Ytukyg

I have a document in Firestore that has a reference to another document in Firestore, I would like to call the constructor for the first document and it build the referenced document at the same time. It seems I'm stuck with using a Future when I can't use a Future (in a constructor).

Is there any way to have ClassA's constructor convert ClassB's DocumentReference to ClassB (probably via ClassB.fromSnapshot())?

In ClassA I tried a ClassB.fromRef(DocumentReference), but in ClassB that has to return a Future, and as far as I know, you can't do Futures in a constructor. In solutions I've seen, they push the Future part to the UI calling ClassA, but I'm not sure how I would handle a Text widget like that (Text(await classA.classB.toString())?)

I can get the DocumentReference to resolve via a .then(), but I can't call a setState from this model (which makes sense, it's model, not view). The only way I can see it working, is if on my view side, I keep an array of strings to display in a ListView, and do a .then(setState()), but that's really gross...

I guess, what I'm wanting is to be able to do a ListView(Item) with ClassA classA = ClassA.fromSnapshot(shapshot); and be able to call classA.classB.name.

The 2 classes are as follows:

ClassA.dart :

import 'package:cloud_firestore/cloud_firestore.dart';

import 'package:msd/models/ClassB.dart';



class ClassA {

  /// The firestore ID

  String id;

  String name;

  ClassB classB;

  String status;

  DocumentReference reference;



  ClassA({id, name, classB, status, reference}) {

    this.id = id;

    this.name = name;

    this.classB = classB;

    this.status = status;

    this.reference = reference;

  }



  ClassA.fromMap(Map<String, dynamic> map, String id, {this.reference}) {

    id = id;

    name = map['name'];

    status = map['status'];

    classB = ClassB.fromRef(map['classB']);

  }



  ClassA.fromSnapshot(DocumentSnapshot snapshot)

      : this.fromMap(snapshot.data, snapshot.documentID, reference: snapshot.reference);



  String toString() {

    return 'ClassA $name at $ClassB';

  }

}

ClassB.dart :

import 'package:cloud_firestore/cloud_firestore.dart';



class ClassB {

  /// The firestore ID

  String id;

  String code;

  String email;

  String name;

  String phone;

  DocumentReference reference;



  ClassB({id, code, email, name, phone, address, reference}) {

    this.id = id;

    this.code = code;

    this.email = email;

    this.name = name;

    this.phone = phone;

    this.reference = reference;

  }



  ClassB.fromMap(Map<String, dynamic> map, String id, {this.reference})

      : assert(map['code'] != null),

        assert(map['email'] != null),

        assert(map['name'] != null),

        assert(map['phone'] != null),

        assert(map['address'] != null),

        id = id,

        code = map['code'],

        email = map['email'],

        name = map['name'],

        phone = map['phone'];



  ClassB.fromSnapshot(DocumentSnapshot snapshot)

      : this.fromMap(snapshot.data, snapshot.documentID, reference: snapshot.reference);



  static Future<ClassB> fromRef(DocumentReference ref) async {

    DocumentSnapshot snapshot = await ref.get();

    return ClassB.fromSnapshot(snapshot);

  }



  String toString() {

    return '$name <$code>';

  }

}