Quick transition between list of widgets

main.dart

// Copyright (c) 2023, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'dart:async';

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  final String title;

  @override
  MyHomePageState createState() => MyHomePageState();
}

  const List<IconData> icons = [
    Icons.brightness_1,
    Icons.brightness_2,
    Icons.brightness_3
  ];

class MyHomePageState extends State<MyHomePage> {
  int _currentIndex = 0;

  Timer? _timer;

  @override
  void initState() {
    super.initState();
    _timer = Timer.periodic(const Duration(seconds: 1), (timer) async {
      if (mounted) {
        setState(() {
          if (_currentIndex + 1 == icons.length) {
            _currentIndex = 0;
          } else {
            _currentIndex = _currentIndex + 1;
          }
        });
      }
    });
  }

  @override
  void dispose() {
    _timer?.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(),
      body: Center(
        child: AnimatedSwitcher(
          duration: const Duration(milliseconds: 500),
          child: Icon(
            icons[_currentIndex],
            key: ValueKey<int>(_currentIndex),
            size: 96,
          ),
        ),
      ),
    );
  }
}