import 'package:flutter/material.dart';

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        useMaterial3: true,
        brightness: Brightness.dark,
      ),
      home: const Example(),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          const Text('TargetPlatform.Android'),
          Theme(
            data: Theme.of(context).copyWith(
              platform: TargetPlatform.android,
            ),
            child: Container(
              height: 250,
              padding: const EdgeInsets.all(8),
              decoration: BoxDecoration(
                border: Border.all(
                  color: Colors.amber,
                  width: 4,
                ),
              ),
              child: const AppBarLeading(
                showLeading: true,
                showTitle: false,
              ),
            ),
          ),
          const Text('TargetPlatform.iOS'),
          Theme(
            data: Theme.of(context).copyWith(
              platform: TargetPlatform.iOS,
            ),
            child: Container(
              height: 250,
              padding: const EdgeInsets.all(8),
              decoration: BoxDecoration(
                border: Border.all(
                  color: Colors.amber,
                  width: 2,
                ),
              ),
              child: const AppBarLeading(
                showLeading: true,
                showTitle: false,
              ),
            ),
          ),
        ],
      ),
    );
  }
}

class AppBarLeading extends StatelessWidget {
  const AppBarLeading({
    super.key,
    required this.showLeading,
    required this.showTitle,
  });

  final bool showLeading;
  final bool showTitle;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      drawer: const Drawer(),
      body: CustomScrollView(
        slivers: [
          SliverAppBar(
            automaticallyImplyLeading: showLeading,
            iconTheme: const IconThemeData(
              color: Colors.amber,
            ),
            title: showTitle ? const Text('AppBar') : null,
            flexibleSpace: FlexibleSpaceBar(
              title: Text('Title ' * 15),
              // centerTitle: true,
            ),
            toolbarHeight: showTitle ? 170 : 100,
          ),
        ],
      ),
    );
  }
}