import 'package:flutter/cupertino.dart';

void main() => runApp(const NavBarApp());

class NavBarApp extends StatelessWidget {
  const NavBarApp({super.key});

  @override
  Widget build(BuildContext context) {
    return CupertinoApp(
      theme: CupertinoThemeData(),
      home: FirstPage(),
    );
  }
}

class FirstPage extends StatefulWidget {
  const FirstPage({super.key});

  @override
  State<FirstPage> createState() => _FirstPageState();
}

class _FirstPageState extends State<FirstPage> {
  @override
  Widget build(BuildContext context) {
    return CupertinoPageScaffold(
      child: CustomScrollView(
        slivers: [
          CupertinoSliverNavigationBar.search(
            searchField: CupertinoSearchTextField(
                suffixMode: OverlayVisibilityMode.always,
                suffixIcon: Icon(
                  CupertinoIcons.mic_solid,
                )),
            largeTitle: Text('Lists'),
          ),
          SliverList(
            delegate: SliverChildBuilderDelegate(
              (BuildContext context, int index) {
                return GestureDetector(
                  onTap: () => Navigator.of(context).push(
                    CupertinoPageRoute(
                      builder: (context) => SecondPage(),
                    ),
                  ),
                  child: CupertinoListTile(
                    title: Text('Item $index'),
                  ),
                );
              },
              childCount: 20,
            ),
          ),
        ],
      ),
    );
  }
}

class SecondPage extends StatelessWidget {
  const SecondPage({super.key});

  @override
  Widget build(BuildContext context) {
    return CupertinoPageScaffold(
      navigationBar: CupertinoNavigationBar(
        transitionBetweenRoutes: true,
        bottom: PreferredSize(
            preferredSize: Size.fromHeight(20), child: Placeholder()),
        middle: Text('Second Page'),
      ),
      child: CustomScrollView(
        slivers: [
          SliverList(
            delegate: SliverChildBuilderDelegate(
              (BuildContext context, int index) {
                return CupertinoListTile(
                  title: Text('Entry $index'),
                );
              },
              childCount: 20,
            ),
          ),
        ],
      ),
    );
  }
}