Menus

Elgg contains helper code to build menus throughout the site.

Every single menu requires a name, as does every single menu item. These are required in order to allow easy overriding and manipulation, as well as to provide events for theming.

Contents

Basic usage
Admin menu
Advanced usage
Creating a new menu
Child Dropdown Menus
Theming
Toggling Menu Items
JavaScript

Basic usage 

Basic functionalities can be achieved through these two functions:

elgg_register_menu_item() to add an item to a menu

elgg_unregister_menu_item() to remove an item from a menu

You normally want to call them from your plugin’s init function.

Examples

// Add a new menu item to the site main menu
elgg_register_menu_item('site', array(
        'name' => 'itemname',
        'text' => 'This is text of the item',
        'href' => '/item/url',
));

// Remove the "Elgg" logo from the topbar menu
elgg_unregister_menu_item('topbar', 'elgg_logo');

Advanced usage 

Headers

For accessibility reasons each menu will get an aria-label which defaults to the menu name, but can be translated by making sure the language key menu:<menu name>:header is available.

It’s also possible to show menu section headers by setting show_section_headers to true in elgg_view_menu()

echo elgg_view_menu('my_menu', [
        'show_section_headers' => true,
]);

The headers have a magic language key available menu:<menu name>:header:<section name> in order to be able to translate the headers.

Events

You can get more control over menus by using events and the public methods provided by the ElggMenuItem class.

There are three events that can be used to modify a menu:

'parameters', 'menu:<menu name>' to add or modify parameters use for the menu building (eg. sorting)
'register', 'menu:<menu name>' to add or modify items (especially in dynamic menus)
'prepare', 'menu:<menu name>' to modify the structure of the menu before it is displayed

When you register an event handler, replace the <menu name> part with the internal name of the menu.

The third parameter passed into a menu handler contains all the menu items that have been registered so far by Elgg core and other enabled plugins. In the handler we can loop through the menu items and use the class methods to interact with the properties of the menu item.

In some cases a more granular version of the register and prepare menu events exist with menu:<menu name>:<type>:<subtype>, this applies when the menu gets provided an \ElggEntity in $params['entity'] or an \ElggAnnotation in $params['annotation'] or an \ElggRelationship in $params['relationship'].

Examples

Example 1: Change the URL for menu item called “albums” in the owner_block menu:

/**
 * Initialize the plugin
 */
function my_plugin_init() {
        // Register an event handler for the owner_block menu
        elgg_register_event_handler('register', 'menu:owner_block', 'my_owner_block_menu_handler');
}

/**
 * Change the URL of the "Albums" menu item in the owner_block menu
 */
function my_owner_block_menu_handler(\Elgg\Event $event) {
        $owner = $event->getEntityParam();

        // Owner can be either user or a group, so we
        // need to take both URLs into consideration:
        switch ($owner->getType()) {
                case 'user':
                        $url = "album/owner/{$owner->guid}";
                        break;
                case 'group':
                        $url = "album/group/{$owner->guid}";
                        break;
        }

        $items = $event->getValue();
        if ($items->has('albums')) {
                $items->get('albums')->setURL($url);
        }

        return $items;
}

Example 2: Modify the entity menu for the ElggBlog objects

Remove the thumb icon
Change the “Edit” text into a custom icon

/**
 * Initialize the plugin
 */
function my_plugin_init() {
        // Register an event handler for the entity menu
        elgg_register_event_handler('register', 'menu:entity', 'my_entity_menu_handler');
}

/**
 * Customize the entity menu for ElggBlog objects
 */
function my_entity_menu_handler(\Elgg\Event $event) {
        // The entity can be found from the $params parameter
        $entity = $event->getEntityParam();

        // We want to modify only the ElggBlog objects, so we
        // return immediately if the entity is something else
        if (!$entity instanceof ElggBlog) {
                return;
        }

        $items = $event->getValue();

        $items->remove('likes');

        if ($items->has('edit')) {
                $items->get('edit')->setText('Modify');
                $items->get('edit')->icon = 'pencil';
        }

        return $items;
}

Creating a new menu 

Elgg provides multiple different menus by default. Sometimes you may however need some menu items that don’t fit in any of the existing menus. If this is the case, you can create your very own menu with the elgg_view_menu() function. You must call the function from the view, where you want to menu to be displayed.

Example: Display a menu called “my_menu” that displays it’s menu items in alphapetical order:

// in a resource view
echo elgg_view_menu('my_menu', array('sort_by' => 'text'));

You can now add new items to the menu like this:

// in plugin init
elgg_register_menu_item('my_menu', array(
        'name' => 'my_page',
        'href' => 'path/to/my_page',
        'text' => elgg_echo('my_plugin:my_page'),
));

Furthermore it is now possible to modify the menu using the events 'register', 'menu:my_menu' and 'prepare', 'menu:my_menu'.

Theming 

The menu name, section names, and item names are all embedded into the HTML as CSS classes (normalized to contain only hyphens, rather that underscores or colons). This increases the size of the markup slightly but provides themers with a high degree of control and flexibility when styling the site.

Example: The following would be the output of the foo menu with sections alt and default containing items baz and bar respectively.

<ul class="elgg-menu elgg-menu-foo elgg-menu-foo-alt">
        <li class="elgg-menu-item elgg-menu-item-baz"></li>
</ul>
<ul class="elgg-menu elgg-menu-foo elgg-menu-foo-default">
        <li class="elgg-menu-item elgg-menu-item-bar"></li>
</ul>

Toggling Menu Items 

There are situations where you wish to toggle menu items that are actions that are the opposite of each other and ajaxify them. E.g. like/unlike, friend/unfriend, ban/unban, etc. Elgg has built-in support for this kind of actions. When you register a menu item you can provide a name of the menu item (in the same menu) that should be toggled. An ajax call will be made using the href of the menu item.

elgg_register_menu_item('my_menu', [
        'name' => 'like',
        'data-toggle' => 'unlike',
        'href' => 'action/like',
        'text' => elgg_echo('like'),
]);

elgg_register_menu_item('my_menu', [
        'name' => 'unlike',
        'data-toggle' => 'like',
        'href' => 'action/unlike',
        'text' => elgg_echo('unlike'),
]);

Note

The menu items are optimistically toggled. This means the menu items are toggled before the actions finish. If the actions fail, the menu items will be toggled back.

JavaScript 

It is common that menu items rely on JavaScript. You can bind client-side events to menu items by placing your JavaScript into a module and defining the requirement during the registration.

elgg_register_menu_item('my_menu', array(
        'name' => 'hide_on_click',
        'href' => '#',
        'text' => elgg_echo('hide:on:click'),
        'item_class' => '.hide-on-click',
        'deps' => ['navigation/menu/item/hide_on_click'],
));

// in navigation/menu/item/hide_on_click.mjs
import 'jquery';

$(document).on('click', '.hide-on-click', function(e) {
    e.preventDefault();
    $(this).hide();
});