问 Flutter：“Future<dynamic>”不是bool类型的子类型

EN

我正在尝试实现一个简单的登录/注销功能。我的场景是这样的：

我有两个页面(登录页面和主页)，在 main.dart 中，我使用SharedPreferences检查用户是否已经登录，如果用户已经登录，我在单击按钮时将布尔值设置为true。

我的问题是，我有一个routeLogin函数，我创建的选择之间的主页和登陆页。我得到了这个错误：

I/flutter ( 9026): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter ( 9026): The following assertion was thrown building MyApp(dirty):
I/flutter ( 9026): type 'Future<dynamic>' is not a subtype of type 'bool'
I/flutter ( 9026):
I/flutter ( 9026): Either the assertion indicates an error in the framework itself, or we should provide substantially
I/flutter ( 9026): more information in this error message to help you determine and fix the underlying cause.
I/flutter ( 9026): In either case, please report this assertion by filing a bug on GitHub:
I/flutter ( 9026):   https://github.com/flutter/flutter/issues/new?template=BUG.md

这是我的代码：

import 'package:credit/src/pages/landing.dart';
import 'package:flutter/material.dart';
import 'package:credit/src/pages/credit/home.dart';
import 'package:shared_preferences/shared_preferences.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
  // This widget is the root of your application.
 bool checkValue;
 checkLoginValue () async{
   SharedPreferences loginCheck = await SharedPreferences.getInstance();
   checkValue = loginCheck.getBool("login");
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Test App',
       debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.blue,
      home: routeLogin());
      //home: LandingPage());      
  routeLogin()
    print("Check value");
    if (checkValue == null){
      return LandingPage();
    else{
      return HomePage();
}

请让我知道我哪里出错了，我是新来的。