Loop Portfolio Next/Previous Button in Wordpress - php

Question

I am new in php, so I like to get some help.
My clients want the next and previous button to be looped in the single page portfolio. Well this is the code I am using.
<?php
$prev_post = get_previous_post();
$next_post = get_next_post();
$prev_post_link = !empty($prev_post) ? get_permalink($prev_post->ID) : true;
$next_post_link = !empty($next_post) ? get_permalink($next_post->ID) : true;
if(!empty($prev_post) && empty($prev_post_thumb)) $prev_post_thumb = prev_next_post_format_icon($prev_post->ID);
if(!empty($next_post) && empty($next_post_thumb)) $next_post_thumb = prev_next_post_format_icon($next_post->ID);
?>
When I use True, for both the Previous & Next Links, Its appearing in the first and last portfolio, but the hyperlink is showing as http://1 and not the next portfolio. Thanks in Advance
This my html code:
<div class="dfd-controls mobile-hide">
<?php if(!empty($prev_post_link)) : ?>
<a href="<?php echo esc_url($prev_post_link); ?>" class="page-inner-nav nav-prev">
<div class="dfd-controler prev">
<div style="margin-top:7px; color:#fff;">Previous</div>
<!-- <div class="thumb prev">
<?php echo $prev_post_thumb; ?>
</div> -->
</div>
<!--<div class="pagination-title">Previous Project</div> -->
</a>
<?php endif; ?>
<?php if(!empty($next_post_link)) : ?>
<a href="<?php echo esc_url($next_post_link); ?>" class="page-inner-nav nav-next">
<div class="dfd-controler next">
<div style="margin-top:7px; color:#fff;">Next</div>
<!-- <div class="thumb next">
<?php echo $next_post_thumb; ?>
</div>-->
</div>
<!--<div class="pagination-title">Next Project</div>-->
</a>
<?php endif; ?>

Answer 1

change the value from true to false. Setting a variable to true will give empty a false value see here.
Now 'next' will only show if there is a next post
your PHP should be:
$prev_post = get_previous_post();
$next_post = get_next_post();
$prev_post_link = !empty($prev_post) ? get_permalink($prev_post->ID) : false;
$next_post_link = !empty($next_post) ? get_permalink($next_post->ID) : false;
if(!empty($prev_post) && empty($prev_post_thumb)) $prev_post_thumb = prev_next_post_format_icon($prev_post->ID);
if(!empty($next_post) && empty($next_post_thumb)) $next_post_thumb = prev_next_post_format_icon($next_post->ID);
UPDATE: To have the posts loop:
if( get_adjacent_post(false, '', true) ) {
previous_post_link('%link', '<div class="dfd-controler prev"><div style="margin-top:7px; color:#fff;">Previous</div></div>');
} else {
$first = new WP_Query('posts_per_page=1&order=DESC'); $first->the_post();
echo '<div class="dfd-controler prev"><div style="margin-top:7px; color:#fff;">Previous</div></div>';
wp_reset_query();
};
if( get_adjacent_post(false, '', false) ) {
next_post_link('%link', '<div class="dfd-controler next"><div style="margin-top:7px; color:#fff;">Next</div></div>');
} else {
$last = new WP_Query('posts_per_page=1&order=ASC'); $last->the_post();
echo '<a href="' . get_permalink() . '"><div class="dfd-controler next"><div style="margin-top:7px; color:#fff;">Next</div></div>';
wp_reset_query();
};

Answer 2

Loop Portfolio Next/Previous Button in Wordpress
<div class='next_post_link_align'>
<?php next_post_link('<span class="previous_post_link">← %link </span> <span class="post_link_text">'.__('(previous entry)','avia_framework'))."</span>";?>
</div>
<div class='previous_post_link_align'>
<?php previous_post_link('<span class="next_post_link"><span class="post_link_text">'.__('(next entry)','avia_framework').'</span> %link →</span>'); ?>
</div>