# Flutter Bloc and Cubit

Guides Flutter state management with Bloc or Cubit, including lifecycle and testing.

- Repository: https://github.com/andrewyng/context-hub (13986 stars)
- Category: Mobile
- License: MIT
- Last updated: 2026-05-31
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add andrewyng/context-hub --skill bloc-cubit -g -a claude-code -y`
Codex: `npx skills add andrewyng/context-hub --skill bloc-cubit -g -a codex -y`
Cursor: `npx skills add andrewyng/context-hub --skill bloc-cubit -g -a cursor -y`
Gemini CLI: `npx skills add andrewyng/context-hub --skill bloc-cubit -g -a gemini-cli -y`

## Description

Use when working with Flutter Bloc/Cubit state management. Covers when to choose Bloc vs Cubit, how to use bloc and flutter_bloc together, lifecycle, testing, and safe defaults.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Flutter Bloc/Cubit State Management

Use this skill when building Flutter state management with `bloc` and `flutter_bloc`.

## Core Rule

- Use `Cubit` for simple, direct state updates.
- Use `Bloc` for event-driven flows, transitions, and replayable business logic.
- Use `bloc` in Dart-only projects.
- Use `flutter_bloc` in Flutter apps when you need widgets like `BlocProvider`, `BlocBuilder`, or `BlocListener`.
- If you install `flutter_bloc`, you do not need to add `bloc` separately in a Flutter app because `flutter_bloc` depends on it.

## Decision Guide

Choose `Cubit` when:
- state changes are simple method calls
- you do not need events
- the feature is local and low complexity
- examples include counters, toggles, filters, form flags, and theme mode

Choose `Bloc` when:
- user actions should be modeled as explicit events
- the flow has loading, success, and failure transitions
- the logic benefits from clear state machines
- examples include auth, pagination, checkout, sync, and multi-step workflows

## Required Project Setup

For Dart-only code:
- add `bloc`
- do not add `flutter_bloc` unless Flutter widgets are needed

For Flutter UI code:
- add `flutter_bloc`
- let it bring `bloc` transitively
- use `BlocProvider` at the feature boundary
- use `BlocBuilder` for rebuilds and `BlocListener` for side effects

## Implementation Pattern

Prefer this structure:
- repository or service owns I/O
- bloc/cubit owns state and orchestration
- UI only dispatches actions and renders state

Keep state immutable.
Keep events explicit when using `Bloc`.
Keep one bloc or cubit per feature responsibility.

## Lifecycle Rules

- Close manually created blocs and cubits with `close()`.
- Do not manually close instances owned by `BlocProvider`.
- Use `BlocProvider` or `MultiBlocProvider` to let Flutter manage disposal.
- If you create a bloc/cubit with `new` or a constructor outside the widget tree, you own its lifecycle.

## UI Binding Rules

The rest: https://github.com/andrewyng/context-hub/blob/HEAD/content/flutter/skills/state-management/bloc-cubit/SKILL.md