'package:flutter/src/animation/animation_controller.dart':失败的断言:第 246 行 pos 15:'vsync != null':不是真的

Shi*_*ath 0 flutter flutter-test flutter-layout flutter-animation

更新 Flutter Environment 后,我​​遇到了这个问题。请帮我解决这个问题。

 @override
  Widget build(BuildContext context) {
    return DefaultTabController(
      length: 4,
      child: Scaffold(
          appBar: topBar(), 
          body: TabBarView( // problem indicates here
            children: _kTabPages,
            controller: _tabController,
          ),

          // Button Navigation
          bottomNavigationBar: Material(
            color: Colors.redAccent,
            child: TabBar(
              tabs: _kTabs,
              controller: _tabController,
            ),
          )),
    );
  }

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请尽快帮助我。

voi*_*oid 6

在这个 github 问题之后:AnimationController has lost it's vsync

您可以按照以下步骤解决问题:

1. Change minimum sdk to 2.8
2. Run flutter upgrade
3. Run flutter pub get
4. Run flutter clean
5. Restart IDE
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