Question 193248 in Flutter Question posted in
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flutter error – Expected a value of type 'String', but got one of type 'int'

This is my function in a Flutter app to calculate the final price of the product by multiplying the product price and product quantity from the list

int calci() {
  int totalPrice = 0;
  for (int i = 0; i < cartitem.length; i++) {
    int price = int.parse(cartitem[i][1]);
    int quantity = int.parse(cartitem[i][4]);
    totalPrice += price * quantity;
  }
  return totalPrice;
}

and here is the code where I am displaying it

Text(
  '₹${calci().toString()}',
  style: const TextStyle(
    fontSize: 18,
    fontWeight: FontWeight.bold,
    color: Colors.white,
  ),
),

Now after running the app, this is giving me an error of typecasting I don’t know I tried a lot but was unable to resolve it.

Expected a value of type 'String', but got one of type 'int'

Tags:

2

Answers


  1. 0

    Int.parse needs a string to parse. The cart item is probably an integer. You can try

    int.parse(cartitem[i][1].toString())
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  2. 0

    Make sure that your cartitem List does not have elements of dynamic types, like:

    List cartitem = [
  ["Apple", 100, 1, 100, 1],
  ["Banana", "50", "1", "50", "1"],
];

    or

    List cartitem = [
  ["Grapes", "120", "1", 120, 4 ],
  ["Mango", "150", "1", 150,  4 ],
];

    Declare cartitem as:

    List<String> cartitem = {
  ["Banana", "50", "1", "50", "1"],
];

    Although I would suggest using a list of objects of type item, something like:

    example:

    import 'package:flutter/material.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    List cartitem = [
      Item(name: "Apple", price: 100, quantity: 1),
      Item(name: "Banana", price: 50, quantity: 1),
      Item(name: "Orange", price: 80, quantity: 1),
      Item(name: "Grapes", price: 120, quantity: 1),
    ];

    num calci() {
      num totalPrice = 0;
      for (var item in cartitem) {
        totalPrice += item.price * item.quantity;
      }
      return totalPrice;
    }

    return MaterialApp(
      home: Scaffold(
        body: Center(
          child: Text(
            '₹${calci().toString()}',
            style: const TextStyle(
              fontSize: 18,
              fontWeight: FontWeight.bold,
              color: Colors.black,
            ),
          ),
        ),
      ),
    );
  }
}

class Item {
  Item({required this.name, required this.price, required this.quantity});
  final String name;
  final double price;
  final int quantity;
}
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