Implicit Animation Example

gistfile1.txt

class MyAnimatedFoo extends StatefulWidget {
  const MyAnimatedFoo({Key? key}) : super(key: key);

  @override
  State<MyAnimatedFoo> createState() => _MyAnimatedFooState();
}

class _MyAnimatedFooState extends State<MyAnimatedFoo> {
  double height = 100;
  double width = 100;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          setState(() {
            height = 200;
            width = 200;
          });
        },
        child: const Icon(
          Icons.add,
          color: Colors.white,
        ),
      ),
      body: Center(
        child: AnimatedContainer(
          duration: const Duration(seconds: 1),
          color: Colors.blue,
          height: height,
          width: width,
        ),
      ),
    );
  }
}