Animated Icon in Flutter

main.dart

import 'package:flutter/material.dart';
void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Animated Icon',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> with TickerProviderStateMixin {
  AnimationController animationController;

  @override
  void initState() {
    super.initState();
    animationController = AnimationController(
      vsync: this,
      duration: Duration(seconds: 1),
    )
      ..forward()
      ..repeat(reverse: true);
  }

  @override
  void dispose() {
    animationController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        color: Colors.blue,
        child: Center(
          child: AnimatedBuilder(
            animation: animationController,
            builder: (context, child) {
              return Container(
                decoration: ShapeDecoration(
                  color: Colors.white.withOpacity(0.5),
                  shape: CircleBorder(),
                ),
                child: Padding(
                  padding: EdgeInsets.all(8.0 * animationController.value),
                  child: child,
                ),
              );
            },
            child: Container(
              decoration: ShapeDecoration(
                color: Colors.white,
                shape: CircleBorder(),
              ),
              child: IconButton(
                onPressed: () {},
                color: Colors.blue,
                icon: Icon(Icons.calendar_today, size: 24),
              ),
            ),
          ),

        ),
      ),
    );
  }
}