Hi @gabyferman,
Hmm… I believe that this should be possible using the acf/load_value
filter. The code should be as shown below:
add_filter('acf/load_value/key=<field_key>', 'my_text_value', 10, 3);
function my_text_value($value, $post_id, $field) {
$value = isset($_GET['foo_name'])?$_GET['foo_name']:'default_value';
return $value;
}
Have a look at the documentation for more information on this filter: http://www.advancedcustomfields.com/resources/acfload_value/