flutter_bloc library Null safety

Classes

Bloc<Event, State>
Takes a Stream of Events as input and transforms them into a Stream of States as output.
BlocBase<State>
An interface for the core functionality implemented by both Bloc and Cubit.
BlocBuilder<B extends Bloc<Object?, S>, S>
BlocBuilder handles building a widget in response to new states. BlocBuilder is analogous to StreamBuilder but has simplified API to reduce the amount of boilerplate code needed as well as bloc-specific performance improvements. Please refer to BlocListener if you want to "do" anything in response to state changes such as navigation, showing a dialog, etc... [...]
BlocBuilderBase<B extends Bloc<Object?, S>, S>
Base class for widgets that build themselves based on interaction with a specified bloc. [...]
BlocConsumer<B extends Bloc<Object?, S>, S>
BlocConsumer exposes a builder and listener in order react to new states. BlocConsumer is analogous to a nested BlocListener and BlocBuilder but reduces the amount of boilerplate needed. BlocConsumer should only be used when it is necessary to both rebuild UI and execute other reactions to state changes in the bloc. [...]
BlocListener<B extends Bloc<Object?, S>, S>
Takes a BlocWidgetListener and an optional bloc and invokes the listener in response to state changes in the bloc. It should be used for functionality that needs to occur only in response to a state change such as navigation, showing a SnackBar, showing a Dialog, etc... The listener is guaranteed to only be called once for each state change unlike the builder in BlocBuilder. [...]
BlocListenerBase<B extends Bloc<Object?, S>, S>
Base class for widgets that listen to state changes in a specified bloc. [...]
BlocObserver
An interface for observing the behavior of Bloc instances.
BlocProvider<T extends Bloc<Object?, Object?>>
Takes a Create function that is responsible for creating the Bloc or Cubit and a child which will have access to the instance via BlocProvider.of(context). It is used as a dependency injection (DI) widget so that a single instance of a Bloc or Cubit can be provided to multiple widgets within a subtree. [...]
Change<State>
A Change represents the change from one State to another. A Change consists of the currentState and nextState.
Cubit<State>
A Cubit is similar to Bloc but has no notion of events and relies on methods to emit new states. [...]
MultiBlocListener
Merges multiple BlocListener widgets into one widget tree. [...]
MultiBlocProvider
Merges multiple BlocProvider widgets into one widget tree. [...]
MultiRepositoryProvider
Merges multiple RepositoryProvider widgets into one widget tree. [...]
RepositoryProvider<T>
Takes a Create function that is responsible for creating the repository and a child which will have access to the repository via RepositoryProvider.of(context). 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. [...]
Transition<Event, State>
A Transition is the change from one state to another. Consists of the currentState, an event, and the nextState.

Extensions

ReadContext
Exposes the read method.
RepositoryProviderExtension
Extends the BuildContext class with the ability to perform a lookup based on a repository type.
SelectContext
Adds a select method on BuildContext.
WatchContext
Exposes the watch method.

Typedefs

BlocBuilderCondition<S>(S previous, S current) bool
Signature for the buildWhen function which takes the previous state and the current state and is responsible for returning a bool which determines whether to rebuild BlocBuilder with the current state.
BlocListenerCondition<S>(S previous, S current) bool
Signature for the listenWhen function which takes the previous state and the current state and is responsible for returning a bool which determines whether or not to call BlocWidgetListener of BlocListener with the current state.
BlocWidgetBuilder<S>(BuildContext context, S state) Widget
Signature for the builder function which takes the BuildContext and state and is responsible for returning a widget which is to be rendered. This is analogous to the builder function in StreamBuilder.
BlocWidgetListener<S>(BuildContext context, S state) → void
Signature for the listener function which takes the BuildContext along with the state and is responsible for executing in response to state changes.
TransitionFunction<Event, State>(Event) Stream<Transition<Event, State>>
Signature for a mapper function which takes an Event as input and outputs a Stream of Transition objects.

Exceptions / Errors

BlocUnhandledErrorException
Exception thrown when an unhandled error occurs within a bloc. [...]