creating listview with getting data from firestore on flutter

Question

I have an app I need to get those data from firestore database to the Listview on flutter one by one. I tried many things like a stream builder and future builder but I could not get because my database works with nested data if you have any suggestions please let me know thanks a lot. is there any solution to reading all this nested data? sometimes item name can be different so can I read if nested data have id or quantity value

I already used this but it does not work:

  import 'package:flutter/material.dart';
  import 'package:cloud_firestore/cloud_firestore.dart';

  class cart_page extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new StreamBuilder<QuerySnapshot>(
    stream: Firestore.instance.collection("cart").where("quantity", 
   isGreaterThanOrEqualTo: 1).snapshots(),
     builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> 
     snapshot) {
      if (!snapshot.hasData) return new Text("There is no expense");
      return new ListView(children: getExpenseItems(snapshot));
    });
     }

     getExpenseItems(AsyncSnapshot<QuerySnapshot> snapshot) {
      return snapshot.data.documents
         .map((doc) => new ListTile(
        title: new Text(doc["itemName"]),
        subtitle: new Text(doc["quantity"]))
  )
    .toList();
  }
 }

Right now are you returning anything from your snapshots stream — wcyankees424
– wcyankees424, Commented Apr 8, 2020 at 3:55
are you getting any log error? if yes then add here. This can also happen when you do not provide permission from firebase. — Viren V Varasadiya
– Viren V Varasadiya, Commented Apr 8, 2020 at 4:02
i am not getting any error but i can not see anything in my app it does not show anything there is nothing wrong with permisson i can write and read data if it is not nested like this — Mehmet Reşat Demir
– Mehmet Reşat Demir, Commented Apr 8, 2020 at 4:05

GJJ2019 · Accepted Answer · 2020-04-08 04:19:15Z

1

Problem here is the specific instance that u r accessing is map so u might want to do this:

title: new Text(doc["Item 9"]["itemName"]),
subtitle: new Text(doc["Item 9"]["quantity"]))

answered Apr 8, 2020 at 4:19

GJJ2019

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5 Comments

Mehmet Reşat Demir Over a year ago

but as i said above the item name could be change so i just want to get all data to the listview

GJJ2019 Over a year ago

may be u can try to wrap the map inside array in firebase so that u can get length of that array and u can draw list view easily

Mehmet Reşat Demir Over a year ago

i did not get what exactly did you mean sorry

GJJ2019 Over a year ago

change ur database structure i mean

GJJ2019 Over a year ago

or try using models that my best guess

wcyankees424 · Accepted Answer · 2020-04-08 06:00:01Z

1

I changed your code around besides the answer above mine you also are querying your nested database wrong and since I need an index to make this work I had to move some things around. You might have to play with this to get it to work but the general idea is there.



class Example extends StatelessWidget {
   var listOfWidgets = [];
  @override
  Widget build(BuildContext context) {
    return ListView.builder(
      itemCount: //number of items ,
      itemBuilder: (BuildContext context, int index) => StreamBuilder(

          stream: Firestore.instance
              .collection("cart")
              .where("Item$index.quantity", isGreaterThanOrEqualTo: 1)
              .snapshots(),
          builder:
              (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
                  if (!snapshot.hasData) return new Text("There is no expense");
                   return ...listOfWidgets;
              }),
    );
  }

  getExpenseItems(AsyncSnapshot<QuerySnapshot> snapshot) {

    var item = snapshot.data.documents
        .map((doc) => new ListTile(
            title: new Text(doc["Item$index.Name"]),
            subtitle: new Text(doc["Item$index.quantity"])))
        .toList();
    listOfWidgets.add(item);
  }
}

edited Apr 8, 2020 at 6:00

answered Apr 8, 2020 at 5:16

wcyankees424

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2 Comments

wcyankees424 Over a year ago

Sorry bout that i made a couple minor changes to it but you still getting nothing back

wcyankees424 Over a year ago

you might want to consider changing your map into an array here @Frank Van Puffelen suggests that heres the link stackoverflow.com/questions/54012380/…

gso_gabriel · Accepted Answer · 2020-04-08 09:10:46Z

0

Firestore doesn't support the type of query that you would need, that would be of you reading the entire "father" collection, so you can read the documents and subcollections. Queris on Firestore are shallow, so they don't permit this much functionalities. As it was informed and commented by others from the Community, it would be better for you to change your database, so it follows a pattern, instead of items having the possibility of having different names every time.

answered Apr 8, 2020 at 9:10

community wiki

gso_gabriel

2 Comments

Mehmet Reşat Demir Over a year ago

So which database should i use for my app do you have any suggestions

gso_gabriel Over a year ago

Hi @MehmetReşatDemir I believe Firestore can be a good choice for you, but you will need to change your data model, so it's not that "free" as it is right now.

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