Admin-plugin elements

<?php
namespace Grav\Plugin;

use Grav\Common\Data;
use Grav\Common\Plugin;
use Grav\Common\Grav;
use Grav\Common\Uri;
use Grav\Common\Taxonomy;
use Grav\Common\Page\Page;
use RocketTheme\Toolbox\Event\Event;

class PluginNamePlugin extends Plugin {

    protected $route = 'pluginname';

    public static function getSubscribedEvents() {
        return [ 
            'onPageInitialized' => ['onPageInitialized', 0],
            'onGetPageTemplates' => ['onGetPageTemplates', 0],
            'onAdminMenu' => ['onAdminMenu', 0],
            'onTwigTemplatePaths' => ['onTwigTemplatePaths', 0]
        ];
    }
    public function onPageInitialized(Event $event) {
        if ($this->isAdmin()) {
            $assets = $this->grav['assets'];
            $pluginsobject = (array) $this->config->get('plugins');
            if (isset($pluginsobject['pluginname'])) {
                if ($pluginsobject['pluginname']['enabled'] && $pluginsobject['pluginname']['current']) {
                    $assets->addCss('plugin://pluginname/styles/' . $pluginsobject['pluginname']['current'] . '.css', 1);
                    $assets->addCss('plugin://pluginname/styles/radioimage.css', 1);
                }
            }
        }
    }
    public function onTwigTemplatePaths() {
        if ($this->isAdmin()) {
            $this->grav['twig']->twig_paths[] = __DIR__ . '/templates';
        }
    }
    public function onGetPageTemplates($event) {
        if ($this->isAdmin()) {
            $types = $event->types;
            $locator = Grav::instance()['locator'];
            $types->scanBlueprints($locator->findResources('plugin://' . $this->name . '/blueprints'));
            $types->scanTemplates($locator->findResources('plugin://' . $this->name . '/templates'));
        }
    }
    public function onAdminMenu() {
        if ($this->isAdmin()) {
            $this->grav['twig']->plugins_hooked_nav['pluginname'] = ['route' => $this->route, 'icon' => 'fa-database'];
        }
    }
}