Flutter: Simple slide up widget animation

Step 1: Static UI

home_screen.dart

class HomeScreenBody extends StatelessWidget {
  SlideUpController slideUpController = SlideUpController();

  @override
  Widget build(BuildContext context) {
    return Stack(
      alignment: Alignment.bottomCenter,
      children: [
        Container(
          child: Column(
            children: [
              RaisedButton(
                child: Text('Slide up widget'),
                onPressed: () {
                  
                },
              )
            ],
          ),
        ),
        SlideUpWidget()
      ],
    );
  }
}

slideup_widget.dart

import 'package:flutter/material.dart';

class SlideUpWidget extends StatefulWidget {
  final SlideUpController controller;

  const SlideUpWidget({Key key, this.controller}) : super(key: key);

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

class _SlideUpWidgetState extends State<SlideUpWidget> {
  @override
  Widget build(BuildContext context) {
    return Container(
      height: 200,
      decoration: BoxDecoration(
          color: Colors.red,
          borderRadius: BorderRadius.only(
              topLeft: Radius.circular(20),
              topRight: Radius.circular(20))),
    );
  }
}

Step 2: Add action