Updating post meta for checkbox

Question

  <div class="vp-field vp-checkbox vp-checked-field vp-meta-single" data-vp-type="vp-checkbox" id="_custom_meta[category][]">
<div class="label">
     <label>Categories</label>
</div>
<div class="field">
    <div class="input">
       <label>
          <input class="vp-input" type="checkbox" name="_custom_meta[category][]" value="star">
         <span></span>star</label>
      <label>
       <input class="vp-input" type="checkbox" name="_custom_meta[category][]" value="triangle">
       <span></span>triangle</label>
     <label>
      <input class="vp-input" type="checkbox" name="_custom_meta[category][]" value="square">
      <span></span>square
     </label>
    </div>
</div>
</div>'

I am trying to update the post meta checkboxes, but the below is not working. Any suggestions what i am doing wrong.

 $features[0] = "star";
 $features[1] = "triangle";
 $features[2] = "square";

update_post_meta($post_id, "category",$features); 

Answer 1

Ok, so probably the meta data is saved correctly, now we are going to retrieve it.

I'm not sure where and how you're adding this code, it looks like a metabox?

The checkboxes aren't magicly getting checked, you need to add some logic to it.

First we need to have a closer look how you save the checkbox data. We want to save to the DB which checkboxes are checked.

This array:

$features = array();
$features[0] = "star";
$features[1] = "triangle";
$features[2] = "square";

Is not going to tell us which categories are checked.

We want to save the array like this:

$features = array();
$features['star'] = 1; // checked
$features['square'] = 0; // not checked
$features['triangle'] = 1; // checked

---

Above the checkbox HTML you need to get the features data (post_meta) from the DB.

Add this above the html:

<?php
global $post;
$features = get_post_meta( $post->ID, 'category', true );
?>

When you want to check a checkbox you need to add the attribute checked="checked" to it. We only want to do this if the features array from the DB is telling us to do so. You can achieve this with this checkbox html:

<input type="checkbox" name="checkbox_name" id="checkbox_id" value="triangle" <?php echo (isset($features['triangle']) && $features['triangle']) ? 'checked="checked"' : '' ?> />

This:

<?php echo (isset($features['triangle']) && $features['triangle']) ? 'checked="checked"' : '' ?>

Checks if the array key (triangle) is present in the $features array and if the value is set to 1 (or any positive value). If yes, it outputs checked="checked", if not, it does nothing.

Regards, Bjorn

Answer 2

Your code:

$features[0] = "star";
$features[1] = "triangle";
$features[2] = "square";

update_post_meta($post_id, 'category', $features); 

Is fine, it will only fail if the $post_id is not found. I'm assuming you want to save custom categories, not real WP taxonomies.

Do you have the debug log activated? Does it tell you anything?

---

Activate debug log.

1. Download and activate a log viewer.

2. Open wp-config.php (located in WP root folder), and change the line:

   define( "WP_DEBUG", false );

into

define( "WP_DEBUG", true );// just toggle this line to false to turn off
if ( WP_DEBUG ) {
    define( "WP_DEBUG_DISPLAY", false );
    define( "WP_DEBUG_LOG", true );
    @ini_set( "display_errors", 0 );
    define( "SCRIPT_DEBUG", true );
}

You can now view error logs. Disable logging when you are done!

---

Working with the debug log
If (for example) you want to check the $post_id that is being used, you can add the following right below the update_post_meta():

error_log('The post id is: '.$post_id);

To check an array i always use:

error_log('The features array is: <pre>'.print_r($features,true).'</pre>');

---

Regards, Bjorn

Answer 3

Just set the last parameter ($prev) the update_post_meta to false, this enable you to insert new values to the meta_key. You can also check if the value is not already in the array before updating. Something like this.

// Get post met first
// false because we want to return all the values 
// saved in the meta key 'category'
$oldValues = get_post_meta($post_ID, "category", false);
foreach($features as $feature){
// Check if value is there, otherwise add it
  if (in_array($feature, $oldValues)){
    continue;
  } esle {
    update_post_meta($post_ID, "category", $feature, false);
   }
}