I try to achieve the following. I have two post types, “projects” & “kuenstlerinnen” (artists) Within the post type “projects”, there’s an ACF relationship field setup, connecting these two to together → “project_to_kunstlerin”
The post-type “künstlerinnen” (Artists) contains two ACF text fields: first-name (“artist_vorname”) & Last- or Group-Name (“artist_nachname”). There is a code snippet running, which saves both fields to the title → “artist_vorname””artist_nachname”
I know would like to have a hidden text field within the projects post type, which is automatically populated with the first value of the “project_to_kunstlerin” field. It should only use the last name field. The reason I try to get this to work, is that I can order by this hidden field, so I get the posts ordered by the last name of the artist.
So far I come up with the following code-snippet:
<?php
//Make special artist field autosave for sorting
function write_artist_name_to_hidden( $post_id ) {
$post_type = 'projects'; //custom post type for events
//Check if we are saving correct post type
if( get_post_type( $post_id ) != $post_type)
return;
//Check it's not an auto save routine
if( defined('DOING_AUTOSAVE') && DOING_AUTOSAVE )
return;
// get the artist id of the post. Note this is in a relationship field
$nameofartist = get_post_field ('project_to_kunstlerin', $post);
// update the artist value
update_field( 'project_kunstlerin_nach_name_sort', $nameofartist, $post_id );
}
add_action('save_post', 'write_artist_name_to_hidden');
In the backend, it now populates the destination ACF field with:
One artist: “[“37″]” Two artists: [“37″,”38”]
These are the IDs.
How can I get another value there instead of the post id?
In theory, it must be something like:
Check with IDs are in the “project_to_kunstlerin” relationship field.
Take the first ID.
Look up, which value is stored in “artist_nachname” of ID in post type “kuenstlerinnen”
Maybe anybody of you has an idea how to get this to work? Your help is highly appreciated!
