如何分配uid？

Question

我刚开始接触Flutter，我在Youtube上得到了一个教程，当应用程序应该发送给我用户uid时，我遇到了一个错误，因为代码在新版本的Firebase上已经过时了，即使在互联网上搜索时，我也找不到为什么firestore总是给我发送一个空的uid。感谢那些会回答我的人，我已经被屏蔽了2天了:)

翻译很抱歉，我不太会说英语，所以我用了google =)

错误来自代码“Firebase.instance.currentUser.then((”

import 'package:flutter/material.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter_tuto/constants/chargement.dart';
import 'package:flutter_tuto/pageCrud/accueil.dart';

class Inscription extends StatefulWidget {
  final Function basculement;
  Inscription({ this.basculement });
  @override
  _InscriptionState createState() => _InscriptionState();
}

class _InscriptionState extends State<Inscription> {

  FirebaseAuth _auth = FirebaseAuth.instance;
  User courantUser;

  //Collection Utilisateur depuis firestore
  final CollectionReference collectionUtil = FirebaseFirestore.instance.collection('utilisateurs');

  String email = '';
  String pseudo = '';
  String motDePasse = '';
  String confirmeMdp = '';

  bool chargement = false;

  final _formKey = GlobalKey<FormState>();

  @override
  Widget build(BuildContext context) {

    FirebaseAuth.instance.currentUser().then((User util){
      setState(() {
        this.courantUser = util;
      });
    });

    String _idUtil(){
      if(courantUser != null){
        return courantUser.uid;
      }else{
        return "pas d'utilisateurs courant";
      }
    }

    return chargement ? Chargement() : Container(
        decoration: BoxDecoration(
            image: DecorationImage(
                image: AssetImage("assets/BackgroundImage.jpg"),
                fit: BoxFit.cover
            )
        ),
        child: Scaffold(
          backgroundColor: Colors.transparent,
          body: SingleChildScrollView(
              child: Container(
                  padding: EdgeInsets.symmetric(vertical: 100.0, horizontal: 30.0),
                child: Form(
                  key: _formKey,
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.stretch,
                    children: [
                      Image.asset("assets/logo.png", height: 100.0, width: 100.0),
                      SizedBox(height: 10.0),
                      Center(
                        child: Text("Créer un compte Stix pour accéder à notre appli", style: TextStyle(fontSize: 20.0, color: Colors.blueAccent[100]))
                      ),
                      SizedBox(height: 10.0),
                      TextFormField(
                        decoration: InputDecoration(
                          labelText: "Adresse Mail",
                          border: OutlineInputBorder()
                        ),
                        validator: (val) => val.isEmpty ? 'Entrez une adresse mail' : null,
                        onChanged: (val) => email = val,
                      ),
                      SizedBox(height: 10.0),
                      TextFormField(
                        decoration: InputDecoration(
                            labelText: "Pseudo",
                            border: OutlineInputBorder()
                        ),
                        validator: (val) => val.isEmpty ? 'Entrez votre pseudo' : null,
                        onChanged: (val) => pseudo = val,
                      ),
                      SizedBox(height: 10.0),
                      TextFormField(
                        decoration: InputDecoration(
                            labelText: "Mot de passe",
                            border: OutlineInputBorder()
                        ),
                        validator: (val) => val.length < 6 ? 'Votre mot de passe doit contenir au moins 6 caractères' : null,
                        onChanged: (val) => motDePasse = val,
                        obscureText: true,
                      ),
                      SizedBox(height: 10.0),
                      TextFormField(
                        decoration: InputDecoration(
                            labelText: "Confirmez le mot de passe",
                            border: OutlineInputBorder()
                        ),
                        validator: (val) => val != motDePasse ? 'Le mot de passe doit correspondre a la confirmation' : null,
                        onChanged: (val) => confirmeMdp = val,
                        obscureText: true,
                      ),
                      FlatButton(
                          onPressed: () async {
                            if (_formKey.currentState.validate()){
                              setState(() {
                                chargement = true;
                              });
                              UserCredential result = await _auth.createUserWithEmailAndPassword(email: email, password: motDePasse);
                            await collectionUtil.doc(_idUtil()).set({
                              'idUtil' : _idUtil(),
                              'pseudo' : pseudo,
                              'email' : email
                            });
                            if(result == null){
                              setState(() => chargement = true);
                            }
                            }
                          },
                          color: Colors.blueAccent,
                        child: Text("S'inscrire"),
                        shape: RoundedRectangleBorder(
                          borderRadius: BorderRadius.circular(20.0)
                        ),
                      ),
                      OutlineButton(
                        onPressed: (){
                          widget.basculement();
                        },
                        borderSide: BorderSide(width: 2.0, color: Colors.blueAccent),
                        child: Text("Déja Inscrit ?"),
                        shape: RoundedRectangleBorder(
                            borderRadius: BorderRadius.circular(20.0)
                        ),
                      ),
                    ],
                  )
                )
              ),
          ),
        )
    );
  }
}

Answer 1

只需使用

 FirebaseAuth.instance.currentUser

在最近的更改中，它被更新为getter。Firebase正在将用户保存在自身之下。

您的代码将如下所示

String _idUtil(){
  var user = FirebaseAuth.instance.currentUser;
  if(user != null){
    return user.uid;
  }else{
    return "pas d'utilisateurs courant";
  }
}

如果您正在检查用户是否已登录，我会考虑使用authStateChanges

示例

@override
  void initState() {
    _firebaseAuth.authStateChanges().listen(_onAuthStateChanged);
    super.initState();
  }

Future<void> _onAuthStateChanged(User firebaseUser) async {
    if (firebaseUser != null) {
      setState((){
        _status = AuthStatus.LOGGED_IN;
      }
    } else {
      setState((){
        _status = AuthStatus.NOT_LOGGED_IN;
      }      
    }
  }

Answer 2

Future<String> getCurrentUID() async{
    final FirebaseUser user = await _auth.currentUser();
    final String uid = user.uid;
    return uid;
  }

使用这段代码来获取uid作为返回。因为这里使用的是Future，所以async关键字是必须的。