/** * Renders the header (if any) * * @return null|string */ public function renderHeader() { if ($this->header !== false || !empty($this->header)) { $content = ArrayHelper::getValue($this->header, 'label', ''); $options = ArrayHelper::getValue($this->header, 'options', ['class' => 'header']); $header = Ui::tag('div', $content, $options); $lines[] = Ui::beginTag('div', ['class' => 'content']); $lines[] = $header; return implode("\n", $lines); } else { return null; } }