`CupertinoActivityIndicator`: Add an interactive example (#103040)

examples/api/lib/cupertino/activity_indicator/cupertino_activity_indicator.0.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.
+
+// Flutter code sample for CupertinoActivityIndicator
+
+import 'package:flutter/cupertino.dart';
+
+void main() => runApp(const CupertinoIndicatorApp());
+
+class CupertinoIndicatorApp extends StatelessWidget {
+  const CupertinoIndicatorApp({Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return const CupertinoApp(
+      theme: CupertinoThemeData(brightness: Brightness.light),
+      home: CupertinoIndicatorExample(),
+    );
+  }
+}
+
+class CupertinoIndicatorExample extends StatelessWidget {
+  const CupertinoIndicatorExample({Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+
+    return CupertinoPageScaffold(
+      child: Center(
+        child: Column(
+          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
+          children: <Widget>[
+            Column(
+              mainAxisAlignment: MainAxisAlignment.center,
+              children: const <Widget>[
+                // Cupertino activity indicator with default properties.
+                CupertinoActivityIndicator(),
+                SizedBox(height: 10),
+                Text('Default'),
+              ],
+            ),
+            Column(
+              mainAxisAlignment: MainAxisAlignment.center,
+              children: const <Widget>[
+                // Cupertino activity indicator with custom radius and color.
+                CupertinoActivityIndicator(radius: 20.0, color: CupertinoColors.activeBlue),
+                SizedBox(height: 10),
+                Text(
+                  'radius: 20.0\ncolor: CupertinoColors.activeBlue',
+                  textAlign: TextAlign.center,
+                ),
+              ],
+            ),
+            Column(
+              mainAxisAlignment: MainAxisAlignment.center,
+              children: const <Widget>[
+                // Cupertino activity indicator with custom radius and disabled animation.
+                CupertinoActivityIndicator(radius: 20.0, animating: false),
+                SizedBox(height: 10),
+                Text(
+                  'radius: 20.0\nanimating: false',
+                  textAlign: TextAlign.center,
+                ),
+              ],
+            ),
+          ],
+        ),
+      )
+    );
+  }
+}

examples/api/test/cupertino/activity_indicator/cupertino_activity_indicator.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/cupertino.dart';
+import 'package:flutter_api_samples/cupertino/activity_indicator/cupertino_activity_indicator.0.dart' as example;
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('Default and customized cupertino activity indicators', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      const example.CupertinoIndicatorApp(),
+    );
+
+    // Cupertino activity indicator with default properties.
+    final Finder firstIndicator = find.byType(CupertinoActivityIndicator).at(0);
+    expect(tester.widget<CupertinoActivityIndicator>(firstIndicator).animating, true);
+    expect(tester.widget<CupertinoActivityIndicator>(firstIndicator).radius, 10.0);
+
+    // Cupertino activity indicator with custom radius and color.
+    final Finder secondIndicator = find.byType(CupertinoActivityIndicator).at(1);
+    expect(tester.widget<CupertinoActivityIndicator>(secondIndicator).animating, true);
+    expect(tester.widget<CupertinoActivityIndicator>(secondIndicator).radius, 20.0);
+    expect(tester.widget<CupertinoActivityIndicator>(secondIndicator).color, CupertinoColors.activeBlue);
+
+    // Cupertino activity indicator with custom radius and disabled animation.
+    final Finder thirdIndicator = find.byType(CupertinoActivityIndicator).at(2);
+    expect(tester.widget<CupertinoActivityIndicator>(thirdIndicator).animating, false);
+    expect(tester.widget<CupertinoActivityIndicator>(thirdIndicator).radius, 20.0);
+  });
+}

packages/flutter/lib/src/cupertino/activity_indicator.dart

@@ -20,6 +20,12 @@ const Color _kActiveTickColor = CupertinoDynamicColor.withBrightness(
 ///
 /// {@youtube 560 315 https://www.youtube.com/watch?v=AENVH-ZqKDQ}
 ///
+/// {@tool dartpad}
+/// This example shows how [CupertinoActivityIndicator] can be customized.
+///
+/// ** See code in examples/api/lib/cupertino/activity_indicator/cupertino_activity_indicator.0.dart **
+/// {@end-tool}
+///
 /// See also:
 ///
 ///  * <https://developer.apple.com/ios/human-interface-guidelines/controls/progress-indicators/#activity-indicators>