[Gallery] Fix directory structure (#312)

gallery/lib/demos/cupertino/cupertino_segmented_control_demo.dart

@@ -0,0 +1,87 @@
+// Copyright 2019 The Flutter team. 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/cupertino.dart';
+import 'package:flutter/material.dart';
+
+import 'package:gallery/l10n/gallery_localizations.dart';
+
+// BEGIN cupertinoSegmentedControlDemo
+
+class CupertinoSegmentedControlDemo extends StatefulWidget {
+  @override
+  _CupertinoSegmentedControlDemoState createState() =>
+      _CupertinoSegmentedControlDemoState();
+}
+
+class _CupertinoSegmentedControlDemoState
+    extends State<CupertinoSegmentedControlDemo> {
+  int currentSegment = 0;
+
+  void onValueChanged(int newValue) {
+    setState(() {
+      currentSegment = newValue;
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final localizations = GalleryLocalizations.of(context);
+    final segmentedControlMaxWidth = 500.0;
+    final children = <int, Widget>{
+      0: Text(localizations.colorsIndigo),
+      1: Text(localizations.colorsTeal),
+      2: Text(localizations.colorsCyan),
+    };
+
+    return CupertinoPageScaffold(
+      navigationBar: CupertinoNavigationBar(
+        automaticallyImplyLeading: false,
+        middle: Text(
+          localizations.demoCupertinoSegmentedControlTitle,
+        ),
+      ),
+      child: DefaultTextStyle(
+        style: CupertinoTheme.of(context)
+            .textTheme
+            .textStyle
+            .copyWith(fontSize: 13),
+        child: SafeArea(
+          child: ListView(
+            children: [
+              const SizedBox(height: 16),
+              SizedBox(
+                width: segmentedControlMaxWidth,
+                child: CupertinoSegmentedControl<int>(
+                  children: children,
+                  onValueChanged: onValueChanged,
+                  groupValue: currentSegment,
+                ),
+              ),
+              SizedBox(
+                width: segmentedControlMaxWidth,
+                child: Padding(
+                  padding: const EdgeInsets.all(16),
+                  child: CupertinoSlidingSegmentedControl<int>(
+                    children: children,
+                    onValueChanged: onValueChanged,
+                    groupValue: currentSegment,
+                  ),
+                ),
+              ),
+              Container(
+                padding: const EdgeInsets.all(16),
+                height: 300,
+                alignment: Alignment.center,
+                child: children[currentSegment],
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}
+
+// END