Null check logic for datatable. (#27632)

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

@@ -543,7 +543,7 @@ class DataTable extends StatelessWidget {
         tableRows[rowIndex].children[0] = _buildCheckbox(
           color: theme.accentColor,
           checked: row.selected,
-          onRowTap: () => row.onSelectChanged(!row.selected),
+          onRowTap: () => row.onSelectChanged != null ? row.onSelectChanged(!row.selected) : null ,
           onCheckboxChanged: row.onSelectChanged,
         );
         rowIndex += 1;
@@ -568,7 +568,7 @@ class DataTable extends StatelessWidget {
         label: column.label,
         tooltip: column.tooltip,
         numeric: column.numeric,
-        onSort: () => column.onSort(dataColumnIndex, sortColumnIndex == dataColumnIndex ? !sortAscending : true),
+        onSort: () => column.onSort != null ? column.onSort(dataColumnIndex, sortColumnIndex == dataColumnIndex ? !sortAscending : true) : null,
         sorted: dataColumnIndex == sortColumnIndex,
         ascending: sortAscending,
       );
@@ -583,7 +583,7 @@ class DataTable extends StatelessWidget {
           placeholder: cell.placeholder,
           showEditIcon: cell.showEditIcon,
           onTap: cell.onTap,
-          onSelectChanged: () => row.onSelectChanged(!row.selected),
+          onSelectChanged: () => row.onSelectChanged != null ? row.onSelectChanged(!row.selected) : null,
         );
         rowIndex += 1;
       }

packages/flutter/test/material/data_table_test.dart

@@ -210,4 +210,61 @@ void main() {
     expect(tester.renderObject<RenderBox>(find.byType(Row).first).size.width, lessThan(800.0));
     expect(tester.takeException(), isNull);
   });
+
+  testWidgets('DataTable column onSort test', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: DataTable(
+            columns: const <DataColumn>[
+              DataColumn(
+                label: Text('Dessert'),
+              ),
+            ],
+            rows: const <DataRow>[
+              DataRow(
+                cells: <DataCell>[
+                  DataCell(
+                    Text('Lollipop'), // wraps
+                  ),
+                ],
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+    await tester.tap(find.text('Dessert'));
+    await tester.pump();
+    expect(tester.takeException(), isNull);
+  });
+
+  testWidgets('DataTable row onSelectChanged test', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: DataTable(
+            columns: const <DataColumn>[
+              DataColumn(
+                label: Text('Dessert'),
+              ),
+            ],
+            rows: const <DataRow>[
+              DataRow(
+                cells: <DataCell>[
+                  DataCell(
+                    Text('Lollipop'), // wraps
+                  ),
+                ],
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+    await tester.tap(find.text('Lollipop'));
+    await tester.pump();
+    expect(tester.takeException(), isNull);
+  });
+
 }