Fix Material 3 `BottomSheet` example (#116112)

fix title

examples/api/lib/material/bottom_sheet/show_modal_bottom_sheet.0.dart

@@ -6,27 +6,24 @@
 
 import 'package:flutter/material.dart';
 
-void main() => runApp(const MyApp());
+void main() => runApp(const BottomSheetApp());
 
-class MyApp extends StatelessWidget {
-  const MyApp({super.key});
-
-  static const String _title = 'Flutter Code Sample';
+class BottomSheetApp extends StatelessWidget {
+  const BottomSheetApp({super.key});
 
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
-      title: _title,
       home: Scaffold(
-        appBar: AppBar(title: const Text(_title)),
-        body: const MyStatelessWidget(),
+        appBar: AppBar(title: const Text('Bottom Sheet Sample')),
+        body: const BottomSheetExample(),
       ),
     );
   }
 }
 
-class MyStatelessWidget extends StatelessWidget {
-  const MyStatelessWidget({super.key});
+class BottomSheetExample extends StatelessWidget {
+  const BottomSheetExample({super.key});
 
   @override
   Widget build(BuildContext context) {

examples/api/lib/material/bottom_sheet/show_modal_bottom_sheet.1.dart

@@ -2,30 +2,32 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flutter code sample for  Material Design 3 TextFields.
 /// Flutter code sample for [showModalBottomSheet].
 
 import 'package:flutter/material.dart';
 
-void main() => runApp(const MyApp());
+void main() => runApp(const BottomSheetApp());
 
-class MyApp extends StatelessWidget {
-  const MyApp({super.key});
+class BottomSheetApp extends StatelessWidget {
+  const BottomSheetApp({super.key});
 
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
-      theme: ThemeData(colorSchemeSeed: const Color(0xff6750a4), useMaterial3: true),
+      theme: ThemeData(
+        colorSchemeSeed: const Color(0xff6750a4),
+        useMaterial3: true,
+      ),
       home: Scaffold(
         appBar: AppBar(title: const Text('Bottom Sheet Sample')),
-        body: const MyStatelessWidget(),
+        body: const BottomSheetExample(),
       ),
     );
   }
 }
 
-class MyStatelessWidget extends StatelessWidget {
-  const MyStatelessWidget({super.key});
+class BottomSheetExample extends StatelessWidget {
+  const BottomSheetExample({super.key});
 
   @override
   Widget build(BuildContext context) {

examples/api/test/material/bottom_sheet/show_modal_bottom_sheet.0_test.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+import 'package:flutter_api_samples/material/bottom_sheet/show_modal_bottom_sheet.0.dart' as example;
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('BottomSheet can be opened and closed', (WidgetTester tester) async {
+    const String titleText = 'Modal BottomSheet';
+    const String closeText = 'Close BottomSheet';
+
+    await tester.pumpWidget(
+      const example.BottomSheetApp(),
+    );
+
+    expect(find.text(titleText), findsNothing);
+    expect(find.text(closeText), findsNothing);
+
+    // Open the bottom sheet.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'showModalBottomSheet'));
+    await tester.pumpAndSettle();
+
+    // Verify that the bottom sheet is open.
+    expect(find.text(titleText), findsOneWidget);
+    expect(find.text(closeText), findsOneWidget);
+  });
+}

examples/api/test/material/bottom_sheet/show_modal_bottom_sheet.1_test.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+import 'package:flutter_api_samples/material/bottom_sheet/show_modal_bottom_sheet.1.dart' as example;
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('BottomSheet can be opened and closed', (WidgetTester tester) async {
+    const String titleText = 'Modal BottomSheet';
+    const String closeText = 'Close BottomSheet';
+
+    await tester.pumpWidget(
+      const example.BottomSheetApp(),
+    );
+
+    expect(find.text(titleText), findsNothing);
+    expect(find.text(closeText), findsNothing);
+
+    // Open the bottom sheet.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'showModalBottomSheet'));
+    await tester.pumpAndSettle();
+
+    // Verify that the bottom sheet is open.
+    expect(find.text(titleText), findsOneWidget);
+    expect(find.text(closeText), findsOneWidget);
+  });
+}

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

@@ -799,6 +799,13 @@ class _BottomSheetSuspendedCurve extends ParametricCurve<double> {
 /// ** See code in examples/api/lib/material/bottom_sheet/show_modal_bottom_sheet.0.dart **
 /// {@end-tool}
 ///
+/// {@tool dartpad}
+/// This sample shows the creation of [showModalBottomSheet], as described in:
+/// https://m3.material.io/components/bottom-sheets/overview
+///
+/// ** See code in examples/api/lib/material/bottom_sheet/show_modal_bottom_sheet.1.dart **
+/// {@end-tool}
+///
 /// See also:
 ///
 ///  * [BottomSheet], which becomes the parent of the widget returned by the