how bbPress and buddypress add their own page templates to the page template drop down on the page editing screen

Question

Im writing a plugin and need to know how to add a page template in the edit page screen from within a plugin. bbPress and Buddypress both add page templates to this drop down and I can't figure out how they do it.

Not looking for template_redirect solution, needs to work in the backend. I am already making use of template_redirect and don't need any help with it!

Any assistance would be appreciated.

Answer 1

Sincerly I don't know how Buddypress and bbPress add options to page templates dropdown, and I can be wrong, but I think the only way to do it (excluding adding files to theme folder or hacking core), is to use javascript.

Create a file containing the following, save it somewhere, I will assume it is named my-script.js and it's in a subfolder 'js' of the theme folder

jQuery(document).ready(function($) {
   if (  $('select#page_template').length ) {
     var tmpl = myscriptdata.template;
     var label = myscriptdata.template_label;
     $('select#page_template').append('<option value="' + tmpl + '">' + label + '</option>');
   }
});

Then enqueue it in post.php and post-new.php, only for pages, and passing the template you want to add:

add_action('admin_enqueue_scripts', 'add_my_scripts');

function add_my_scripts( $page ) {
  if ( $page === 'post.php' || $page === 'post-new.php' ) {
    global $typenow;
    if ( $typenow === 'page' ) {
      wp_enqueue_script('myscript', get_template_directory_uri() . '/js/my-script.js', array('jquery'), null);
      $data = array(
        'template' => "my-template", // what you want to assign to dropdown value
        'template_label' => "My Template" // what you want to assign to dropdown label
      ); 
      wp_localize_script('myscript', 'myscriptdata', $data );
    }
  }
}