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riverpod - Notifiers are NOT recreated
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////////////////////////////////// | |
// To run this gist, run: https://dartpad.dev/?id=6431062c2b8aff81b41aeea61b9987aa | |
////////////////////////////////// | |
import 'package:riverpod/riverpod.dart'; | |
/// A Provider that reads a json file and decodes it into a [Configuration]. | |
final authProvider = FutureProvider<String>((_) async { | |
print("executed authProvider"); | |
return "my-auth-state"; | |
}); | |
final repositoryProvider = AsyncNotifierProvider<RepositoryNotifier, String>( | |
RepositoryNotifier.new, | |
); | |
class RepositoryNotifier extends AsyncNotifier<String> { | |
RepositoryNotifier() { | |
// ERKENNTNIS, UNERWARTET: dieser Constructor wird nur 1x aufgerufen, | |
// AUCH wenn der Provider invalidiert und neu erzeugt wird. | |
// => die build() Methode wird erneut aufgerufen, die Objektinstanz des Providers BLEIBT ABER DIE GLEICHE. | |
// => daher bleiben auch die Eigenschaften auf der Klasse die gleichen. | |
print("executed repositoryProvider::Constructor"); | |
} | |
@override | |
Future<String> build() async { | |
// ERKENNTNIS: Build wird nach der Invalidierung erneut aufgerufen (as expected) | |
print("executed repositoryProvider::build 1"); | |
/// Reads the configurations from [configurationProvider]. This is type-safe. | |
final authConfig = await ref.watch(authProvider.future); | |
print("executed repositoryProvider::build 2"); | |
return authConfig + "processed"; | |
} | |
} | |
Future<void> main() async { | |
// Where the state of our providers will be stored. | |
// Avoid making this a global variable, for testability purposes. | |
// If you are using Flutter, you do not need this. | |
final container = ProviderContainer(); | |
print("executed main 1"); | |
/// Obtains the [Repository]. This will implicitly load [Configuration] too. | |
var repository = await container.read(repositoryProvider.future); | |
print("executed main 2"); | |
print("---INVALIDATING authProvider ---"); | |
container.invalidate(authProvider); | |
print("executed main 3"); | |
repository = await container.read(repositoryProvider.future); | |
/// Disposes the providers associated with [container]. | |
container.dispose(); | |
} |
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