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flutter - 如何在颤动中使用 hydated_bloc 保持状态？

问题描述

我正在尝试使用库 hydrad_bloc 保持状态，问题是该库的所有示例都非常基本，我想通过使用示例 api rest 来维护状态，但我仍然无法实现此示例的逻辑：

userbloc_bloc.dart

import 'dart:async';
import 'package:di/users/model/user.dart';
import 'package:di/users/repository/cloud_api_repository.dart';
import 'package:equatable/equatable.dart';
import 'package:hydrated_bloc/hydrated_bloc.dart';

part 'userbloc_event.dart';
part 'userbloc_state.dart';

class UserblocBloc extends HydratedBloc<UserblocEvent, UserblocState> {
  @override
  UserblocState get initialState {
     return super.initialState ?? UserblocInitial();

  }

    @override
  UserblocState fromJson(Map<String, dynamic> json) {
    try {
      final usermodel = UserModel.fromJson(json);
      return UserblocLoaded(usermodel);
    } catch (_) {
      return null;
    }
  }

  @override
  Map<String, dynamic> toJson(UserblocState state) {

    if (state is UserblocLoaded) {
      return state.userModel.toJson();
    }else{
      return null;
    }

  }

  @override
  Stream<UserblocState> mapEventToState(
    UserblocEvent event,
  ) async* {

  }


}

userbloc_state.dart

part of 'userbloc_bloc.dart';


abstract class UserblocState extends Equatable {
  UserblocState([List props = const[]]);
}

class UserblocInitial extends UserblocState {
   CloudApiRepository _cloudApiRepository;
  @override
  List<Object> get props => null;
  Future<UserModel> getlistUser() => _cloudApiRepository.getlistUser();
}

    class UserblocLoading extends UserblocState {
      @override
      Li

st<Object> get props => null;
}
class UserblocLoaded extends UserblocState {
  final UserModel userModel;
  UserblocLoaded(this.userModel);

  @override
  List<Object> get props => null;

}

HomeUser.dart

import 'package:di/users/bloc/userbloc/userbloc_bloc.dart';
import 'package:di/users/model/user.dart';
import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
class HomeUser extends StatefulWidget {
  HomeUser({Key key}) : super(key: key);

  @override
  _HomeUserState createState() => _HomeUserState();
}

class _HomeUserState extends State<HomeUser> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
          body: BlocProvider(create: (context) => UserblocBloc(),
          child: BlocBuilder<UserblocBloc, UserblocState>(
            builder: (BuildContext context, UserblocState state) {
              if (state is UserblocInitial) {
                return showanytext();
              } else if (state is UserblocLoading) {
                return buildLoading();
              } else if (state is UserblocLoaded) {
                return buildColumnWithData(state.userModel.data);
              }
            },
          ),
        ),
    );
  }
}

Widget buildColumnWithData(List<User> users){
  final user = users;

  return ListView.builder(
    itemCount: users.length,
    itemBuilder: (BuildContext context, int i){

      return Container(
        padding: EdgeInsets.all(15),
        child: Text("${user[i].firstName}", style: TextStyle(color:Colors.white),),
        decoration: BoxDecoration(
          color: Colors.black
        ),
      );
    });
}
Widget buildLoading(){

  return Center(
    child: Container(
      child: CircularProgressIndicator(),
    ),
  );
}

Widget showanytext(){

  return Center(
    child: Container(
      child: Text("Construyendo el widget"),
    ),
  );
}

关于我如何保持我的pad使用api的状态的一些想法，如果我关闭应用程序并在上次关闭她时离开她的同一个地方重新打开它

标签： flutterbloc

解决方案

好问题 - 我有一个非常相似的问题。

简而言之 - 我的 Cubit 状态反映了填写表格并将其发送到 API 的阶段： - 初始， - 开始， - 勾选， - 完成和 - 发送。

由于无法确定 Hydrated Bloc 功能应该返回哪个状态，我实际上将 state 属性添加到 Cubit State 作为枚举以反映 Cubit“最后一次看到”的状态，并且在某些情况下返回相同来自存储库的状态。有了它，最后填写的字段将被提取。这听起来和看起来像是一种冗余，但我想不出更好的解决方案。我很乐意听到一些想法:)

这是 Cubit 的 State 类声明：

part of 'job_realization_cubit.dart';

enum Status {
  initial,
  started,
  tick,
  completed,
  sent,
}

abstract class JobRealizationState extends Equatable {
  const JobRealizationState({
    this.status,
    this.timeLeft,
    this.jobRealization,
    this.message,
  });
  final Status status;
  final int timeLeft;
  final JobRealization jobRealization;
  final String message;

  @override
  List<Object> get props => [status, timeLeft, jobRealization, message];
}

class JobRealizationInitial extends JobRealizationState {
  const JobRealizationInitial();
}

class JobRealizationStarted extends JobRealizationState {
  const JobRealizationStarted({status, timeLeft, jobRealization, message})
      : super(
          status: status,
          timeLeft: timeLeft,
          jobRealization: jobRealization,
          message: message,
        );
}

//Timekeeping after start of Realization
class JobRealizationTick extends JobRealizationState {
  const JobRealizationTick({status, timeLeft, jobRealization, message})
      : super(
          status: status,
          timeLeft: timeLeft,
          jobRealization: jobRealization,
          message: message,
        );
}


class JobRealizationDone extends JobRealizationState {
  const JobRealizationDone({status, timeLeft, jobRealization, message})
      : super(
          status: status,
          timeLeft: timeLeft,
          jobRealization: jobRealization,
          message: message,
        );
}

class JobRealizationSent extends JobRealizationState {
  const JobRealizationSent({status, timeLeft, jobRealization, message})
      : super(
          status: status,
          timeLeft: timeLeft,
          jobRealization: jobRealization,
          message: message,
        );
}

class JobRealizationSendError extends JobRealizationState {
  const JobRealizationSendError({status, timeLeft, jobRealization, message})
      : super(
          status: status,
          timeLeft: timeLeft,
          jobRealization: jobRealization,
          message: message,
        );
}

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