Riverpod — Refs

Instructions

Ref (and WidgetRef in widgets) is how you interact with providers: read state, listen to changes, reset state, and register lifecycle callbacks. Providers get a Ref as the first parameter of their function or as this.ref in a Notifier. Widgets get a WidgetRef via Consumer / ConsumerWidget / ConsumerState.

Obtaining a Ref

• Inside a provider: First parameter of the provider function, or ref property in a Notifier.
• Inside a widget: Use a Consumer (builder gives ref), ConsumerWidget (build(context, ref)), or ConsumerStatefulWidget (state has ref). Pass ref to other functions if needed.

Listening to state

• ref.watch(provider) — Declarative. Your widget/provider rebuilds when the provider changes. Use this by default in build methods.
• ref.listen(provider, (prev, next) { ... }) — Imperative. Run side effects when the provider changes (e.g. show a dialog, navigate). Safe to use in build; for initState use ref.listenManual and manage the subscription.