In Flutter, the Provider package is a dependency injection library that makes it easy to manage the state of your app and share it with other widgets. It works by wrapping a value (such as a piece of data or an object) in a Provider widget, which can then be accessed by other widgets that are descendants of the Provider in the widget tree.
Here is an example of how you could use the Provider package to share a piece of data with multiple widgets:
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
void main() {
runApp(
ChangeNotifierProvider(
create: (context) => MyModel(),
child: MyApp(),
),
);
}
class MyModel with ChangeNotifier {
int _count = 0;
int get count => _count;
void increment() {
_count++;
notifyListeners();
}
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
home: MyHomePage(),
);
}
}
class MyHomePage extends StatelessWidget {
@override
Widget build(BuildContext context) {
final model = Provider.of<MyModel>(context);
return Scaffold(
body: Center(
child: Text(model.count.toString()),
),
floatingActionButton: FloatingActionButton(
onPressed: model.increment,
child: Icon(Icons.add),
),
);
}
}
In this example, the MyModel class defines a count property and a method to increment it. The MyModel instance is wrapped in a ChangeNotifierProvider widget and passed as the child of the MyApp widget. The MyHomePage widget can then access the count property and the increment method using the Provider.of method. When the increment method is called, it updates the count property and triggers a rebuild of the MyHomePage widget, causing the text in the center of the screen to update.