Add customizable mouse cursor to DataTable

[TahaTesser]

fixes #123020

Description

1. Add mouseCursor to the DataColumn for the header cell.
2. Add mouseCursor MaterialStateProperty to the DataRow for the data row
3. Add headingCellCursor to customize the cursor in the header cell from DataTableTheme.
4. Add dataRowCursor to customize the cursor in the data row from DataTableTheme.

code sample

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      theme: ThemeData(useMaterial3: true),
      home: const DataTableExample(),
    );
  }
}

class DataTableExample extends StatelessWidget {
  const DataTableExample({super.key});

  @override
  Widget build(BuildContext context) {
    final MaterialStateProperty<MouseCursor?> rowCursor =
        MaterialStateProperty.resolveWith<MouseCursor?>(
      (Set<MaterialState> states) {
        if (states.contains(MaterialState.disabled)) {
          return SystemMouseCursors.forbidden;
        }

        if (states.contains(MaterialState.selected)) {
          return SystemMouseCursors.copy;
        }
        return SystemMouseCursors.grab;
      },
    );

    return Scaffold(
      appBar: AppBar(
        title: const Text('DataTable'),
      ),
      body: DataTable(
        columns: <DataColumn>[
          DataColumn(
            label: const Expanded(
              child: Text(
                'Name',
              ),
            ),
            mouseCursor: MaterialStateProperty.resolveWith(
              (Set<MaterialState> states) {
                if (states.contains(MaterialState.disabled)) {
                  return SystemMouseCursors.forbidden;
                }
                return SystemMouseCursors.grab;
              },
            ),
            onSort: (int columnIndex, bool ascending) {},
          ),
          DataColumn(
            mouseCursor: MaterialStateProperty.resolveWith(
              (Set<MaterialState> states) {
                if (states.contains(MaterialState.disabled)) {
                  return SystemMouseCursors.forbidden;
                }
                return SystemMouseCursors.grab;
              },
            ),
            label: const Expanded(
              child: Text(
                'State',
              ),
            ),
          ),
        ],
        rows: <DataRow>[
          DataRow(
            mouseCursor: rowCursor,
            cells: const <DataCell>[
              DataCell(Text('Row')),
              DataCell(Text('disabled')),
            ],
          ),
          DataRow(
            mouseCursor: rowCursor,
            onSelectChanged: (bool? selected) {},
            cells: const <DataCell>[
              DataCell(Text('Row')),
              DataCell(Text('enabled')),
            ],
          ),
          DataRow(
            mouseCursor: rowCursor,
            selected: true,
            onSelectChanged: (bool? selected) {},
            cells: const <DataCell>[
              DataCell(Text('Row')),
              DataCell(Text('selected')),
            ],
          ),
        ],
      ),
    );
  }
}

Screen.Recording.2023-03-22.at.16.16.59.mov

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read and followed the Flutter Style Guide, including Features we expect every widget to implement.
• I signed the CLA.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is test-exempt.
• All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel on Discord.

[jpnurmi]

Hey @TahaTesser, thanks for working on this! Is it intentional that the checkbox in the header doesn't get any mouse cursor assigned? Personally, given that checkbox mouse cursors are themeable, I'd be fine with not assigning a mouse cursor to data row checkboxes either just to keep it consistent.

[TahaTesser]

Hey @TahaTesser, thanks for working on this! Is it intentional that the checkbox in the header doesn't get any mouse cursor assigned? Personally, given that checkbox mouse cursors are themeable, I'd be fine with not assigning a mouse cursor to data row checkboxes either just to keep it consistent.

That makes sense. Just updated the PR to not update the checkboxes cursor and include a test that verifies it.
Also added update video and code sample in the description.

[HansMuller]

LGTM