public function renderTableFooter()
{
$cells = [];
foreach ($this->columns as $column) {
/* @var $column Column */
$cells[] = $column->renderFooterCell();
}
$content = Html::tag('tr', implode('', $cells), $this->footerRowOptions);
if ($this->filterPosition === self::FILTER_POS_FOOTER) {
$content .= $this->renderFilters();
}
return "<tfoot>\n" . $content . "\n</tfoot>";
}