CODEWITHSUNDEEP
flutterdartgoogle-cloud-firestore
David Escobar
David Escobar

Reputation: 81

Getting data from FireStore using Stream and Map it to Class Flutter

I am attempting to Deserialize data from Firestore Map into a new Class and call that Class using Provider. I have followed several tutorials (https://fireship.io/lessons/advanced-flutter-firebase/) with no success.

///auth_class.dart
import 'package:flutter/material.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:cloud_firestore/cloud_firestore.dart';

class UserCheck extends ChangeNotifier {
  final _auth = FirebaseAuth.instance;
  FirebaseUser loggedInUser;

  var userDetails;
  final String id;
  String firstName;
  final String lastName;
  final String userEmail;
  final String userOrg;
  final Timestamp regDate;
  final String date;

  UserCheck({
    this.id,
    this.firstName,
    this.lastName,
    this.userEmail,
    this.userOrg,
    this.regDate,
    this.date,
  });

  factory UserCheck.fromSnap(DocumentSnapshot ds) {
    Map data = ds.data;

    return UserCheck(
      id: ds.documentID,
      firstName: ds['fname'] ?? '',
      lastName: data['lname'] ?? '',
      userEmail: data['regEmail'] ?? '',
      userOrg: data['org'] ?? '',

    );
  }

I then try to call using 

//database_service.dart

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:oast_app/widgets/auth_class.dart';

class DatabaseService {

    Stream<List<UserCheck>> streamUser(FirebaseUser user){
    var ref = Firestore.instance.collection('users').document('${user.uid}').snapshots();
    return ref.map((list) => {
      return list.data.map((ds) => UserCheck.fromSnap(ds)).toList()
    });
    }
}

Error Messages: < Compiler message: lib/widgets/database_service.dart:12:7: Error: Unexpected token 'return'. return list.data.map((ds) => UserCheck.fromSnap(ds)).toList() ^^^^^^ lib/widgets/database_service.dart:12:55: Error: The argument type 'String' can't be assigned to the parameter type 'DocumentSnapshot'. - 'DocumentSnapshot' is from 'package:cloud_firestore/cloud_firestore.dart' ('../../Downloads/flutter/.pub-cache/hosted/pub.dartlang.org/cloud_firestore-0.12.11/lib/cloud_firestore.dart'). return list.data.map((ds) => UserCheck.fromSnap(ds)).toList() ^ lib/widgets/database_service.dart:12:46: Error: A value of type 'UserCheck' can't be assigned to a variable of type 'MapEntry'. - 'UserCheck' is from 'package:oast_app/widgets/auth_class.dart' ('lib/widgets/auth_class.dart'). - 'MapEntry' is from 'dart:core'. return list.data.map((ds) => UserCheck.fromSnap(ds)).toList() ^ lib/widgets/database_service.dart:12:28: Error: The argument type 'MapEntry Function(String)' can't be assigned to the parameter type 'MapEntry Function(String, dynamic)'. - 'MapEntry' is from 'dart:core'. return list.data.map((ds) => UserCheck.fromSnap(ds)).toList() ^ lib/widgets/database_service.dart:12:60: Error: The method 'toList' isn't defined for the class 'Map'. - 'Map' is from 'dart:core'. Try correcting the name to the name of an existing method, or defining a method named 'toList'. return list.data.map((ds) => UserCheck.fromSnap(ds)).toList() ^^^^^^ lib/widgets/database_service.dart:11:30: Error: A value of type 'Set' can't be assigned to a variable of type 'List'. - 'Set' is from 'dart:core'. - 'List' is from 'dart:core'. - 'UserCheck' is from 'package:oast_app/widgets/auth_class.dart' ('lib/widgets/auth_class.dart'). return ref.map((list) => { >

Upvotes: 2

Views: 4990

Answers (3)

Filipe Piletti Plucenio
Filipe Piletti Plucenio

Reputation: 729

You can use asyncMap

Stream<FirestoreResponse> getStream(String collection) {
    var snapshots =
        FirebaseFirestore.instance.collection(collection).snapshots();
    return snapshots.asyncMap((event) => FirestoreResponse(
        event.docs, event.docChanges, event.metadata, event.size));
}

Using a model like this

class FirestoreResponse extends Equatable {
  /// Gets a list of all the documents included in this snapshot.
  final List<QueryDocumentSnapshot<Map<String, dynamic>>> docs;

  /// An array of the documents that changed since the last snapshot. If this
  /// is the first snapshot, all documents will be in the list as Added changes.
  final List<DocumentChange<Map<String, dynamic>>> docChanges;

  /// Returns the [SnapshotMetadata] for this snapshot.
  final SnapshotMetadata metadata;

  /// Returns the size (number of documents) of this snapshot.
  final int size;

  /// Constructor
  const FirestoreResponse(this.docs, this.docChanges, this.metadata, this.size);

  @override
  List<Object?> get props => [
        docs,
        docChanges,
        metadata,
        size,
      ];
}

Upvotes: 0

Waelmas
Waelmas

Reputation: 1962

Instead of using .data; you need to use .data(); to actually get the document data.

However you can directly get each value of the Firestore map by using .data().map['[FIELD_NAME]']

Also the part of firstName should be data['fname'] as already stated.

Upvotes: 1

Jah
Jah

Reputation: 41

Just a guess, shouldn't your following code;

firstName: ds['fname'] ?? '',

be

firstName: data['fname'] ?? '',

instead?

Upvotes: 0

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