In this example, I'm going to share the code which will help you to show a Loader icon when an operation is being performed.
 async { await new Future.delayed(const Duration(seconds: 5), () ); return 'Hello World'; }
void main() => runApp(MyApp(str: fetchStr()));
class MyApp extends StatelessWidget { final Future str; MyApp({Key key, this.str}) : super(key: key); @override Widget build(BuildContext context) { return MaterialApp( title: 'Fetch Data Example', theme: ThemeData( primarySwatch: Colors.blue, ), home: Scaffold( appBar: AppBar( title: Text('Fetch Data Example'), ), body: Center( child: FutureBuilder( future: str, builder: (context, snapshot) { if (snapshot.hasData) { return Text(snapshot.data); } else if (snapshot.hasError) { return Text("$"); } // By default, show a loading spinner return CircularProgressIndicator(); }, ), ), ), ); } }
Hope this will be useful to you.
Thanks, Srikanth