Flutter bloc 6.0.1

Flutter bloc 6.0.1

  • MultiRepositoryProvider
  • Merges multiple RepositoryProvider widgets into one widget tree.
  • RepositoryProvider
  • It is used as a dependency injection (DI) widget so that a single instance of a repository can be provided to multiple widgets within a subtree.
  • Lazily creates the provided repository unless `lazy` is set to `false`.

Note : flutter bloc 6.0.1 create 2 classes. 1) state 2) cubit

here is a programming of flutter bloc 6.0.1

Flutter bloc 6.0.1

lib Package

Inside Lib Package Create

  • cubite package
  • data package
  • model package
  • res package
  • ui package
  • main.dart

cubite package

post_cubit.dart

import 'package:bloc/bloc.dart';
import 'package:bloc_new/data/network_service.dart';
import 'post_state.dart';

class PostCubit extends Cubit<PostState> {
  final NetworkService networkService;

  PostCubit({this.networkService}) : super(PostInitial());

  Future<void> clear() async {
    emit(PostInitial());
  }

  Future<void> getPost() async {
    emit(PostLoading());
    await networkService.fetchPosts().then((posts) {
      emit(PostLoaded(posts));
    }).catchError(() {
      emit(PostError(message: "Some error"));
    });
  }
}

post_state.dart

import 'package:equatable/equatable.dart';
import 'package:bloc_new/model/post.dart';

abstract class PostState {
  const PostState();
}

class PostInitial extends PostState {
  const PostInitial();
}

class PostLoading extends PostState {
  const PostLoading();
}

class PostLoaded extends PostState with EquatableMixin {
  final List<Post> posts;

  PostLoaded(this.posts);

  @override
  List<Object> get props => [posts];
}

class PostError extends PostState with EquatableMixin {
  final String message;

  PostError({this.message});

  @override
  List<Object> get props => [message];
}

Data Package

network_service.dart

import 'dart:convert';
import 'package:bloc_new/model/post.dart';
import 'package:http/http.dart';

const String BASE_URL = "https://jsonplaceholder.typicode.com/";
const String POSTS = "posts";

class NetworkService {
  Future<List<Post>> fetchPosts() async {
    Response response = await get(BASE_URL + POSTS);
    List decodeResponse = json.decode(response.body);
    return decodeResponse.map((value) => Post.fromJson(value)).toList();
  }
}

Model Package

post.dart

import 'package:equatable/equatable.dart';

class Post extends Equatable {
  final int userId;
  final int id;
  final String title;
  final String body;

  Post({this.userId, this.id, this.title, this.body});

  factory Post.fromJson(Map<String, dynamic> json) {
    return Post(
        userId: json['userId'],
        id: json['id'],
        title: json['title'],
        body: json['body']);
  }

  @override
  List<Object> get props => [userId, id, title, body];

  @override
  bool get stringify => true;
}

res package

string.dart

class Strings {
  // App
  static const appName = "Flutter Bloc";

  // Home Screen
  static const homeScreen_title = "Home Screen";
  static const homeScreen_openPostScreen = "Open PostScreen";

  // News Screen
  static const newsScreen_title = "News Screen";
}

ui package

home.dart

import 'package:flutter/material.dart';
import 'package:bloc_new/res/strings.dart';
import 'file:///C:/Users/kamlesh/AndroidStudioProjects/bloc_new/lib/ui/home/post_screen.dart';

class HomeScreen extends StatefulWidget {
  @override
  HomeScreenState createState() => HomeScreenState();
}

class HomeScreenState extends State {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(title: Text(Strings.homeScreen_title)),
        body: SafeArea(
            child: Center(
                child: Container(
                    padding: EdgeInsets.only(top: 20.0),
                    child: Column(children: <Widget>[
                      RaisedButton(
                          child: Text(Strings.homeScreen_openPostScreen),
                          onPressed: () {
                            Navigator.push(
                                context,
                                MaterialPageRoute(
                                    builder: (context) => PostScreen()));
                          })
                    ])))));
  }
}

post_screen.dart

import 'package:bloc_new/cubit/post/post_cubit.dart';
import 'package:bloc_new/cubit/post/post_state.dart';
import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:bloc_new/model/post.dart';
import 'package:bloc_new/res/strings.dart';

class PostScreen extends StatefulWidget {
  @override
  PostScreenState createState() => PostScreenState();
}

class PostScreenState extends State {
  @override
  void initState() {
    BlocProvider.of<PostCubit>(context).getPost();
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(title: Text(Strings.newsScreen_title)),
        body: BlocBuilder<PostCubit, PostState>(builder: (context, postState) {
          if (postState is PostInitial) {
            return buildInitialWidget();
          } else if (postState is PostLoading) {
            return buildLoadingWidget();
          } else if (postState is PostLoaded) {
            return buildLoadedWidget(postState.posts);
          } else if (postState is PostError) {
            return buildErrorWidget(postState.message);
          } else {
            return null;
          }
        }));
  }

  Widget buildInitialWidget() {
    return Center(child: RaisedButton(child: Text("Load data")));
  }

  Widget buildLoadingWidget() {
    return Center(child: CircularProgressIndicator());
  }

  Widget buildLoadedWidget(List<Post> posts) {
    return buildPostListWidget(posts);
  }

  var dividerWidget = Padding(
      padding: const EdgeInsets.only(left: 8.0, right: 8.0),
      child: Divider(height: 1, thickness: 1, color: Colors.black38));

  Widget buildPostListWidget(List<Post> posts) {
    return ListView.separated(
        physics: BouncingScrollPhysics(),
        separatorBuilder: (context, index) => dividerWidget,
        itemBuilder: (context, index) => _postItemWidget(context, posts[index]),
        itemCount: posts.length);
  }

  Widget _postItemWidget(BuildContext context, Post post) {
    return Container(
        margin: EdgeInsets.only(left: 8.0, right: 8.0),
        child: Card(
            shape: RoundedRectangleBorder(
                borderRadius: BorderRadius.all(Radius.circular(20.0))),
            elevation: 4.0,
            child: InkWell(
                customBorder: RoundedRectangleBorder(
                    borderRadius: BorderRadius.all(Radius.circular(20.0))),
                child: Container(
                    margin: EdgeInsets.all(20.0), child: Text(post.body)),
                onTap: () {
                  Scaffold.of(context)
                      .showSnackBar(SnackBar(content: Text("${post.title}")));
                })));
  }

  Widget buildErrorWidget(String message) {
    return Center(child: Text(message));
  }
}

outside all package

main.dart

import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:bloc_new/data/network_service.dart';
import 'package:bloc_new/res/strings.dart';
import 'package:bloc_new/ui/home/home.dart';
import 'cubit/post/post_cubit.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MultiRepositoryProvider(
        providers: [RepositoryProvider(create: (context) => NetworkService())],
        child: MultiBlocProvider(
            providers: [
              BlocProvider<PostCubit>(
                  create: (context) => PostCubit(
                      networkService: context.repository<NetworkService>()))
            ],
            child: MaterialApp(
                title: Strings.appName,
                theme: ThemeData(
                    primarySwatch: Colors.blue,
                    visualDensity: VisualDensity.adaptivePlatformDensity),
                home: HomeScreen())));
  }
}

pubspec.yaml

name: bloc_new
description: A new Flutter application.

publish_to: 'none'
version: 1.0.0+1

environment:
  sdk: ">=2.7.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter

  cupertino_icons:
  http:
  flutter_bloc:
  equatable:

dev_dependencies:
  flutter_test:
    sdk: flutter

flutter:
  uses-material-design: true

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