import 'package:flutter/material.dart';

final Color darkBlue = Color.fromARGB(255, 18, 32, 47);

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(

      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: Center(
          child: DefaultTabController(
              length: 2,
              child: NestedScrollView(
                  headerSliverBuilder:
                      (BuildContext context, bool innerBoxIsScrolled) {
                    return [
                      SliverOverlapAbsorber(
                        handle: NestedScrollView.sliverOverlapAbsorberHandleFor(
                            context),
                        sliver: SliverAppBar(
                          pinned: true,
                          expandedHeight: 240,
                          floating: true,
                          flexibleSpace: FlexibleSpaceBar(
                            background: Container(
                              height: 200,
                              color: Colors.red,
                            ),
                          ),
                          bottom: TabBar(tabs: [
                            Tab(
                              text: '1',
                            ),
                            Tab(
                              text: '2',
                            ),
                          ]),
                        ),
                      ),
                    ];
                  },
                  body: TabBarView(children: [Center(),Center(),]))),
        ),
      ),
    );
  }
}

NoSuchMethodError: method not found: 'get$value' on null
js_primitives.dart:47     at _TabBarState.get$_indicator (http://localhost:51322/main.dart.js:70701:17)
js_primitives.dart:47     at _TabBarState._initIndicatorPainter$0 (http://localhost:51322/main.dart.js:70745:20)
js_primitives.dart:47     at _TabBarState.didChangeDependencies$0 (http://localhost:51322/main.dart.js:70766:12)
js_primitives.dart:47     at StatefulElement._firstBuild$0 (http://localhost:51322/main.dart.js:91626:19)
js_primitives.dart:47     at StatefulElement.mount$2 (http://localhost:51322/main.dart.js:91498:12)
js_primitives.dart:47     at MultiChildRenderObjectElement.inflateWidget$2 (http://localhost:51322/main.dart.js:91273:16)
js_primitives.dart:47     at MultiChildRenderObjectElement.mount$2 (http://localhost:51322/main.dart.js:92085:26)
js_primitives.dart:47     at InheritedElement.inflateWidget$2 (http://localhost:51322/main.dart.js:91273:16)
js_primitives.dart:47     at InheritedElement.updateChild$3 (http://localhost:51322/main.dart.js:91197:26)
js_primitives.dart:47     at InheritedElement.performRebuild$0 (http://localhost:51322/main.dart.js:91521:41)

Analyzing demo_bug...
No issues found! (ran in 1.0s)

[√] Flutter (Channel stable, 2.2.2, on Microsoft Windows [Version 10.0.19043.1055], locale zh-CN)
    • Flutter version 2.2.2 at C:\Develop\flutter
    • Framework revision d79295af24 (12 days ago), 2021-06-11 08:56:01 -0700
    • Engine revision 91c9fc8fe0
    • Dart version 2.13.3
    • Flutter download mirror "https://mirrors.tuna.tsinghua.edu.cn/flutter"

[!] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
    • Android SDK at C:\Users\zzy\AppData\Local\Android\sdk
    • Platform android-30, build-tools 30.0.3
    • Java binary at: C:\Develop\jdk-11\bin\java
    • Java version OpenJDK Runtime Environment 18.9 (build 11+28)
    X Android license status unknown.
      Run `flutter doctor --android-licenses` to accept the SDK licenses.
      See https://flutter.dev/docs/get-started/install/windows#android-setup for more details.

[√] Chrome - develop for the web
    • Chrome at C:\Program Files\Google\Chrome\Application\chrome.exe

[!] Android Studio (not installed)
    • Android Studio not found; download from https://developer.android.com/studio/index.html
      (or visit https://flutter.dev/docs/get-started/install/windows#android-setup for detailed instructions).

[√] Connected device (2 available)
    • Chrome (web) • chrome • web-javascript • Google Chrome 91.0.4472.114
    • Edge (web)   • edge   • web-javascript • Microsoft Edge 91.0.864.54

! Doctor found issues in 2 categories.