How to create a horizontally scrolling table with fixed column in Flutter? - flutter

Question

I would like to create a series of tables that you can scroll through vertically, each of which may have a different number of rows/columns from each other.
Within each table, I would like to have the leftmost column frozen in place, and the remaining columns in that table to be horizontally scrollable, in case there are a number of columns that do not fit in the width of the screen. See screenshot:
My initial plan was to use a ListView for the page-level vertical scrolling between tables, and within each table, there is a Row of Columns, where the first column is a static width, and the remaining columns are enclosed within a horizontally scrolling ListView. The error I'm getting from Flutter is not helping me determine what I need to do, but it clearly has to do with having to set bounds on child Widgets.
Error: (Fixed 7/9/19 by wrapping horizontal ListView with a fixed height container and shrinkwrapping the ListView)
The following assertion was thrown during performResize():
Horizontal viewport was given unbounded width.
Viewports expand in the scrolling direction to fill their container.In this case, a horizontal
viewport was given an unlimited amount of horizontal space in which to expand. This situation
typically happens when a scrollable widget is nested inside another scrollable widget.
If this widget is always nested in a scrollable widget there is no need to use a viewport because
there will always be enough horizontal space for the children. In this case, consider using a Row
instead. Otherwise, consider using the "shrinkWrap" property (or a ShrinkWrappingViewport) to size
the width of the viewport to the sum of the widths of its children.
New Error 7/9/19:
The following message was thrown during layout:
A RenderFlex overflowed by 74 pixels on the right.
The overflowing RenderFlex has an orientation of Axis.horizontal.
The edge of the RenderFlex that is overflowing has been marked in the rendering with a yellow and
black striped pattern. This is usually caused by the contents being too big for the RenderFlex.
Consider applying a flex factor (e.g. using an Expanded widget) to force the children of the
RenderFlex to fit within the available space instead of being sized to their natural size.
This is considered an error condition because it indicates that there is content that cannot be
seen. If the content is legitimately bigger than the available space, consider clipping it with a
ClipRect widget before putting it in the flex, or using a scrollable container rather than a Flex,
like a ListView.
The specific RenderFlex in question is:
RenderFlex#9bf67 relayoutBoundary=up5 OVERFLOWING
creator: Row ← RepaintBoundary-[<0>] ← IndexedSemantics ←
NotificationListener ← KeepAlive ← AutomaticKeepAlive ← SliverList ←
SliverPadding ← Viewport ← IgnorePointer-[GlobalKey#74513] ← Semantics ← Listener ← ⋯
parentData: (can use size)
constraints: BoxConstraints(w=404.0, 0.0<=h<=Infinity)
size: Size(404.0, 300.0)
direction: horizontal
mainAxisAlignment: start
mainAxisSize: max
crossAxisAlignment: center
textDirection: ltr
This was the issue I ran into originally before getting side-tracked with the first issue reported; I can't understand why my ListView is not creating a scrollable container.
Code:
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'My App',
home: Scaffold(
appBar: AppBar(
title: Text('My App'),
backgroundColor: Colors.teal[400],
),
body: MyClass(),
),
);
}
}
const double headerCellWidth = 108.0;
const double cellPadding = 8.0;
const double focusedColumnWidth = 185.0;
const double rowHeight = 36.0;
class MyClass extends StatefulWidget {
#override
_MyClassState createState() => _MyClassState();
}
class _MyClassState extends State<MyClass> {
#override
void initState() {
super.initState();
}
#override
Widget build(BuildContext context) {
return ListView(
padding: EdgeInsets.all(5.0),
children: <Widget>[
Row(
children: <Widget>[
Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Container(
color: Colors.grey,
padding: EdgeInsets.all(cellPadding),
width: headerCellWidth,
),
HeaderCell('ABC'),
HeaderCell('123'),
HeaderCell('XYZ'),
],
),
Container(
height: 300.0, // Could compute height with fixed rows and known number of rows in advance
child: ListView(
shrinkWrap: true,
scrollDirection: Axis.horizontal,
children: <Widget>[
Column(
children: <Widget>[
Container(
color: Colors.grey[300],
padding: EdgeInsets.all(cellPadding),
height: rowHeight,
width: focusedColumnWidth,
),
NumberCell('89'),
NumberCell('92'),
NumberCell('91'),
NumberCell('90'),
NumberCell('91'),
NumberCell('89'),
],
),
Column(
children: <Widget>[
Container(
color: Colors.grey[300],
padding: EdgeInsets.all(cellPadding),
height: rowHeight,
width: focusedColumnWidth,
),
NumberCell('89'),
NumberCell('92'),
NumberCell('91'),
NumberCell('90'),
NumberCell('91'),
NumberCell('89'),
],
),
],
),
),
],
),
],
);
}
}
class HeaderCell extends StatelessWidget {
HeaderCell(this.text);
final String text;
#override
Widget build(BuildContext context) {
return Container(
height: rowHeight,
padding: EdgeInsets.all(cellPadding),
width: headerCellWidth,
child: Text(
text,
textAlign: TextAlign.left,
overflow: TextOverflow.ellipsis,
maxLines: 1,
style: TextStyle(
fontWeight: FontWeight.bold,
),
),
);
}
}
class NumberCell extends StatelessWidget {
NumberCell(this.text);
final String text;
#override
Widget build(BuildContext context) {
return Container(
height: rowHeight,
width: focusedColumnWidth,
padding: EdgeInsets.all(cellPadding),
child: Text(
text,
),
);
}
}

Answer 1

Here is a quick example and this would be the result: Video
List<Widget> _buildCells(int count) {
return List.generate(
count,
(index) => Container(
alignment: Alignment.center,
width: 120.0,
height: 60.0,
color: Colors.white,
margin: EdgeInsets.all(4.0),
child: Text("${index + 1}", style: Theme.of(context).textTheme.title),
),
);
}
List<Widget> _buildRows(int count) {
return List.generate(
count,
(index) => Row(
children: _buildCells(10),
),
);
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(),
body: SingleChildScrollView(
child: Row(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: _buildCells(20),
),
Flexible(
child: SingleChildScrollView(
scrollDirection: Axis.horizontal,
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: _buildRows(20),
),
),
)
],
),
),
);
}

Answer 2

So I tried to produce a minimum working bit of code, and ended up with a workable solution (even if all the details aren't ironed out, like the first locked column being of flexible width instead of a fixed width as desired). Hopefully this will help others trying to produce something similar. What's interesting is that the Table construct is needed here, because replacing the TableRow (wrapped by Table) with just a Row causes an overflow error. I would still be interested in understanding why that is since it seems crucial to the layout engine.
#override
Widget build(BuildContext context) {
return ListView(
padding: EdgeInsets.all(5.0),
children: <Widget>[
Table(
children: <TableRow>[
TableRow(
children: <Widget>[
Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
// first locked column items
],
),
SingleChildScrollView(
scrollDirection: Axis.horizontal,
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Row(
children: <Widget>[
// table header items
],
),
Row(
children: <Widget>[
// data cells
],
),
Row(
children: <Widget>[
// data cells
],
),
],
),
),
],
),
],
),
],
);
}

Answer 3

If there is not much customization needed, for those needed a fixed header and first column table may also consider to use the horizontal_data_table package:
https://pub.dev/packages/horizontal_data_table
It basically is using the two list view approach.