我正在用flutter开发一个应用程序，遇到了一个大问题-当我重新启动代码时，需要10-20秒才能显示主页面，这通常不会是一个问题，除了圆形进度指示器没有显示-实际上它正在显示，但只是在屏幕中心显示一个蓝色的方形点。然后当页面加载完成时，它开始旋转一毫秒，然后进入主页。我很困惑为什么会发生这种情况，真的需要帮助。谢谢！
TLDR：圆形按钮冻结，并在结束时开始旋转这是我的代码，如果它有帮助：

import 'package:flutter/material.dart';
import 'package:workout_app/Screens/Components/Sign_Up_Screens/screen1.dart';
import 'package:workout_app/Screens/Components/homepage.dart';
import 'package:workout_app/Screens/Components/login.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'dart:io';

class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(children: [
        FutureBuilder(
          future: Firebase.initializeApp(),
          builder: (context, snapshot) {
            if (snapshot.connectionState == ConnectionState.done) {
              return Main();
            } else {
              return const Center(
                child: CircularProgressIndicator(),
              );
            }
          },
        )
      ]),
    );
  }
}

class Main extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => _MainState();
}

class _MainState extends State<Main> {
  final FirebaseAuth _auth = FirebaseAuth.instance;
  bool _isLoading = false;
  String? uid;
  String? name;
  String? userEmail;
  String? imageUrl;

  @override
  void initState() {
    Firebase.initializeApp();
    start();
    super.initState();
  }

  Future<bool> isLoggedIn() async {
    User? user = _auth.currentUser;
    return user != null;
  }

  void start() async {
    setState(() {
      _isLoading = true;
    });
    bool loggedIn = await isLoggedIn();
    SharedPreferences prefs = await SharedPreferences.getInstance();
    if (loggedIn) {
      String uid = _auth.currentUser!.uid;
      prefs.setString('id', uid);
      Navigator.of(context).pushReplacement(
        MaterialPageRoute(
            fullscreenDialog: true, builder: (context) => home_page()),
      );
    } else {
      setState(() {
        _isLoading = false;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    //this isn't important for the code - it doesn't impact the circular spinner
  }
}

Route _createRouteToLogin() {
  return PageRouteBuilder(
    pageBuilder: (context, animation, secondaryAnimation) => login_page(),
    transitionsBuilder: (context, animation, secondaryAnimation, child) {
      const begin = Offset(0.0, 1.0);
      const end = Offset.zero;
      const curve = Curves.ease;

      var tween = Tween(begin: begin, end: end).chain(CurveTween(curve: curve));

      return SlideTransition(
        position: animation.drive(tween),
        child: child,
      );
    },
  );
}

Route _createRouteToSignUp() {
  return PageRouteBuilder(
    pageBuilder: (context, animation, secondaryAnimation) => screen1(),
    transitionsBuilder: (context, animation, secondaryAnimation, child) {
      const begin = Offset(0.0, 1.0);
      const end = Offset.zero;
      const curve = Curves.ease;

      var tween = Tween(begin: begin, end: end).chain(CurveTween(curve: curve));

      return SlideTransition(
        position: animation.drive(tween),
        child: child,
      );
    },
  );
}