not pressing button

not_touch_bottom.dart

import 'package:flutter/material.dart';


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

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

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Flutter Demo',
      theme:
          ThemeData(primarySwatch: Colors.blue, brightness: Brightness.light),
      home: const BasicDemo(),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: CustomScrollView(
        slivers: <Widget>[
          SliverAppBar(
            pinned: true,
            expandedHeight: 300.0,
            flexibleSpace: const FlexibleSpaceBar(
              centerTitle: true,
              titlePadding: EdgeInsets.only(bottom: 25),
              title: Text('Title here'),
            ),
            bottom: PreferredSize(
              preferredSize: const Size.fromHeight(0.0),
              child: Transform.translate(
                offset: const Offset(0, 50),
                child: TextButton(
                  child: const Text("Click Here"),
                  onPressed: () {
                    debugPrint("Click Here");
                  },
                ),
              ),
            ),
          ),
          const SliverPadding(
            padding: EdgeInsets.only(top: 50),
          ),
          SliverList(
            delegate: SliverChildListDelegate(
              List.generate(
                20,
                (index) {
                  return Padding(
                    padding: const EdgeInsets.all(5.0),
                    child: ListTile(
                      title: Text(
                        '$index',
                        style: Theme.of(context)
                            .textTheme
                            .headline5
                            ?.copyWith(color: Colors.black),
                      ),
                      onTap: () {},
                    ),
                  );
                },
              ),
            ),
          ),
        ],
      ),
    );
  }
}