CODEWITHSUNDEEP
flutterflutter-provider
L. Gangemi
L. Gangemi

Reputation: 3290

Flutter Provider, update StreamProvider when his parameter changes

I've been developing this Flutter application in which one widget needs to read a list of Objects from firestore database.

To do so, I've a model for the specific Object (which is called Polizza).

I've a class called DatabaseService which contains the methods for getting the Streams.

In this case, this is the method I use to query the DB and get a stream:

Stream<List<Polizza>> streamPolizze({String id, String filter = ''}) {
    var ref = _db
        .collection('polizze')
        .doc(id)
        .collection('elenco')
        .orderBy('indice');

    if (filter.isNotEmpty) {
      List<String> list = filter.split(' ').map((e) => e.toUpperCase());
      ref = ref.where('indice', arrayContainsAny: list);
    }

    return ref.limit(10).snapshots().map(
        (list) => list.docs.map((doc) => Polizza.fromFirestore(doc)).toList());
  }

In the parent widget I was using a StreamProvider to enable his children to access the List of Polizza:

@override
  Widget build(BuildContext context) {
    var user = Provider.of<User>(context);
    var filter = Provider.of<FilterPolizze>(context);
    return MultiProvider(
      providers: [
        StreamProvider(create: (BuildContext context) => DatabaseService().streamPolizze(id: user.uid))
      ],
      child: ...
    );
  }

It worked.

But now I want to apply a filter to the query. For doing so I've built a simple TextField widget, which is able to provide me the filter value throught a ChangeNotifierProvider. This works fine, in fact I can read the filter and his updates from Provider.of(context). FilterPolizze is the Object type I've built for the filter.

I've tried to update the StreamProvider like that:

StreamProvider(create: (BuildContext context) => DatabaseService().streamPolizze(id: user.uid, filter: filter.value))

But it seems like it doesn't rebuild.

How can I notify the StreamProvider to rebuild itself if one of his parameters change?

Upvotes: 0

Views: 1327

Answers (1)

Pieter van Loon
Pieter van Loon

Reputation: 5648

Give the SteamProvider a Key which you change when the filter changes. So for instance use a key with the value 'polizze${filter.value}'

Upvotes: 4

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