jnet_views.module

<?php

define('JNET_VIEWS_PATH', drupal_get_path('module', 'jnet_views'));

include_once JNET_VIEWS_PATH . '/theme/theme.inc';

/**
 * Implements hook_views_api().
 */
function jnet_views_views_api() {
  return array(
    'api' => 2,
    'path' => JNET_VIEWS_PATH . '/views',
  );
}

/**
 * Implements hook_field_formatter_info().
 */
function jnet_views_field_field_formatter_info() {
  return array(
    'jnet_views_image_as_url' => array(
      'label' => t('My Fancy Label'),
      'field types' => array('image'),
    ),
  );
}

/**
 * Implements hook_field_formatter_view().
 */
function jnet_views_field_field_formatter_view($entity_type, $entity, $field, $instance, $langcode, $items, $display) {
  $element = array();

  foreach ($items as $delta => $item) {
    // Do nothing with empty date fields.
    if (empty($item['value'])) {
      continue;
    }

    $element[$delta] = array(
      '#markup' => $item->uri,
    );
  }

  return $element;
}

plugin_style_fields.inc.php

<?php

class subsplash_xml_plugin_style_fields extends views_plugin_style {

  function option_definition() {
    $options = parent::option_definition();
    return $options;
  }

  /**
   * Provide a form for setting options.
   */
  function options_form(&$form, &$form_state) {
    parent::options_form($form, $form_state);

    // Build a list of fields currently attached to this view display.
    $field_list = array();
    $handlers = $this->display->handler->get_handlers('field');
    foreach ($handlers as $handler_id => $handler) {
      $field_list[$handler_id] = "{$handler->definition['title']} ({$handler->field})";
    }

    // Build a special field list various uses
    $utility_field_list = array_merge(array('none' => 'None'), $field_list);



    $xml_template_options = array(
      'subtabs' => 'Sub Tabs View',
      'table_view' => 'Table View',
      'detail_view' => 'Standard Detail View',
      'media_detail' => 'Media Detail View',
    );

    $form['xml_title'] = array(
      '#type' => 'textfield',
      '#title' => t("XML Title"),
      '#description' => t('The title of the XML feed.'),
      '#default_value' => $this->options['xml_title'],
    );

    $form['xml_title_field'] = array(
      '#type' => 'select',
      '#title' => 'Title Field',
      '#description' => 'If you would like to use a field for the above title, please select one.',
      '#options' => $utility_field_list,
      '#default_value' => $this->options['xml_title_field'],
    );

    $form['xml_template'] = array(
      '#type' => 'select',
      '#title' => t("XML Template"),
      '#description' => t('Select a tempalte to use for the XML feed.'),
      '#options' => $xml_template_options,
      '#default_value' => $this->options['xml_template'],
    );

    // Add an image to be used in "banner" field
    $form['media_detail_image_field'] = array(
      '#type' => 'select',
      '#title' => 'Banner Image Field',
      '#description' => 'Optionally, select the image to be used in the "banner" for this view.',
      '#options' => $utility_field_list,
      '#default_value' => $this->options['media_detail_image_field'],
    );

    // Show all fields with options to set the 'wrapper' for each.
    $form['field_wrappers'] = array(
      '#type' => 'fieldset',
      '#title' => 'Field XML Wrappers',
      '#tree' => TRUE,
      '#description' => 'The field will be wrapped in an xml element. Please provide the element, minus &lt; or &gt;.',
    );

    foreach ($field_list as $field_machine => $field_human) {
      $form['field_wrappers'][$field_machine] = array(
        '#type' => 'textfield',
        '#title' => $field_human,
        '#default_value' => $this->options['field_wrappers'][$field_machine],
      );
    }

  }

  /**
   * Allow other modules to validate options form values prior to submit.
   */
  function options_validate(&$form, &$form_state) {

  }

  /**
   * Allow other modules to perform any necessary changes
   * to options form values prior to storage.
   */
  function options_submit(&$form, &$form_state) {

  }

  /**
   * Make sure the display and all associated handlers are valid.
   */
  function validate() {
    parent::validate();
    $errors = array();
    // .. do stuff here
    return $errors;
  }

  function pre_render($result) {

  }

}

theme.inc.php

<?php

function template_preprocess_views_view_subsplash_xml(&$vars) {
  $vars['subsplash_content'] = array();

  switch ($vars['view']->style_options['xml_template']) {


    case 'subtabs':

      break;

    case 'table_view':
      $view_style = 'Table View';
      $vars['subsplash_content'] = array(
        '#prefix' => '<table>',
        '#suffix' => '</table>',
        '#markup' => '',
      );

      foreach ($vars['view']->style_plugin->rendered_fields as $row) {
        $vars['subsplash_content']['#markup'] .= "<row>";

        // We only care about fields that have a wrapper defined for them.
        foreach ($vars['view']->style_options['field_wrappers'] as $field => $wrapper) {
          if (!empty($wrapper)) {
            $vars['subsplash_content']['#markup'] .= "<{$wrapper}>{$row[$field]}</{$wrapper}>";
          }
        }

        $vars['subsplash_content']['#markup'] .= "</row>";
    }
      break;

    case 'media_detail':

      break;

    case 'detail_view':
      $view_style = 'Detail View';
      $vars['subsplash_content'] = array(
        '#prefix' => '<table>',
        '#suffix' => '</table>',
        '#markup' => '',
      );

      break;

    default:
      $view_style = 'ERROR: No View Style';
      break;
  }

  if (isset($vars['view']->style_options['xml_title_field']) && $vars['view']->style_options['xml_title_field'] !== 'none') {
    // $vars['rows'][0]->_field_data['nid']['entity']->{$vars['view']->style_options['xml_title_field']}['und'][0]['#value'];
  } else {
    $vars['subsplash_title'] = $vars['view']->style_options['xml_title'];
  }



  if (isset($vars['view']->style_options['media_detail_image_field']) && $vars['view']->style_options['media_detail_image_field'] !== 'none') {

      $vars['subsplash_header'] = array(
        '#prefix' => '<banner>',
        '#suffix' => '</banner>',
        '#markup' => '',
      );

      // Set the image.

      if(isset($vars['rows'][0]->_field_data['nid']['entity']->{$vars['view']->style_options['media_detail_image_field']}['und'][0]['uri'])) {

        $uri = $vars['rows'][0]->_field_data['nid']['entity']->{$vars['view']->style_options['media_detail_image_field']}['und'][0]['uri'];

      }



      $image_url = image_style_url('churchapp_featured', $uri);
      $image_double_url = image_style_url('churchapp_featured_dbl', $uri);
      $vars['subsplash_header']['#markup'] = "<image>{$image_url}</image><double:image>{$image_double_url}</double:image>";

  }


  // Set XML header.
  drupal_add_http_header('Content-Type', 'application/rss+xml; charset=utf-8');
}