example.php

<?php



function my_modify_view($view_name) {

  $view = views_get_view($view_name, TRUE);

  $view->display['default']->display_options['row_plugin'] = 'fields';
  unset($view->display['default']->display_options['row_options']['view_mode']);

  // node title
  $view->display['default']->display_options['fields']['title']['id'] = 'title';
  $view->display['default']->display_options['fields']['title']['table'] = 'search_api_index_search_index';
  $view->display['default']->display_options['fields']['title']['field'] = 'title';
  $view->display['default']->display_options['fields']['title']['label'] = '';
  $view->display['default']->display_options['fields']['title']['element_type'] = 'h3';
  $view->display['default']->display_options['fields']['title']['element_label_colon'] = FALSE;
  $view->display['default']->display_options['fields']['title']['link_to_entity'] = 0;


  /* Field: foo */
$view->display['default']->display_options['fields']['field_foo']['id'] = 'field_foo';
$view->display['default']->display_options['fields']['field_foo']['table'] = 'search_api_index_search_index';
$view->display['default']->display_options['fields']['field_foo']['field'] = 'field_foo';
$view->display['default']->display_options['fields']['field_foo']['element_label_type'] = 'strong';
$view->display['default']->display_options['fields']['field_foo']['delta_offset'] = '0';

/* Field: bar */
$view->display['default']->display_options['fields']['field_bar']['id'] = 'field_bar';
$view->display['default']->display_options['fields']['field_bar']['table'] = 'search_api_index_search_index';
$view->display['default']->display_options['fields']['field_bar']['field'] = 'field_bar';
$view->display['default']->display_options['fields']['field_bar']['element_label_type'] = 'strong';
$view->display['default']->display_options['fields']['field_bar']['delta_offset'] = '0';


  views_save_view($view);

}



?>

debugging: 1. add the fields via the ui, 2. change the field labels programmatically, 3. save the view, 4. perform an export of the view and check the export code