Flutterの Firebaseの認証でトラブル

前提・実現したいこと

Flutter のアプリでFirebaseのAuthenticationを利用した電話番号認証をしたい。

発生している問題・エラーメッセージ

android studio を使っています。
認証ボタンを押した瞬間に

Xcode build done.                                           21.5s
	path: satisfied (Path is satisfied), interface: en0
Configuring the default Firebase app...
Configured the default Firebase app __FIRAPP_DEFAULT.
	path: satisfied (Path is satisfied), interface: en0
Syncing files to device iPhone 11 Pro Max...
*** First throw call stack:
(
	0   CoreFoundation                      0x00007fff23c7127e __exceptionPreprocess + 350
	1   libobjc.A.dylib                     0x00007fff513fbb20 objc_exception_throw + 48
	2   CoreFoundation                      0x00007fff23c710bc +[NSException raise:format:] + 188
	3   Runner                              0x0000000103e97d81 -[FIRPhoneAuthProvider verifyPhoneNumber:UIDelegate:completion:] + 193
	4   Runner                              0x000000010440dc3d -[FLTFirebaseAuthPlugin handleMethodCall:result:] + 18109
	5   Flutter                             0x000000010600ddb5 __45-[FlutterMethodChannel setMethodCallHandler:]_block_invoke + 104
	6   Flutter                             0x0000000105fa1ba0 _ZNK7flutter21PlatformMessageRouter21HandlePlatf<…>
Lost connection to device.

のようなエラーが発生します。

自分のコード

dart
1import 'package:flutter/material.dart';
2
3import 'package:firebase_auth/firebase_auth.dart';
4
5
6void main() => runApp(MyApp());
7
8class MyApp extends StatelessWidget {
9  @override
10  Widget build(BuildContext context) {
11    return MaterialApp(
12      home: MyHomePage(),
13
14//      initialRoute: '/',
15//      routes: {
16//        '/' : (context) => WelcomeClass(),
17//        '/LoginClass' : (context) => LoginClass(),
18//        '/SignUpClass' : (context) => SignUpClass(),
19//      },
20    );
21  }
22}
23
24class MyHomePage extends StatefulWidget {
25  @override
26  _MyHomePageState createState() => _MyHomePageState();
27}
28
29class _MyHomePageState extends State<MyHomePage> {
30  String phoneNo;
31  String smsCode;
32  String verificationId;
33
34  Future<void> verifyPhone() async {
35    final PhoneCodeAutoRetrievalTimeout autoRetrieve = (String verId) {
36      this.verificationId = verId;
37    };
38
39    final PhoneCodeSent smsCodeSent = (String verId, [int forceCodeResend]) {
40      this.verificationId = verId;
41      smsCodeDialog(context).then((value){
42        print('signed in');
43      });
44    };
45
46    final PhoneVerificationCompleted verificationSuccess = (AuthCredential user){
47      print('Phone Verification Completed');
48    };
49
50    final PhoneVerificationFailed verificationFailed =
51        (AuthException exception) {
52      print('${exception.message}');
53    };
54
55    await FirebaseAuth.instance.verifyPhoneNumber(
56      phoneNumber: this.phoneNo,
57      codeAutoRetrievalTimeout: autoRetrieve,
58      codeSent: smsCodeSent,
59      timeout: const Duration(seconds: 60),
60      verificationCompleted: verificationSuccess,
61      verificationFailed: verificationFailed,
62    );
63  }
64
65  Future<bool> smsCodeDialog(BuildContext context) {
66    return showDialog(
67        context: context,
68        barrierDismissible: false,
69        builder: (BuildContext context) {
70          return new AlertDialog(
71            title: Text('Enter sms code'),
72            content: TextField(
73              onChanged: (value) {
74                this.smsCode = value;
75              },
76            ),
77            contentPadding: EdgeInsets.all(10),
78            actions: <Widget>[
79              FlatButton(
80                child: Text('Done'),
81                onPressed: () {
82                  FirebaseAuth.instance.currentUser().then((user) {
83                    if (user != null) {
84                      Navigator.of(context).pop();
85                      Navigator.of(context)
86                          .pushReplacementNamed('/SignUpClass');
87                    } else {
88                      Navigator.of(context).pop();
89                      signIn();
90                    }
91                  });
92                },
93              )
94            ],
95          );
96        });
97  }
98
99  signIn() {
100    final AuthCredential credential = PhoneAuthProvider.getCredential(
101        verificationId: verificationId, smsCode: smsCode);
102
103    FirebaseAuth.instance.signInWithCredential(credential).then((user) {
104      Navigator.of(context).pushReplacementNamed('/homepage');
105    }).catchError((e) {
106      print('Auth Credential Error : $e');
107    });
108  }
109  @override
110  Widget build(BuildContext context) {
111    return Scaffold(
112      body: Padding(
113        padding: const EdgeInsets.all(38.0),
114        child: Column(
115          crossAxisAlignment: CrossAxisAlignment.start,
116          children: <Widget>[
117            TextField(
118              onChanged: (value) {
119                this.phoneNo = value;
120              },
121            ),
122            SizedBox(
123              height: 40,
124            ),
125            FlatButton(
126              child: Text("Send code"),
127              onPressed: verifyPhone,
128            ), //FlatButton
129          ], // Widget
130        ),
131      ), // Column
132    );
133  }
134}
135
136
137