Piwik\Category\Subcategory::setCategoryId PHP Method

    public function setCategoryId($categoryId)
    {
        $this->categoryId = $categoryId;
        return $this;
    }

 public function addSubcategories(&$subcategories)
 {
     $idSite = Common::getRequestVar('idSite', 0, 'int');
     if (!$idSite) {
         // fallback for eg API.getReportMetadata which uses idSites
         $idSite = Common::getRequestVar('idSites', 0, 'int');
         if (!$idSite) {
             return;
         }
     }
     $dimensions = $this->configuration->getCustomDimensionsForSite($idSite);
     $order = 70;
     foreach ($dimensions as $dimension) {
         if (!$dimension['active']) {
             continue;
         }
         $category = new Subcategory();
         $category->setName($dimension['name']);
         if ($dimension['scope'] === CustomDimensions::SCOPE_ACTION) {
             $category->setCategoryId('General_Actions');
         } elseif ($dimension['scope'] === CustomDimensions::SCOPE_VISIT) {
             $category->setCategoryId('General_Visitors');
         }
         $category->setId('customdimension' . $dimension['idcustomdimension']);
         $category->setOrder($order++);
         $subcategories[] = $category;
     }
 }