How to do it...

In the following steps, you will create a new screen that shows an animation with an AnimatedContainer widget:

1. Create a new Flutter app and call it myanimations.
2. Remove the MyHomePage class created in the sample app.
3. Refactor the MyApp class as shown here:

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Animations Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
     home: MyAnimation(),
   );
  }
}

4. Create a file called my_animation.dart and add a new stateful widget called MyAnimation, using the stful shortcut. The result is shown here:

class MyAnimation extends StatefulWidget {
  @override
  _MyAnimationState createState() => _MyAnimationState();
}

class _MyAnimationState extends State<MyAnimation> {
  @override
  Widget build(BuildContext context) {
    return Container()...