Class yii\bootstrap4\Dropdown

Inheritanceyii\bootstrap4\Dropdown » yii\bootstrap4\Widget » yii\base\Widget
Uses Traitsyii\bootstrap4\BootstrapWidgetTrait
Source Code https://github.com/yiisoft/yii2-bootstrap4/blob/master/src/Dropdown.php

Dropdown renders a Bootstrap dropdown menu component.

For example,

<div class="dropdown">
    <a href="#" data-toggle="dropdown" class="dropdown-toggle">Label <b class="caret"></b></a>
    <?php
        echo Dropdown::widget([
            'items' => [
                ['label' => 'DropdownA', 'url' => '/'],
                ['label' => 'DropdownB', 'url' => '#'],
            ],
        ]);
    ?>
</div>

See also https://getbootstrap.com/docs/4.5/components/dropdowns/.

Public Properties

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Property Type Description Defined By
$clientEvents array The event handlers for the underlying Bootstrap JS plugin. yii\bootstrap4\BootstrapWidgetTrait
$clientOptions array The options for the underlying Bootstrap JS plugin. yii\bootstrap4\BootstrapWidgetTrait
$encodeLabels boolean Whether the labels for header items should be HTML-encoded. yii\bootstrap4\Dropdown
$items array List of menu items in the dropdown. yii\bootstrap4\Dropdown
$options array The HTML attributes for the widget container tag. yii\bootstrap4\Widget
$submenuOptions array|null The HTML attributes for sub-menu container tags. yii\bootstrap4\Dropdown

Public Methods

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Method Description Defined By
getView() yii\bootstrap4\BootstrapWidgetTrait
init() Initializes the widget. yii\bootstrap4\Dropdown
run() Renders the widget. yii\bootstrap4\Dropdown

Protected Methods

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Method Description Defined By
registerClientEvents() Registers JS event handlers that are listed in $clientEvents. yii\bootstrap4\BootstrapWidgetTrait
registerPlugin() Registers a specific Bootstrap plugin and the related events yii\bootstrap4\BootstrapWidgetTrait
renderItems() Renders menu items. yii\bootstrap4\Dropdown

Property Details

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$encodeLabels public property

Whether the labels for header items should be HTML-encoded.

public boolean $encodeLabels true
$items public property

List of menu items in the dropdown. Each array element can be either an HTML string, or an array representing a single menu with the following structure:

  • label: string, required, the label of the item link.
  • encode: bool, optional, whether to HTML-encode item label.
  • url: string|array, optional, the URL of the item link. This will be processed by \yii\helpers\Url::to(). If not set, the item will be treated as a menu header when the item has no sub-menu.
  • visible: bool, optional, whether this menu item is visible. Defaults to true.
  • disabled: bool, optional, whether this menu item is disabled. Defaults to false.
  • linkOptions: array, optional, the HTML attributes of the item link.
  • options: array, optional, the HTML attributes of the item.
  • active: bool, optional, whether the item should be on active state or not.
  • items: array, optional, the submenu items. The structure is the same as this property. Note that Bootstrap doesn't support dropdown submenu. You have to add your own CSS styles to support it.
  • submenuOptions: array, optional, the HTML attributes for sub-menu container tag. If specified it will be merged with $submenuOptions.

To insert divider use -.

public array $items = []
$submenuOptions public property

The HTML attributes for sub-menu container tags.

Method Details

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getView() public abstract method

Defined in: yii\bootstrap4\BootstrapWidgetTrait::getView()

See also \yii\base\Widget::getView().

public abstract \yii\web\View getView ( )
return \yii\web\View

The view object that can be used to render views or view files.

                abstract function getView();

            
init() public method

Initializes the widget.

This method will register the bootstrap asset bundle. If you override this method, make sure you call the parent implementation first.

public void init ( )

                public function init()
{
    parent::init();
    Html::addCssClass($this->options, ['widget' => 'dropdown-menu']);
}

            
registerClientEvents() protected method

Defined in: yii\bootstrap4\BootstrapWidgetTrait::registerClientEvents()

Registers JS event handlers that are listed in $clientEvents.

protected void registerClientEvents ( )

                protected function registerClientEvents()
{
    if (!empty($this->clientEvents)) {
        $id = $this->options['id'];
        $js = [];
        foreach ($this->clientEvents as $event => $handler) {
            $js[] = "jQuery('#$id').on('$event', $handler);";
        }
        $this->getView()->registerJs(implode("\n", $js));
    }
}

            
registerPlugin() protected method

Defined in: yii\bootstrap4\BootstrapWidgetTrait::registerPlugin()

Registers a specific Bootstrap plugin and the related events

protected void registerPlugin ( $name )
$name string

The name of the Bootstrap plugin

                protected function registerPlugin($name)
{
    $view = $this->getView();
    BootstrapPluginAsset::register($view);
    $id = $this->options['id'];
    if ($this->clientOptions !== false) {
        $options = empty($this->clientOptions) ? '' : Json::htmlEncode($this->clientOptions);
        $js = "jQuery('#$id').$name($options);";
        $view->registerJs($js);
    }
    $this->registerClientEvents();
}

            
renderItems() protected method

Renders menu items.

protected string renderItems ( $items, $options = [] )
$items array

The menu items to be rendered

$options array

The container HTML attributes

return string

The rendering result.

throws \yii\base\InvalidConfigException

if the label option is not specified in one of the items.

throws Exception

                protected function renderItems($items, $options = [])
{
    $lines = [];
    foreach ($items as $item) {
        if (is_string($item)) {
            $lines[] = ($item === '-')
                ? Html::tag('div', '', ['class' => 'dropdown-divider'])
                : $item;
            continue;
        }
        if (isset($item['visible']) && !$item['visible']) {
            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'];
        $itemOptions = ArrayHelper::getValue($item, 'options', []);
        $linkOptions = ArrayHelper::getValue($item, 'linkOptions', []);
        $active = ArrayHelper::getValue($item, 'active', false);
        $disabled = ArrayHelper::getValue($item, 'disabled', false);
        Html::addCssClass($linkOptions, ['widget' => 'dropdown-item']);
        if ($disabled) {
            ArrayHelper::setValue($linkOptions, 'tabindex', '-1');
            ArrayHelper::setValue($linkOptions, 'aria-disabled', 'true');
            Html::addCssClass($linkOptions, ['disable' => 'disabled']);
        } elseif ($active) {
            Html::addCssClass($linkOptions, ['activate' => 'active']);
        }
        $url = array_key_exists('url', $item) ? $item['url'] : null;
        if (empty($item['items'])) {
            if ($url === null) {
                $content = Html::tag('h6', $label, ['class' => 'dropdown-header']);
            } else {
                $content = Html::a($label, $url, $linkOptions);
            }
            $lines[] = $content;
        } else {
            $submenuOptions = $this->submenuOptions;
            if (isset($item['submenuOptions'])) {
                $submenuOptions = array_merge($submenuOptions, $item['submenuOptions']);
            }
            Html::addCssClass($submenuOptions, ['widget' => 'dropdown-submenu dropdown-menu']);
            Html::addCssClass($linkOptions, ['toggle' => 'dropdown-toggle']);
            $lines[] = Html::beginTag('div', array_merge_recursive(['class' => ['dropdown'], 'aria-expanded' => 'false'], $itemOptions));
            $lines[] = Html::a($label, $url, array_merge([
                'data-toggle' => 'dropdown',
                'aria-haspopup' => 'true',
                'aria-expanded' => 'false',
                'role' => 'button'
            ], $linkOptions));
            $lines[] = static::widget([
                'items' => $item['items'],
                'options' => $submenuOptions,
                'submenuOptions' => $submenuOptions,
                'encodeLabels' => $this->encodeLabels
            ]);
            $lines[] = Html::endTag('div');
        }
    }
    return Html::tag('div', implode("\n", $lines), $options);
}

            
run() public method

Renders the widget.

public void run ( )
throws \yii\base\InvalidConfigException

                public function run()
{
    BootstrapPluginAsset::register($this->getView());
    $this->registerClientEvents();
    return $this->renderItems($this->items, $this->options);
}