flutter-provider

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 providers
• MultiProvider 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