Tipe argumen 'Map <String, dynamic> Function ()' tidak bisa ditugaskan ke tipe parameter 'Map <String, dynamic>'

Question

Ini awalnya bisa berfungsi tetapi setelah pembaruan firebase, sekarang memberi saya kesalahan ini. Saya telah menambahkan tanda bintang ke bagian yang memberikan kesalahan. Pesan kesalahan telah ditambahkan di bawah kode.

import 'package:cloud_firestore/cloud_firestore.dart';

class Record {
  final String name;
  final int totalVotes;
  final DocumentReference reference;

  Record.fromMap(Map<String, dynamic> map, {this.reference})
      : assert(map['name'] != null),
        assert(map['totalVotes'] != null),
        name = map['name'],
        totalVotes = map['totalVotes'];

  Record.fromSnapshot(DocumentSnapshot snapshot)
      : this.fromMap(**snapshot.data**, reference: snapshot.reference);

  @override
  String toString() => "Record<$name:$totalVotes>";
}

class Voters {
  String uid;
  String voteId;
  String markedVoteOption;
}

Tipe argumen 'Map <String, dynamic> Function ()' tidak bisa ditetapkan ke tipe parameter 'Map <String, dynamic>'.

Answer 1

Coba yang berikut ini:

  Record.fromSnapshot(DocumentSnapshot snapshot)
      : this.fromMap(snapshot.data(), reference: snapshot.reference);

data() adalah sebuah metode:

  /// Contains all the data of this [DocumentSnapshot].
  Map<String, dynamic> data() {
    return _CodecUtility.replaceDelegatesWithValueInMap(
        _delegate.data(), _firestore);
  }

yang mengembalikan a Map<String, dynamic>

Answer 2

Itu karena DocumentSnapshot.data () adalah fungsi yang mengembalikan Map<String, dynamic>.

Jadi, jawabannya adalah:

  Record.fromSnapshot(DocumentSnapshot snapshot)
      : this.fromMap(snapshot.data(), reference: snapshot.reference);

Answer 3

Rupanya yang dibutuhkan hanyalah tanda kurung di peta

import 'package:cloud_firestore/cloud_firestore.dart';

class Record {
  final String name;
  final int votes;
  final DocumentReference reference;

  Record.fromMap(Map<String, dynamic> map(), {this.reference})
      : assert(map()['name'] != null),
        assert(map()['votes'] != null),
        name = map()['name'],
        votes = map()['votes'];

  Record.fromSnapshot(DocumentSnapshot snapshot)
      : this.fromMap(snapshot.data, reference: snapshot.reference);

  @override
  String toString() => "Record<$name:$votes>";
}

Answer 4

Beginilah cara saya menyelesaikannya.

import 'package:cloud_firestore/cloud_firestore.dart';

class Record {
  final String name;
  final int totalVotes;
  final DocumentReference reference;

  Record.fromMap(Map<String, dynamic> map(), {this.reference})
      : assert(map()['name'] != null),
        assert(map()['totalVotes'] != null),
        name = map()['name'],
        totalVotes = map()['totalVotes'];

  Record.fromSnapshot(DocumentSnapshot snapshot)
      : this.fromMap(snapshot.data, reference: snapshot.reference);

  @override
  String toString() => "Record<$name:$totalVotes>";
}

class Voters {
  String uid;
  String voteId;
  String markedVoteOption;
}


 /// Contains all the data of this [DocumentSnapshot].
  Map<String, dynamic> data() {
    return _CodecUtility.replaceDelegatesWithValueInMap(
        _delegate.data(), _firestore);
  }