how to add multiple ChangeNotifierProvider in same type in Flutter using Provider State Mangaement Technique - flutter-provider

Question

Is it possible to add the same type multiple ChangeNotifierProvider? Because I'm not getting the expected results.
I am unable to deal with a list of model classes while using Provider.
return MultiProvider(
providers: [
ChangeNotifierProvider<ValueNotifier<double>>(
create: (_) => ValueNotifier<double>(0.0),
),
ChangeNotifierProvider<ValueNotifier<double>>(
create: (_) => ValueNotifier<double>(0.0),
),
],
In my build method
#override
Widget build(BuildContext context) {
ValueNotifier<double> firstNotifier = Provider.of(context, listen: true);
ValueNotifier<double> secondNotifier = Provider.of(context, listen: true);
print('First value ${firstNotifier.value} Second value ${secondNotifier.value}');
...
onTap:(){
firstNotifier.value = 20.0;
secondNotifier.value = 30.0;
}
both printed values are the `enter code here same First value is 20 Second value is 20

Answer 1

Flutter uses the type of ChangeNotifierProvider to find it in the widget tree. So you can't have the same types in your MultiProvider, because Provider.of will always find one of these, as it happens in your code.
To solve this, you can define different classes for the providers, and use the class members to store values. For example, if you want to have two int type providers, you can do something like this:
class MyFirstProvider with ChangeNotifier {
int _myValue = 0;
int get myValue => _myValue;
set myValue(int newValue) {
_myValue = newValue;
notifyListeners();
}
}
class MySecondProvider with ChangeNotifier {
int _myValue = 0;
int get myValue => _myValue;
set myValue(int newValue) {
_myValue = newValue;
notifyListeners();
}
}
Create MultiProvider:
return MultiProvider(
providers: [
ChangeNotifierProvider(create: (context) => MyFirstProvider()),
ChangeNotifierProvider(create: (context) => MySecondProvider()),
],
Different ways to access these providers:
context.read<MyFirstProvider>()
context.watch<MySecondProvider>()
Provider.of<MyFirstProvider>(context, listen: false)
Provider.of<MySecondProvider>(context, listen: true)
You can adopt this to your case, you can use any type.
(Keep in mind, that ValueNotifier is a ChangeNotifier holding a single value, so it might not be the best approach to use a ValueNotifier as the type of a ChangeNotifierProvider.)