bootstrap collapse accordion with ACF repeater loop.php

<div class="panel-group" id="accordion" role="tablist" aria-multiselectable="true">
	<?php $i=1; while(has_sub_field('sections')) : ?>
		<div class="panel panel-default">
		    <div class="panel-heading" role="tab" id="heading-<?php echo $i; ?>">
		      <h2 class="panel-title">
		        <a data-toggle="collapse" data-parent="#accordion" href="#collapse-<?php echo $i; ?>" aria-expanded="true" aria-controls="collapseOne">
		         <?php the_sub_field('heading'); ?>
		        </a>
		      </h2>
		    </div>
		    <div id="collapse-<?php echo $i; ?>" class="panel-collapse collapse <?php if ($i==1) { echo 'in'; } ?>" role="tabpanel" aria-labelledby="heading-<?php echo $i; ?>">
		      <div class="panel-body">
		       	<?php the_sub_field('text'); ?>
		      </div>
		    </div>
		</div>
	<?php $i++; endwhile; ?>
</div>