CODEWITHSUNDEEP
flutterfirebasedartgoogle-cloud-firestore
J L
J L

Reputation: 755

Firestore The argument type 'AsyncSnapshot<QuerySnapshot>' can't be assigned to the parameter type 'Map<String, dynamic>'

I am working to retrieve Firestore Database into Graph - failing to use fromMap() - with .fromMap(Map<String, dynamic> map) placed into Data Models.

What is the best way to get the data in the Widget?

class Sales {
  final int saleVal;
  final String saleYear;
  final String colorVal;
  Sales(this.saleVal,this.saleYear,this.colorVal);

  Sales.fromMap(Map<String, dynamic> map)
      : assert(map['saleVal'] != null),
        assert(map['saleYear'] != null),
        assert(map['colorVal'] != null),
        saleVal = map['saleVal'],
        colorVal = map['colorVal'],
        saleYear=map['saleYear'];

  @override
  String toString() => "Record<$saleVal:$saleYear:$colorVal>";
}

  Widget _buildBody(BuildContext context) {
    return StreamBuilder<QuerySnapshot>(
      stream: FirebaseFirestore.instance.collection('sales').snapshots(),
      builder: (context, snapshot) {
        if (!snapshot.hasData) {
          return LinearProgressIndicator();
        } else {
          List<Sales> sales = snapshot.data.docs
              .map((documentSnapshot) => Sales.fromMap(snapshot))
              .toList();
          return _buildChart(context, sales);
        }
      },
    );
  }

Upvotes: 0

Views: 593

Answers (1)

Doug Stevenson
Doug Stevenson

Reputation: 317372

The error message is telling you that snapshot is of type AsyncSnapshot and can't be used where a Map is required in the call to Sales.fromMap().

If your question is actually asking how to turn a DocumentSnapshot (which is in the variable documentSnapshot, not snapshot) into a Map, maybe what you're looking for is using the data() method on it:

Sales.fromMap(documentSnapshot.data())

Upvotes: 0

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