BlocConsumer<S extends Cubit<V>, V> class

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 cubit.

BlocConsumer takes a required BlocWidgetBuilder and BlocWidgetListener and an optional stream/cubit, BlocBuilderCondition, and BlocListenerCondition.

If the stream parameter is omitted, BlocConsumer will automatically perform a lookup using Builders.systemInjector defined on MainApp.

BlocConsumer<BlocA, BlocAState>(
  listener: (context, state) {
    // do stuff here based on BlocA's state
  },
  builder: (context, state) {
    // return widget here based on BlocA's state
  }
)

An optional listenWhen and buildWhen can be implemented for more granular control over when listener and builder are called. The listenWhen and buildWhen will be invoked on each cubit state change. They each take the previous state and current state and must return a bool which determines whether or not the builder and/or listener function will be invoked. The previous state will be initialized to the state of the cubit when the BlocConsumer is initialized. listenWhen and buildWhen are optional and if they aren't implemented, they will default to true.

BlocConsumer<BlocA, BlocAState>(
  listenWhen: (previous, current) {
    // return true/false to determine whether or not
    // to invoke listener with state
  },
  listener: (context, state) {
    // do stuff here based on BlocA's state
  },
  buildWhen: (previous, current) {
    // return true/false to determine whether or not
    // to rebuild the widget with state
  },
  builder: (context, state) {
    // return widget here based on BlocA's state
  }
)