Question

我正在尝试使用Flutter官方文档中的Firebase for Flutter示例应用程序，并用“ DataTable”更改了“ ListTile”小部件，现在该DataTable正在为每个DataRow打印一个单独的Datacolumn。

请查看Output screenshot以可视化该问题，因为我的解释和编程技能都很糟糕！谢谢您的时间。

Database layout

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

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Baby Names',
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() {
    return _MyHomePageState();
  }
}

class Record {
  final String name;
  final String rName;
  final int votes;
  final DocumentReference reference;

  Record.fromMap(Map<String, dynamic> map, {this.reference})
      : assert(map['name'] != null),
        assert(map['r_name'] != null),
        assert(map['votes'] != null),
        name = map['name'],
        rName = map['r_name'],
        votes = map['votes'];

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

  @override
  String toString() => "Record<$name:$votes:$rName>";
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Baby Name Votes')),
      body: _buildBody(context),
    );
  }

  Widget _buildBody(BuildContext context) {
    return StreamBuilder<QuerySnapshot>(
      stream: Firestore.instance.collection('baby').snapshots(),
      builder: (context, snapshot) {
        if (!snapshot.hasData) return LinearProgressIndicator();

        return _buildList(context, snapshot.data.documents);
      },
    );
  }

  Widget _buildList(BuildContext context, List<DocumentSnapshot> snapshot) {
    return ListView(
      padding: const EdgeInsets.only(top: 20.0),
      children: snapshot.map((data) => _buildListItem(context, data)).toList(),
    );
  }

  Widget _buildListItem(BuildContext context, DocumentSnapshot data) {
    final record = Record.fromSnapshot(data);

    return Padding(
      key: ValueKey(record.name),
      padding: const EdgeInsets.symmetric(horizontal: 16.0, vertical: 8.0),
      child: Container(
        decoration: BoxDecoration(
          border: Border.all(color: Colors.grey),
          borderRadius: BorderRadius.circular(5.0),
        ),
        child: DataTable(
          columns: [
            DataColumn(label: Text('Name')),
            DataColumn(label: Text('Votes')),
            DataColumn(label: Text('Rapper\nname')),
          ],
          rows: [
            DataRow(cells: [
              DataCell(Text(record.name)),
              DataCell(Text(record.votes.toString())),
              DataCell(Text(record.rName)),
            ])
          ],
        ),
      ),
    );
  }
}

Answer 1

从您的代码中可以看出，很明显，您将返回整个新的DataTable，因此每次都将获得列名。

您必须在_buildBody方法中创建Datatable，然后仅从_buildListItem方法返回DataRow的列表。

我希望以下代码对您有用。我没有测试下面的代码，因为没有正确的设置。如果您再次遇到任何问题，请添加评论。

Widget _buildBody(BuildContext context) {
    return StreamBuilder<QuerySnapshot>(
      stream: Firestore.instance.collection('baby').snapshots(),
      builder: (context, snapshot) {
        if (!snapshot.hasData) return LinearProgressIndicator();

        return DataTable(
          columns: [
            DataColumn(label: Text('Name')),
            DataColumn(label: Text('Votes')),
            DataColumn(label: Text('Rapper\nname')),
          ],
          rows: _buildList(context, snapshot.data.documents)
        );
      },
    );
  }




    Widget _buildList(BuildContext context, List<DocumentSnapshot> snapshot) {
        return  snapshot.map((data) => _buildListItem(context, data)).toList();
    }



 List<Widget> _buildListItem(BuildContext context, DocumentSnapshot data) {
    final record = Record.fromSnapshot(data);

    return DataRow(cells: [
              DataCell(Text(record.name)),
              DataCell(Text(record.votes.toString())),
              DataCell(Text(record.rName)),
            ]);
  }

Answer 2

Widget build(BuildContext context) {
    final products = Provider.of<List<Product>>(context);
    return Scaffold(
        body: Container(
          child: DataTable(
            columns: [
              DataColumn(label: Text('Id')),
              DataColumn(label: Text('Name')),
              DataColumn(label: Text('Price')),
            ],
            rows: List<DataRow>.generate(
                products.length,
                (index) => DataRow(cells: [
                      DataCell(Text(products[index].productId)),
                      DataCell(Text(products[index].name)),
                      DataCell(Text(products[index].price.toString())),
                    ])),
          ),
        ),


  Stream<List<Product>> getProducts(){
    return _db.collection('products').snapshots().map((snapshot) => snapshot.docs.map((document) => Product.fromFirestore(document.data())).toList());
  }

我使用提供商进行状态管理，希望我能为您提供帮助

在数据表中显示扑朔迷离的Firestore数据

2 个答案: