How to display custom fields in single post based on category?

I'm developing a site locally using WordPress and have used the plugin Advanced Custom Fields to create a group of fields that will display when post category is set to 'Front Page Events'. This category has a slug of fpe.

I put the code below in my child theme's functions.php to create a path to a single template folder:

/*
* Creates a path to single template folder for Front Page Events to be viewed as single posts
*/
define('SINGLE_PATH', TEMPLATEPATH . '/single');
 
/**
* Filter the single_template with our custom function
*/
add_filter('single_template', 'my_single_template');
 
/**
* Single template function which will choose our template
*/
function my_single_template($single) {
global $wp_query, $post;
 
/**
* Checks for single template by category
* Check by category slug and ID
*/
foreach((array)get_the_category() as $cat) :
 
if(file_exists('SINGLE_PATH' . '/single-cat-' . $cat->slug . '.php'))
return SINGLE_PATH . '/single-cat-' . $cat->slug . '.php';
 
elseif(file_exists('SINGLE_PATH' . '/single-cat-' . $cat->term_id . '.php'))
return SINGLE_PATH . '/single-cat-' . $cat->term_id . '.php';
 
endforeach;
}

I then manually created a folder in my theme (a child of twentyseventeen) called 'single'.

I copied single.php from the parent theme and pasted it into twentyseventeen-child/single. I then renamed this file to single-cat-fpe.php. I then added some code to get the custom fields from the post:

<?php
/**
 * Template Name: Front Page Events
 * Template Post Type: post, page
 * 
 * @link https://developer.wordpress.org/themes/basics/template-hierarchy/#single-post
 *
 * @package WordPress
 * @subpackage Twenty_Seventeen
 * @since Twenty Seventeen 1.0
 * @version 1.0
 */

get_header(); ?>

<div class="wrap">
    <div id="primary" class="content-area">
        <main id="main" class="site-main" role="main">



            <?php
            // Start the Loop.
            while ( have_posts() ) :
                the_post(); ?>

                <h1>TEST</h1>
                
                <?php 

                get_template_part( 'template-parts/post/content', get_post_format() ); ?>

                <p><?php echo the_field('event_title'); ?></p>
                <p><?php echo the_field('event_description'); ?></p>
                <p><?php echo the_field('event_link'); ?></p> 
        

                // If comments are open or we have at least one comment, load up the comment template.
                if ( comments_open() || get_comments_number() ) :
                    comments_template();
                endif;

                the_post_navigation(
                    array(
                        'prev_text' => '<span class="screen-reader-text">' . __( 'Previous Post', 'twentyseventeen' ) . '</span><span aria-hidden="true" class="nav-subtitle">' . __( 'Previous', 'twentyseventeen' ) . '</span> <span class="nav-title"><span class="nav-title-icon-wrapper">' . twentyseventeen_get_svg( array( 'icon' => 'arrow-left' ) ) . '</span>%title</span>',
                        'next_text' => '<span class="screen-reader-text">' . __( 'Next Post', 'twentyseventeen' ) . '</span><span aria-hidden="true" class="nav-subtitle">' . __( 'Next', 'twentyseventeen' ) . '</span> <span class="nav-title">%title<span class="nav-title-icon-wrapper">' . twentyseventeen_get_svg( array( 'icon' => 'arrow-right' ) ) . '</span></span>',
                    )
                );

            endwhile; // End the loop.
            ?>

        </main><!-- #main -->
    </div><!-- #primary -->
    <?php get_sidebar(); ?>
</div><!-- .wrap -->

<?php
get_footer();

I am able to get the data from the custom fields to show up in a slider on the front page of the site. However, the custom fields are not showing up when I just try to view the single post. (Nor is the test line with the h1 tags.) I am also not able to see the template I created in the post editor. Can anyone help me figure out how I can correctly display the custom fields when viewing a single post in this category?

Solution

Actually it looks like this might have been a theme-related issue. Because I'm using a child of twenty seventeen, it was necessary to put the single post file in template-parts/post/content-php. I've solved it now.