Change List Tile trailing using provider - flutter

Question

The problem is that when a List Tile is tapped the quantity is incremented for all the list tiles.
I have a stateless widget which has this build method :
final ProductsList productsList = ProductsList(context);
return Scaffold(
body: Center(child: productWidget(productsList, args)));
}
This is the ProductWidget
FutureBuilder productWidget(productsList) {
return FutureBuilder(
future: getProducts,
builder: (context, products) {
switch (products.connectionState) {
case ConnectionState.waiting:
return Text('Loading....');
default:
return Scaffold(
body: productsList.build(products.data));
}
},
);
And this is what productsList.build does:
ProductsList(this.context);
Padding getProduct(name) {
int _quantity = Provider.of<Quantity>(context).getQuantity();
return ListTile(
key: UniqueKey(),
onTap: () {
Provider.of<Quantity>(context, listen: false).incrementQuantity();
},
title: Text(name),
trailing: Text("$_quantity"),
),
);
}
ListView build(products) {
List<Widget> _products = new List();
for (var i = 0; i < products.length; i++) {
_products.add(getProduct(products[i].name));
}
return ListView(
children: _products,
);
}
and I am using this changeNotifier :
class Quantity extends ChangeNotifier {
int _quantity = 0;
void incrementQuantity(){
_quantity += 1;
notifyListeners();
}
int getQuantity() {
return _quantity;
}
}
I want to tap a list tile and increment just it's value which is displayed in the trailing, but not of the others.
I am using multi-provider in the main file of the application.

Answer 1

Provider needs to track quantity by product. Your Provider is tracking quantity as a single int so the result you are seeing is correct for your code.
Quantity should be List. You can also set the initial value.
Then
incrementQuantity(int index) {
increment quantity[index] here
}
And
get quantity(int index){
return quantity[index]
}
On a side note, in my opinion, your efforts would benifit greatly by researching using ListTile with Provider.