在 Flutter 中添加记录时，Cloud Firestore 未正确更新

Question

我正在开发一个 Flutter 应用程序，我正在使用 cloud_firestore 插件。我有一个提交的集合，我正在使用StreamBuilder 来显示它们（我假设它会在流更改时更新）。我从插件示例中直接拿了这个例子，因为没有太多关于如何使用插件做事的文档。当我添加一条记录时，我显示的文档列表变长了，但它似乎是在复制其中一个提交，而不是插入新的提交。新提交的内容添加后不显示。这是我如何显示列表的代码：

// At the top of the class home.dart. 
final submissions = Firestore.instance.collection('submissions');

// This is in submission-list.dart and the above submissions 
// is passed in to the contructor
Widget build(BuildContext context) {
    return new StreamBuilder<QuerySnapshot>(
      stream: submissions
          .where('owner_uid', isEqualTo: this.user.uid)
          .orderBy('timestamp', descending: true)
          .snapshots,
      builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
        if (!snapshot.hasData) return new Text('Loading...');
        return new ListView(
          children: snapshot.data.documents.map((DocumentSnapshot document) {
            var date = _formatDate(document['timestamp']);
            String body = _constructCardBody(document['weight'],
                bodyFat: document['bodyFat']);
            String id = document.documentID;
            return new SubmissionCard(id: id, title: date, body: body, submissions: submissions);
          }).toList(),
        );
      },
    );
  }

这是submission-card.dart的完整内容：

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

import '../utils/logger.dart';
import './block-button.dart';

class SubmissionCard extends StatefulWidget {
  final String id;
  final String title;
  final String body;
  final CollectionReference submissions;

  SubmissionCard({this.id, this.title, this.body, this.submissions});

  @override
  State<StatefulWidget> createState() =>
      new _SubmissionCardState(id: this.id, title: this.title, body: this.body, submissions: this.submissions);
}

class _SubmissionCardState extends State<SubmissionCard> {
  final String id;
  final String title;
  final String body;
  bool showActionButtons = false;
  final CollectionReference submissions;

  _SubmissionCardState({this.id, this.title, this.body, this.submissions});

  void _showEditScreen() {}

  void _showActionButtons() {
    setState(() {
      showActionButtons = true;
    });
  }

  void _hideActionButtons() {
    setState(() {
      showActionButtons = false;
    });
  }

  Future<Null> _deleteSubmission() async {
    try {
      await submissions.document(id).delete();
      await Logger.log('error', 'stackTrace');
    } catch (error, stackTrace) {
      await Logger.log(error, stackTrace);
    }
  }

  void _closeDialog() {
    Navigator.of(context).pop();
    _hideActionButtons();
  }

  Future<Null> _warnAboutDeletion() async {
    return showDialog(
        context: context,
        child: new SimpleDialog(
          title: new Text('Are you sure?'),
          children: <Widget>[
            new SimpleDialogOption(
              onPressed: () {
                this._deleteSubmission();
                this._closeDialog();
              },
              child: new Text("I'm sure. Delete it."),
            ),
            new SimpleDialogOption(
              onPressed: _closeDialog,
              child: new Text("Nope. Take me back."),
            ),
          ],
        )
    );
  }

  @override
  Widget build(BuildContext context) {
    return new GestureDetector(
      onLongPress: _showActionButtons,
      onTap: _hideActionButtons,
      child: new Card(
        elevation: showActionButtons ? 8.0 : 2.0,
        key: new GlobalKey(),
        child: new Column(
          mainAxisSize: MainAxisSize.min,
          children: <Widget>[
            new ListTile(
              trailing: showActionButtons
                  ? new Row(
                      children: <Widget>[
                        new IconButton(
                          padding: const EdgeInsets.all(0.0),
                          icon: const Icon(Icons.edit),
                          onPressed: _showEditScreen,
                          color: Colors.black12,
                          splashColor: Colors.black26,
                          highlightColor: Colors.black12,
                        ),
                        new IconButton(
                          padding: const EdgeInsets.all(0.0),
                          icon: const Icon(Icons.delete),
                          onPressed: _warnAboutDeletion,
                          color: Colors.redAccent,
                          splashColor: Colors.black26,
                          highlightColor: Colors.black12,
                        ),
                      ],
                    )
                  : new Container(),
              isThreeLine: true,
              title: new Text(title),
              subtitle: new Text(
                body,
                style: new TextStyle(height: 3.0),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

回购链接：https://github.com/dericgw/bodwatch

以前，当我使用 Firebase 时，这个集合会自动更新。我以前从未见过这种奇怪的行为。现在，我是 Flutter 和 Dart 的新手，所以我肯定会遗漏一些东西。

Answer 1

您需要在 firebase 控制台中添加索引。

在您的情况下，您需要多个索引。 1.owner_uid，升序 2. 时间戳，降序

问题应该解决了。