.uid:没有为类型“”UserCredential“”定义getter“”uid“”。“”- Flutter，FirebaseAuth

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

class AuthScreen extends StatefulWidget {
  @override
  _AuthScreenState createState() => _AuthScreenState();
}

class _AuthScreenState extends State<AuthScreen> {
  final FirebaseAuth _auth = FirebaseAuth.instance;
  TextEditingController _emailController = TextEditingController();
  TextEditingController _passwordController = TextEditingController();

  void _registerUser() async {
    try {
      UserCredential userCredential = await _auth.createUserWithEmailAndPassword(
        email: _emailController.text,
        password: _passwordController.text,
      );
      User user = userCredential.user;
      print('Registered user: ${user.uid}');
    } catch (e) {
      print('Error registering user: $e');
    }
  }

  void _loginUser() async {
    try {
      UserCredential userCredential = await _auth.signInWithEmailAndPassword(
        email: _emailController.text,
        password: _passwordController.text,
      );
      User user = userCredential.user;
      print('Logged in user: ${user.uid}');
    } catch (e) {
      print('Error logging in user: $e');
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Authentication'),
      ),
      body: Padding(
        padding: EdgeInsets.all(16.0),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            TextField(
              controller: _emailController,
              decoration: InputDecoration(
                labelText: 'Email',
              ),
            ),
            TextField(
              controller: _passwordController,
              decoration: InputDecoration(
                labelText: 'Password',
              ),
              obscureText: true,
            ),
            SizedBox(height: 16.0),
            RaisedButton(
              child: Text('Register'),
              onPressed: _registerUser,
            ),
            RaisedButton(
              child: Text('Login'),
              onPressed: _loginUser,
            ),
          ],
        ),
      ),
    );
  }
}