How can I update one acf value with another on save?

• Seblito

• October 7, 2022 at 7:12 am

Hi,

Don’t know if this is even possible but here’s an explanation.

The theme I’m using is a block theme (GeneratePress Pro).
I don’t use any pagebuilder of any kind other than what’s shipped with GeneratePress (GP).
I’m using a custom post type named ‘realestate’.

With ACF I have created:

• 1 Google map field (field name ‘location’)
• 1 text field (field name ‘street_name’)

By using the Google map field I can get the field values I need when working directly in my template files. However now I need to grab the values while in the block editor.

GP offers to insert “dynamic data” from a custom field (of type ‘string’, not an array). This is why I have also created a simple text field.
My idea is to somehow extract the value from Google map field – $location[‘street_name’] and update the text field value by using a method like update_value or similar. The problem is, I don’t know how to use the method or even if it’s the right one to use.

How can I make sure that the text field gets updated with the value from $location[‘street_name’] whenever I save the current post?

Thank you!

• Seblito

• October 7, 2022 at 8:50 am

I have tried with the following instead:

// Testing to save/update field value using another field value
function my_acf_save_post( $post_id ) {

    
// Get newly saved values.
    $values = get_fields( $post_id );
    $location = get_field('location', $post_id);
    $street_name = get_field('street_name', $post_id);

	if ( ! get_post_type == 'realestate') {
	   // Stop right away
	   return;
	}  else {
                // Check the new value of a specific field.
		if ($location['street_name']) {
		   $street_name = $location['street_name'];
		}
	}
}
add_action('acf/save_post', 'my_acf_save_post');

Of course this is not doing anything because I don’t understand the documentation properly. Please help.

• John Huebner

• October 7, 2022 at 8:53 pm

An ACF GM field stores an array with 3 indexes: “lat”, “lng”, “address”.

to set a value of a field based on another field first you get the value and then you use update_field() to update the other.

• Seblito

• October 8, 2022 at 1:06 pm

I don’t get the documentation for acf/update_field() either. It says the $field parameter is the field array containing all settings. All the settings of what? The field I want to collect data from? In that case it seems this should work but it doesn’t.

function save_updated_acf_fields($location)
{
    // Collect GM field data
    $location = get_field('field_634147f894e08', $post_id);
    $gmap_street_name = $location['street_name'];
    $gmap_street_nbr = $location['street_number'];

    // Fields retrieving updated values
    $empty_street_name = get_field('field_6341483d94e09', $post_id);
    $empty_street_nbr = get_field('field_634151528a090', $post_id);

    if ($location) {
        $empty_street_name = $gmap_street_name;
        $empty_street_nbr = $gmap_street_nbr;
    }
}

add_filter('acf/update_field ', 'save_updated_acf_fields', 10, 1);

Would you please translate the documentation into something a plain dummy like myself can understand?

• John Huebner

• October 8, 2022 at 4:13 pm

You had the correct filter the first time “acf/save_post” because you will be working with multiple values. The other field may or may not have been saved when the acf/update_field hook happens for this field.

You cannot update a field value simply by setting a variable equal to something, you must call update_field() to have ACF save that value to the DB.

• John Huebner

• October 8, 2022 at 9:31 pm

Simple example:

add_action('acf/save_post', 'my_acf_save_post', 30);
function my_acf_save_post($post_id) {
  // get value from a field
  $value = get_field('field_name', $post_id);
  // update another field to this value
  update_field('other_field', $value, $post_id);
}

• Seblito

• October 9, 2022 at 3:24 am

Thank you John! It really wasn’t that clear to me that I had to use update_field() inside acf/save_post. It isn’t all too obvious in the documentation, at least not to me.