Flutter slivers (CustomScrollView) example

main.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.dark(),
      home: FriendsPage(),
    );
  }
}

final requests = ['A', 'B', 'C'];
final friends = ['Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'];

class FriendsPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: CustomScrollView(
        slivers: [
          SliverToBoxAdapter(
            child: ListTile(
              title: Center(
                child: Text('Requests'),
              ),
            ),
          ),
          SliverGrid(
            gridDelegate: SliverGridDelegateWithMaxCrossAxisExtent(
              maxCrossAxisExtent: 400,
              childAspectRatio: 3.0,
            ),
            delegate: SliverChildBuilderDelegate(
              (context, i) => Card(
                child: Center(
                  child: ListTile(
                    leading: CircleAvatar(),
                    title: Text(requests[i]),
                  ),
                ),
              ),
              childCount: requests.length,
            ),
          ),
          SliverToBoxAdapter(
            child: ListTile(
              title: Center(
                child: Text('Friends'),
              ),
            ),
          ),
          SliverList(
            delegate: SliverChildBuilderDelegate(
              (context, i) => ListTile(
                leading: CircleAvatar(),
                title: Text(friends[i]),
              ),
              childCount: friends.length,
            ),
          ),
        ],
      ),
    );
  }
}