我正在为我和我的团队正在开发的应用程序寻求帮助。数周以来，我们一直面临以下问题:

flutter type 'Timestamp' is not a subtype of type 'DateTime'

我们想从 Cloud Firestore 获取这些用户数据:

• 出生[日期时间]
• 性别[字符串]
• 许可[日期时间]
• 姓名[字符串]
• 大小[字符串]
• 重量[字符串]

只有birth 和license 在 Cloud Firestore 中存储为 1681720252，因此我们将这些数据解析为 [DateTime]。

这是获取用户数据的代码:

import 'package:cloud_firestore/cloud_firestore.dart';

class User{
  final String _name;
  final String _gender; // 'homme' or 'femme' or 'autre'
  final DateTime _birth;
  final DateTime _license;
  final double _weight;
  final int _size;
  DocumentReference ref;

  User(this._birth,this._gender,this._license,this._name,this._size,this._weight,this.ref);

  User.fromMap(Map<String, dynamic> map, {this.ref})
      : assert(map['name'] != null && map['gender'] != null && map['birth'] != null && map['weight'] != null && map['size'] != null),
        _name = map['name'],
        _gender = map['gender'],
        _birth = map['birth'] as DateTime,
        _license = map['license'] as DateTime,
        _weight = double.parse(map['weight']),
        _size = int.parse(map['size']);

  User.fromSnapshot(DocumentSnapshot snapshot)
      : this.fromMap(snapshot.data, ref: snapshot.reference);

  String get name => _name;
  String get gender => _gender;
  DateTime get birth => _birth;
  DateTime get license => _license;
  double get weight => _weight;
  int get size => _size;
}

这里是我们调用这些函数的地方，也是问题似乎出现的地方:

import 'package:bappsalcolit/pages/homepage.dart';
import 'package:flutter/material.dart';
import 'package:bappsalcolit/sign_in/auth.dart';
import 'package:bappsalcolit/sign_in/log_page.dart';
import 'package:bappsalcolit/ads_display.dart';
import 'package:bappsalcolit/dbase/model/global_info.dart';

import 'package:cloud_firestore/cloud_firestore.dart';

User currentUser = User(null, null, null, null, null, null, null);

class RootPage extends StatefulWidget {
  RootPage({this.auth});

  final AuthImpl auth;

  @override
  State<StatefulWidget> createState() => new _RootPageState();
}

enum AuthStatus {
  NOT_DETERMINED,
  NOT_SIGNED_IN,
  SIGNED_IN,
}

class _RootPageState extends State<RootPage> {
  AuthStatus authStatus = AuthStatus.NOT_DETERMINED;
  String _userID = "";

  @override
  void initState(){
    super.initState();
    Ads.hideBanner();
    widget.auth.getCurrentUser().then((user) {
      setState(() {
        if(user != null) {
          _userID = user?.uid;
        }
        authStatus =
        user?.uid == null ? AuthStatus.NOT_SIGNED_IN : AuthStatus.SIGNED_IN;
      });
    });
  }

  void _signedIn() {
    widget.auth.getCurrentUser().then((user){
      setState(() {
        _userID = user?.uid.toString();
      });
    });
    setState(() {
      authStatus = AuthStatus.SIGNED_IN;
    });
  }

  void _signedOut() {
    setState(() {
      authStatus = AuthStatus.NOT_SIGNED_IN;
      _userID = "";
    });
  }

  Widget _buildWaitingScreen() {
    return Scaffold(
      body: Container(
        height: 20.0,
        width: 20.0,
        alignment: Alignment.center,
        child: CircularProgressIndicator(),
      ),
    );
  }

  //========== Here's where the problem seems to appear ==========\\
  gettingSnapshots(){
    Firestore db = Firestore.instance;
    DocumentSnapshot userDS;
    db.collection('users').document(_userID).snapshots().listen((ds) async{
      if (ds.exists) {
        userDS = await db.collection('users').document(_userID).get();
        try {
          currentUser = User.fromSnapshot(userDS);
        } catch (e) {
          print('Error 1131: $e');
        }
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    switch (authStatus) {
      case AuthStatus.NOT_SIGNED_IN:
        return new SignIn(
          auth: widget.auth,
          onSignedIn: _signedIn,
        );
        break;
      case AuthStatus.SIGNED_IN:
        if(_userID.length > 0 && _userID != null) {
          gettingSnapshots();
          return new HomePage(
            userID: _userID,
            auth: widget.auth,
            onSignedOut: _signedOut,
          );
        }
        break;
      case AuthStatus.NOT_DETERMINED:
        return _buildWaitingScreen();
        break;
    }
    return _buildWaitingScreen();
  }
}

此问题仅出现在 iOS 上。在 Android 上一切正常。

问题应该不是来自 Cloud Firestore 和应用程序之间的链接，因为我们可以获取其他存储的信息。

最佳答案

在我的项目中我使用

birth: parsedJson['birth'].toDate()

而且效果很好，这是另一种选择。

关于firebase - flutter 问题 : type 'Timestamp' is not a subtype of type 'DateTime' ，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/55170087/