get_field_object return false

• maculotti.a

• January 3, 2019 at 10:19 am

Hi everybody,
I’m using the function get_field_object in a custom post type archive for filter some parameters.

I’ve followed this tutorial: https://www.advancedcustomfields.com/resources/creating-wp-archive-custom-field-filter

On the archive-cars.php everything it’s working fine. When I try to use the same code on a category field I get a warning because the $field = get_field_object($key, false, true);
doesn’t get any result but return false..

Do you know Why?

“Ivalid argument supplied for foreach() in /Applications/MAMP/htdocs/www.rr1985.localhost/wp-content/themes/rr1985/template-parts/archive-cars-filter.php on line 29”

Thanks

<?php foreach( $GLOBALS['my_query_filters'] as $key => $name ):
      // get the field's settings without attempting to load a value
      $field = get_field_object($key, false, true);

      // create filter ?>
      <h3><b><?php echo $name; ?></b></h3>
      <div class="filter" data-filter="<?php echo $name; ?>">
        <?php  //Print the list in a checbox

        if ($field) :

          // BUG: funziona solo se trova risultati o nell'url iniziale
          foreach ($field['choices'] as $choice_value => $choice_label) :
            $checkAtt = '';

            // set value if available
            if( isset($_GET[ $name ]) ) {
              $values = explode(',', $_GET[ $name ]);

              if (in_array($choice_value, $values, false) ){
                $checkAtt = "checked";
              }
            }
            ?>

            <p>
              <label>
                <input name="brand" type="checkbox" value="<?php echo $choice_value;?>" <?php echo $checkAtt; ?>/>
                <span><?php echo $choice_label; ?></span>
              </label>
            </p>
        <?php endforeach;?>
      <?php endif;?>
      </div>

    <?php endforeach; ?>

• John Huebner

• January 3, 2019 at 10:38 am

The reason is likely that a value has never been saved for this field for the current post and you are using the field name in $key. Under this condition you need to use the field key instead of the field name.

You can solve this by building an array like this

$fields = array(
  // field name => key pairs
  'name-of-field-1' => 'field_123456',
  'name-of-field-2' => 'field_234567',
  // etc...
)

Then use

$field = get_field_object($field[$key], false, true);

• maculotti.a

• January 3, 2019 at 8:32 pm

Thanks a lot John for the reply.
I saved the value in a global array on my functions.php (or at least I think so..)

Any clue why on the archive-cars.php is working and in the category.php isn’t?

Here my functions.php file

**
 * Archive cars FILTER using pre get post?
 */

 // array of filters
 //NOTE: it's a sub field inside a field group so the meta query becomes => groupname_subfield
	$GLOBALS['my_query_filters'] = array(
	 'car_info_petrol'	=> 'carburante',
	 'car_info_gearshift'	=> 'cambio',
	 'car_info_brand'	=> 'marca'
	);

 function my_pre_get_posts( $query ) {

 	// do not modify queries in the admin
 	if( is_admin() ) {return $query;}

 	// only modify queries for 'cars' post type
 	if( isset($query->query_vars['post_type']) && $query->query_vars['post_type'] == 'cars' ) {

		// loop over filters
		foreach( $GLOBALS['my_query_filters'] as $key => $name ) {

			//allow the url to alter the query
	 		if( isset($_GET[$name]) ) {

				$meta_query[] = array(
					'key' => $key,
					'value' => $_GET[$name],
					'compare' => 'IN'
				);

				//Update the meta query args
				$query->set('meta_query', $meta_query);

	     }
		}

 	} //End of the if only on the post type cars

 	// return
 	return $query;

 }

 add_action('pre_get_posts', 'my_pre_get_posts');

• John Huebner

• January 3, 2019 at 11:20 pm

I don’t know why it might work in one location and not in another. The only thing that I do know is that get_field_object() will fail if the field has never been set and you use the field name but it should work when using the field key.

• maculotti.a

• January 4, 2019 at 10:17 am

Thanks John that fixed my issue.