Widget _buildBody() {
    if (Global.profile.accessToken == null) {
      Navigator.of(context).pushNamed('/log-in');
    }
    return const Center(
      child: Text('No memory found...'),
    );
  }

  @override
  Widget build(BuildContext context) {
    return MultiProvider(
      providers: [
        ChangeNotifierProvider.value(value: UserModel()),
        ChangeNotifierProvider.value(value: LocaleModel())
      ],
      child: Consumer2<UserModel, LocaleModel>(
        builder: (BuildContext context, userModel, localeModel, child) {
          return Scaffold(
            appBar: _buildAppBar(userModel),
            body: _buildBody(),
          );
        },
      ),
    );
  }

老师你看，我其实是想进入页面的时候判断是否有 access_token，如果没有我要跳转到登录页。

但是每次启动的时候都会报错：

‘package:flutter/src/widgets/navigator.dart’: Failed assertion: line 5127 pos 12: ‘!_debugLocked’: is not true.

或者

======== Exception caught by widgets library =======================================================
The following assertion was thrown building Consumer2<UserModel, LocaleModel>(dirty, dependencies: [_InheritedProviderScope<LocaleModel?>, _InheritedProviderScope<UserModel?>]):
setState() or markNeedsBuild() called during build.

不知道是什么原因，还请教教我怎么做才是对的？谢谢！