Custom show_item_metadata function for Omeka that loops through an internal array of labels and their associated fields.

custom.php

<?php

/**
 * Show Item Metadata function that loops through an internal array of labels
 * and their associated fields.
 *
 * @param Item|null $item
 * @return string The HTML for the item metadata.
 */
function berlin_show_item_metadata($item = null)
{
    $html = '';

    $item = $item ? $item : get_current_item();

    // The list of fields we want to display, using 'Label' => item() Put them
    // in the order you want them displayed. Add more to the array, separated 
    // by a comma.
    $fields = array(
        'Header' => item('Dublin Core', 'Description', null, $item),
        'Primary Source' => item('Item Type Metadata', 'Text', null, $item),
        'Further Reading' => item('Dublin Core', 'Relation', null, $item)
    );

    // Loop through our array of fields, breaking out the label and value.
    foreach ($fields as $label => $value) {

        // Only display the field if it has a value.
        if ($value) {

            // Construct the HTML for displaying the label and value.
            $html .= '<div class="field field-'. text_to_id($label) .'">'
                   . '<h2>'.$label.'</h2>'
                   . '<div class="field-value">'
                   . $value
                   . '</div>'
                   . '</div>';

        }

    }

    return $html;

}