atravelblog/functions.php

<?php

add_action( 'wp_enqueue_scripts', 'td_theme_styles' );
function td_theme_styles() {
    wp_enqueue_style( 'parent-style', get_template_directory_uri() . '/style.css' );
    wp_enqueue_script(
      'google-maps',
      '//maps.googleapis.com/maps/api/js?key=AIzaSyDHNT102YHu-TP50F78bPyvf5ia6K6cjU8&callback=initMap',
      array(),
      '1.0',
      true
    );
}

// Add google API key
function my_acf_google_map_api( $api ){
	$api['key'] = 'AIzaSyDHNT102YHu-TP50F78bPyvf5ia6K6cjU8';
	return $api;
}

add_filter('acf/fields/google_map/api', 'my_acf_google_map_api');

// Only show posts of category Urlaub (id=2)
function my_home_category( $query ) {
	if ( $query->is_home() && $query->is_main_query() ) {
		$query->set( 'cat', '2');
	}
}

add_action( 'pre_get_posts', 'my_home_category' );

// Related posts function
function atravelblog_related_posts() {
	global $post;
	$thisID = get_the_ID();
	$cat = get_the_category()[0]->name;
	if ( $cat == 'Urlaub' ){
		$tagebuch = new WP_Query( array(
			'category_name' => 'Tagebuch',
			'posts_per_page' => -1,
			'meta_query'	=> array(
				array(
					'key' => 'urlaub', // name of custom field
					'value' => get_the_ID(), // matches exaclty "123", not just 123. This prevents a match for "1234"
					'compare' => '='
				)
			)
		) );
	    if ($tagebuch->have_posts()) :
		    echo('<h4 style="color: white; margin-top: 20px;" class="section-inner">Tagebuch Einträge:</h4>');
			echo('<div class="related-posts posts section-inner">');
	        while ( $tagebuch->have_posts() ) : $tagebuch->the_post();
		        global $post;
		        get_template_part( 'content', get_post_format() );
	        endwhile;
		    echo('<div class="clear"></div>');
		    echo('</div> <!-- /related-posts -->');
        endif;
		wp_reset_query();
		$album = new WP_Query( array(
			'category_name' => 'Album',
			'posts_per_page' => -1,
			'meta_query'	=> array(
				array(
					'key' => 'urlaub', // name of custom field
					'value' => get_the_ID(), // matches exaclty "123", not just 123. This prevents a match for "1234"
					'compare' => '='
				)
			)
		) );
		if ($album->have_posts()) :
			echo('<h4 style="color: white; margin-top: 20px;" class="section-inner">Fotoalben:</h4>');
			echo('<div class="related-posts posts section-inner">');
			while ( $album->have_posts() ) : $album->the_post();
				global $post;
				get_template_part( 'content', get_post_format() );
			endwhile;
			echo('<div class="clear"></div>');
			echo('</div> <!-- /related-posts -->');
		endif;
		wp_reset_query();
		$touren = new WP_Query( array(
			'category_name' => 'Tour',
			'posts_per_page' => -1,
			'meta_query'	=> array(
				array(
					'key' => 'urlaub', // name of custom field
					'value' => get_the_ID(), // matches exaclty "123", not just 123. This prevents a match for "1234"
					'compare' => '='
				)
			)
		) );
		if ($touren->have_posts()) :
			echo('<h4 style="color: white; margin-top: 20px;" class="section-inner">Touren:</h4>');
			echo('<div class="related-posts posts section-inner">');
			while ( $touren->have_posts() ) : $touren->the_post();
				global $post;
				get_template_part( 'content', get_post_format() );
			endwhile;
			echo('<div class="clear"></div>');
			echo('</div> <!-- /related-posts -->');
		endif;
		wp_reset_query();
    } elseif($cat == 'Tour' || $cat == 'Album' || $cat == 'Tagebuch') {
        $urlaub = new WP_Query(array('p' => get_field('urlaub')[0]));
		if ($urlaub->have_posts()) :
			echo('<h4 style="color: white; margin-top: 20px;" class="section-inner">Urlaub:</h4>');
			echo('<div class="related-posts posts section-inner">');
			while ( $urlaub->have_posts() ) : $urlaub->the_post();
				global $post;
				get_template_part( 'content', get_post_format() );
			endwhile;
			echo('<div class="clear"></div>');
			echo('</div> <!-- /related-posts -->');
		endif;
		wp_reset_query();
    }
}