Show calendar to specific users based on custom field - arrays

Question

I use the calendar plugin from http://tri.be/ on a worpress website for a private website (it’s like an intranet..).
On this calendar I put all the planned meetings, but I would like that the current logged in user can see only the events he/she is supposed to join.
I thought that I can create a custom field, named, for example, “mustjoin” and put there a list of registered usernames as values.
Then do a check on the page.
If the current logged in username is in that list, he/she can see the event on the calendar.. otherwise not.
Something like :
if ( $current_user->user_login == get_field(mustjoin)) { ?>
//CODE IF OK
<?php } else { ?>
//CODE ELSE<?php } ?>
This of course is working when I have only one username in the ACF box, as soon as I put more than one username.. it doesn't work anymore because it is not an Array..
How can I create an array with ACF? what function and how can I interrogate that array?
This is the part of the code I need to show IF the current user username is in the value list ‘mustjoin’
<?php while ($day['events']->have_posts()) : $day['events']->the_post() ?>
<?php tribe_get_template_part('month/single', 'event') ?>
<?php endwhile; ?>
On another forum a guy told me to use this snippet :
function searchForName($name, $array) {
foreach ($array as $key => $val) {
if ($val['nickname'] === $name) {
return true;
}
}
return null;
}
$current_user = wp_get_current_user();
if(searchForName($current_user->user_login,get_field('mustjoin'))):
//CODE GOES HERE
endif;
But it doesn't work..

Answer 1

Thank you for your comment. This is the code, and it works at 99%.
<?php $current_user = wp_get_current_user(); ?>
<?php global $user_login;
get_currentuserinfo(); ?>
<?php $lookforuser = get_field('mustjoin') ?>
<?php if (strpos($lookforuser, $user_login) !== false) { ?>
<?php while ($day['events']->have_posts()) : $day['events']->the_post() ?>
<?php tribe_get_template_part('month/single', 'event') ?>
<?php endwhile; ?>
<?php } ?>
But I need to ask you if this code is "clean" or if I can make it better/faster.
Because when I open the calendar page, I can't see anything.. as soon as I refresh the page, all the events (where I am supposed to join) appear.
How can I fix it? (I tried with different computers/browsers, no changes..)
Thank you.
Thanks to another guy on another website, finally it works at 100%!
I just needed to check the user before the events loop :
<?php $current_user = wp_get_current_user(); ?>
<?php global $user_login;
get_currentuserinfo(); ?>
<?php while ($day['events']->have_posts()) : $day['events']->the_post(); ?>
<?php $lookforuser = get_field('mustjoin'); ?>
<?php if (strpos($lookforuser, $user_login) !== false)
tribe_get_template_part('month/single', 'event'); ?>
<?php endwhile; ?>
Thank you anyway for the right suggestion and help.