Using builder and create both in Flutter's ChangeNotifierProvider

Question

This is from: https://firebase.google.com/codelabs/firebase-get-to-know-flutter#1

void main() {
  runApp(
    ChangeNotifierProvider(
      create: (context) => ApplicationState(),
      builder: (context, _) => App(),
    ),
  );
}

That's flutter's website so I thought code is trustworthy which means perhaps create and builder both are required.

This answer: https://stackoverflow.com/a/59101137/462608. says that builder is depreciated and create should be used instead.

But the above code is using create and builder both. What is the use of this builder here when create is also there? How are builder and create different from each other?

score 1 · Accepted Answer · answered Jun 17 '21 at 09:49

yeah, there big difference between create and builder

create : if you want to instantiate you notifier you should use create but if you notifier already instantiate you don't need use create simply use ChangeNotifierProvider.value
builder : usefull if you have some condition to show specific widget for example if in your logic you need tp choose between 2 widget to be showen you will use builder and you passe it child it's the static widget

ChangeNotifierProvider(
      create: (context) => ApplicationState(),
      builder: (context, child){
           if(condition){
             return SomeWidget();
           }
          return child;
      },
     child:App(),
    )

except that no need for builder

Please talk about buider being depreciated and people saying use create instead. — Aquarius_Girl, Jun 17 '21 at 09:51
it's deprecated because the most of cases no need for it and you can directly use create and child parameter — Dali Hamza, Jun 17 '21 at 09:56

Using builder and create both in Flutter's ChangeNotifierProvider

1 Answers1