Question 376462 in Flutter Question posted in
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Flutter – How to get a list of documents from Cloud Firestore using dart cloud_firestore package

I made a function to read a the data from a specific document and it works(code below)

Future<List<String>> getAllServicesFromDatabase()async{
  List<String> services = [];
  FirebaseFirestore db = FirebaseFirestore.instance;
  DocumentSnapshot<Map<String, dynamic>> results = await db.collection(dbCollection).doc(servicesDocument).get();
  if(results.data() != null){
    Map<String,dynamic> fetchedData = results.data()!;
    for(String service in fetchedData.keys.toList()){
      services.add(service);
    }
  }
  return services;
}

Table belonging to the first code sample:
enter image description here

Now I’d like something similar but this time I don’t know the name of the documents. I’d like to create a Function that returns a Lists of document names so that I can then Read each individual document.
(my failed attempt below)

class Customer {
  Customer({
    required this.document,
    required this.customer,
  });
  final String document;
  final Map<String,dynamic> customer;
}
Future<List<Customer>> getAllCustomersFromDatabase()async{
  List<Customer> customers = [];
  FirebaseFirestore db = FirebaseFirestore.instance;
  QuerySnapshot<Map<String, dynamic>> response = await db.collection(customersCollection).get();
  response.docs.map((doc){
    String docName = doc.id;
    Map<String, dynamic> document = doc.data();
    Customer customer = Customer(
      document: docName,
      customer: document,
    );
    print(customer.document);
    print(customer.customer);
  });
  return customers;
}

Table belonging to the second code sample:
enter image description here

Tags:

2

Answers


  1. 0

    Your getAllCustomersFromDatabase function always returns an empty list. It starts by creating an empty list named customers, performs a Firestore query, does absolutely nothing with customers after the query is done, and then returns the unchanged empty list.

    You probably want to actually populate the customers list at some point. Maybe you meant to return a Customer object from response.docs.map, then return the result of the map.

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  2. 0

    Problem:

    The current code is mapping over the response.docs and creating a Customer object on each run but not doing anything with either the created Customer object or the result of the map:

    response.docs.map((doc){
    String docName = doc.id;
    Map<String, dynamic> document = doc.data();
    Customer customer = Customer(
      document: docName,
      customer: document,
    );
    print(customer.document);
    print(customer.customer);
  });

    Solution:

    To fix this, do the following:

    1. Return the created Customer object at the end of the map block.
    2. Assign the result of the mapping to the customers variable.

    Like this:

    customers = response.docs.map((doc){  /// Modified this line
    String docName = doc.id;
    Map<String, dynamic> document = doc.data();
    Customer customer = Customer(
      document: docName,
      customer: document,
    );
    print(customer.document);
    print(customer.customer);

    return customer;   /// Added this line
  });
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