Example 1: flutter show loading spinner when list loading
import 'dart:async';
import 'package:flutter/material.dart';
Future fetchStr() 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("${snapshot.error}");
}
// By default, show a loading spinner
return CircularProgressIndicator();
},
),
),
),
);
}
}
Example 2: spinner in flutter
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(title: Text('Spinner Drop Down List in Flutter')),
body: DropDown(),
),
);
}
}
class DropDown extends StatefulWidget {
@override
DropDownWidget createState() => DropDownWidget();
}
class DropDownWidget extends State {
String dropdownValue = 'One';
List spinnerItems = [
'One',
'Two',
'Three',
'Four',
'Five'
] ;
@override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child :
Column(children: [
DropdownButton(
value: dropdownValue,
icon: Icon(Icons.arrow_drop_down),
iconSize: 24,
elevation: 16,
style: TextStyle(color: Colors.red, fontSize: 18),
underline: Container(
height: 2,
color: Colors.deepPurpleAccent,
),
onChanged: (String data) {
setState(() {
dropdownValue = data;
});
},
items: spinnerItems.map>((String value) {
return DropdownMenuItem(
value: value,
child: Text(value),
);
}).toList(),
),
Text('Selected Item = ' + '$dropdownValue',
style: TextStyle
(fontSize: 22,
color: Colors.black)),
]),
),
);
}
}