我正在使用Firebase和Flutter进行电话身份验证的应用程序。我没有使用任何表单字段，但我得到了AutoValidateMode未找到的错误。我一直在寻找解决方案，因为2天在网上，但无法找到一个。代码如下。

import 'dart:async';

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

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(
        primarySwatch: Colors.green,
      ),
      home: MyHomePage(title: 'Phone Auth'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final FirebaseAuth _auth = FirebaseAuth.instance;

  final _scaffoldKey = GlobalKey<ScaffoldState>();

  final TextEditingController _phoneNumberController = TextEditingController();
  final TextEditingController _smsController = TextEditingController();
  String _verificationId;
  final SmsAutoFill _autoFill = SmsAutoFill();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text(widget.title),
        ),
        key: _scaffoldKey,
        resizeToAvoidBottomInset: false,
        body: Padding(
          padding: const EdgeInsets.all(8),
          child: Padding(
              padding: EdgeInsets.all(16),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: <Widget>[
                    TextFormField(
                    controller: _phoneNumberController,
                    decoration: const InputDecoration(
                        labelText: 'Phone number (+xx xxx-xxx-xxxx)'),
                  ),],
              )),
        ));
  }
}

对于这个代码，我得到如下错误。

../../../../.pub-cache/hosted/pub.dartlang.org/pin_input_text_field-3.3.0/lib/src/widget/pin_widget.dart:402:5: Error: Type 'AutovalidateMode' not found.
    AutovalidateMode autovalidateMode = AutovalidateMode.disabled,
    ^^^^^^^^^^^^^^^^
../../../../.pub-cache/hosted/pub.dartlang.org/pin_input_text_field-3.3.0/lib/src/widget/pin_widget.dart:402:5: Error: 'AutovalidateMode' isn't a type.
    AutovalidateMode autovalidateMode = AutovalidateMode.disabled,
    ^^^^^^^^^^^^^^^^
../../../../.pub-cache/hosted/pub.dartlang.org/pin_input_text_field-3.3.0/lib/src/widget/pin_widget.dart:402:41: Error: Getter not found: 'AutovalidateMode'.
    AutovalidateMode autovalidateMode = AutovalidateMode.disabled,
                                        ^^^^^^^^^^^^^^^^
../../../../.pub-cache/hosted/pub.dartlang.org/pin_input_text_field-3.3.0/lib/src/widget/pin_widget.dart:436:13: Error: No named parameter with the name 'autovalidateMode'.
            autovalidateMode: autovalidateMode,
            ^^^^^^^^^^^^^^^^

如何解决这个问题？在哪里编辑AutoValidateMode总是？您的帮助是非常感谢。