Advanced Custom Fields: Select values and create repeater rows - php

Question

I have a list of posts from a custom post type. What I want to do, is for the user to select (checkboxes) all the posts they want to add and create a repeater row for each selection.
Within the repeater, I am using a Post Object field - this post object field is the same as the checkboxes of custom post type posts. (I am doing this, as I need to pull information from each post and the user can then assign further options to this row)
So, how would I allow the user to select these posts and then upon clicking a button, populate the repeater rows? The select value is the post object value from this repeater...
Any help would be appreciated, as I have spent far too long on this, with no solution in sight!

Answer 1

Create a new field group and link it with the post type you require.
In this field group create a field called posts and make it a relationship type field, filtered with the post type you want to be selectable to create repeater field rows.
Make sure return format is set to Post ID.
Then create a repeater field called posts_repeater with sub rows post (post object field) and quantity (number field).
Make sure the post (post object field) return format is also set to Post ID
Now add this to your functions. (read my code comments)
// run modifications when saving or updating the post
add_action('acf/save_post', 'acf_save_post_type', 20);
/**
* action to run modifications when saving or updating the post
* #param int $post_id
* #return void
*/
function acf_save_post_type($post_id) {
// get our current global post object
global $post;
// check we are on the correct post type else return now
if($post->post_type <> 'post') return;
// if post post status is publish or draft
if($post->post_status == 'publish' || $post->post_status == 'draft') {
// if posts repeater does not already have any rows set
if (!get_field('posts_repeater', $post_id)) {
// get the posts relationship field
$posts = get_field('posts', $post_id);
// create an empty repeater field array
$repeater = [];
// for each post selected in posts relationship field
foreach ($posts as $key => $value) {
// add repeater row and assign current posts field id to post object field
$repeater[] = [
'post' => $value
];
}
// temp remove the save post action
remove_action('acf/save_post', 'acf_save_post_type', 20);
// create the repeater field rows
update_field('posts_repeater', $repeater, $post_id);
// re add the save post action
add_action('acf/save_post', 'acf_save_post_type', 20);
}
}
}
This will then populate the repeater with the posts selected in the posts field when updating the post in the admin.
But if the posts_repeater field already has rows, then nothing with happen.
So in your post editor, if you select some posts in the posts acf relationship field...
Then click update, you will now notice the posts_repeater field has the select posts from the posts field defined in each repeater row. Ready to populate quantities.
If you update the post again, because the repeater field now has row data, nothing will happen.
User will have to manually add any extra posts via the repeater field.