Flutter 将值传递到bloc存储库

试图在《颤栗》中研究集团。我有bloc、events和存储库文件。我知道如何在页面之间传递数据，但无法将参数传递到存储库 我需要向存储库传递一个参数，以便对数据库进行查询。例如，类别id

按类别分类的产品存储库。dart

import 'package:billfort/models/products_model.dart';
import 'package:billfort/strings/strings.dart';
import 'package:http/http.dart' as http;
import 'dart:convert';

abstract class ProductsByCategoryRepository {
  Future<List<HydraMember>> getProducts();
}

class ProductsByCategoryRepositoryImpl implements ProductsByCategoryRepository {

  @override
  Future<List<HydraMember>> getProducts() async {
    var response = await http.get(Uri.parse("${AppStrings.api}products?category=here need pass id"));
    if (response.statusCode == 200) {
      var data = json.decode(response.body);
      List<HydraMember> products = Products.fromJson(data).hydraMember;
      return products;
    } else {
      throw Exception();
    }
  }

}

import 'package:bloc/bloc.dart';
import 'package:billfort/bloc/products_event.dart';
import 'package:billfort/bloc/products_state.dart';
import 'package:billfort/models/products_model.dart';
import 'package:billfort/repository/products_repository.dart';
import 'package:meta/meta.dart';

class ProductsBloc extends Bloc < ProductsEvent, ProductsState > {

    ProductsRepository repository;

    ProductsBloc({
        @required this.repository
    }): super(null);

    @override
    // TODO: implement initialState
    ProductsState get initialState => ProductsInitialState();

    @override
    Stream < ProductsState > mapEventToState(ProductsEvent event) async *{
        if (event is FetchProductsEvent) {
            yield ProductsLoadingState();
            try {
                List < HydraMember > products = await repository.getProducts();
                yield ProductsLoadedState(products: products);
            } catch (e) {
                yield ProductsErrorState(message: e.toString());
            }
        }
    }

}

import'包：billfort/models/products_model.dart'；
导入“package:billfort/strings/strings.dart”；
将“package:http/http.dart”导入为http；
导入“dart:convert”；
抽象类ProductsByCategoryRepository{
未来产品（）；
}
类ProductsByCategoryRepositoryImpl实现ProductsByCategoryRepository{
@凌驾
Future getProducts（）异步{
var response=wait http.get（Uri.parse（${AppStrings.api}products？category=here need pass id））；
如果（response.statusCode==200）{
var data=json.decode（response.body）；
List products=products.fromJson（data）.hydraMember；
退货产品；
}否则{
抛出异常（）；
}
}
}

产品\u-bloc.dart

import 'package:billfort/models/products_model.dart';
import 'package:billfort/strings/strings.dart';
import 'package:http/http.dart' as http;
import 'dart:convert';

abstract class ProductsByCategoryRepository {
  Future<List<HydraMember>> getProducts();
}

class ProductsByCategoryRepositoryImpl implements ProductsByCategoryRepository {

  @override
  Future<List<HydraMember>> getProducts() async {
    var response = await http.get(Uri.parse("${AppStrings.api}products?category=here need pass id"));
    if (response.statusCode == 200) {
      var data = json.decode(response.body);
      List<HydraMember> products = Products.fromJson(data).hydraMember;
      return products;
    } else {
      throw Exception();
    }
  }

}

import 'package:bloc/bloc.dart';
import 'package:billfort/bloc/products_event.dart';
import 'package:billfort/bloc/products_state.dart';
import 'package:billfort/models/products_model.dart';
import 'package:billfort/repository/products_repository.dart';
import 'package:meta/meta.dart';

class ProductsBloc extends Bloc < ProductsEvent, ProductsState > {

    ProductsRepository repository;

    ProductsBloc({
        @required this.repository
    }): super(null);

    @override
    // TODO: implement initialState
    ProductsState get initialState => ProductsInitialState();

    @override
    Stream < ProductsState > mapEventToState(ProductsEvent event) async *{
        if (event is FetchProductsEvent) {
            yield ProductsLoadingState();
            try {
                List < HydraMember > products = await repository.getProducts();
                yield ProductsLoadedState(products: products);
            } catch (e) {
                yield ProductsErrorState(message: e.toString());
            }
        }
    }

}

import'包：bloc/bloc.dart'；
导入“package:billfort/bloc/products_event.dart”；
进口“包装：billfort/bloc/products_state.dart”；
进口“包装：billfort/models/products_model.dart”；
导入“package:billfort/repository/products_repository.dart”；
导入“package:meta/meta.dart”；
类别ProductsBloc扩展了集团{
产品存储库；
ProductsBloc({
@此存储库是必需的
})：super（空）；
@凌驾
//TODO:实现初始状态
ProductsState get initialState=>ProductsSinitialState（）；
@凌驾
流mapEventToState（ProductsEvent事件）异步*{
if（事件为FetchProductsEvent）{
产量产品sloadingstate（）；
试一试{
Listproducts=wait repository.getProducts（）；
产量产品等级（产品：产品）；
}捕获（e）{
yield ProductsErrorState（消息：e.toString（））；
}
}
}
}

如果获取产品的过程需要输入，那么类

FetchProductsEvent

应该有一个提供输入的属性，就像state类

ProductsLoadedState

有一个提供输出的

products

属性一样

---

也就是说，您是否在没有真正了解更改的情况下升级了bloc包？为什么要将

null

传递给基本构造函数，但仍然为

initialState

提供重载？您的基本构造函数应该直接获取

ProductsInitialState（）

，并且应该删除重载。如果它没有为您发出警告，您可能需要启动编译器设置，以便编译器更好地指导您。

我现在删除了ProductsBloc中的super（null）。在ide中有警告但工作正常如果同一个bloc category实例的id保持不变，则将其传递给bloc构造函数，否则正如@nvoigt编写的那样，使用

FetchProductsEvent