Class yii\bootstrap\Tabs

                protected function activateFirstVisibleTab()
{
    foreach ($this->items as $i => $item) {
        $active = ArrayHelper::getValue($item, 'active', null);
        $visible = ArrayHelper::getValue($item, 'visible', true);
        if ($visible && $active !== false) {
            $this->items[$i]['active'] = true;
            return;
        }
    }
}

            

                protected function hasActiveTab()
{
    foreach ($this->items as $item) {
        if (isset($item['active']) && $item['active'] === true) {
            return true;
        }
    }
    return false;
}

            

                public function init()
{
    parent::init();
    Html::addCssClass($this->options, ['widget' => 'nav', $this->navType]);
    Html::addCssClass($this->tabContentOptions, 'tab-content');
}

            

                protected function renderDropdown($itemNumber, &$items, &$panes)
{
    $itemActive = false;
    foreach ($items as $n => &$item) {
        if (is_string($item)) {
            continue;
        }
        if (isset($item['visible']) && !$item['visible']) {
            continue;
        }
        if (!(array_key_exists('content', $item) xor array_key_exists('url', $item))) {
            throw new InvalidConfigException("Either the 'content' or the 'url' option is required, but only one can be set.");
        }
        if (array_key_exists('url', $item)) {
            continue;
        }
        $content = ArrayHelper::remove($item, 'content');
        $options = ArrayHelper::remove($item, 'contentOptions', []);
        Html::addCssClass($options, ['widget' => 'tab-pane']);
        if (ArrayHelper::remove($item, 'active')) {
            Html::addCssClass($options, 'active');
            Html::addCssClass($item['options'], 'active');
            $itemActive = true;
        }
        $options['id'] = ArrayHelper::getValue($options, 'id', $this->options['id'] . '-dd' . $itemNumber . '-tab' . $n);
        $item['url'] = '#' . $options['id'];
        if (!isset($item['linkOptions']['data-toggle'])) {
            $item['linkOptions']['data-toggle'] = 'tab';
        }
        $panes[] = Html::tag('div', $content, $options);
        unset($item);
    }
    return $itemActive;
}

            

                protected function renderItems()
{
    $headers = [];
    $panes = [];
    if (!$this->hasActiveTab()) {
        $this->activateFirstVisibleTab();
    }
    foreach ($this->items as $n => $item) {
        if (!ArrayHelper::remove($item, 'visible', true)) {
            continue;
        }
        if (!array_key_exists('label', $item)) {
            throw new InvalidConfigException("The 'label' option is required.");
        }
        $encodeLabel = isset($item['encode']) ? $item['encode'] : $this->encodeLabels;
        $label = $encodeLabel ? Html::encode($item['label']) : $item['label'];
        $headerOptions = array_merge($this->headerOptions, ArrayHelper::getValue($item, 'headerOptions', []));
        $linkOptions = array_merge($this->linkOptions, ArrayHelper::getValue($item, 'linkOptions', []));
        if (isset($item['items'])) {
            $label .= ' <b class="caret"></b>';
            Html::addCssClass($headerOptions, ['widget' => 'dropdown']);
            if ($this->renderDropdown($n, $item['items'], $panes)) {
                Html::addCssClass($headerOptions, 'active');
            }
            Html::addCssClass($linkOptions, ['widget' => 'dropdown-toggle']);
            if (!isset($linkOptions['data-toggle'])) {
                $linkOptions['data-toggle'] = 'dropdown';
            }
            /** @var Widget $dropdownClass */
            $dropdownClass = $this->dropdownClass;
            $header = Html::a($label, "#", $linkOptions) . "\n"
                . $dropdownClass::widget(['items' => $item['items'], 'clientOptions' => false, 'view' => $this->getView()]);
        } else {
            $options = array_merge($this->itemOptions, ArrayHelper::getValue($item, 'options', []));
            $options['id'] = ArrayHelper::getValue($options, 'id', $this->options['id'] . '-tab' . $n);
            Html::addCssClass($options, ['widget' => 'tab-pane']);
            if (ArrayHelper::remove($item, 'active')) {
                Html::addCssClass($options, 'active');
                Html::addCssClass($headerOptions, 'active');
            }
            if (isset($item['url'])) {
                $header = Html::a($label, $item['url'], $linkOptions);
            } else {
                if (!isset($linkOptions['data-toggle'])) {
                    $linkOptions['data-toggle'] = 'tab';
                }
                $header = Html::a($label, '#' . $options['id'], $linkOptions);
            }
            if ($this->renderTabContent) {
                $tag = ArrayHelper::remove($options, 'tag', 'div');
                $panes[] = Html::tag($tag, isset($item['content']) ? $item['content'] : '', $options);
            }
        }
        $headers[] = Html::tag('li', $header, $headerOptions);
    }
    $headersHtml = Html::tag('ul', implode("\n", $headers), $this->options);
    $panesHtml = $this->renderPanes($panes);
    return strtr($this->template, [
        '{headers}' => $headersHtml,
        '{panes}' => $panesHtml,
    ]);
}

            

                public function renderPanes($panes)
{
    return $this->renderTabContent ? "\n" . Html::tag('div', implode("\n", $panes), $this->tabContentOptions) : '';
}

            

                public function run()
{
    $this->registerPlugin('tab');
    return $this->renderItems();
}