How to describe Knowledge category object for sub categories

Question

As per Salesforce documentation, 5 levels of categories are supported. Following code is giving information only about category with name Group_Category, but no information about child categories are returned. Is there a way to pull information about child categories using describe call.

List <DataCategoryGroupSobjectTypePair> pairs = new List<DataCategoryGroupSobjectTypePair>();
DataCategoryGroupSobjectTypePair pair = new DataCategoryGroupSobjectTypePair();
pair.setSobject('KnowledgeArticleVersion');
pair.setDataCategoryGroupName('Group_Category');
pairs.add(pair);

List<Schema.DescribeDataCategoryGroupStructureResult> groupResult = Schema.describeDataCategoryGroupStructures(pairs, true);
System.debug('groupResult:::' + groupResult);

Answer 1

Yes you can get all the child level categories. i have already done to get all the levels of category using the following code.

public List<DescribeDataCategoryGroupStructureResult> getDescribeDataCategoryGroupStructureResults(){
    List<DescribeDataCategoryGroupResult> describeCategoryResult;
    List<DescribeDataCategoryGroupStructureResult> describeCategoryStructureResult;
    try {
        //Making the call to the describeDataCategoryGroups to
        //get the list of category groups associated
        List<String> objType = new List<String>();
        objType.add('KnowledgeArticleVersion');
        describeCategoryResult = Schema.describeDataCategoryGroups(objType);

        //Creating a list of pair objects to use as a parameter
        //for the describe call
        List<DataCategoryGroupSobjectTypePair> pairs = new List<DataCategoryGroupSobjectTypePair>();

        //Looping throught the first describe result to create
        //the list of pairs for the second describe call
        for(DescribeDataCategoryGroupResult singleResult : describeCategoryResult){
           DataCategoryGroupSobjectTypePair p = new DataCategoryGroupSobjectTypePair();
           p.setSobject(singleResult.getSobject());
           p.setDataCategoryGroupName(singleResult.getName());
           pairs.add(p);
         }

        //describeDataCategoryGroupStructures()
        describeCategoryStructureResult = Schema.describeDataCategoryGroupStructures(pairs, false);

         //Getting data from the result
         for(DescribeDataCategoryGroupStructureResult singleResult : describeCategoryStructureResult){
            //Get name of the associated Sobject

            //Get the name of the data category group
            singleResult.getName();

            //Get the top level categories
            DataCategory [] toplevelCategories =  singleResult.getTopCategories();

            //Recursively get all the categories
            List<DataCategory> allCategories = getAllCategories(toplevelCategories);

            for(DataCategory category : allCategories) {
               //Get the name of the category
               category.getName();

            }
         }
       } 
       catch (Exception e){

        }
        System.debug(categoryToSubCategoryMap);
        return describeCategoryStructureResult;
   }

   public  DataCategory[] getAllCategories(DataCategory [] categories){
      if(categories.isEmpty()){
         return new DataCategory[]{};
      } else {
         DataCategory [] categoriesClone = categories.clone();
         DataCategory category = categoriesClone[0];
         DataCategory[] allCategories = new DataCategory[]{category};
         categoriesClone.remove(0);
         categoriesClone.addAll(category.getChildCategories());
         allCategories.addAll(getAllCategories(categoriesClone));
         return allCategories;
      }
   }

public class JSONCategory{
    public String label{set;get;}
    public String name{set;get;}
    public List<TopLevelCategory> topCategories{set;get;}
}

public class TopLevelCategory{
    public List<ChildLevelCategory> childCategories{set;get;}
}

public class ChildLevelCategory{
    public List<ChildLevelCategory> childCategories{set;get;}
    public String label{set;get;}
    public String name{set;get;}
}


List<JSONCategory> categories = (List<JSONCategory>)System.JSON.deserialize(JSON.serialize(getDescribeDataCategoryGroupStructureResults());