I ended up using a sligtily modified version. You have to place this code in your functions.php and have to save each individual post in order to show/update your featured image (unfortunately, if you already have many posts this may prove to be a tedious task). Make sure you run these functions only for the custom post types you need.
add_action('acf/save_post', 'flex_CustomExcerptSetByACF', 50);
function flex_CustomExcerptSetByACF() {
global $post;
$post_id = ( $post->ID ); // Current post ID
$post_excerpt = get_field( 'post_excerpt', $post_id ); // ACF field
if ( ( !empty( $post_id ) ) AND ( $post_excerpt ) ) {
$post_array = array(
'ID' => $post_id,
'post_excerpt' => $post_excerpt
);
remove_action('save_post', 'flex_CustomExcerptSetByACF', 50); // Unhook this function so it doesn't loop infinitely
wp_update_post( $post_array );
add_action( 'save_post', 'flex_CustomExcerptSetByACF', 50); // Re-hook this function
}
}
add_action('acf/save_post', 'flex_FeaturedImageSetByACF', 50);
function flex_FeaturedImageSetByACF() {
$current_screen = get_current_screen(); // Current admin screen needed to identify the current cpt
$current_cpt_name = $current_screen->post_type; // Current cpt name
$current_cpt_support = 'thumbnail'; // We want to check if the CPT supports this feature
global $post;
$post_id = ( $post->ID ); // Current post ID
$post_image_field = get_field('post_head_img', $post_id ); // ACF field
if ( !empty( $post_id ) ) {
if ( !empty( $post_image_field ) ) {
$post_image_id = $post_image_field['id']; // ACF image filed ID
$post_image_url = $post_image_field['url']; // ACF image filed URL
// If current cpt supports thumbnails/featured images
if ( post_type_supports( $current_cpt_name, $current_cpt_support ) ) {
if ( ( $post_image_url ) AND ( ( $post_image_url ) != ( get_the_post_thumbnail() ) ) ) {
update_post_meta($post_id, '_thumbnail_id', $post_image_id);
}
}
} else {
update_post_meta( $post_id, '_thumbnail_id', 0 );
}
}
}
On a side note, if your issue is limited to showing exceprt & featured images on certain template files, it may prove easier to edit these.
