How to call await correctly?

Question

I'm new to Flutter and Dart. I have a following code:

class ItemRepository {

  final Firestore _firestore = Firestore.instance;

  Future<List<Item>> loadItems() async {
    List<Item> itemList = [];
    _firestore.collection('items').snapshots().listen((data) {
      data.documents.forEach((doc){
        print("------- KODE: ${doc['kode']}");
        itemList.add(Item(doc['kode'], doc['name']));
      });
    });
    return itemList;
  }
}

When I call my loadItems with following code:

Stream<ItemState> _mapLoadItemsToState() async* {
    try {
      final data = await this.repo.loadItems();
      print('-------------------------------');
      print(data.length);
    } catch(e) {
      print(e.toString());
    }
  }

It's not WAIT to data return from firebase. I added await to _firestore.collection('items').snapshots() but no luck.

Any idea? Thank for any advice. Sorry for poor English.

diegoveloper · Accepted Answer · 2019-04-06 04:04:43Z

5

That's because you are listening the data, you will need to get the Future<QuerySnapshot> then the documents . Try something like this :

Future<List<Item>> loadItems() async {
   final List<Item> itemList = (await Firestore.instance.collection('items').getDocuments()).documents.map((snapshot) => Item(doc['kode'], doc['name'])).toList();
   return itemList;
}

edited Apr 6, 2019 at 4:04

answered Apr 6, 2019 at 3:56

diegoveloper

104k25 gold badges253 silver badges201 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Kalpesh Khandla · Accepted Answer · 2024-10-30 06:58:23Z

0

Create a asynchronous function with with await like a below

performAction() async {
// var data = await perform operation 
}

answered Oct 30, 2024 at 6:58

Kalpesh Khandla

1

Collectives™ on Stack Overflow

How to call await correctly?

2 Answers 2

Comments

Comments

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Related