Problem Statement
When should you use Cubit instead of Bloc? Explain how to implement and use Cubit effectively.
Explanation
Use Cubit when your state logic is simple and doesn't benefit from the event-driven architecture of Bloc. Cubit is perfect for straightforward state changes like toggling switches, incrementing counters, managing form state, or simple CRUD operations where direct method calls are clearer than events. If you find yourself creating one event per method, Cubit might be simpler.
Implement Cubit by extending Cubit<StateType>, defining methods that emit new states using emit(newState). For example, class CounterCubit extends Cubit<int> with increment() method calling emit(state + 1). Methods can be async, emit multiple times during processing, and contain any logic. Cubit exposes concrete methods that UI calls directly, making the API clear and discoverable.
Provide Cubit using BlocProvider<CounterCubit>, use BlocBuilder<CounterCubit, int> for rebuilding UI, and call methods directly with context.read<CounterCubit>().increment(). The same ecosystem of BlocBuilder, BlocListener, and BlocConsumer works with Cubit. While simpler than Bloc, Cubit still provides benefits like separating logic from UI, testability, and reactive state management.
Cubit is ideal for small to medium state requirements where event-driven architecture adds unnecessary complexity. Many apps don't need the full power of Bloc's event system. Start with Cubit and migrate to Bloc if you need event replay, complex event processing, or event logging. Understanding both patterns lets you choose the right tool for each state management challenge.
