Howto check version of another plugin and then add a submenu page to it

Question

i'm writing a plugin which requires another plugin. So i have to check first if the other plugin exists in a correct version.

If yes i want to add a submenu page to the plugin page but here my code doesn't seem to work.

I think the problem is, that i only can check the existence of other plugins with a late hook (admin_init). But to add submenus i have to use an earlier hook (admin_menu). How to solve that?

class acf_multisite_sync {

    function __construct() {

        add_action('admin_init', array($this, 'acf_sync_init'));

    }

    function acf_sync_init() {

        $plugins = get_plugins();

        if (isset($plugins['advanced-custom-fields-pro/acf.php'])) {

            if ($plugins['advanced-custom-fields-pro/acf.php']['Version'] >= 5 
                && is_plugin_active('advanced-custom-fields-pro/acf.php')
                && is_main_site()) {

                add_action('admin_menu', array($this, 'acf_sync_submenu'));

            }

        }

    }

    function acf_sync_submenu() {

        add_submenu_page(
            'edit.php?post_type=acf-field-group', 
            'Multisite', 
            'Multisite', 
            'manage_options', 
            'acf-sync', 
            array($this, 'acf_sync_callback')
        );

    }

    function acf_sync_callback() {

        echo 'My Submenu Content';

    }

}

new acf_multisite_sync();

Answer 1

Ok i got it. The solution is to use an earlier hook for checking plugins. But then the function get_plugins() is not available so i have to include it for using. The working code:

class acf_multisite_sync {

    function __construct() {

        add_action('plugins_loaded', array($this, 'acf_sync_init'));

    }

    function acf_sync_init() {

        if (!function_exists('get_plugins')) {
            require_once ABSPATH . 'wp-admin/includes/plugin.php';
        }

        $plugins = get_plugins();

        if (isset($plugins['advanced-custom-fields-pro/acf.php'])) {

            if ($plugins['advanced-custom-fields-pro/acf.php']['Version'] >= 5 
                && is_plugin_active('advanced-custom-fields-pro/acf.php')
                && is_main_site()) {

                add_action('admin_menu', array($this, 'acf_sync_submenu'), 100);

            }

        }

    }

    function acf_sync_submenu() {

        add_submenu_page(
            'edit.php?post_type=acf-field-group', 
            'Multisite', 
            'Multisite', 
            'manage_options', 
            'acf-sync', 
            array($this, 'acf_sync_callback')
        );

    }

    function acf_sync_callback() {

        echo 'My Submenu Content';

    }

}

new acf_multisite_sync();