如何从自定义模板中使用自己的类扩展Joomla 3的组件'

我正在处理一个自定义模板，并且我到了必须修改组件的辅助源代码的地步。为了防止这种情况，我想知道是否有相应的方法来扩展某些组件的特定助手类与自己的函数，或者覆盖它?

在我的自定义模板jmlroot/templates/mytemplate/html/com_hikashop/product/listing_div.php中引入覆盖文件:

<form action="<?php echo hikashop_currentURL(); ?>" method="post" name="adminForm_<?php echo $this->params->get('main_div_name').$this->category_selected;?>_bottom">
    <div class="hikashop_products_pagination hikashop_products_pagination_bottom">
    <?php echo $this->pagination->getListFooter($this->params->get('limit')); ?>
    <span class="hikashop_results_counter"><?php echo $this->pagination->getResultsCounter(); ?></span>
    </div>
    <input type="hidden" name="filter_order_<?php echo $this->params->get('main_div_name').$this->category_selected;?>" value="<?php echo $this->pageInfo->filter->order->value; ?>" />
    <input type="hidden" name="filter_order_Dir_<?php echo $this->params->get('main_div_name').$this->category_selected;?>" value="<?php echo $this->pageInfo->filter->order->dir; ?>" />
    <?php echo JHTML::_( 'form.token' ); ?>
</form>

表单里面有一个PHP代码:

<?php echo $this->pagination->getListFooter($this->params->get('limit')); ?>

从辅助文件jmlroot/administrator/components/com_hikashop/helpers/pagination.php中调用:

class hikashopPaginationHelper extends hikashopBridgePaginationHelper{
    function _item_active(JPaginationObject $item){
        $class = 'pagenav';
        $specials = array('start','end','previous','next');
        foreach($specials as $special){
            if(!empty($item->$special)){
                $class.=' hikashop_'.$special.'_link';
            }
        }
        if($item->base>0)
            return "<a class='"".$class."'" title='"".$item->text."'" onclick='"javascript: document.adminForm".$this->hikaSuffix.$this->form.".limitstart".$this->hikaSuffix.".value=".$item->base."; document.adminForm".$this->hikaSuffix.$this->form.".submit();return false;'">".$item->text."</a>";
        else
            return "<a class='"".$class."'" title='"".$item->text."'" onclick='"javascript: document.adminForm".$this->hikaSuffix.$this->form.".limitstart".$this->hikaSuffix.".value=0; document.adminForm".$this->hikaSuffix.$this->form.".submit();return false;'">".$item->text."</a>";
    }
    function _item_inactive(JPaginationObject $item){
        $mainframe = JFactory::getApplication();
        if ($mainframe->isAdmin()) {
            return "<span>".$item->text."</span>";
        } else {
            $class = 'pagenav';
            if(!is_numeric($item->text)){
                $class .= ' pagenav_text';
            }
            return '<span class="'.$class.'">'.$item->text."</span>";
        }
    }
}

我需要用稍微修改的代码覆盖hikashopPaginationHelper类(通过用<li/>替换<spans />)。

我试图将这部分代码添加到jmlroot/templates/mytemplate/html/com_hikashop/product/listing_div.php文件的开头:

jimport('joomla.application.component.controller');
jimport('joomla.html.pagination');
require_once JPATH_ADMINISTRATOR . '/components/com_hikashop/helpers/pagination.php';
class MY_hikashopPaginationHelper extends hikashopBridgePaginationHelper{
    function _item_active(JPaginationObject $item){
        $class = 'pagenav';
        $specials = array('start','end','previous','next');
        foreach($specials as $special){
            if(!empty($item->$special)){
                $class.=' hikashop_'.$special.'_link';
            }
        }
        if($item->base>0)
            return "<li><a class='"".$class."'" title='"".$item->text."'" onclick='"javascript: document.adminForm".$this->hikaSuffix.$this->form.".limitstart".$this->hikaSuffix.".value=".$item->base."; document.adminForm".$this->hikaSuffix.$this->form.".submit();return false;'">".$item->text."</a></li>";
        else
            return "<li><a class='"".$class."'" title='"".$item->text."'" onclick='"javascript: document.adminForm".$this->hikaSuffix.$this->form.".limitstart".$this->hikaSuffix.".value=0; document.adminForm".$this->hikaSuffix.$this->form.".submit();return false;'">".$item->text."</a></li>";
    }
    function _item_inactive(JPaginationObject $item){
        $mainframe = JFactory::getApplication();
        if ($mainframe->isAdmin()) {
            return "<li>".$item->text."</li>";
        } else {
            $class = 'pagenav';
            if(!is_numeric($item->text)){
                $class .= ' pagenav_text';
            }
            return '<li class="'.$class.'">'.$item->text."</li>";
        }
    }
}

但这一点帮助也没有。我觉得我做错了什么，有人注意到吗?