问调用方法时onTap属性中的错误

EN

import 'package:flash_chat_app/screen/chat_screen.dart';
import 'package:flutter/material.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'chat_screen.dart';
import 'package:modal_progress_hud_nsn/modal_progress_hud_nsn.dart';

class LoginScreen extends StatefulWidget {
  static const String id = 'login_screen';
  const LoginScreen({Key? key}) : super(key: key);
  @override
  LoginScreenState createState() => LoginScreenState();
}


class LoginScreenState extends State<LoginScreen> {
  final _auth = FirebaseAuth.instance;
  late String email;
  late String password;
  bool showSpinner = false;
  bool _obscureText = true;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.white,
      body: ModalProgressHUD(
        inAsyncCall: showSpinner,
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 24.0),
          child: SingleChildScrollView(
            child: Padding(
              padding: const EdgeInsets.only(top: 180.0),
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: <Widget>[
                  Hero(
                    tag: "logo",
                    child: SizedBox(
                      height: 200.0,
                      child: Image.asset('images/chat.png'),
                    ),
                  ),
                  const SizedBox(
                    height: 48.0,
                  ),
                  TextField(
                    keyboardType: TextInputType.emailAddress,
                    textAlign: TextAlign.center,
                    obscureText: false,
                    onChanged: (value) {
                      email = value;
                    },
                    style: const TextStyle(color: Colors.black),
                    decoration: const InputDecoration(
                      hintText: 'Enter your Email',
                      hintStyle: TextStyle(color: Colors.black26),


                      contentPadding:
                      EdgeInsets.symmetric(vertical: 10.0, horizontal: 20.0),
                      border: OutlineInputBorder(
                        borderRadius: BorderRadius.all(Radius.circular(32.0)),
                      ),
                      enabledBorder: OutlineInputBorder(
                        borderSide:
                        BorderSide(color: Colors.lightBlueAccent, width: 1.0),
                        borderRadius: BorderRadius.all(Radius.circular(32.0)),
                      ),
                      focusedBorder: OutlineInputBorder(
                        borderSide:
                        BorderSide(color: Colors.lightBlueAccent, width: 2.0),
                        borderRadius: BorderRadius.all(Radius.circular(32.0)),
                      ),
                    ),
                  ),
                  const SizedBox(
                    height: 8.0,
                  ),
                  TextField(
                    textAlign: TextAlign.center,
                    obscureText: _obscureText,
                    onChanged: (value) {
                      //Do something with the user input.
                      password = value;
                    },
                    style: const TextStyle(color: Colors.black),
                    decoration: const InputDecoration(
                      hintText: 'Enter your Password.',
                      hintStyle: TextStyle(color: Colors.black26),
                      suffix: InkWell(
                        child: Icon(Icons.visibility),
                        onTap: _togglePasswordView,
                        //here is error in onTap
                        
                      ),
                      contentPadding:
                      EdgeInsets.symmetric(vertical: 10.0, horizontal: 20.0),
                      border: OutlineInputBorder(
                        borderRadius: BorderRadius.all(Radius.circular(32.0)),
                      ),
                      enabledBorder: OutlineInputBorder(
                        borderSide:
                        BorderSide(color: Colors.lightBlueAccent, width: 1.0),
                        borderRadius: BorderRadius.all(Radius.circular(32.0)),
                      ),
                      focusedBorder: OutlineInputBorder(
                        borderSide:
                        BorderSide(color: Colors.lightBlueAccent, width: 2.0),
                        borderRadius: BorderRadius.all(Radius.circular(32.0)),
                      ),
                    ),
                  ),
                  const SizedBox(
                    height: 24.0,
                  ),
                  Padding(
                    padding: const EdgeInsets.symmetric(vertical: 16.0),
                    child: Material(
                      color: Colors.lightBlueAccent,
                      borderRadius: const BorderRadius.all(
                          Radius.circular(30.0)),
                      elevation: 5.0,
                      child: MaterialButton(
                        onPressed: () async {
                          setState(() {
                            showSpinner = true;
                          });
                          try {
                            final user = await _auth.signInWithEmailAndPassword(
                                email: email, password: password);
                            if (user != null) {
                              Navigator.pushNamed(context, ChatScreen.id);
                            }
                            setState(() {
                              showSpinner = false;
                            });
                          }
                          catch (e) {
                            print(e);
                          }
                        },
                        minWidth: 200.0,
                        height: 42.0,
                        child: const Text(
                          'Log In',
                        ),
                      ),
                    ),
                  ),
                ],
              ),
            ),
          ),
        ),
      ),
    );
  }

  void _togglePasswordView() {
    setState(() {
      _obscureText = !_obscureText;
    });
  }
}