Drag from bottom sheet to body target

main.dart

import 'package:flutter/material.dart';

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

class HomePage extends StatelessWidget {
  static const double dim = 50;
  final _scaffoldKey = GlobalKey<ScaffoldState>();
  HomePage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        title: 'Flutter Demo',
        debugShowCheckedModeBanner: false,
        theme: ThemeData(
          primarySwatch: Colors.blue,
        ),
        home: Scaffold(
            key: _scaffoldKey,
            floatingActionButton: FloatingActionButton(
              onPressed: () {
                _scaffoldKey.currentState!.showBottomSheet((context) {
                  return Container(
                      height: 200,
                      color: Colors.lightGreen,
                      child: Center(
                          child: Draggable<int>(
                              data: 1,
                              onDragStarted: () => Future.delayed(
                                  Duration(seconds: 1),
                                  () => Navigator.pop(context)),
                              feedback: Container(
                                  width: dim,
                                  height: dim,
                                  color: Colors.greenAccent),
                              child: Container(
                                  width: dim,
                                  height: dim,
                                  color: Colors.grey,
                                  child: Text('Draggable!')))));
                });
              },
            ),
            body: Center(
                child: DragTarget<int>(
                    builder: (context, candidateData, _) => Container(
                        width: dim * 2,
                        height: dim * 2,
                        color: candidateData.isNotEmpty
                            ? Colors.redAccent
                            : Colors.lightBlue,
                        child: Text('DragTarget!')),
                    onWillAccept: (_) => true,
                    onAccept: (_) => true))));
  }
}