Flutter State

State

State management is about ownership and lifecycle. Choose patterns by state category, not by library popularity.

State Categories

UI State

Short-lived values local to one widget tree branch (tab index, text focus, toggle visibility).

Feature state

Domain state shared across screens within a feature (cart contents, selected account, draft form flows).

Server state

Remote data requiring loading/error/cache semantics and invalidation strategy.

Layers

Layering

presentation (widgets, controllers)
    -> application (use cases)
        -> domain (entities, policies)
            -> data (api, local cache, adapters)

Tool Choice

• Start simple with ValueNotifier/ChangeNotifier for small feature scope.
• Use Riverpod/Bloc when state graph and async orchestration become complex.
• Standardize one primary approach per project to reduce cognitive switching.

Async State

State Model

sealed class UsersState {}
class UsersLoading extends UsersState {}
class UsersReady extends UsersState {
  UsersReady(this.items);
  final List<User> items;
}
class UsersFailure extends UsersState {
  UsersFailure(this.message);
  final String message;
}

Recovery

Expose explicit retry actions in UI and record failure reasons for observability.

Injection

Inject Services

class UsersController {
  UsersController(this.api);
  final UsersApi api;
}

This allows deterministic unit tests and easier substitution in integration environments.

Engineering Notes

Keep a state ownership map per feature: who owns it, who reads it, and how it is invalidated.

Common Mistakes

• Globalizing local state too early.
• Using one mega-controller for unrelated domains.
• Ignoring async error states and showing empty UI with no diagnostics.

Practice Scope

Implement one feature with explicit state classes, async lifecycle handling, and unit tests for controller logic.

Back to roadmap: Flutter Roadmap