如何从文档中获取所有子集合并将其加载到Flutter小部件

Question

问题是我已经在应用程序中收集了所有必需的数据，但是无法加载到 Flutter 小部件。

  final QuerySnapshot result =
    await Firestore.instance.collection('Category01').getDocuments();
    final List<DocumentSnapshot> documents = result.documents;
    debugPrint("Sub Category Name:${documents.length.toString()}");

    for (DocumentSnapshot document in documents){
      String name = document.documentID; // Extract name of Document jesy Labor , Hospital care
      debugPrint("Category Name:$name");

      List<DocumentSnapshot> subCategories = (await document.reference.collection('Sub Categories').getDocuments()).documents;
      for (DocumentSnapshot subDoc in subCategories){
        String subCategory=subDoc.documentID.toString();

        debugPrint("Sub Category Name:${subCategory}");
        debugPrint("Sub Category Image ${subDoc.data['sub-category-image']}");
        List<DocumentSnapshot> subChild =  (await subDoc.reference.collection('Sub Childs').getDocuments()).documents;
        for (DocumentSnapshot subchild in subChild){

          debugPrint("Sub child name:${subchild.documentID}");
          debugPrint("Sub Child Image ${subchild.data['provider-id']}");


        }
      }
    }