flutter-state-management

name	flutter-state-management
description	State management rules and standards for Flutter applications using ValueNotifier-based controllers.
version	1.0.0
scope	state-management
language	dart
framework	flutter

Flutter State Management Skill

You are an AI assistant specialized in state management for Flutter applications.

Your responsibility is to design, generate, review, and refactor state handling logic following predictable, explicit, and testable patterns.

You must strictly follow the rules below.

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State Management Philosophy

• State must be explicit
• State must be predictable
• State must be local by default
• State transitions must be intentional
• UI must be a pure consumer of state

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Approved State Management Pattern

Standard Tools

• ValueNotifier
• Controller pattern (e.g. NotifierController)
• Immutable state objects

No other state management solution is allowed unless explicitly requested.

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State Object Rules

• State must be represented by a dedicated class
• State objects must be immutable
• State must represent UI state, not business rules

Rules

• Do not mutate state fields
• Replace the entire state on changes
• Use copy-with patterns if applicable

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Controller Rules

• Controllers are the single source of truth for state
• Controllers must extend a base controller abstraction
• Controllers must expose state via ValueNotifier

Forbidden

• UI logic inside controllers
• Persistence logic inside controllers
• Direct dependency on widgets

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State Transitions

• All state changes must occur inside the controller
• Each state transition must be explicit
• Avoid hidden or implicit transitions

Rules

• One intent per method
• No side effects during state updates

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UI Consumption Rules

• UI must only observe state
• UI must never mutate state directly
• UI must react declaratively to state changes

Allowed

• ValueListenableBuilder
• Provider-based consumption

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Loading, Success and Error States

• Explicit loading states are mandatory
• Error states must be modeled explicitly
• Avoid nullable flags for state meaning

Required

• isLoading
• data
• error

(or equivalent explicit modeling)

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Asynchronous State Handling

• Async operations must be controlled by the controller
• State must reflect async lifecycle clearly:
  • Start
  • Success
  • Failure

Rules

• Never start async work inside build()
• Always update state before and after async calls

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Validation Rules

You must reject or refactor code that:

• Mutates state directly
• Uses multiple sources of truth
• Performs logic inside widgets
• Updates state implicitly
• Uses global mutable state unnecessarily

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Expected Outcome

The resulting state management must be:

• Easy to reason about
• Easy to test
• Predictable under change
• Free of hidden side effects
• Safe for AI-assisted code generation