add_action within foreach loop.

class TmeBlockShortcode
{

function __construct()
{
add_action( 'init', array($this, 'DetectBlockShortcode') );
add_shortcode( 'block', array($this,'GetSingleBlock') );

//add_action( 'wp_head', array($this,'SingleBlockCSS') );
$this->post_content = '';
}

function GetSingleBlock($atts)
{
$data = shortcode_atts(
array(
'id' => ''
), $atts);

$posts = $this->GetPosts(1,$data, true);

if(count($posts) == 0)
{
return 'Block id (unieke naam) niet gevonden.';
}

if(get_field('active',$posts[0]->ID) == 1)
{
return do_shortcode( $posts[0]->post_content );
}

return '';
}

public function SingleBlockCSS()
{
$css = '<style>';

$css .= '</style>';
return $css;
}

public function DetectBlockShortcode()
{
$posts = $this->GetPosts('-1');
foreach ($posts as $post)
{
global $test;
$test = $post->ID;
$this->post_content = '321';
$this->post_content = $post->ID;

add_action( get_field('on_action',$post->ID), array($this, 'DetectBlockShortcode_add_action'));

echo '

';
                print_r( $this->post_content  );
            echo '

';
}
}

public function DetectBlockShortcode_add_action()
{
$nu = $this->post_content;
global $test;
echo '

';
            print_r($this->post_content);
            print_r($test);
            print_r($nu);
        echo '

';
//echo do_shortcode( $this->post_content );
$this->post_content = '';
}

private function GetPosts($posts_per_page = 1,$data = array(), $shortcode = false)
{
if(!isset($data['id']) && $shortcode == true)
{
return 'vegeet niet het block id (unieke naam) op te geven.';
}

if(isset($data['id']))
{
$meta = array(
'relation' => 'AND',
array(
'key' => 'unique_name',
'value' => $data['id'],
'compare' => '!='
),
array(
'key' => 'active',
'value' => 1,
'compare' => '='
)
);
}
else
{
$meta = array(
'relation' => 'AND',
array(
'key' => 'on_action',
'value' => 'no_action',
'compare' => '!='
),
array(
'key' => 'active',
'value' => 1,
'compare' => '='
)
);
}

$args = array(
'post_type' => 'blocks',
'posts_per_page' => $posts_per_page,
'meta_query' => $meta
);

$posts = get_posts($args);

return $posts;
}