InfiniteScrollingFeature.inc.php

<?php
 
import('lib.pkp.classes.controllers.grid.feature.GeneralPagingFeature');
 
class InfiniteScrollingFeature extends GeneralPagingFeature {
 
   function __construct($id = 'infiniteScrolling', $itemsPerPage = null) {
      parent::__construct($id, $itemsPerPage);
   }
 
 
   //
   // Extended methods from GridFeature.
   //
   function getJSClass() {
      return '$.pkp.classes.features.InfiniteScrollingFeature';
   }
 
   function fetchUIElements($request, $grid) {
      $options = $this->getOptions();
 
      $shown = $options['currentItemsPerPage'] * $options['currentPage'];
      if ($shown > $options['itemsTotal']) $shown = $options['itemsTotal'];
 
      $moreItemsLinkAction = false;
      if ($shown < $options['itemsTotal']) {
         import('lib.pkp.classes.linkAction.request.NullAction');
         $moreItemsLinkAction = new LinkAction(
            'moreItems',
            new NullAction(),
            __('grid.action.moreItems'),
            'more_items'
         );
      }
 
      $templateMgr = TemplateManager::getManager($request);
      $templateMgr->assign(array(
         'iterator' => $this->getItemIterator(),
         'shown' => $shown,
         'grid' => $grid,
         'moreItemsLinkAction' => $moreItemsLinkAction,
      ));
 
      return array(
         'pagingMarkup' => $templateMgr->fetch('controllers/grid/feature/infiniteScrolling.tpl'),
      );
   }
 
 
   //
   // Hooks implementation.
   //
   function fetchRows($args) {
      $request = $args['request'];
      $grid = $args['grid'];
      $jsonMessage = $args['jsonMessage'];
 
      // Render the paging options, including updated markup.
      $this->setOptions($request, $grid);
      $pagingAttributes = array('pagingInfo' => $this->getOptions());
 
      // Add paging attributes to json so grid can update UI.
      $additionalAttributes = (array) $jsonMessage->getAdditionalAttributes();
      $jsonMessage->setAdditionalAttributes(array_merge(
         $pagingAttributes,
         $additionalAttributes)
      );
   }
 
   function fetchRow($args) {
      $request = $args['request'];
      $grid = $args['grid'];
      $row = $args['row'];
      $jsonMessage = $args['jsonMessage'];
      $pagingAttributes = array();
 
      // Render the paging options, including updated markup.
      $this->setOptions($request, $grid);
      $pagingAttributes['pagingInfo'] = $this->getOptions();
 
      if (is_null($row)) {
         $gridData = $grid->getGridDataElements($request);
 
         // Get the last data element id of the current page.
         end($gridData);
         $lastRowId = key($gridData);
 
         // Get the row and render it.
         $args = array('rowId' => $lastRowId);
         $row = $grid->getRequestedRow($request, $args);
         $pagingAttributes['deletedRowReplacement'] = $grid->renderRow($request, $row);
      } else {
         // No need for paging markup.
         unset($pagingAttributes['pagingInfo']['pagingMarkup']);
      }
 
      // Add paging attributes to json so grid can update UI.
      $additionalAttributes = $jsonMessage->getAdditionalAttributes();
 
      // Unset sequence map until we support that.
      unset($additionalAttributes['sequenceMap']);
      $jsonMessage->setAdditionalAttributes(array_merge(
         $pagingAttributes,
         $additionalAttributes)
      );
   }
}