如何用Firebase在flutter中用电话号码认证？

Question

我是一个新的flutter，并使用firebase验证电话号码，但我无法验证。我浏览了它，但没有得到任何满意的解决办法。

我从StackOverflow实现了一些代码，但出现异常“Unhanded Exception：type”(FirebaseUser)=>Null'不是type Cast“中类型”(AuthCredential)=>Void“的子类型，因此无法捕获该异常。

signIn()async{
    AuthCredential credential= PhoneAuthProvider.getCredential(
      verificationId: verificationId,
      smsCode: smsCode
    );
    await firebaseAuth.signInWithCredential(credential).then((user){
       Navigator.of(context).pushReplacementNamed('/homepage');
         print('signed in with phone number successful: user -> $user');
    }).catchError((e){
       print(e);
    });
  }

Future<void> verifyPhone()async{
    final PhoneCodeAutoRetrievalTimeout autoRetrieval=(String verId){
      this.verificationId=verId;
    };

    final PhoneCodeSent smsCodeSent=(String verId, [int forceCodeResend]){
      this.verificationId=verId;
      smsCodeDialog(context).then((value){
        print("Signed in");
      });
    };

    final PhoneVerificationCompleted verificationCompleted = (FirebaseUser user) {
     print('verified');
    } as PhoneVerificationCompleted;



    final PhoneVerificationFailed verfifailed=(AuthException exception){
      print("${exception.message}");
    };

    await firebaseAuth.verifyPhoneNumber(
     phoneNumber: this.phoneNo,
     codeAutoRetrievalTimeout: autoRetrieval,
     codeSent: smsCodeSent,
     timeout: const Duration(seconds: 10),
     verificationCompleted: verificationCompleted,
     verificationFailed: verfifailed
    );
  }

pubspec.yaml

name: babilok
description: A new Flutter project.

version: 1.0.0+1

environment:
  sdk: ">=2.1.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter


  cupertino_icons: ^0.1.2
  page_transition:
  firebase_auth:

dev_dependencies:
  flutter_test:
    sdk: flutter


  uses-material-design: true

  # To add assets to your application, add an assets section, like this:
  assets:
    - assets/login_wheel.png
    - assets/login_wheel1.png
    - assets/forward_arrow.png
    - assets/google_ads.png
    - assets/wheel.png
    - assets/red_cross.png
    - assets/welcome_logo.png
    - assets/money_bag.png
    - assets/user.png
    - assets/money_bag.png
    - assets/up_gift_wheel.png
    - assets/cross.png
    - assets/icons/facebook_logo1.png
    - assets/icons/twitter_logo1.png
    - assets/icons/instagram_logo1.png

Answer 1

我在这里找到了stackOverflow的解决方案,

final PhoneVerificationCompleted verificationCompleted = (AuthCredential credential) {
   print('verified');
  };