Passing values from a widget to a function within a plugin

First of all I can say why your code doesn’t work.

The custom css is created inside the widget function that is called by WordPress in the moment that the widget is displayed.

I guess, that you on document ready send an ajax request that call advanced_widget_pack_css() function. But every ajax request is a completely new http request that the only scope is running a function, sure not embed widget.

For this reason, the new request via ajax never call the widget() method in your widget class and so of course no css are added.

Said that, think one minute for what you are doing.

Assuming your workflow will work, it fail if user has no js enabled. And even if the the js are enabled, the page is loaded withou custom css, that should be loaded on ajax request (and Ajax in WordPress are not very fast…) so:

  • if no js no css as well
  • even if js page load with no css, so you have unstyled widget for a
    second or more
  • browser are not allowed to cache the css

So your code does’t work (an I explained yopu why) but even if you find a way to make it works is not a great solution.

What can be a solution?

First of all in the widget isolate the function that generates the custom css.

After that, you should call the function not on the widget() method but on the update method. In this way the css is generated everytime the widget is updated, and you can save the newly generated css to store it in a css file.

As a good practise is better saving this file in the uploads folder, because you are sure that folder is writable from WP.

Pseudo code:

class Advanced_Widget_Pack_Widget_Archives extends WP_Widget {

   function generate_css( $instance ) {
     // some code here to generate css from instance arguments...
     return $sc_css;
   }

   function update( $new_instance, $old_instance ) {
     // some code here to update the widget instance...
     $css = $this->generate_css( $new_instance );
     $upload_dir = wp_upload_dir();
     $path = $upload_dir['basedir'] . '/myplugin/myplugin-customwidget.css';
     if ( ! file_exists($upload_dir['basedir'] . '/myplugin') )
       mkdir($upload_dir['basedir'] . '/myplugin');
     file_put_contents($path, $css);
   }

}

After that, you can enqueue the file just created using WordPress standard way…

Alternative to this method is generate the css in the widget() method (as you are already doing) and just output as inline style in the markup.

Related Posts:

  1. How to influence the information displayed on widget inside wp-admin
  2. Replace a menu with widget or a custom template file programmatically
  3. Issues with title-tag and document_title_parts
  4. Define custom Page Template without its own .php file
  5. Using add_filter() in Widgets
  6. Remove Page Title from Static Frontpage
  7. Programmatically Add Font-Awesome Icons to Category Widget
  8. Increment price for Woocommerce Minicart [closed]
  9. Gravity Forms field entries into wp_query loop [closed]
  10. Accepted arguments value in hook functions
  11. Get current page_id before loop, in functions.php
  12. Which action hook to use for function?
  13. Modify a function without editing template
  14. What did I do wrong in my functions code, that will not change the “Get New Password” text to “Send It”?
  15. Override the WordPress core function wp_referer_field
  16. How to edit the Tags within the image file URLs?
  17. Can’t properly set the_title add_filter to show short_URL
  18. How to add_filter html template to middle of content
  19. (Woocommerce) Order by price when entering specific category
  20. Possible to hook into Media Library preview File column and use a custom image?
  21. Is it possible to use add_filter in an included file in the child theme’s functions.php?
  22. Insert Content Before div#main from the functions.php File
  23. Add Adsense code between job listings – wp job manager plugin
  24. How to conditionally add a widget via a hook in functions.php
  25. Changing the text of Upload/Insert on Posts and Pages Screen
  26. Save_post – Warning: Cannot modify header information
  27. custom error message for empty username and password using authenticate filter not working
  28. How Do I Unhook This Parent Theme Function?
  29. Force resize for all video content
  30. Trying to get this function to show below the content
  31. Custom page with variables in url. Nice url with add_rewrite_rule
  32. Does hooking into the same action multiple times drain memory?
  33. How to hook into unregistering a widget instance?
  34. Extract image from content and set it as the featured image
  35. How to restrict actions and filters “properly” by conditions
  36. Is it possible to be more page/post specific with admin_enqueue_script?
  37. What is the most efficient method for loading widgets in functions.php
  38. Issue adding text after short description on product pages Woocommerce [closed]
  39. Exclude Empty Child Categories in Menu
  40. add_filter priority problem
  41. Ajaxing function in widget class
  42. Clean-up script tags
  43. Is it better to assign functions like get_the_id() to a variable if it’s used multiple times?
  44. Super simple shortcode not working
  45. How to filter out shortcode when displaying the_excerpt() in the loop?
  46. Gravity Forms – Using a Form to Pre-populate A Gravity Form [closed]
  47. Adding multiple taxonomy filters to functions.php
  48. Last updated date function
  49. How to set default archive image without overriding first attached image? [closed]
  50. Only let plugin add actions to wp_head & wp_footer on single posts
  51. Trigger a custom function when option are saved in admin area
  52. How to use wp_trash_post (or wp_delete_post) for deleting a (or all) post(s) from custom post type?
  53. How can I add a filter for specific categories on functions.php?
  54. How would I go about replacing this function in my child theme located in inc/template-tags.php
  55. Retrieve a value from Yoast SEO to use to set a default twitter card image honoring overrides
  56. Filter an WordPress Function in (general-template.php)
  57. How do I hook into the container of wp_nav_menu?
  58. Remove links from the_content when using filters wp_trim_excerpt
  59. Can’t Write Custom Widget Code In One ECHO
  60. Is there a way to prevent a function/method from being called outside a specific hook?
  61. Function not working inside of a function in functions.php
  62. How can I add a class to a nav li depending on URL?
  63. Modify gform_other_choice_value for specific form and specific field in Gravity Forms
  64. Adding code before post title with the_title produces weird results
  65. Set “woocommerce_is_purchasable” to false for specific “$product->is_stock_status”
  66. The correct way to add a JavaScript in the functions.php [closed]
  67. This code works, but the way I integrated it is breaking the media uploader. How can I integrate it properly?
  68. Problem with images URL after filter applying
  69. remove_action not working, even after changing priority [duplicate]
  70. remove/hide wp-editor
  71. Add a class to post if it has been recently updated
  72. Creating a custom wordpress widget and stopping js from running twice(once in active widget once in widget selector)?
  73. how to add_filter to non hook function
  74. Include widget file in functions.php of child theme
  75. WordPress comment processing . Default unapproved comments detection before posting
  76. Overwrite text in a complicated filter hook
  77. How to use WP conditional tag in a functions.php with OCEANWP Theme?
  78. Add #primary at the end of navlink permalinks on single posts
  79. remove_filter function to unhook twentysixteen parent theme function
  80. Get post_author email for Zapier Integration
  81. How can I automatically delete comments that contain a URL?
  82. Appending „read more” to the excerpt conditionally
  83. How to add class dynamically from templates
  84. my wordpress doesn’t save items to customized widget area
  85. ACF Filter return value
  86. Copying a widget class to functions.php results on a blank page
  87. WordPress hooks to call a function inside a construct
  88. WordPress undefined function error on using add_action() in functions.php
  89. How to make an If Else on Excerpt Filter
  90. Add array of category IDs to global variable?
  91. Regex works in regexr, but not if I filter content [closed]
  92. Retrieve a custom form field modified by a filter
  93. Function the_content
  94. save_post hook – headers already sent?
  95. Add custom fields after post/page title
  96. Way of getting queried loop before the query with a filter hook?
  97. Unhook the comment form in Buddypress
  98. Add the title of a widget as an ID – for anchor links
  99. Passing value from one hook to another
  100. Is there a hook that I can use when a fatal error occurs?