Flutter load ListView item async

Question

How can a ListView item refresh after each async task?

I have 2 collections on firebase that needs to be accessed and please, if there's another way please advise since I'm new in Firebase and Flutter.

My users have a collection inside called favorites with the userID field (same of the document id) and I load the ListView with all the users data BUT only with the ones that match that IDs (to avoid loading for example 1000 users for no reason = $$$).

According my code and my tests on the Run window I get the value of each user but my ListView on the app shows blank. I tried to place a setstate but the app refreshs non-stop.

I tried to create a separated function but simply I can't get it returning the list of document snapshots.

Thank you

FutureBuilder(
              future: Firestore.instance.collection('users').document(id).collection('favorites').getDocuments(),
              builder: (context, snapshot) {
                if (snapshot.hasData) {
                  List<DocumentSnapshot> userDocs = [];
                  snapshot.data.documents.forEach((doc) async {
                    await Firestore.instance.collection('users').document(doc.documentID).get().then((user) {
                      userDocs.add(user);
                    });
                  });
                  return ListView(
                    children: userDocs.map((document) {
                      return buildItem(context, document);
                    }).toList(),
                  );
                }
              },
            ),

FilipeOS · Accepted Answer · 2019-06-24 15:46:46Z

1

So, after weeks on this without any help I finally done it.

StreamBuilder is getting only the documents on favorites:

stream: Firestore.instance.collection('u').document(id).collection('f').snapshots()
ListView.Builder is returning a new Widget (MessageTile Stateful widget)

return MessageTile(ctx: context, doc: snapshot.data.documents[index]);
Inside the Statefull widget I'm returning a FutureBuilder<DocumentSnapshot> that is fetching ONLY the user matching the userId:

future: Firestore.instance.collection('u').document(doc['userId']).get()

Simple right? ..

answered Jun 24, 2019 at 15:46

FilipeOS

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1 Comment

v i c Over a year ago

thank you for posting your answer i think its similar to a problem I'm having but can't figure out... stackoverflow.com/questions/58527613/… . I have multiple async/await so it's a bit different but i'm hoping your method will work.

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