我正在开发一个 wordpress 主题并且有一个警告。 如何解决这个问题

Question

Warning is " Invalid argument supplied for foreach() "

<?php
    $tags = get_the_tags();
    foreach($tags as $tag):?>

        <a href="<?php echo get_tag_link($tag->term_id);?>" class="badge badge-success">
            <?php echo $tag->name;?>
        </a>

    <?php endforeach;?>

Answer 1

Check if your $tags variable is an actual array of elements before trying to loop through it all...

ie:

<?php
$tags = get_the_tags(array('hide_empty' => false)); // show all tags, even empty 1s

// debug - uncomment below to view output
/* 
   echo "<pre>";
   print_r($tags);
   echo "</pre>";
*/

if( is_array($tags) )
{
   foreach($tags as $tag):
    ?>
      <a href="<?php echo get_tag_link($tag->term_id);?>" class="badge badge-success">
         <?php echo $tag->name;?>
      </a>
   <?php 
   endforeach; 
}else{
  echo "<p>Not an Array!</p>";
}
?>

Answer 2

In general, don't assume that a variable returned from a function will always be an array, you can check this before calling foreach like this:

$tags = get_the_tags();
if (is_array($tags) || is_object($tags)) {
    foreach ($tags as $tag) {
        ...
    }
}

In the specific case of get_the_tags() , this might be enough though:

$tags = get_the_tags();
if ($tags) {
    foreach ($tags as $tag) {
        ...
    }
}