| name | flutter-provider |
| description | Provider state management for Flutter. Use when exposing values with Provider, ChangeNotifierProvider, FutureProvider, StreamProvider, scoping with context.watch/read/select, ProxyProvider, or testing provider-based state. |
Flutter Provider
Provider Types
- Provider — exposes a value (no change notification)
- ChangeNotifierProvider — auto-disposes notifier when removed from tree
- FutureProvider — exposes Future result
- StreamProvider — exposes Stream values
- ProxyProvider — depends on other providers; refreshes when upstream changes
- Provider.value — for existing instances managed elsewhere
Scope each provider to the narrowest subtree that consumes it.
Accessing State
| Method | Where | Purpose |
|---|
context.watch<T>() | build() | Subscribe and rebuild on change |
context.read<T>() | Callbacks, event handlers | One-off access, no subscription |
context.select<T, R>() | build() | Subscribe to specific state slice |
- Always specify generic type:
Provider<MyType>, context.watch<MyType>()
- Place
Consumer/Selector as deep in the tree as practical
- Outside
build: access only at didChangeDependencies or in callbacks — not in constructors or initState
Lifecycle
- Use
create/update callbacks — don't instantiate from external mutable variables
ChangeNotifierProxyProvider when notifier depends on other providersMultiProvider to avoid nested declarations; for very large apps consider incremental mounting during splash
Diagnostics
- Add
DiagnosticableTreeMixin to provided objects for DevTools readability
Migration
ValueListenableProvider is deprecated — use ValueListenableBuilder + Provider.value
Testing
- Shallow provider wiring per test; override providers to inject mock/fake dependencies
- Scope to what each test needs, keep setup minimal
