Display posts in the order of their selection - php

Question

I've offert the possibility to my client to choose one by one the related post for each post. I've set up a custom field with ACF and use this to display the choosen posts or random posts :
<?php $terms = get_the_terms( $post->ID , 'custom-taxonomy1' ); if ( !empty( $terms ) ) :?>
<?php
$related_acf = get_field('related_group');
$rel_posts = $related_acf["related posts"];
$related_ids = array();
foreach ( $rel_posts as $rel_post) {
array_push($related_ids, $rel_post['post']);
}
global $post;
$current_post_type = get_post_type( $post );
$terms = get_the_terms( $post->ID , 'custom-taxonomy1' );
$term_ids = array_values( wp_list_pluck( $terms,'term_id' ) );
$post_count_skrn = get_theme_mod('progression_studios_media_more_like_post_count', '3');
if ( count($related_ids) > 0 ) {
$args=array(
'post_type' => array('custompost1', 'custompost2', 'post'),
'post__in' => $related_ids
);
} else {
$args=array(
'post_type' => $current_post_type,
'posts_per_page'=> $post_count_skrn,
'orderby'=>'rand', // Randomize the posts
'post__not_in' => array( $post->ID ),
'tax_query' => array(
array(
'taxonomy' => 'video-genres',
'terms' => $term_ids,
'field' => 'id',
'operator' => 'IN'
)
),
);
}
So I wonder if I can add something like :
if ( count($related_ids) > 0 ) {
$args=array(
'post_type' => array('custompost1', 'custompost2', 'post'),
'orderby'=>'XXXXX', // Ordering the posts with the order of selection
'post__in' => $related_ids
);
Best regards,
Clément

Answer 1

Wordpress have 'orderby'=>'post__in'
Posts will now be displayed according to their position in the $related_ids array
$args=array(
'post_type' => array('custompost1', 'custompost2', 'post'),
'orderby'=>'post__in', // Ordering the posts with the order of selection
'post__in' => $related_ids
);