How to initialize widget's provider with riverpod 2? - flutter

Question

My question concerns Riverpod.
I have a widget with 2 tabs. When i change the tab, i want to update a property (infoShare) with a "address" value if i choose the 1st tab and with a "publicKey" value if i choose the 2nd tab.
I used notifier to do that. No issue with that.
But when i instanciate the 1st time the main widget, my provider is not initialize.
So i need to fix it to create a specific provider to initialize it and use a ProviderScope.
Is it the good way to initialize my widget ?
Here's my code. It works but i don't know if it's the good solution.
And perhaps Riverpod's annotations could be helpfull
final _contactDetailInfoShareProviderArgs = Provider<Contact>(
(ref) {
throw UnimplementedError();
},
);
final _contactDetailInfoShareProvider = NotifierProvider.autoDispose
.family<ContactDetailInfoShareNotifier, String, Contact>(
() {
return ContactDetailInfoShareNotifier();
},
);
class ContactDetailInfoShareNotifier
extends AutoDisposeFamilyNotifier<String, Contact> {
ContactDetailInfoShareNotifier();
#override
String build(Contact arg) {
return arg.address.toUpperCase();
}
void setInfoShare(int tab, Contact contact) {
if (tab == 1) {
state = contact.publicKey.toUpperCase();
} else {
state = contact.address.toUpperCase();
}
}
}
abstract class ContactDetailProvider {
static final contactDetailInfoShare = _contactDetailInfoShareProvider;
static final contactDetailInfoShareProviderArgs =
_contactDetailInfoShareProviderArgs;
}
class ContactDetail extends ConsumerWidget {
const ContactDetail({
required this.contact,
super.key,
});
final Contact contact;
#override
Widget build(BuildContext context, WidgetRef ref) {
return ProviderScope(
overrides: [
ContactDetailProvider.contactDetailInfoShareProviderArgs
.overrideWithValue(
contact,
),
],
child: ContactDetailBody(
contact: contact,
),
);
}
}
class ContactDetailBody extends ConsumerWidget {
const ContactDetailBody({
required this.contact,
super.key,
});
final Contact contact;
#override
Widget build(BuildContext context, WidgetRef ref) {
return Column(
children: <Widget>[
Expanded(
child: Container(
child: ContainedTabBarView(
tabs: [
Text('tab1'),
Text('tab2'),
],
views: [
ContactDetailTab1(),
ContactDetailTab2(),
],
onChange: (p0) {
ref
.watch(
ContactDetailProvider.contactDetailInfoShare(contact)
.notifier,
)
.setInfoShare(p0, contact);
},
),
),
),
AppButton(
'Share',
onPressed: () {
print(
ref.watch(
ContactDetailProvider.contactDetailInfoShare(
ref.read(
ContactDetailProvider.contactDetailInfoShareProviderArgs,
),
),
),
);
},
)
],
);
}
}

Answer 1

ProviderScope should not be used other than the root of your app, or just for testing. It is not designed to be used in your widgets. There are many other options to init your providers, consider using .family or using some StateNotifierProvider with three states loading, error, value, and you can have the initial value to be loading and after initialization you can have the value state. Or consider using new Riverpod code generation to have some more complex logic to init your provider.