的数据
代码是自我解释的：

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

void main() => runApp(TestApp());

class TestApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: HomePage(),
    );
  }
}

class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return CupertinoPageScaffold(
      child: NestedScrollView(
        headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
          return <Widget>[
            CupertinoSliverNavigationBar(
              largeTitle: Text('Settings'),
            )
          ];
        },
        body: Center(
          child: Material(child: Text('Home Page')),
        ),
      ),
    );
  }
}

字符串
代码来自我最近看到的一个视频：

• Large Title IOS Nav Bar with Flutter (Youtube)