Flutter - How to call an API every n minutes? - flutter

Question

I need to call an API every n minutes. The data should be available across all screens. How can I implement this at app level. I am not using any state management tools.
void main() {
periodicSub = Stream.periodic(const Duration(seconds: 10))
.listen((_) {
///fetch data
someFuture =
Future<List<someObject>>.delayed(
const Duration(milliseconds: 500), () async {
return someFunction();
});
});
someFuntions returns a list. I want a certain FutureBuilder on HomePage to execute whenever the list is updated.

Answer 1

Here is an example using "https://pub.dev/packages/provider"
First create a Notifier:
import 'dart:async';
import 'package:flutter/material.dart';
class CustomNotifier with ChangeNotifier {
int counter = 0;
CustomNotifier() {
Stream.periodic(const Duration(seconds: 10)).listen((_) {
///fetch data
Future<List<dynamic>>.delayed(const Duration(milliseconds: 500),
() async {
return someFunction();
});
});
}
someFunction() {
counter++;
notifyListeners();
}
}
Then you could use it like:
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'notifier.dart';
void main() {
final customNotifier = CustomNotifier();
runApp(
MultiProvider(
providers: [
ChangeNotifierProvider(
create: (context) => customNotifier,
),
//You could add more providers
],
builder: (context, _) {
return const MyApp();
},
),
);
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: const MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({Key? key, required this.title}) : super(key: key);
final String title;
#override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(BuildContext context) {
var customNotifier = Provider.of<CustomNotifier>(
context,
);
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
const Text(
'someFunction runs this many times:',
),
Text(
'${customNotifier.counter}',
style: Theme.of(context).textTheme.headline4,
),
],
),
),
);
}
}