"Invalid argument(s)" error on snapshot of StreamBuilder - Flutter

Question

I have a quick question. "snapshot.hasError" condition is getting true and "snapshot.hasData" condition is false. Output that I am getting on print in "snapshot.hasError" is "Invalid argument(s)". What does it mean?

Stream is getting data from database using "databaseServices" class but snapshot is not retrieving any data and it has error

class CustProfile extends StatefulWidget {
  @override
  _CustProfileState createState() => _CustProfileState();
}

class _CustProfileState extends State<CustProfile> {
 final AuthService _auth = AuthService();

@override
Widget build(BuildContext context) { 
 final user = Provider.of<User>(context);
return StreamBuilder<CustData>(
      stream: user != null ? DatabaseService(uid: user.uid).getCustData : null,
      builder: (context, snapshot) {
       debugPrint("User: " + user.toString());
     
 //  <<<<<< ---- Below condition is TRUE ---- >>>>>> 
       if (snapshot.hasError) {
          print("Snapshot error: " + snapshot.error.toString());
        }

        if (snapshot.hasData) {
    // ... Here is the widget which simply display the snapshot data but 
                 }
            }

Below is the DataServices.dart class that sends the data to database and retrieve data from database

class DatabaseService {

  // collection reference is just reference for certain collection
  final CollectionReference custCollection =
      Firestore.instance.collection('cust');
   
final String uid;
  DatabaseService({this.uid});

// Cust data from snapshot
  CustData _custDataFromSnapshot(DocumentSnapshot snapshot) {
    print(" UiD DB TEST" + uid + " USerNAme: " + snapshot.data['username']);
    return CustData(
      custId: uid,
      custPhNo: snapshot.data['custPhNo'] ?? "",
      custName: snapshot.data['custName'] ?? "",
      custDateOfBirth: (snapshot.data['custDateOfBirth'] as Timestamp).toDate() ?? "",
      custAddDate: (snapshot.data['custDateOfBirth'] as Timestamp).toDate() ?? "",
    );
  }

  // Get user doc stream
  Stream<CustData> get getCustData {
    return custCollection.document(uid).snapshots().map(_custDataFromSnapshot);
  }

  // ------------------------------- UPDATION AND RETRIVAL OF CUSTOMER DATA
  Future updateCustData(Map<String, dynamic> dataMap) async {
   
    // - Setting ID first in a document
    await custCollection.document(uid).setData(
      {
        'custID': uid,
        'custAddDate': DateTime.now(),
      },
      merge: true,
    );

    // - Dynamically adding data in the db
    dataMap.forEach(
      (key, value) async {
        await custCollection.document(uid).setData(
          {
            key: value,
          },
          merge: true,
        );
      },
    );
  }

Below is the User.dart class

class User {
  final String uid;
  User({this.uid});
}

class CustData {
  String custId;
  String custName;
  String custPhNo;
  DateTime custDateOfBirth;
  DateTime custAddDate;

  CustData({
    this.custId,
    this.custName,
    this.custPhNo,
    this.custDateOfBirth,
    this.custAddDate,
  });
}

Below is the output

I/flutter (21627): User: Instance of 'User'
I/flutter (21627): Snapshot error: Invalid argument(s)

Please share more code. It's unclear what `user` and `DatabaseService` is. There is a repetition in output because you hot reloaded/restarted. — Christopher Moore, Jul 20 '20 at 20:29

score 2 · Accepted Answer · answered Jul 23 '20 at 20:43

Was having the same issue, please refer to this post: StreamBuilder throws Dirty State saying Invalid Arguments

Your print statement is the line causing the error you're getting, specifically this line:

print(" UiD DB TEST" + uid + " USerNAme: " + snapshot.data['username']);

"Invalid argument(s)" error on snapshot of StreamBuilder - Flutter

1 Answers1