 'filter', 'field_data_field_status', 'field_status_value', $filter);
   $view->display_handler->set_option('css_class', 'view-status');
}

what should be the structure of the array $options (in my case $filter)?

As a result of this I can see the submit button 'Apply' and the label "Status" in an empty widget 'div'.

Here is the code edited following suggestions in comments:

function my_module_views_default_views_alter(&$views) {
  if (array_key_exists('my_view_name', $views)) {

    $options = array (
      0 => 'Blocked',
      1 => 'Active',
    );

    $display = $views['my_view_name']->display['my_view_page'];

    $display->display_options['filters']['field_status']['id'] = 'field_status';
    $display->display_options['filters']['field_status']['table'] = 'field_data_field_status';
    $display->display_options['filters']['field_status']['field'] = 'field_status';
    $display->display_options['filters']['field_status']['exposed'] = TRUE;
    $display->display_options['filters']['field_status']['expose']['operator_id'] = 'field_status_value';
    $display->display_options['filters']['field_status']['expose']['label'] = 'Status';
    $display->display_options['filters']['field_status']['expose']['operator'] = 'field_status_value';
    $display->display_options['filters']['field_status']['expose']['identifier'] = 'field_status';
    $display->display_options['filters']['field_status']['value'] = $options;

    $views['my_view_name']->display['my_view_page'] = $display;
  }
}

--- ALTERNATIVE SOLUTION ---

Since this problem seems to be hard to fix (@ least for my specific case) I have used a workaround to achieve the goal. The solution consists basically on a Views Block Clone with Exposed Filters which overrides the Views Block (without exposed filters) according to specific cases (Is User LoggedIn, Content Type, Contextual Filters ecc..).

Answer 1

Can you please try with hook_views_default_views_alter function. This function should be defined in MODULE_NAME/views/MODULE_NAME.views.inc file. And don't forget to include this file on .info file as files[] = views/MODULE_NAME.views.inc.

 function MODULE_NAME_views_default_views_alter(&$views) {
        if (array_key_exists('MY_VIEW_NAME', $views)) {
          $options = array(
          0 => 'Blocked',
          1 => 'Active',
          ); 
          $display = $views['MY_VIEW_NAME']->display['MY_VIEW_PAGE'];
          $display->display_options['filters']['field_status']['id'] = 'field_status';
          $display->display_options['filters']['field_status']['table'] = 'field_data_field_status';
          $display->display_options['filters']['field_status']['field'] = 'field_status';
          $display->display_options['filters']['field_status']['value'] = $options;
          $display->display_options['filters']['field_status']['exposed'] = TRUE;
          $display->display_options['filters']['field_status']['expose']['operator_id'] = 'field_status_value';
          $display->display_options['filters']['field_status']['expose']['label'] = 'Status';
          $display->display_options['filters']['field_status']['expose']['operator'] = 'field_status_value';
          $display->display_options['filters']['field_status']['expose']['identifier'] = 'field_status';
          $views['MY_VIEW_NAME']->display['MY_VIEW_PAGE'] = $display;
          }
    }