Using Provider in the same widget in flutter

Question

I have declared MultipleProviders in my widget and i want to use it to change the color of the App by assaining the variable to the ThemeData Primary swatch but it's giving me this error related to provider . and i have use in other widgets and it's working .i think i am getting this error bacause i am using it in the same widget how i can solve it ?

void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    var u = Provider.of<prov>(context);
    return MultiProvider(
      providers: [ChangeNotifierProvider(create: (_)=>prov())],
      child: GetMaterialApp(
        theme: ThemeData(primarySwatch: u.col),
        title: 'Material App',
        home: f(),
      ),
    );

  }
} 

this is the error

Error: Could not find the correct Provider above this MyApp Widget

This happens because you used a BuildContext that does not include the provider of your choice. There are a few common scenarios:

• You added a new provider in your main.dart and performed a hot-reload. To fix, perform a hot-restart.

• The provider you are trying to read is in a different route.

  Providers are "scoped". So if you insert of provider inside a route, then other routes will not be able to access that provider.

• You used a BuildContext that is an ancestor of the provider you are trying to read.

  Make sure that MyApp is under your MultiProvider/Provider. This usually happens when you are creating a provider and trying to read it immediately.

  For example, instead of:

  Widget build(BuildContext context) {
    return Provider<Example>(
      create: (_) => Example(),
      // Will throw a ProviderNotFoundError, because `context` is associated
      // to the widget that is the parent of `Provider<Example>`
      child: Text(context.watch<Example>()),
    ),
  }
  

  consider using builder like so:

  Widget build(BuildContext context) {
    return Provider<Example>(
      create: (_) => Example(),
      // we use `builder` to obtain a new `BuildContext` that has access to the provider
      builder: (context) {
        // No longer throws
        return Text(context.watch<Example>()),
      }
    ),
  }
  

Answer 1

You're getting the error because the context you're using does not have access to the provider.

The solution is like it says in the error message: you can use a builder instead of a child property for your provider. That creates a new context that reads the provider created.

You should change your build method to this.

  Widget build(BuildContext context) {
    return MultiProvider(
      providers: [ChangeNotifierProvider(create: (_)=>prove())],
    
      //From here is where you make the change
    
      builder: (context, child) {
      var u = Provider.of<prov>(context);
    
      return GetMaterialApp(
        theme: ThemeData(primarySwatch: u.col),
        title: 'Material App',
        home: f(),
      ),
    );
  }