MDL-86654 customfield: Show drag handles only when necessary

* Show category drag handles when there are 2 or more categories
* Show custom field drag handles when there are a total of 2 or more
fields on the page.

customfield/classes/output/management.php

@@ -76,7 +76,7 @@ class management implements renderable, templatable {
         $categories = $this->handler->get_categories_with_fields();
 
         $categoriesarray = array();
-
+        $fieldscount = 0;
         foreach ($categories as $category) {
 
             $categoryarray = array();
@@ -97,6 +97,7 @@ class management implements renderable, templatable {
                 $fieldarray['movetitle'] = get_string('movefield', 'core_customfield', $fieldname);
 
                 $categoryarray['fields'][] = $fieldarray;
+                $fieldscount++;
             }
 
             $menu = new \action_menu();
@@ -116,6 +117,9 @@ class management implements renderable, templatable {
         }
 
         $data->categories = $categoriesarray;
+        $data->canmovecategories = count($data->categories) > 1;
+        // Can move fields if there are more than one field or if there are multiple categories.
+        $data->canmovefields = $fieldscount > 1 || $data->canmovecategories;
 
         if (empty($data->categories)) {
             $data->nocategories = get_string('nocategories', 'core_customfield');

customfield/externallib.php

@@ -133,6 +133,8 @@ class core_customfield_external extends external_api {
                         )
                     )
                 ),
+                'canmovefields' => new external_value(PARAM_BOOL, 'Whether fields can be moved', VALUE_DEFAULT, false),
+                'canmovecategories' => new external_value(PARAM_BOOL, 'Whether categories can be moved', VALUE_DEFAULT, false),
             )
         );
     }

customfield/templates/list.mustache

@@ -38,6 +38,8 @@
       "area": "course",
       "itemid": 0,
       "usescategories": 1,
+      "canmovecategories": 1,
+      "canmovefields": 1,
       "categories": [
           { "id": "0",
             "nameeditable": "Other fields",
@@ -78,7 +80,9 @@
             <div class="col-6 categoryinstance">
                 {{#usescategories}}
                     <h3>
-                        <span class="movecategory icon-size-3">{{> core/drag_handle}}</span>
+                        {{#canmovecategories}}
+                            <span class="movecategory icon-size-3">{{> core/drag_handle}}</span>
+                        {{/canmovecategories}}
                         {{{nameeditable}}}
                         <a class="icon-size-3" href="#" data-role="deletecategory" data-id="{{id}}">
                             {{#pix}} t/delete, core, {{#str}} delete, moodle {{/str}} {{/pix}}
@@ -103,7 +107,12 @@
                 <tbody>
                 {{#fields}}
                     <tr data-field-name="{{name}}" data-field-id="{{id}}"  class="field">
-                        <td class="col-5"><span class="movefield">{{> core/drag_handle}}</span>{{{name}}}</td>
+                        <td class="col-5">
+                            {{#canmovefields}}
+                                <span class="movefield">{{> core/drag_handle}}</span>
+                            {{/canmovefields}}
+                            {{{name}}}
+                        </td>
                         <td class="col-3">{{{shortname}}}</td>
                         <td class="col-2">{{{type}}}</td>
                         <td class="col-2 text-end">