The getter 'price' isn't defined for the type 'String'

Issue

The getter 'id' isn't defined for the type 'String'.Try importing the library that defines 'id', correcting the name to the name of an existing getter, or defining a getter or field named >

I am trying to show my Cart Items when I add them using the cart icon. When I will click on the cart icon it will take me to the CartScrren page, where it will show me the selected items. But I can not get the values from my cart.

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../providers/cart.dart'  ;
import '../widgets/cart_items_display.dart';

class CartScreen extends StatelessWidget {
 
  static const route = '/cart';

  @override
  Widget build(BuildContext context) {
    final cart = Provider.of<Cart>(context);
    
    return Scaffold(
      appBar: AppBar(
        title: Text('Your Cart'),
      ),
      body: Column(
        children: <Widget>[
          Card(
            margin: EdgeInsets.all(25),
            child: Padding(
              padding: EdgeInsets.all(8),
              child: Row(
                mainAxisAlignment: MainAxisAlignment.spaceBetween,
                children: <Widget>[
                  Text(
                    'Total',
                    style: TextStyle(fontSize: 25),
                  ),
                  Spacer(),
                  Chip(
                    label: Text(
                      '\$${cart.totalAmount}',
                      style: TextStyle(
                        color: Colors.white,
                      ),
                    ),
                    backgroundColor: Theme.of(context).primaryColor,
                  ),
                  TextButton(onPressed: () {}, child: Text('Order Now')),
                ],
              ),
            ),
          ),
          SizedBox(
            height: 10,
          ),
          Expanded(
            child: ListView.builder(
              itemCount: cart.items.length,
              itemBuilder: (ctx, i) => CartItemDisplay(
              //Having problem Here**
               cart.items.values.toString()[i].id,
               cart.items.values.toString()[i].price,
               cart.items.values.toString()[i].quantity,
                cart.items.values.toString()[i].title,
                ///////**
              ),
            ),
          ),
        ],
      ),
    );
  }
}

Below this is my Cart here I am using this map.

import 'package:flutter/foundation.dart';

class CartItem {
  final String id;
  final String title;
  final int quantity;
  final double price;

  CartItem({
    required this.id,
    required this.title,
    required this.quantity,
    required this.price,
  });
}

class Cart with ChangeNotifier {
  Map<String, CartItem> _items ={} ;
  Map<String, CartItem> get items {
    return  {..._items};
  }
  int get itemCount {
    return _items.length;

  }

  double get totalAmount{
    var total=0.0;
    _items.forEach((key, cartItem) {
      total += cartItem.price*cartItem.quantity;
    });
    

    return total;
  }

  void addItem(String productId, double price, String title) {
    if (_items.containsKey(productId)) {
      _items.update(
          productId,
          (existingCartItem) => CartItem(
              id: existingCartItem.id,
              title: existingCartItem.title,
              quantity: existingCartItem.quantity + 1,
              price: existingCartItem.price));
    } else {
      _items.putIfAbsent(
          productId,
          () => CartItem(
                id: DateTime.now().toString(),
                title: title,
                quantity: 1,
                price: price,
              ));
    }
    notifyListeners();
  }
}

But if don't use values.toString() its throw this error

Solution

Please try to get cart items from cart value.

final cart = Provider.of<Cart>(context);
final cartItems = cart.items.entries.map((e) => e.value).toList();

...

     Expanded(
        child: ListView.builder(
          itemCount: cartItems.length,
          itemBuilder: (ctx, i) => CartItemDisplay(
          ////* Change these lines.
           cartItems[i].id,
           cartItems[i].price,
           cartItems[i].quantity,
           cartItems[i].title,
            ///////**
          ),
        ),
      ),
...

Answered By - Joe Hu