问如何在类对象中转换API的响应

EN

import 'dart:convert';

SuperHero superHeroFromJson(String str) => SuperHero.fromJson(json.decode(str));

String superHeroToJson(SuperHero data) => json.encode(data.toJson());

class SuperHero {
    SuperHero({
        this.name,
        this.mainPower,
        this.worstEnemy,
    });

    String name;
    String mainPower;
    String worstEnemy;

    factory SuperHero.fromJson(Map<String, dynamic> json) => SuperHero(
        name: json["name"],
        mainPower: json["mainPower"],
        worstEnemy: json["worstEnemy"],
    );

    Map<String, dynamic> toJson() => {
        "name": name,
        "mainPower": mainPower,
        "worstEnemy": worstEnemy,
    };
}

class SuperHeroController {
  final String hero;

  SuperHeroController({this.hero}){
    loadData(hero);
  }

  Future<Map<String, dynamic>> loadData(String usuario) async {
    final String url = ****;

    final Map<String, dynamic> queryParams = {
      'hero': hero,
    };

    var uri = Uri.parse(url).resolveUri(Uri(queryParameters: queryParams));

    final response = await http.get(
      uri,
      headers: {"Content-Type": "application/json"},
    );

    var data = json.decode(response.body);

    print(data);
  }
}

SuperHero hero;
  SuperHeroController _superHeroController;

  HeroWidget(hero){
    hero = hero;
  }

  @override
  void initState() {
    super.initState();
    _heroController = SuperHeroController (hero: Provider.of<Auth>(context, listen: false).id); // getting the user's hero id
  }