Added checkboxHorizontalMargin to DataTable and PaginatedDataTable (#71217)

packages/flutter/lib/src/material/data_table.dart

@@ -469,6 +469,7 @@ class DataTable extends StatelessWidget {
     this.showBottomBorder = false,
     this.dividerThickness,
     required this.rows,
+    this.checkboxHorizontalMargin,
   }) : assert(columns != null),
        assert(columns.isNotEmpty),
        assert(sortColumnIndex == null || (sortColumnIndex >= 0 && sortColumnIndex < columns.length)),
@@ -636,6 +637,10 @@ class DataTable extends StatelessWidget {
   ///
   /// If null, [DataTableThemeData.horizontalMargin] is used. This value
   /// defaults to 24.0 to adhere to the Material Design specifications.
+  ///
+  /// If [checkboxHorizontalMargin] is null, then [horizontalMargin] is also the
+  /// margin between the edge of the table and the checkbox, as well as the
+  /// margin between the checkbox and the content in the first data column.
   final double? horizontalMargin;
 
   /// {@template flutter.material.dataTable.columnSpacing}
@@ -679,6 +684,16 @@ class DataTable extends StatelessWidget {
   /// around the table defined by [decoration].
   final bool showBottomBorder;
 
+  /// {@template flutter.material.dataTable.checkboxHorizontalMargin}
+  /// Horizontal margin around the checkbox, if it is displayed.
+  /// {@endtemplate}
+  ///
+  /// If null, [DataTableThemeData.checkboxHorizontalMargin] is used. If that is
+  /// also null, then [horizontalMargin] is used as the margin between the edge
+  /// of the table and the checkbox, as well as the margin between the checkbox
+  /// and the content in the first data column. This value defaults to 24.0.
+  final double? checkboxHorizontalMargin;
+
   // Set by the constructor to the index of the only Column that is
   // non-numeric, if there is exactly one, otherwise null.
   final int? _onlyTextColumn;
@@ -746,12 +761,18 @@ class DataTable extends StatelessWidget {
     final double effectiveHorizontalMargin = horizontalMargin
       ?? themeData.dataTableTheme.horizontalMargin
       ?? _horizontalMargin;
+    final double effectiveCheckboxHorizontalMarginStart = checkboxHorizontalMargin
+      ?? themeData.dataTableTheme.checkboxHorizontalMargin
+      ?? effectiveHorizontalMargin;
+    final double effectiveCheckboxHorizontalMarginEnd = checkboxHorizontalMargin
+      ?? themeData.dataTableTheme.checkboxHorizontalMargin
+      ?? effectiveHorizontalMargin / 2.0;
     Widget contents = Semantics(
       container: true,
       child: Padding(
         padding: EdgeInsetsDirectional.only(
-          start: effectiveHorizontalMargin,
+          start: effectiveCheckboxHorizontalMarginStart,
-          end: effectiveHorizontalMargin / 2.0,
+          end: effectiveCheckboxHorizontalMarginEnd,
         ),
         child: Center(
           child: Checkbox(
@@ -933,6 +954,12 @@ class DataTable extends StatelessWidget {
     final double effectiveHorizontalMargin = horizontalMargin
       ?? theme.dataTableTheme.horizontalMargin
       ?? _horizontalMargin;
+    final double effectiveCheckboxHorizontalMarginStart = checkboxHorizontalMargin
+      ?? theme.dataTableTheme.checkboxHorizontalMargin
+      ?? effectiveHorizontalMargin;
+    final double effectiveCheckboxHorizontalMarginEnd = checkboxHorizontalMargin
+      ?? theme.dataTableTheme.checkboxHorizontalMargin
+      ?? effectiveHorizontalMargin / 2.0;
     final double effectiveColumnSpacing = columnSpacing
       ?? theme.dataTableTheme.columnSpacing
       ?? _columnSpacing;
@@ -976,7 +1003,7 @@ class DataTable extends StatelessWidget {
 
     int displayColumnIndex = 0;
     if (displayCheckboxColumn) {
-      tableColumns[0] = FixedColumnWidth(effectiveHorizontalMargin + Checkbox.width + effectiveHorizontalMargin / 2.0);
+      tableColumns[0] = FixedColumnWidth(effectiveCheckboxHorizontalMarginStart + Checkbox.width + effectiveCheckboxHorizontalMarginEnd);
       tableRows[0].children![0] = _buildCheckbox(
         context: context,
         checked: someChecked ? null : allChecked,
@@ -1004,7 +1031,9 @@ class DataTable extends StatelessWidget {
       final DataColumn column = columns[dataColumnIndex];
 
       final double paddingStart;
-      if (dataColumnIndex == 0 && displayCheckboxColumn) {
+      if (dataColumnIndex == 0 && displayCheckboxColumn && checkboxHorizontalMargin != null) {
+        paddingStart = effectiveHorizontalMargin;
+      } else if (dataColumnIndex == 0 && displayCheckboxColumn) {
         paddingStart = effectiveHorizontalMargin / 2.0;
       } else if (dataColumnIndex == 0 && !displayCheckboxColumn) {
         paddingStart = effectiveHorizontalMargin;

packages/flutter/lib/src/material/data_table_theme.dart

@@ -45,6 +45,7 @@ class DataTableThemeData with Diagnosticable {
     this.horizontalMargin,
     this.columnSpacing,
     this.dividerThickness,
+    this.checkboxHorizontalMargin,
   });
 
   /// {@macro flutter.material.dataTable.decoration}
@@ -79,6 +80,9 @@ class DataTableThemeData with Diagnosticable {
   /// {@macro flutter.material.dataTable.dividerThickness}
   final double? dividerThickness;
 
+  /// {@macro flutter.material.dataTable.checkboxHorizontalMargin}
+  final double? checkboxHorizontalMargin;
+
   /// Creates a copy of this object but with the given fields replaced with the
   /// new values.
   DataTableThemeData copyWith({
@@ -92,6 +96,7 @@ class DataTableThemeData with Diagnosticable {
     double? horizontalMargin,
     double? columnSpacing,
     double? dividerThickness,
+    double? checkboxHorizontalMargin,
   }) {
     return DataTableThemeData(
       decoration: decoration ?? this.decoration,
@@ -104,6 +109,7 @@ class DataTableThemeData with Diagnosticable {
       horizontalMargin: horizontalMargin ?? this.horizontalMargin,
       columnSpacing: columnSpacing ?? this.columnSpacing,
       dividerThickness: dividerThickness ?? this.dividerThickness,
+      checkboxHorizontalMargin: checkboxHorizontalMargin ?? this.checkboxHorizontalMargin,
     );
   }
 
@@ -124,7 +130,8 @@ class DataTableThemeData with Diagnosticable {
       headingTextStyle: TextStyle.lerp(a.headingTextStyle, b.headingTextStyle, t),
       horizontalMargin: lerpDouble(a.horizontalMargin, b.horizontalMargin, t),
       columnSpacing: lerpDouble(a.columnSpacing, b.columnSpacing, t),
-      dividerThickness: lerpDouble(a.dividerThickness, b.dividerThickness, t)
+      dividerThickness: lerpDouble(a.dividerThickness, b.dividerThickness, t),
+      checkboxHorizontalMargin: lerpDouble(a.checkboxHorizontalMargin, b.checkboxHorizontalMargin, t)
     );
   }
 
@@ -141,6 +148,7 @@ class DataTableThemeData with Diagnosticable {
       horizontalMargin,
       columnSpacing,
       dividerThickness,
+      checkboxHorizontalMargin,
     );
   }
 
@@ -160,7 +168,8 @@ class DataTableThemeData with Diagnosticable {
       && other.headingTextStyle == headingTextStyle
       && other.horizontalMargin == horizontalMargin
       && other.columnSpacing == columnSpacing
-      && other.dividerThickness == dividerThickness;
+      && other.dividerThickness == dividerThickness
+      && other.checkboxHorizontalMargin == checkboxHorizontalMargin;
   }
 
   @override
@@ -176,6 +185,7 @@ class DataTableThemeData with Diagnosticable {
     properties.add(DoubleProperty('horizontalMargin', horizontalMargin, defaultValue: null));
     properties.add(DoubleProperty('columnSpacing', columnSpacing, defaultValue: null));
     properties.add(DoubleProperty('dividerThickness', dividerThickness, defaultValue: null));
+    properties.add(DoubleProperty('checkboxHorizontalMargin', checkboxHorizontalMargin, defaultValue: null));
   }
 
   static MaterialStateProperty<T>? _lerpProperties<T>(MaterialStateProperty<T>? a, MaterialStateProperty<T>? b, double t, T Function(T?, T?, double) lerpFunction ) {

packages/flutter/lib/src/material/paginated_data_table.dart

@@ -86,6 +86,7 @@ class PaginatedDataTable extends StatefulWidget {
     this.onRowsPerPageChanged,
     this.dragStartBehavior = DragStartBehavior.start,
     required this.source,
+    this.checkboxHorizontalMargin,
   }) : assert(actions == null || (actions != null && header != null)),
        assert(columns != null),
        assert(dragStartBehavior != null),
@@ -166,6 +167,10 @@ class PaginatedDataTable extends StatefulWidget {
   /// the content in the first data column.
   ///
   /// This value defaults to 24.0 to adhere to the Material Design specifications.
+  ///
+  /// If [checkboxHorizontalMargin] is null, then [horizontalMargin] is also the
+  /// margin between the edge of the table and the checkbox, as well as the
+  /// margin between the checkbox and the content in the first data column.
   final double horizontalMargin;
 
   /// The horizontal margin between the contents of each data column.
@@ -224,6 +229,13 @@ class PaginatedDataTable extends StatefulWidget {
   /// {@macro flutter.widgets.scrollable.dragStartBehavior}
   final DragStartBehavior dragStartBehavior;
 
+  /// Horizontal margin around the checkbox, if it is displayed.
+  ///
+  /// If null, then [horizontalMargin] is used as the margin between the edge
+  /// of the table and the checkbox, as well as the margin between the checkbox
+  /// and the content in the first data column. This value defaults to 24.0.
+  final double? checkboxHorizontalMargin;
+
   @override
   PaginatedDataTableState createState() => PaginatedDataTableState();
 }
@@ -513,6 +525,7 @@ class PaginatedDataTableState extends State<PaginatedDataTable> {
                     dataRowHeight: widget.dataRowHeight,
                     headingRowHeight: widget.headingRowHeight,
                     horizontalMargin: widget.horizontalMargin,
+                    checkboxHorizontalMargin: widget.checkboxHorizontalMargin,
                     columnSpacing: widget.columnSpacing,
                     showCheckboxColumn: widget.showCheckboxColumn,
                     showBottomBorder: true,

packages/flutter/test/material/data_table_test.dart

@@ -1540,4 +1540,93 @@ void main() {
       const Offset(width - borderVertical, height - borderHorizontal),
     );
   });
+
+  testWidgets('checkboxHorizontalMargin properly applied', (WidgetTester tester) async {
+    const double _customCheckboxHorizontalMargin = 15.0;
+    const double _customHorizontalMargin = 10.0;
+    Finder cellContent;
+    Finder checkbox;
+    Finder padding;
+
+    Widget buildCustomTable({
+      int? sortColumnIndex,
+      bool sortAscending = true,
+      double? horizontalMargin,
+      double? checkboxHorizontalMargin,
+    }) {
+      return DataTable(
+        sortColumnIndex: sortColumnIndex,
+        sortAscending: sortAscending,
+        onSelectAll: (bool? value) {},
+        horizontalMargin: horizontalMargin,
+        checkboxHorizontalMargin: checkboxHorizontalMargin,
+        columns: <DataColumn>[
+          const DataColumn(
+            label: Text('Name'),
+            tooltip: 'Name',
+          ),
+          DataColumn(
+            label: const Text('Calories'),
+            tooltip: 'Calories',
+            numeric: true,
+            onSort: (int columnIndex, bool ascending) {},
+          ),
+          DataColumn(
+            label: const Text('Fat'),
+            tooltip: 'Fat',
+            numeric: true,
+            onSort: (int columnIndex, bool ascending) {},
+          ),
+        ],
+        rows: kDesserts.map<DataRow>((Dessert dessert) {
+          return DataRow(
+            key: ValueKey<String>(dessert.name),
+            onSelectChanged: (bool? selected) {},
+            cells: <DataCell>[
+              DataCell(
+                Text(dessert.name),
+              ),
+              DataCell(
+                Text('${dessert.calories}'),
+                showEditIcon: true,
+                onTap: () {},
+              ),
+              DataCell(
+                Text('${dessert.fat}'),
+                showEditIcon: true,
+                onTap: () {},
+              ),
+            ],
+          );
+        }).toList(),
+      );
+    }
+
+    await tester.pumpWidget(MaterialApp(
+      home: Material(child: buildCustomTable(
+        checkboxHorizontalMargin: _customCheckboxHorizontalMargin,
+        horizontalMargin: _customHorizontalMargin,
+      )),
+    ));
+
+    // Custom checkbox padding.
+    checkbox = find.byType(Checkbox).first;
+    padding = find.ancestor(of: checkbox, matching: find.byType(Padding));
+    expect(
+      tester.getRect(checkbox).left - tester.getRect(padding).left,
+      _customCheckboxHorizontalMargin,
+    );
+    expect(
+      tester.getRect(padding).right - tester.getRect(checkbox).right,
+      _customCheckboxHorizontalMargin,
+    );
+
+    // First column padding.
+    padding = find.widgetWithText(Padding, 'Frozen yogurt').first;
+    cellContent = find.widgetWithText(Align, 'Frozen yogurt'); // DataTable wraps its DataCells in an Align widget.
+    expect(
+      tester.getRect(cellContent).left - tester.getRect(padding).left,
+      _customHorizontalMargin,
+    );
+  });
 }

packages/flutter/test/material/data_table_theme_test.dart

@@ -24,6 +24,7 @@ void main() {
     expect(themeData.horizontalMargin, null);
     expect(themeData.columnSpacing, null);
     expect(themeData.dividerThickness, null);
+    expect(themeData.checkboxHorizontalMargin, null);
 
     const DataTableTheme theme = DataTableTheme(data: DataTableThemeData(), child: SizedBox());
     expect(theme.data.decoration, null);
@@ -36,6 +37,7 @@ void main() {
     expect(theme.data.horizontalMargin, null);
     expect(theme.data.columnSpacing, null);
     expect(theme.data.dividerThickness, null);
+    expect(theme.data.checkboxHorizontalMargin, null);
   });
 
   testWidgets('Default DataTableThemeData debugFillProperties', (WidgetTester tester) async {
@@ -67,6 +69,7 @@ void main() {
       horizontalMargin: 3.0,
       columnSpacing: 4.0,
       dividerThickness: 5.0,
+      checkboxHorizontalMargin: 6.0,
     ).debugFillProperties(builder);
 
     final List<String> description = builder.properties
@@ -84,6 +87,7 @@ void main() {
     expect(description[7], 'horizontalMargin: 3.0');
     expect(description[8], 'columnSpacing: 4.0');
     expect(description[9], 'dividerThickness: 5.0');
+    expect(description[10], 'checkboxHorizontalMargin: 6.0');
   });
 
   testWidgets('DataTable is themeable', (WidgetTester tester) async {

packages/flutter/test/material/paginated_data_table_test.dart

@@ -855,4 +855,72 @@ void main() {
     // Reset the surface size.
     await binding.setSurfaceSize(originalSize);
   });
+
+  testWidgets('PaginatedDataTable custom checkboxHorizontalMargin properly applied', (WidgetTester tester) async {
+    const double _customCheckboxHorizontalMargin = 15.0;
+    const double _customHorizontalMargin = 10.0;
+
+    const double _width = 400;
+    const double _height = 400;
+
+    final Size originalSize = binding.renderView.size;
+
+    // Ensure the containing Card is small enough that we don't expand too
+    // much, resulting in our custom margin being ignored.
+    await binding.setSurfaceSize(const Size(_width, _height));
+
+    final TestDataSource source = TestDataSource(
+      onSelectChanged: (bool? value) {},
+    );
+    Finder cellContent;
+    Finder checkbox;
+    Finder padding;
+
+    // CUSTOM VALUES
+    await tester.pumpWidget(MaterialApp(
+      home: Material(
+        child: PaginatedDataTable(
+          header: const Text('Test table'),
+          source: source,
+          rowsPerPage: 2,
+          availableRowsPerPage: const <int>[
+            2, 4,
+          ],
+          onRowsPerPageChanged: (int? rowsPerPage) {},
+          onPageChanged: (int rowIndex) {},
+          onSelectAll: (bool? value) {},
+          columns: const <DataColumn>[
+            DataColumn(label: Text('Name')),
+            DataColumn(label: Text('Calories'), numeric: true),
+            DataColumn(label: Text('Generation')),
+          ],
+          horizontalMargin: _customHorizontalMargin,
+          checkboxHorizontalMargin: _customCheckboxHorizontalMargin,
+        ),
+      ),
+    ));
+
+    // Custom checkbox padding.
+    checkbox = find.byType(Checkbox).first;
+    padding = find.ancestor(of: checkbox, matching: find.byType(Padding)).first;
+    expect(
+      tester.getRect(checkbox).left - tester.getRect(padding).left,
+      _customCheckboxHorizontalMargin,
+    );
+    expect(
+      tester.getRect(padding).right - tester.getRect(checkbox).right,
+      _customCheckboxHorizontalMargin,
+    );
+
+    // Custom first column padding.
+    padding = find.widgetWithText(Padding, 'Frozen yogurt (0)').first;
+    cellContent = find.widgetWithText(Align, 'Frozen yogurt (0)'); // DataTable wraps its DataCells in an Align widget.
+    expect(
+      tester.getRect(cellContent).left - tester.getRect(padding).left,
+      _customHorizontalMargin,
+    );
+
+    // Reset the surface size.
+    await binding.setSurfaceSize(originalSize);
+  });
 }