How to scope a ChangeNotifier to some routes using Provider?

Question

I have a ChangeNotifier, and I would like to share it between multiple routes but not all routes:

Page1 is my first page. I need share data of ChangeNotifierProvider with Page2, Page3 and Page only and on enter Page1 call dispose of my ChangeNotifierProvider.

How can I do this using provider?

score 3 · Answer 1 · answered Sep 16 '19 at 19:24

3

To do so, the easiest solution is to have one provider per route, such that instead of:

Provider(
  builder: (_) => SomeValue(),
  child: MaterialApp(),
)

you have:

final value = SomeValue();

MaterialApp(
  routes: {
    '/foo': (_) => Provider.value(value: value, child: Foo()),
    '/bar': (_) => Provider.value(value: value, child: Bar()),
    '/cannot-access-provider': (_) => CannotAccessProvider(),
  }
)

It is, on the other hand, not possible to have your model "automatically disposed".

provider is not able in such a situation to know that it is safe to dispose of the object.

answered Sep 16 '19 at 19:24

Rémi Rousselet

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But I have a problem, the provider of Page2, Page3 and Page4 must be shared with each other – Adejair Júnior Sep 17 '19 at 10:10
What's the current behavior – Rémi Rousselet Sep 17 '19 at 10:11
I need page 2, page 3 and page 4, if I share with ChangeNotifier, but page 1 is not, it is first in the stack. – Adejair Júnior Sep 17 '19 at 13:45
Again that's exactly what this answer does. – Rémi Rousselet Sep 17 '19 at 13:47
1

And how to make the value automatically disposed in this case? That is what I been trying to figure out. Do I really need to make my own solution for this? Shouldn`t that be a very common use case? – Daniel Dec 16 '19 at 22:51

How to scope a ChangeNotifier to some routes using Provider?

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