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I want to add an object to Google Cloud Firestore in my Flutter app like this:

Firestore image

I have already made a Reply class:

class Reply { Reply(this.replyName, this.replyText, this.replyVotes); final String replyName; final String replyText; final String replyVotes; String getName() { return replyName; } String getText() { return replyText; } String getVotes() { return replyVotes; } }

How do I add a Reply object to cloud Firestore?

Edit: Just to clarify, I want to create a field with the data type Object which has fields inside it: Reply Object Image

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  • Have you tried adding a Map? Commented Jul 4, 2018 at 13:18
  • 1
    How do you use a map to create a new Object inside a Firestore document? I am able to add values inside the document using a map but not create an object which has these values. Commented Jul 5, 2018 at 15:23

4 Answers 4

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22

first, i highly recommend you have a single file that defines all of your schemas and/or models so there's a single point of reference for your db structure. like some file named dbSchema.dart:

import 'package:meta/meta.dart'; class Replies { final String title; final Map coordinates; Replies({ @required this.title, @required this.coordinates, }); Map<String, dynamic> toJson() => { 'title': title, 'coordinates': coordinates, }; }

and make the field that you want to be an object type Map. then, on the page you're going to insert into the db, import dbSchema.dart and create a new model:

Replies _replyObj = new Replies( title: _topic, coordinates: _coordinates, );

this assumes you've defined your local _coordinates (or whatever) object prior to this, with something like :

_coordinates = { 'lat': '40.0000', 'lng': '110.000', };

and to then insert into Firestore, add the object's toJson method (you cannot insert/update a plain Dart model):

CollectionReference dbReplies = Firestore.instance.collection('replies'); Firestore.instance.runTransaction((Transaction tx) async { var _result = await dbReplies.add(_replyObj.toJson()); ....

Update (5/31)

To convert the document read back into an object you need to add a fromJson to the class, like so:

Replies.fromJson(Map parsedJson) { id = parsedJson['id']; // the doc ID, helpful to have title = parsedJson['title'] ?? ''; coordinates = parsedJson['coordinates'] ?? {}; }

so when you query the db:

QuerySnapshot _repliesQuery = await someCollection .where('title', isEqualTo: _title) .getDocuments(); List<DocumentSnapshot> _replyDocs = _repliesQuery.documents;

you can create an object out of each snapshot:

for (int _i = 0; _i < _replyDocs.length; _i++) { Replies _reply = Replies.fromJson(_replyDocs[_i].data); _reply.id = _replyDocs[_i].documentID; // do something with the new _reply object }
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4 Comments

Nice answer. Adding some details on converting Firestore read document back to Dart model could be an additional help.
Great answer, useful and straightforward. +1 for @KrishnaShetty feedback. Would be great to have additional help for the reverse process. Would someone be so kind to help on that?
updated to include the mapping from a document read back into the object.
that is the case of having 2 attributes in the Replies object. What if you have more?
5

Null safe code:

Say this is your object.

class MyObject { final String foo; final int bar; MyObject._({required this.foo, required this.bar}); factory MyObject.fromJson(Map<String, dynamic> data) { return MyObject._( foo: data['foo'] as String, bar: data['bar'] as int, ); } Map<String, dynamic> toMap() { return { 'foo': foo, 'bar': bar, }; } }

To add this object to the cloud firestore, do:

MyObject myObject = MyObject.fromJson({'foo' : 'hi', bar: 0}); // Instance of MyObject. var collection = FirebaseFirestore.instance.collection('collection'); collection .add(myObject.toMap()) // <-- Convert myObject to Map<String, dynamic> .then((_) => print('Added')) .catchError((error) => print('Add failed: $error'));
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4

You can run a Firestore transaction like this: 

 Firestore.instance.runTransaction((transaction) async { await transaction.set(Firestore.instance.collection("your_collection").document(), { 'replyName': replyName, 'replyText': replyText, 'replyVotes': replyVotes, }); });
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3 Comments

Using this method, I am able to add values to a document. Instead what I want to do is create an Object inside a Firestore document which stores these values.
You can't not create a document (object) inside another document, first you should create a collection. Collections > documents > collections > documents ...
How do you access a sub-collection in Flutter?
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@Laksh22 As far as I understand, you mean something like this:

Firestore.instance.runTransaction((transaction) async { await transaction.set(Firestore.instance.collection("your_collection").document(), { 'reply' : { 'replyName': replyName, 'replyText': replyText, 'replyVotes': replyVotes, } });

just like the screenshot above.

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