How to alter field values on a display page?

Question

I am trying to alter field values in a page display. I can get the field values easily using field_get_items(), but depending on the values of other fields, I may need to manipulate the text and/or display based on some PHP logic in my template file. I am trying to do it using either hook_page_alter() or hook_preprocess_HOOK().

I cannot get the text to be altered when the page is displayed using hook_page_alter() or hook_preprocess_HOOK(). I can confirm those 2 functions are working and that I can pull the values from the DB ($page['content']), but I cannot override the variable to set them. For example:

function standard_submission_page_alter(&$page) {
    $node = menu_get_object();
    $page['content']['system_main']['nodes'][$node->nid]['field_title_nickname']['#items'][0]['value'] = 'A new nickname title!';
}

function standard_submission_preprocess_page(&$vars) {
    $vars['node']->field_title_nickname['und'][0]['value'] = 'A new nickname title 2x';
}

Any ideas on why my altering of this field_title_nickname text field value isn't being accepted and displayed? It keeps reverting back to whatever is originally in the database.

Answer 1

If I need to manipulate the text and/or display based on some PHP logic, I would do it using hook_node_view() in a custom module, not in a template file.

function MYMODULE_node_view($node, $view_mode = 'full', $langcode = NULL) {
    if( $view_mode == 'full' ){
        if( some conditions here ){
            $node->content['field_title_nickname'] = array(
                '#markup' => '<div>A new nickname title 2x</div>'
            );
        }
    }
}

Answer 2

You can do that by implementing template_preprocess_field(&$variables, $hook) in your template.php

function THEMENAME_preprocess_field(&$variables, $hook) {
  if ($node = menu_get_object()) {
    if ($node->type == 'car') {
      if($variables['element']['#field_name'] == 'field_price') {
        $variables['items']['0']['#markup'] = $new_value; //new value;
      }
    }
  }
}

Check here: http://tassaf.moriamedia.com/change-field-value-in-node-view/

Answer 3

If use Display Suite implement hook_ds_pre_render_alter() to alter entity render array.

Example:

/**
 * Implements hook_ds_pre_render_alter().
 */
function MYMODULE_ds_pre_render_alter(&$layout_render_array, $context, &$vars) {
  $entity_type = $context['entity_type'];
  if ($entity_type == 'node') {
    $layout_render_array['ds_content']['Foo']['#markup'] = 'Bar';
  }
}