Question

我在flutter应用程序中有一个登录页面，用于验证和注册用户。当我想将用户电子邮件地址保存到Firestore（注册后）时，出现错误：

flutter: Error: NoSuchMethodError: The method 'saveRegisterUserData' was called on null.
Receiver: null
Tried calling: saveRegisterUserData(email: "test@test.de", userID: "EVDnVFMkYeYd291Yzu2j2r8HLpC2")'

我为Firestore Functions创建了一个单独的dart文件。看起来像这样：

import 'package:cloud_firestore/cloud_firestore.dart';
import 'dart:async';

abstract class BaseFire {
Future <void> saveRegisterUserData({String userID, String email});
}

class Fire implements BaseFire {
 final Firestore firestore = new Firestore();
 DocumentReference usersdocuments;

 Future <void> saveRegisterUserData({String userID, String email}) async {
   usersdocuments = Firestore.instance.collection("Users").document(userID);
   Map<String, String> registerdata = <String, String>{
   "Email": email,
   };
   usersdocuments.setData(registerdata).whenComplete(() {
   return print("Document Added");
   }).catchError((error) => print(error));
 }
}

我将这个文件导入我的登录页面并执行此功能：

import '../Firebase/firestore.dart';

class SignInPage extends StatefulWidget {
  SignInPage({this.firestore});
  final BaseFire firestore;

@override
State<StatefulWidget> createState() {
  return _SignInPageState();
  }
}

class _SignInPageState extends State<SignInPage> {
   String _email;
   String _password;

 ...

 void submitRegister() async {
   if (validateAndSave()) {
     try {
       String userId = await widget.auth.createUserWithEmailAndPassword(_email, _password);
       await widget.firestore.saveRegisterUserData(userID: userId, email: _email);
      } catch (error) {
        print(error);
     }
    }
   }
}

我的错误在哪里？谢谢您的帮助

Answer 1

您在以下位置具有自动的类成员变量初始化

SignInPage({this.firestore});

{}将参数设为可选，除非您确实打算将

firebase //variable

可选或具有默认值，请勿将其括在{}中，只需将其删除即可。您会在使用SignInPage的位置收到任何错误消息，只需修复参数即可，希望一切正常。

Flutter和Firestore：NoSuchMethodError：方法'...'在null上调用

1 个答案: