无法将参数类型'Widget Function（BuildContext）'分配给Flutter中的参数类型'Widget Function（BuildContext，Widget）'错误

Question

这是代码：

import 'package:flutter/material.dart';
import 'package:flutterapp/ui/pages/notes_home.dart';
import 'package:provider/provider.dart';
import 'package:flutterapp/ui/pages/splash.dart';
import 'package:flutterapp/ui/pages/user_info.dart';
import 'package:flutterapp/ui/pages/auth/login.dart';
import 'package:flutterapp/model/user_repository.dart';
import 'package:path/path.dart';

class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return ChangeNotifierProvider(
      builder: (_) => UserRepository.instance(),
      child: Consumer
        // ignore: missing_return
        (builder: (context, UserRepository user, _) {
          // ignore: missing_return
          switch (user.status){
            case Status.Uninitialized:
              return Splash();
            case Status.Unauthenticated:
            case Status.Authenticating:
              return LoginPage();
            case Status.Authenticated:
              return NotesHomePage();
          }
      }),
    );
  }
}

以上代码中的“ builder：（_）=> UserRepository.instance（），这一行显示错误

无法将参数类型'Widget Function（BuildContext）'分配给参数类型'Widget Function（BuildContext，Widget）'

并且每当我运行程序时，它就会显示出来

在此LoginPage小部件上方找不到正确的提供程序

UserRepository代码：

import 'package:flutter/material.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:google_sign_in/google_sign_in.dart';

enum Status { Uninitialized, Authenticated, Authenticating, Unauthenticated }

class UserRepository with ChangeNotifier {
  FirebaseAuth _auth;
  FirebaseUser _user;
  GoogleSignIn _googleSignIn;
  Status _status = Status.Uninitialized;

  UserRepository.instance()
      : _auth = FirebaseAuth.instance,
        _googleSignIn = GoogleSignIn() {
      _auth.onAuthStateChanged.listen(_onAuthStateChanged);
  }

  Status get status => _status;
  FirebaseUser get user => _user;

  Future<bool> signIn(String email, String password) async{
    try {
      _status = Status.Authenticating;
      notifyListeners();
      await _auth.signInWithEmailAndPassword(email: email, password: password);
      return true;
    }catch(e){
      _status = Status.Unauthenticated;
      notifyListeners();
      return false;
    }
  }

  Future<bool> signUp(String email, String password) async{
    try {
      _status = Status.Authenticating;
      notifyListeners();
      await _auth.createUserWithEmailAndPassword(email: email, password: password);
      return true;
    }catch(e){
      _status = Status.Unauthenticated;
      notifyListeners();
      return false;
    }
  }

  Future<bool> signInWithGoogle() async{
    try{
      _status =Status.Authenticating;
      notifyListeners();
      final GoogleSignInAccount googleUser = await _googleSignIn.signIn();
      final GoogleSignInAuthentication googleAuth =
          await googleUser.authentication;
      final AuthCredential credential = GoogleAuthProvider.getCredential(idToken: googleAuth.idToken, accessToken: googleAuth.accessToken);
      await _auth.signInWithCredential(credential);
      return true;
    }catch(e) {
      print(e);
      _status = Status.Unauthenticated;
      notifyListeners();
      return false;
    }
  }

  Future signOut() async {
    _auth.signOut();
    _googleSignIn.signOut();
    _status = Status.Unauthenticated;
    notifyListeners();
    return Future.delayed(Duration.zero);
  }

  Future<void> _onAuthStateChanged(FirebaseUser firebaseUser) async{
    if(firebaseUser == null) {
      _status = Status.Unauthenticated;
    }else{
      _user = firebaseUser;
      _status = Status.Authenticated;
    }
    notifyListeners();
  }
}

请帮助

enter image description here

Answer 1

尝试一下：

class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return ChangeNotifierProvider<UserRepository>(
      create: (context) => UserRepository.instance(),
      child: Consumer
        // ignore: missing_return
        (builder: (context, UserRepository user, child) {
          // ignore: missing_return
          switch (user.status){
            case Status.Uninitialized:
              return Splash();
            case Status.Unauthenticated:
            case Status.Authenticating:
              return LoginPage();
            case Status.Authenticated:
              return NotesHomePage();
          }
      }),
    );
  }
}