Mapping a map field object in Firestore in Flutter

Question

This is how my data look like. I'm trying to convert a map field object in Firestore to flutter.

If there isn't a rating map in my Firestore database, I can easily use the following code to convert the data in Flutter

firestore.collection('test').doc('I1raMaJArb1sWXWqQErE')
          .snapshots().listen((snapshot) {
        if (snapshot.docs != null) {
          var map = snapshot.docs;
          if (map != null) {
            map.forEach((change) {
              Review review = Review.fromJson(change.data());
            });
          }

But with the rating map in Firestore, I'm not sure how to convert it. Can anyone share how they would convert a map datatype in Firestore to flutter? Thanks in advance!

Below shows the code for the model.

class Reviews {
  String UserID;
  String UserName;
//what do I put for the rating

  Review({
    this.UserID,
    this.UserName
//what do I put for the rating
});

 factory ChatChannel.fromJson(Map<dynamic, dynamic> json) => ChatChannel(
      UserID: json['UserID'],
      UserName: json['UserName'],
//what do I put for the rating

 );

  Map<String, dynamic> toJson() => {
    "UserID": UserID,
    "UserName": UserName,
//what do I put for the rating

);
}

TheAlphamerc · Accepted Answer · 2021-06-17 04:33:29Z

4

You can create a model for ratings and add its parameter in Review Model. Have a look in below code.

    class Reviews {
      String UserID;
      String UserName;
      Ratings ratings;
      Review({
        this.UserID,
        this.UserName
    //what do I put for the rating
    });
    
     factory ChatChannel.fromJson(Map<dynamic, dynamic> json) => ChatChannel(
          UserID: json['UserID'],
          UserName: json['UserName'],
          Ratings: Ratings.fromJson(json['ratings'])
     );
    
      Map<String, dynamic> toJson() => {
        "UserID": UserID,
        "UserName": UserName,
         "ratings": ratings.toJson(),
    
     );
   }

class Ratings{
  String oneStar;
  String twoStar;
  String threeStar;
  Ratings({this.oneStar, this.twoStar,this.threeStar});

factory Ratings.fromJson(Map<dynamic, dynamic> json) => Ratings(
   oneStar: json['1-star'],
   twoStar: json['2-star'],
   threeStar: json['3-star'],
  );

Map<String, dynamic> toJson() => {
   "1-star": oneStar,
   "2-star": twoStar,
   "3-star": threeStar,
);
}

answered Jun 17, 2021 at 4:33

TheAlphamerc

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2 Comments

scott lee Over a year ago

ok thank you :) let me try this and revert

scott lee Over a year ago

thanks for your help. It worked! And thanks for your twitter clone. I got a lot of inspiration from that too :)

Ashok Kuvaraja · Accepted Answer · 2021-06-17 04:26:54Z

1

You can maintain the ratings field as a Map<String, int> type in the Reviews class like how you hold other fields.

class Reviews {
  Reviews({
    this.userID,
    this.userName,
    this.ratings,
  });

  String userID;
  String userName;
  Map<String, int> ratings;

  factory ChatChannel.fromJson(Map<dynamic, dynamic> json) => ChatChannel(
      userID: json['userID'],
      userName: json['userName'],
      ratings: json['ratings']);

  Map<String, dynamic> toJson() =>
      {"userID": userID, "userName": userName, 'ratings': ratings};
}

answered Jun 17, 2021 at 4:26

Ashok Kuvaraja

7264 silver badges12 bronze badges

3 Comments

scott lee Over a year ago

thanks, I tried your code but I received the following error: Unhandled Exception: type 'int' is not a subtype of type 'Map<String, int>'. do you know what's the issue?

Ashok Kuvaraja Over a year ago

Have you provided rating field type as Map<String, int>?

scott lee Over a year ago

Hi Ashok, I managed to get it to work with TheAlphamerc's code. But thanks for your suggestion tho. Appreciate it! :)

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