Flutter Question posted in
The official Flutter documentation can be found here.

Flutter – Add a new JSON object to an existing list array firebase firestore

My app has a feature where users can add their reviews. For example, it’s like leaving a comment on Facebook. posting a user review should be stored in the reviews list. I think it can’t be done this way .doc(DocId).update(review.toJson()).

This is a screenshot of the data structure of my Firebase Firestore.
enter image description here

I tried to solve this firestore.FieldValue if I do that, an error message will come like this: I/flutter (21250): type '_Map<String, String?>' is not a subtype of type 'List<dynamic>'

this is my Firestore query.

Future<void> addReview (placeId,Review review) async{

    try{

      await FirebaseFirestore.instance.collection('attractions')
      .where('placeId',isEqualTo: placeId).get()
      .then((querySnapshot) {
        for (var ele in querySnapshot.docs) {

            FirebaseFirestore.instance
            .collection('attractions')
            .doc(ele.id)
            .update({
              'reviews': FieldValue.arrayUnion(review.toJson())});
          
        }

      });

    }catch(e){
      print(e);
    }
    
  }



}

this is my review.dart model class :

class Review {

  final String reviewId;
  final String? name;
  final String publishAt;
  final String? reviewerPhotoUrl;
  final String text;

  Review({
    required this.reviewId,
    required this.name,
    required this.publishAt,
    required this.reviewerPhotoUrl,
    required this.text,
  });

  toJson ()=>{
    "reviewId":reviewId,
    "name":name,
    "publishAt":publishAt,
    "reviewerPhotoUrl":reviewerPhotoUrl,
    "text":text
  };

  

}

I think there is a way around this or there is an alternative to doing this.

Tags:

2

Answers


  1. 0

    Try Using :

     FirebaseFirestore.instance
            .collection('attractions')
            .doc(ele.id)
            .update({
              'reviews': [review.toJson()]});

    I think your review type on firestore is List still it is not working provide proper typing

    Login or Signup to reply.
  2. 0

    When you iterate through querySnapshot.docs the ele object is of type QueryDocumentSnapshot. So there is no need to create a reference you can simply call reference. Besides that, the review is an object of type Review, so as far as I know there is no need to map the object to JSON, you can directly pass the object. So in code, it will be as simple as:

    //    👇
ele.reference.update({
    'reviews': FieldValue.arrayUnion(review)
}); //                                👆

    If you want to add the object as a Map, then you should define it as:

    Map<String, dynamic> review = {
  'reviewId': reviewId,
  'name': name,
  'publishAt': publishAt,
  'reviewerPhotoUrl': reviewerPhotoUrl,
  'text': text
};
    Login or Signup to reply.
Please signup or login to give your own answer.

Back To Top
Search