How do I get the placeholder attribute into a Search API Solr Search field?
The problem is the views exposed filter form always has an ID of "views_exposed_form", nothing more specific. My low-rent way round it was this:

function MYMODULE_form_views_exposed_form_alter(&amp;$form, &amp;$form_state, $form_id) {
  if (isset($form['search_api_views_fulltext'])) {
    $form['search_api_views_fulltext']['#attributes']['placeholder'] = t('blah');
  }
}


That works fine for my use case, but if you need something more specific you should be able to look in the $form or $form_state and find the View object, which you can use to identify which view/display is currently being altered.