How to add a subtitle to a page template

add subtitle to page template

.theme file could have something like this...


function hook_preprocess_page(&$variables){
  $variables['subtitle'] = FALSE;

  if (arg(0) == 'node' && is_numeric(arg(1)) && !arg(2)) {
    $node = node_load(arg(1)); // entity cache (in core) should save us here.
    if (property_exists($node, 'field_subtitle')) {
      if (!empty($node->field_subtitle)) {
        $lang = $node->langcode;
        $variables['subtitle'] = check_plain($node->field_subtitle[$lang][0]['value']);
      }
    }
  }
}

template file would then look something like this

  <div class="l-page-title gdlr-page-title-wrapper gdlr-parallax-wrapper" data-bgspeed="0.5">
    <div class="gdlr-page-title-overlay"></div>
    <div class="gdlr-page-title-container container container-fluid">
      <?php print render($title_prefix); ?>
      <?php if ($title): ?>
        <h1 class="page-title"><?php print $title; ?></h1>
      <?php endif; ?>
      <?php if ($subtitle): ?>
        <h2 class="subtitle gdlr-page-caption"><?php print $subtitle; ?></h2>
      <?php endif; ?>
      <?php print render($title_suffix); ?>
    </div>
  </div>

Going from the post arg() is deprecated and will be removed (https://www.drupal.org/node/2274705)

function hook_preprocess_page(&$variables){
  $variables['subtitle'] = FALSE;

  // Load the current node.
  $node = \Drupal::routeMatch()->getParameter('node');
  if ($node) {
    if (property_exists($node, 'field_subtitle')) {
      if (!empty($node->field_subtitle)) {
        $lang = $node->langcode;
        $variables['subtitle'] = check_plain($node->field_subtitle[$lang][0]['value']);
      }
    }
  }
}

I still don't think subtitle is being populated or if I am checking the right $node. I updated the template file block--page-title-block.html.twig:

<section id="page-title" class="img-title-bg">
  <div{{ attributes.addclass(classes) }}>
    {{ title_prefix }}
    {% if label %}
      <h2{{ title_attributes }}>{{ label }}</h2>
    {% endif %}
    {% if subtitle %}
      <h2 class="subtitle">{{ subtitle }}</h2>
    {% endif %}
    {{ title_suffix }}
  </div>
</section>

The preprocess function you have would be adding the subtitle variable to page templates, so you would have to move this logic to themename_preprocess_block to add it to the block template you're referencing.

Going from the post arg() is deprecated and will be removed

@Gustavo we talked about this in the meeting, that example is from Drupal 7. You will need to find the Drupal 8 equivalent way to load a node from the page template.

you would have to move this logic to themename_preprocess_block to add it to the block template you're referencing.

There should be no block template in use (if so, it should be removed) -- the page title should only appear in the page template.

@jenlampton D8 moved the page title out of the page template and into a block. Same with messages and tabs (local actions). So in the page twig template, it's actually placing the rendered block.

Is this also true for layout-builder pages? Does the layout-builder area still only replace the main-page-content block like it did with panels in D7?

@Gustavo I tried the following on abag and it worked like a charm:

In .theme file:

/**
 * Implements hook_preprocess_block()
 */
function abag_preprocess_block(&$variables) {
  $variables['node'] = \Drupal::routeMatch()->getParameter('node');
}

in block template block--page-title-block.html.twig:

{% if not is_front %}
  <div class="container container-fluid">
    <div class="row">
      <div{{ attributes.addClass(title_wrapper_classes) }}>
        {% block content %}
          {{ content }}
        {% endblock %}
      </div>
      {{ node.field_subtitle.value }}
    </div>
  </div>
{% endif %}

You will of course need to add the markup you want around the subtitle, and some logic to ensure that it won't show on pages that don't have a subtitle.