To import the annotations and Service abstract class add flutter_bloc_annotations to your pubspec.yaml.

  flutter_bloc_annotations: <latest_version>

Import Requirements

flutter_bloc_annotations uses InheritedWidget, StatefulWidget, State, Widget and BuildContext from package:flutter/material.dart. This needs to be imported as the generated part file cannot have import statements. Any services that are used also need to be imported.

Class Member Requirements

All the members of your BLoC class that have annotations must be public as the generated code uses them. Members without annotations can still be used in @BLoCMapper methods as the member is called and not copied to the output class. @BLoCValues initial data will not be copied to the BLoC class and will have no effect on the initial data.

Different Controllers

Using StreamController isn't required so rxdarts subjects such as BehaviourSubject can be used as shown in the example.

Output Classes

The output classes can be seen in the generated .bloc.dart file. Generally a BLoC, Provider and Disposer are created. The BLoC class defines the inputs and outputs of the bloc and calls your @BLoCMappers when somthing is added to the input streams and adds the output to the output streams. The BLoC class will also create, initialize and dispose of any services you require.


Services are automatic inputs to a BLoC that are initialized when the bloc is created. This makes it easier to make database connections that automatically add to the BLoC while still being testable without creating a an entire BLoC to add to as they only require a Sink to add to.


// main.dart
import "dart:async";
import "package:flutter/material.dart";
import "package:flutter_bloc_annotations/flutter_bloc_annotations.dart";
import "service.dart";
part "main.bloc.dart";

@BLoCService("TestService", "setCounter")
class _Test {
  StreamController<int> setCounter = StreamController<int>();

  StreamController<int> counter = StreamController<int>();

  int counterValue;

  @BLoCMapper("setCounter", "counter")
  Future<int> setCounterToCounter(int inputData) async => inputData;
// service.dart
import "package:flutter_bloc_annotations/flutter_bloc_annotations.dart";

class TestService extends InputService<int> {
  void init(Sink<int> sink) async {
    await Future.delayed(Duration(seconds: 10));

  void dispose() {}

More extensive examples can be found in the root example/ directory.