node.js - 在Flutter App中检查Firebase Auth中是否已存在电子邮件

Question

通过电子邮件和密码进行注册时可以使用，但是当我使用已经注册的ID时，它不会显示错误。相反，它重定向到主页，并在控制台中显示PlatformException(ERROR_EMAIL_ALREADY_IN_USE, The email address is already in use by another account

Future validateForm() async {
FormState formState = _formKey.currentState;
if (formState.validate()) {
  FirebaseUser user = await firebaseAuth.currentUser();
  if (user == null) {
    firebaseAuth
        .createUserWithEmailAndPassword(
            email: _emailTextController.text,
            password: _passwordTextController.text)
        .then((user) => {
              _userServices.createUser(user.user.uid, {
                "username": _nameTextController.text,
                "email": _emailTextController.text,
                "userId": user.user.uid,
                "gender": gender,
              }),
            })
        .catchError((err) {
      showDialog(
          context: context,
          builder: (BuildContext context) {
            return AlertDialog(
              title: Text("User Already Exists"),
              content: Text(err.message),
              actions: [
                FlatButton(
                  child: Text("Ok"),
                  onPressed: () {
                    Navigator.of(context).pop();
                  },
                )
              ],
            );
          });
    });
    Navigator.pushReplacement(
        context, MaterialPageRoute(builder: (context) => HomePage()));
  } else {
    return ("already a user");
  }
}

}

Answer 1

您将进入第二页，因为您有:

   Navigator.pushReplacement(
        context, MaterialPageRoute(builder: (context) => HomePage()));

在if块之后。因此，如果user == null将输入if，然后进入catchError，然后导航至HomePage，则应将上述代码移至else:

  } else {
  Navigator.pushReplacement(
        context, MaterialPageRoute(builder: (context) => HomePage()));
    return ("already a user");
  }