How to implement a table with fixed headers in Flutter?

Question

How to implement a table with fixed vertical and horizontal headers in Flutter? For example, the horizontal header should only scroll horizontally and the vertical header vertically. Both headers should always be visible. How to set-up the layout?

Example

I already tried to use a Row with two nested Columns to set-up the overall 2x2 layout: (0, 0) empty; (0, 1) vertical header; (1,0) horizontal header, and (1, 1) data. To visualize the actual data I used GridViews for the two headers and the data. Moreover, I want to use the scroll controller to achieve the scroll behavior.

1. Row
   1. Column: (0) empty, (1) GridView
   2. Column: (0) GridView (1) GridView

Another solution I thought about was to have nested GridViews instead of the Row and the two Columns.

This code shows the first column:

Widget build(BuildContext context) {
    return Container(
      width: double.maxFinite,
      child: Row(
        children: <Widget>[
            Column(
              children: <Widget>[
                Text("empty"), // (0,0)
                Container( // (0, 1)
                  child: Flexible(
                    child: GridView.count(
                      controller: _vScrollController1,
                      crossAxisCount: 1,
                      childAspectRatio: 3.0,
                      children: List.generate(
                        widget.data.length,
                        (index) => Text("my cell")
                      ),
                    ),
                  ),
                ),
              ],
            ),
        ],
      ),
    );

However, it produces the following error message:

════════ Exception caught by rendering library
The method '>' was called on null.
Receiver: null. Tried calling: >(1e-10). User-created ancestor of the error-causing widget was Container. ═════════════════════════════════

Probably, some width/height properties are not properly set? How would you achieve this table layout? Thanks for your help!

Answer 1

There are actually existing Flutter plugins for this. Consider using one.

Here is an example taken from horizontal_data_table:

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

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key? key, required this.title}) : super(key: key);
  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  HDTRefreshController _hdtRefreshController = HDTRefreshController();

  static const int sortName = 0;
  static const int sortStatus = 1;
  bool isAscending = true;
  int sortType = sortName;

  @override
  void initState() {
    user.initData(100);
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: _getBodyWidget(),
    );
  }

  Widget _getBodyWidget() {
    return Container(
      child: HorizontalDataTable(
        leftHandSideColumnWidth: 100,
        rightHandSideColumnWidth: 600,
        isFixedHeader: true,
        headerWidgets: _getTitleWidget(),
        leftSideItemBuilder: _generateFirstColumnRow,
        rightSideItemBuilder: _generateRightHandSideColumnRow,
        itemCount: user.userInfo.length,
        rowSeparatorWidget: const Divider(
          color: Colors.black54,
          height: 1.0,
          thickness: 0.0,
        ),
        leftHandSideColBackgroundColor: Color(0xFFFFFFFF),
        rightHandSideColBackgroundColor: Color(0xFFFFFFFF),
        verticalScrollbarStyle: const ScrollbarStyle(
          thumbColor: Colors.yellow,
          isAlwaysShown: true,
          thickness: 4.0,
          radius: Radius.circular(5.0),
        ),
        horizontalScrollbarStyle: const ScrollbarStyle(
          thumbColor: Colors.red,
          isAlwaysShown: true,
          thickness: 4.0,
          radius: Radius.circular(5.0),
        ),
        enablePullToRefresh: true,
        refreshIndicator: const WaterDropHeader(),
        refreshIndicatorHeight: 60,
        onRefresh: () async {
          //Do sth
          await Future.delayed(const Duration(milliseconds: 500));
          _hdtRefreshController.refreshCompleted();
        },
        htdRefreshController: _hdtRefreshController,
      ),
      height: MediaQuery.of(context).size.height,
    );
  }

  List<Widget> _getTitleWidget() {
    return [
      TextButton(
        style: TextButton.styleFrom(
          padding: EdgeInsets.zero,
        ),
        child: _getTitleItemWidget(
            'Name' + (sortType == sortName ? (isAscending ? '↓' : '↑') : ''),
            100),
        onPressed: () {
          sortType = sortName;
          isAscending = !isAscending;
          user.sortName(isAscending);
          setState(() {});
        },
      ),
      TextButton(
        style: TextButton.styleFrom(
          padding: EdgeInsets.zero,
        ),
        child: _getTitleItemWidget(
            'Status' +
                (sortType == sortStatus ? (isAscending ? '↓' : '↑') : ''),
            100),
        onPressed: () {
          sortType = sortStatus;
          isAscending = !isAscending;
          user.sortStatus(isAscending);
          setState(() {});
        },
      ),
      _getTitleItemWidget('Phone', 200),
      _getTitleItemWidget('Register', 100),
      _getTitleItemWidget('Termination', 200),
    ];
  }

  Widget _getTitleItemWidget(String label, double width) {
    return Container(
      child: Text(label, style: TextStyle(fontWeight: FontWeight.bold)),
      width: width,
      height: 56,
      padding: EdgeInsets.fromLTRB(5, 0, 0, 0),
      alignment: Alignment.centerLeft,
    );
  }

  Widget _generateFirstColumnRow(BuildContext context, int index) {
    return Container(
      child: Text(user.userInfo[index].name),
      width: 100,
      height: 52,
      padding: EdgeInsets.fromLTRB(5, 0, 0, 0),
      alignment: Alignment.centerLeft,
    );
  }

  Widget _generateRightHandSideColumnRow(BuildContext context, int index) {
    return Row(
      children: <Widget>[
        Container(
          child: Row(
            children: <Widget>[
              Icon(
                  user.userInfo[index].status
                      ? Icons.notifications_off
                      : Icons.notifications_active,
                  color:
                      user.userInfo[index].status ? Colors.red : Colors.green),
              Text(user.userInfo[index].status ? 'Disabled' : 'Active')
            ],
          ),
          width: 100,
          height: 52,
          padding: EdgeInsets.fromLTRB(5, 0, 0, 0),
          alignment: Alignment.centerLeft,
        ),
        Container(
          child: Text(user.userInfo[index].phone),
          width: 200,
          height: 52,
          padding: EdgeInsets.fromLTRB(5, 0, 0, 0),
          alignment: Alignment.centerLeft,
        ),
        Container(
          child: Text(user.userInfo[index].registerDate),
          width: 100,
          height: 52,
          padding: EdgeInsets.fromLTRB(5, 0, 0, 0),
          alignment: Alignment.centerLeft,
        ),
        Container(
          child: Text(user.userInfo[index].terminationDate),
          width: 200,
          height: 52,
          padding: EdgeInsets.fromLTRB(5, 0, 0, 0),
          alignment: Alignment.centerLeft,
        ),
      ],
    );
  }
}

User user = User();

class User {
  List<UserInfo> userInfo = [];

  void initData(int size) {
    for (int i = 0; i < size; i++) {
      userInfo.add(UserInfo(
          "User_$i", i % 3 == 0, '+001 9999 9999', '2019-01-01', 'N/A'));
    }
  }

  ///
  /// Single sort, sort Name's id
  void sortName(bool isAscending) {
    userInfo.sort((a, b) {
      int aId = int.tryParse(a.name.replaceFirst('User_', '')) ?? 0;
      int bId = int.tryParse(b.name.replaceFirst('User_', '')) ?? 0;
      return (aId - bId) * (isAscending ? 1 : -1);
    });
  }

  ///
  /// sort with Status and Name as the 2nd Sort
  void sortStatus(bool isAscending) {
    userInfo.sort((a, b) {
      if (a.status == b.status) {
        int aId = int.tryParse(a.name.replaceFirst('User_', '')) ?? 0;
        int bId = int.tryParse(b.name.replaceFirst('User_', '')) ?? 0;
        return (aId - bId);
      } else if (a.status) {
        return isAscending ? 1 : -1;
      } else {
        return isAscending ? -1 : 1;
      }
    });
  }
}

class UserInfo {
  String name;
  bool status;
  String phone;
  String registerDate;
  String terminationDate;

  UserInfo(this.name, this.status, this.phone, this.registerDate,
      this.terminationDate);
}

Actual output:

You can check other existing plugins.

• table_sticky_headers
• linked_scroll_controller

Also, here are some answered SO questions related to your:

• Fixed column and row header for DataTable on Flutter Dart
• How to create a horizontally scrolling table with fixed column in Flutter?

For other reference, you can check the blog "Flutter: Creating a two direction scrolling table with fixed head and column"