stream_loader 1.1.0-beta02

A flutter plugin for loading content asynchronously with Dart stream.

stream_loader

A flutter plugin for loading content asynchronously with Dart stream.

Author: Petrus Nguyễn Thái Học

Getting Started

In your flutter project, add the dependency to your pubspec.yaml

dependencies:
  ...
  stream_loader: <latest_version>

Examples

• stream_loader/example
• stream_loader_demo

Usage

Model and api

abstract class Comment implements Built<Comment, CommentBuilder> { ... }

class Api {
  Stream<BuiltList<Comment>> getComments() { ... }
  Stream<Comment> getCommentBy({@required int id}) { ... }
}
final api = Api();

Create LoaderWidget load comments from api

import 'package:stream_loader/stream_loader.dart';

LoaderWidget<BuiltList<Comment>>(
  blocProvider: () => LoaderBloc(
    loaderFunction: api.getComments,
    refresherFunction: api.getComments,
    initialContent: <Comment>[].build(),
    logger: print,
  ),
  messageHandler: (message, bloc) {
    message.fold(
      onFetchFailure: (error, stackTrace) => context.snackBar('Fetch error'),
      onFetchSuccess: (_) {},
      onRefreshSuccess: (data) => context.snackBar('Refresh success'),
      onRefreshFailure: (error, stackTrace) => context.snackBar('Refresh error'),
    );
  },
  builder: (context, state, bloc) {
    if (state.error != null) {
      return ErrorWidget(error: state.error);
    }
    if (state.isLoading) {
      return LoadingWidget();
    }
    return RefreshIndicator(
      onRefresh: bloc.refresh,
      child: CommentsListWidget(comments: state.content),
    );
  }
);

Create LoaderWidget load comment detail from api

import 'package:stream_loader/stream_loader.dart';

final Comment comment;
final loadDetail = () => api.getCommentBy(id: comment.id);

LoaderWidget<Comment>(
  blocProvider: () => LoaderBloc(
    loaderFunction: loadDetail,
    refresherFunction: loadDetail,
    initialContent: comment,
    logger: print,
  ),
  messageHandler: (message, _) {
    message.fold(
      onFetchFailure: null,
      onFetchSuccess: null,
      onRefreshFailure: null,
      onRefreshSuccess: (_) => context.snackBar('Refresh success'),
    );
  },
  builder: (context, state, bloc) {
    return RefreshIndicator(
      onRefresh: bloc.refresh,
      child: CommentDetailWidget(comment: state.content),
    );
  },
);

Note: Can use LoaderBloc without LoaderWidget easily

class _CommentsState extends State<Comments> {
  LoaderBloc<BuiltList<Comment>> bloc;

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();

    bloc ??= LoaderBloc(
      loaderFunction: api.getComments,
      refresherFunction: api.getComments,
      initialContent: <Comment>[].build(),
      logger: print,
    )..fetch();
  }

  @override
  void dispose() {
    bloc.dispose();
    super.dispose();
  }
  
  @override
  Widget build(BuildContext context) {
    return StreamBuilder<LoaderState<BuiltList<Comment>>>(
      stream: bloc.state$,
      initialData: bloc.state$.value, // <- required because bloc.state$ does not replay the latest value
      builder: (context, snapshot) {
        final state = snapshot.data;
        
        if (state.error != null) {
          return ErrorWidget(error: state.error);
        }
        if (state.isLoading) {
          return LoadingWidget();
        }
        return RefreshIndicator(
          onRefresh: bloc.refresh,
          child: CommentsListWidget(comments: state.content),
        );
      }
    );
  }
}

License

MIT License

Copyright (c) 2020 Petrus Nguyễn Thái Học

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.