Question 275295 in Flutter Question posted in
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Flutter – custom function: cant return int value of firestore document

Im trying to sum an integer field in my firestore document collection, although I keep gettings errors. It looks like because firestore store integers as "num".

A value of type 'Future<int>' can't be returned from the function 'calculateTotalItemQty' because it has a return type of 'int'.

import 'dart:convert';
import 'dart:math' as math;

import 'package:flutter/material.dart';
import 'package:google_fonts/google_fonts.dart';
import 'package:intl/intl.dart';
import 'package:timeago/timeago.dart' as timeago;
import '/flutter_flow/lat_lng.dart';
import '/flutter_flow/place.dart';
import '/flutter_flow/uploaded_file.dart';
import '/flutter_flow/custom_functions.dart';
import '/backend/backend.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import '/backend/schema/structs/index.dart';
import '/auth/firebase_auth/auth_util.dart';

int calculateTotalItemQty(
  String? itemId,
  String? businessId,
) {
  /// MODIFY CODE ONLY BELOW THIS LINE

  // sum value of all itemQty in purchaseLine where itemId is itemId and businessId is businessId
  return FirebaseFirestore.instance
      .collection('purchases')
      .where('itemId', isEqualTo: itemId)
      .where('businessId', isEqualTo: businessId)
      .get()
      .then((querySnapshot) {
    int totalQty = 0;
    querySnapshot.docs.forEach((doc) {
      int value = doc['itemQty'];
      totalQty += value.toInt();
    });
    return totalQty;
  }).catchError((error) {
    print('Error getting total item qty: $error');
    return null;
  });

  /// MODIFY CODE ONLY ABOVE THIS LINE
}

Tried to use .toInt() but still not working

Tags:

2

Answers


  1. 0

    You need to add await key word front of Firebase method. Like blow code

    Future calculateTotalItemQty(
    String? itemId,
    String? businessId,
    ) async{

      return await FirebaseFirestore.instance
      .collection('purchases')
      .where('itemId', isEqualTo: itemId)
      .where('businessId', isEqualTo: businessId)
      .get()
      .then((querySnapshot) {
    int totalQty = 0;
    querySnapshot.docs.forEach((doc) {
      int value = doc['itemQty'];
      totalQty += value.toInt();
    });
    return totalQty;
  }).catchError((error) {
    print('Error getting total item qty: $error');
    return null;
  });


}
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  2. 0

    @Mike Yates The problem is that your function is attempting to return a Future<int> instead of just an int. To resolve this, make your function async and utilize the await keyword for the Firestore query.

    Future<int> calculateTotalItemQty(
  String? itemId,
  String? businessId,
) async {
  try {
   /// MODIFY CODE ONLY BELOW THIS LINE

  // sum value of all itemQty in purchaseLine where itemId is itemId and businessId is businessId
    QuerySnapshot querySnapshot = await FirebaseFirestore.instance
        .collection('purchases')
        .where('itemId', isEqualTo: itemId)
        .where('businessId', isEqualTo: businessId)
        .get();

    int totalQty = 0;
    querySnapshot.docs.forEach((doc) {
      int value = doc['itemQty'] as int;
      totalQty += value;
    });

    return totalQty;
  } catch (error) {
    print('Error getting total item qty: $error');
    return 0;
  }
  
  
  /// MODIFY CODE ONLY ABOVE THIS LINE
}

    I hope this helps.

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