@xuzo – It is save to use this, even if there is only one accordion. You will anyway need a uniqe ID for the rows of the accordion.
In this example I use get_row_index() to give the ID:
<?php if ( have_rows('columns') ) : ?>
<div class="row">
<?php while ( have_rows('columns') ) : the_row(); ?>
<?php if ( get_row_layout() == 'columns_row_row_accordion'): ?>
<section class="column column_accordion __ col-12">
<?php $Acc = get_row_index(); ?>
<?php if( have_rows('accordion_zeile') ) : ?>
<div id="accordion_<?php echo $Acc; ?>">
<?php while ( have_rows('accordion_zeile') ) : the_row(); ?>
<div class="card">
<div class="card-header" id="heading_<?php echo get_row_index(); ?>_<?php echo $Acc; ?>">
<h4 class="mb-0">
<button class="btn btn-link" data-toggle="collapse" data-target="#collapse_<?php echo get_row_index(); ?>_<?php echo $Acc; ?>" aria-expanded="true" aria-controls="collapse_<?php echo get_row_index(); ?>_<?php echo $Acc; ?>">
<?php the_sub_field("accordion_titel"); ?>
</button>
</h4>
</div>
<div id="collapse_<?php echo get_row_index(); ?>_<?php echo $Acc; ?>" class="collapse" aria-labelledby="heading_<?php echo get_row_index(); ?>_<?php echo $Acc; ?>" data-parent="#accordion_<?php echo $Acc; ?>">
<div class="card-body">
<?php the_sub_field("accordion_text"); ?>
</div>
</div>
</div>
<?php endwhile; ?>
</div>
<?php endif; ?>
</section>
<?php endif; ?>
<?php endwhile; ?>
</div>
<?php endif; ?>
And in this example I use “uniqid” to give an ID:
https://codepen.io/herrfischer/pen/yqrZzm
Feel free to ask if you need more help.
