offscreen_slide_animation.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.dark(),
      debugShowCheckedModeBanner: false,
      home: const MyHomePage(),
    );
  }
}

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

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  var open = false;

  @override
  Widget build(BuildContext context) {
    final slider = TweenAnimationBuilder<double>(
      tween: Tween(begin: -1.0, end: open ? 0.0 : -1.0),
      duration: const Duration(milliseconds: 200),
      curve: Curves.ease,
      builder: (context, value, child) {
        return FractionalTranslation(
          translation: Offset(0, value),
          child: const SizedBox(
            width: 300,
            height: 200,
            child: Card(
              child: Center(child: Text('Hello, World!')),
            ),
          ),
        );
      },
    );

    return Scaffold(
      backgroundColor: Colors.white,
      body: GestureDetector(
        onTap: () {
          setState(() {
            open = !open;
          });
        },
        behavior: HitTestBehavior.opaque,
        child: Center(
          child: Container(
            decoration: BoxDecoration(
              border: Border.all(color: Colors.black12),
            ),
            child: slider,
          ),
        ),
      ),
    );
  }
}