use variables of one class in another class Flutter - flutter

Question

# cartmodel
`class CartModel extends ChangeNotifier {
// list of items on sale
final List _shopItems = const [
// [ itemName, itemPrice, imagePath, color ]
["Avocado", "4", "assets/images/avocado.png", Colors.green],
["Banana", "2", "assets/images/banana.png", Colors.yellow],
["pollo", "12", "assets/images/chicken.png", Colors.brown],
["acqua", "1", "assets/images/water.png", Colors.blue],
["mela", "3", "assets/images/mela.png", Colors.red],
["broccoli", "3", "assets/images/broccoli.png", Colors.brown],
];
final List _faidate = const [
["Avocado", "14000", "assets/images/avocado.png", Colors.orange],
["Banana", "2", "assets/images/banana.png", Colors.blueGrey],
["pollo", "12", "assets/images/chicken.png", Colors.red],
["acqua", "1", "assets/images/water.png", Colors.blue],
];
// list of cart items
final List _cartItems = [];
get faidate => _faidate;
get cartItems => _cartItems;
get shopItems => _shopItems;
// add item to cart
void addItemToCart(int index) {
_cartItems.add(_shopItems[index]);
notifyListeners();
}
// remove item from cart
void removeItemFromCart(int index) {
_cartItems.removeAt(index);
notifyListeners();
}
// calculate total price
String calculateTotal() {
double totalPrice = 0;
for (int i = 0; i < cartItems.length; i++) {
totalPrice += double.parse(cartItems[i][1].toString());
}
return totalPrice.toStringAsFixed(2);
}
}`
cartpage
`class CartPage extends StatelessWidget {
CartPage({
Key? key,
}) : super(key: key);
#override
Widget build(BuildContext context) {
Device.screenType == ScreenType.tablet;
return Container(
width: 100.w,
height: 90.5.h,
child: Container(
width: 100.w,
height: 20.5.h,
child: Scaffold(
appBar: AppBar(
backgroundColor: Colors.transparent,
elevation: 0,
iconTheme: IconThemeData(
color: Colors.grey[800],
),
),
body: Consumer<CartModel>(
builder: (context, value, child) {
return Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
// Let's order fresh items for you
Padding(
padding: EdgeInsets.symmetric(horizontal: 24.0),
child: Text(
"Cart",
style: GoogleFonts.notoSerif(
fontSize: 36,
fontWeight: FontWeight.bold,
),
),
),
// list view of cart
Expanded(
child: Padding(
padding: const EdgeInsets.all(12.0),
child: ListView.builder(
itemCount: (value.cartItems.length),
padding: EdgeInsets.all(12),
itemBuilder: (context, index) {
return Padding(
padding: const EdgeInsets.all(12.0),
child: Container(
decoration: BoxDecoration(
color: Colors.grey[200],
borderRadius: BorderRadius.circular(8)),
child: ListTile(
leading: Image.asset(
value.cartItems[index][2],
height: 36,
),
title: Text(
value.cartItems[index][0],
style: const TextStyle(fontSize: 18),
),
subtitle: Text(
'\points ' + value.cartItems[index][1],
style: const TextStyle(fontSize: 12),
),
trailing: IconButton(
icon: const Icon(Icons.cancel),
onPressed: () => Provider.of<CartModel>(
context,
listen: false)
.removeItemFromCart(index),
),
),
),
);
},
),
),
),
// total amount + pay now
Padding(
padding: const EdgeInsets.all(25.0),
child: Container(
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(8),
color: Colors.blueGrey[900]),
padding: const EdgeInsets.all(24),
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text(
'total price',
style: TextStyle(color: Colors.green[200]),
),
const SizedBox(height: 8),
// total price
Text(
'\Points ${value.calculateTotal()}',
style: const TextStyle(
fontSize: 18,
fontWeight: FontWeight.bold,
color: Colors.white,
),
),
],
),
// pay now
Container(
),
padding: const EdgeInsets.all(1),
child: Row(
children: [
ElevatedButton(
onPressed: () {},
child: const Text('order now')),
],
),
),
],
),
),
)
],
);
},
),
),
),
);
}
}
`
# points page
`class points extends StatefulWidget {
points({Key? key,}) :super(key: key);
_pointsState createState() => _pointsState();
}
class _pointsState extends State<points> {
int _points = 0;
#override
void initState() {
super.initState();
_loadPunti();
}
_loadPunti() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
setState(() {
_points = (prefs.getInt('points') ?? 0);
});
}
_savePunti() async {
await FirebaseFirestore.instance.collection('xxxx').add({
'Points': _points,
});
}
other code...
hi all, I was looking for a solution for this test of a flutter shopping app and I'm having problems in being able to use the "points" variable in the cart page to be able to confirm a purchase on the "onpressed" in the cartpage, I also attached the cartmodel like this to be able to verify. Thank you all