Class yii\bootstrap\Nav

                public function init()
{
    parent::init();
    if ($this->route === null && Yii::$app->controller !== null) {
        $this->route = Yii::$app->controller->getRoute();
    }
    if ($this->params === null) {
        $this->params = Yii::$app->request->getQueryParams();
    }
    if ($this->dropDownCaret === null) {
        $this->dropDownCaret = '<span class="caret"></span>';
    }
    Html::addCssClass($this->options, ['widget' => 'nav']);
}

            

                protected function isChildActive($items, &$active)
{
    foreach ($items as $i => $child) {
        if (is_array($child) && !ArrayHelper::getValue($child, 'visible', true)) {
            continue;
        }
        if (ArrayHelper::remove($items[$i], 'active', false) || $this->isItemActive($child)) {
            Html::addCssClass($items[$i]['options'], 'active');
            if ($this->activateParents) {
                $active = true;
            }
        }
        $childItems = ArrayHelper::getValue($child, 'items');
        if (is_array($childItems)) {
            $activeParent = false;
            $items[$i]['items'] = $this->isChildActive($childItems, $activeParent);
            if ($activeParent) {
                Html::addCssClass($items[$i]['options'], 'active');
                $active = true;
            }
        }
    }
    return $items;
}

            

                protected function isItemActive($item)
{
    if (!$this->activateItems) {
        return false;
    }
    if (isset($item['url']) && is_array($item['url']) && isset($item['url'][0])) {
        $route = $item['url'][0];
        if ($route[0] !== '/' && Yii::$app->controller) {
            $route = Yii::$app->controller->module->getUniqueId() . '/' . $route;
        }
        if (ltrim($route, '/') !== $this->route) {
            return false;
        }
        unset($item['url']['#']);
        if (count($item['url']) > 1) {
            $params = $item['url'];
            unset($params[0]);
            foreach ($params as $name => $value) {
                if ($value !== null && (!isset($this->params[$name]) || $this->params[$name] != $value)) {
                    return false;
                }
            }
        }
        return true;
    }
    return false;
}

            

                protected function renderDropdown($items, $parentItem)
{
    /** @var Widget $dropdownClass */
    $dropdownClass = $this->dropdownClass;
    return $dropdownClass::widget([
        'options' => ArrayHelper::getValue($parentItem, 'dropDownOptions', []),
        'items' => $items,
        'encodeLabels' => $this->encodeLabels,
        'clientOptions' => false,
        'view' => $this->getView(),
    ]);
}

            

                public function renderItem($item)
{
    if (is_string($item)) {
        return $item;
    }
    if (!isset($item['label'])) {
        throw new InvalidConfigException("The 'label' option is required.");
    }
    $encodeLabel = isset($item['encode']) ? $item['encode'] : $this->encodeLabels;
    $label = $encodeLabel ? Html::encode($item['label']) : $item['label'];
    $options = ArrayHelper::getValue($item, 'options', []);
    $items = ArrayHelper::getValue($item, 'items');
    $url = ArrayHelper::getValue($item, 'url', '#');
    $linkOptions = ArrayHelper::getValue($item, 'linkOptions', []);
    if (isset($item['active'])) {
        $active = ArrayHelper::remove($item, 'active', false);
    } else {
        $active = $this->isItemActive($item);
    }
    if (empty($items)) {
        $items = '';
    } else {
        $linkOptions['data-toggle'] = 'dropdown';
        Html::addCssClass($options, ['widget' => 'dropdown']);
        Html::addCssClass($linkOptions, ['widget' => 'dropdown-toggle']);
        if ($this->dropDownCaret !== '') {
            $label .= ' ' . $this->dropDownCaret;
        }
        if (is_array($items)) {
            $items = $this->isChildActive($items, $active);
            $items = $this->renderDropdown($items, $item);
        }
    }
    if ($active) {
        Html::addCssClass($options, 'active');
    }
    return Html::tag('li', Html::a($label, $url, $linkOptions) . $items, $options);
}

            

                public function renderItems()
{
    $items = [];
    foreach ($this->items as $i => $item) {
        if (isset($item['visible']) && !$item['visible']) {
            continue;
        }
        $items[] = $this->renderItem($item);
    }
    return Html::tag('ul', implode("\n", $items), $this->options);
}

            

                public function run()
{
    BootstrapAsset::register($this->getView());
    return $this->renderItems();
}