Overridable default platform key bindings (#45102)

This adds actions and shortcuts arguments to WidgetsApp (and MaterialApp and CupertinoApp) to allow developers to override the default mappings on an application, and to allow for a more complex definition of the default mappings.

I've stopped using SelectAction here, in favor of using ActivateAction for all activations, but haven't removed it, to avoid a breaking change, and to allow a common base class for these types of actions. This is because some platforms use the same mapping (web) for both kinds of activations (both select and activate).

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

@@ -91,6 +91,8 @@ class CupertinoApp extends StatefulWidget {
     this.checkerboardOffscreenLayers = false,
     this.showSemanticsDebugger = false,
     this.debugShowCheckedModeBanner = true,
+    this.shortcuts,
+    this.actions,
   }) : assert(routes != null),
        assert(navigatorObservers != null),
        assert(title != null),
@@ -192,6 +194,67 @@ class CupertinoApp extends StatefulWidget {
   /// {@macro flutter.widgets.widgetsApp.debugShowCheckedModeBanner}
   final bool debugShowCheckedModeBanner;
 
+  /// {@macro flutter.widgets.widgetsApp.shortcuts}
+  /// {@tool sample}
+  /// This example shows how to add a single shortcut for
+  /// [LogicalKeyboardKey.select] to the default shortcuts without needing to
+  /// add your own [Shortcuts] widget.
+  ///
+  /// Alternatively, you could insert a [Shortcuts] widget with just the mapping
+  /// you want to add between the [WidgetsApp] and its child and get the same
+  /// effect.
+  ///
+  /// ```dart
+  /// Widget build(BuildContext context) {
+  ///   return WidgetsApp(
+  ///     shortcuts: <LogicalKeySet, Intent>{
+  ///       ... WidgetsApp.defaultShortcuts,
+  ///       LogicalKeySet(LogicalKeyboardKey.select): const Intent(ActivateAction.key),
+  ///     },
+  ///     color: const Color(0xFFFF0000),
+  ///     builder: (BuildContext context, Widget child) {
+  ///       return const Placeholder();
+  ///     },
+  ///   );
+  /// }
+  /// ```
+  /// {@end-tool}
+  /// {@macro flutter.widgets.widgetsApp.shortcuts.seeAlso}
+  final Map<LogicalKeySet, Intent> shortcuts;
+
+  /// {@macro flutter.widgets.widgetsApp.actions}
+  /// {@tool sample}
+  /// This example shows how to add a single action handling an
+  /// [ActivateAction] to the default actions without needing to
+  /// add your own [Actions] widget.
+  ///
+  /// Alternatively, you could insert a [Actions] widget with just the mapping
+  /// you want to add between the [WidgetsApp] and its child and get the same
+  /// effect.
+  ///
+  /// ```dart
+  /// Widget build(BuildContext context) {
+  ///   return WidgetsApp(
+  ///     actions: <LocalKey, ActionFactory>{
+  ///       ... WidgetsApp.defaultActions,
+  ///       ActivateAction.key: () => CallbackAction(
+  ///         ActivateAction.key,
+  ///         onInvoke: (FocusNode focusNode, Intent intent) {
+  ///           // Do something here...
+  ///         },
+  ///       ),
+  ///     },
+  ///     color: const Color(0xFFFF0000),
+  ///     builder: (BuildContext context, Widget child) {
+  ///       return const Placeholder();
+  ///     },
+  ///   );
+  /// }
+  /// ```
+  /// {@end-tool}
+  /// {@macro flutter.widgets.widgetsApp.actions.seeAlso}
+  final Map<LocalKey, ActionFactory> actions;
+
   @override
   _CupertinoAppState createState() => _CupertinoAppState();
 
@@ -312,6 +375,8 @@ class _CupertinoAppState extends State<CupertinoApp> {
                     onPressed: onPressed,
                   );
                 },
+                shortcuts: widget.shortcuts,
+                actions: widget.actions,
               );
             },
           ),

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

@@ -189,6 +189,8 @@ class MaterialApp extends StatefulWidget {
     this.checkerboardOffscreenLayers = false,
     this.showSemanticsDebugger = false,
     this.debugShowCheckedModeBanner = true,
+    this.shortcuts,
+    this.actions,
   }) : assert(routes != null),
        assert(navigatorObservers != null),
        assert(title != null),
@@ -455,6 +457,67 @@ class MaterialApp extends StatefulWidget {
   /// {@macro flutter.widgets.widgetsApp.debugShowCheckedModeBanner}
   final bool debugShowCheckedModeBanner;
 
+  /// {@macro flutter.widgets.widgetsApp.shortcuts}
+  /// {@tool sample}
+  /// This example shows how to add a single shortcut for
+  /// [LogicalKeyboardKey.select] to the default shortcuts without needing to
+  /// add your own [Shortcuts] widget.
+  ///
+  /// Alternatively, you could insert a [Shortcuts] widget with just the mapping
+  /// you want to add between the [WidgetsApp] and its child and get the same
+  /// effect.
+  ///
+  /// ```dart
+  /// Widget build(BuildContext context) {
+  ///   return WidgetsApp(
+  ///     shortcuts: <LogicalKeySet, Intent>{
+  ///       ... WidgetsApp.defaultShortcuts,
+  ///       LogicalKeySet(LogicalKeyboardKey.select): const Intent(ActivateAction.key),
+  ///     },
+  ///     color: const Color(0xFFFF0000),
+  ///     builder: (BuildContext context, Widget child) {
+  ///       return const Placeholder();
+  ///     },
+  ///   );
+  /// }
+  /// ```
+  /// {@end-tool}
+  /// {@macro flutter.widgets.widgetsApp.shortcuts.seeAlso}
+  final Map<LogicalKeySet, Intent> shortcuts;
+
+  /// {@macro flutter.widgets.widgetsApp.actions}
+  /// {@tool sample}
+  /// This example shows how to add a single action handling an
+  /// [ActivateAction] to the default actions without needing to
+  /// add your own [Actions] widget.
+  ///
+  /// Alternatively, you could insert a [Actions] widget with just the mapping
+  /// you want to add between the [WidgetsApp] and its child and get the same
+  /// effect.
+  ///
+  /// ```dart
+  /// Widget build(BuildContext context) {
+  ///   return WidgetsApp(
+  ///     actions: <LocalKey, ActionFactory>{
+  ///       ... WidgetsApp.defaultActions,
+  ///       ActivateAction.key: () => CallbackAction(
+  ///         ActivateAction.key,
+  ///         onInvoke: (FocusNode focusNode, Intent intent) {
+  ///           // Do something here...
+  ///         },
+  ///       ),
+  ///     },
+  ///     color: const Color(0xFFFF0000),
+  ///     builder: (BuildContext context, Widget child) {
+  ///       return const Placeholder();
+  ///     },
+  ///   );
+  /// }
+  /// ```
+  /// {@end-tool}
+  /// {@macro flutter.widgets.widgetsApp.actions.seeAlso}
+  final Map<LocalKey, ActionFactory> actions;
+
   /// Turns on a [GridPaper] overlay that paints a baseline grid
   /// Material apps.
   ///
@@ -626,6 +689,8 @@ class _MaterialAppState extends State<MaterialApp> {
           mini: true,
         );
       },
+      shortcuts: widget.shortcuts,
+      actions: widget.actions,
     );
 
     assert(() {

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

@@ -164,8 +164,7 @@ class _CheckboxState extends State<Checkbox> with TickerProviderStateMixin {
   void initState() {
     super.initState();
     _actionMap = <LocalKey, ActionFactory>{
-      SelectAction.key: _createAction,
-      if (!kIsWeb) ActivateAction.key: _createAction,
+      ActivateAction.key: _createAction,
     };
   }
 
@@ -189,7 +188,7 @@ class _CheckboxState extends State<Checkbox> with TickerProviderStateMixin {
 
   Action _createAction() {
     return CallbackAction(
-      SelectAction.key,
+      ActivateAction.key,
       onInvoke: _actionHandler,
     );
   }

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

@@ -152,7 +152,7 @@ class _DropdownMenuItemButtonState<T> extends State<_DropdownMenuItemButton<T>>
   }
 
   static final Map<LogicalKeySet, Intent> _webShortcuts =<LogicalKeySet, Intent>{
-    LogicalKeySet(LogicalKeyboardKey.enter): const Intent(SelectAction.key),
+    LogicalKeySet(LogicalKeyboardKey.enter): const Intent(ActivateAction.key),
   };
 
   @override
@@ -1059,8 +1059,7 @@ class _DropdownButtonState<T> extends State<DropdownButton<T>> with WidgetsBindi
       _internalNode ??= _createFocusNode();
     }
     _actionMap = <LocalKey, ActionFactory>{
-      SelectAction.key: _createAction,
-      if (!kIsWeb) ActivateAction.key: _createAction,
+      ActivateAction.key: _createAction,
     };
     focusNode.addListener(_handleFocusChanged);
     final FocusManager focusManager = WidgetsBinding.instance.focusManager;

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

@@ -505,8 +505,7 @@ class _InkResponseState<T extends InkResponse> extends State<T> with AutomaticKe
   void initState() {
     super.initState();
     _actionMap = <LocalKey, ActionFactory>{
-      SelectAction.key: _createAction,
-      if (!kIsWeb) ActivateAction.key: _createAction,
+      ActivateAction.key: _createAction,
     };
     FocusManager.instance.addHighlightModeListener(_handleFocusHighlightModeChange);
   }

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

@@ -192,8 +192,7 @@ class _RadioState<T> extends State<Radio<T>> with TickerProviderStateMixin {
   void initState() {
     super.initState();
     _actionMap = <LocalKey, ActionFactory>{
-      SelectAction.key: _createAction,
-      if (!kIsWeb) ActivateAction.key: _createAction,
+      ActivateAction.key: _createAction,
     };
   }
 
@@ -207,7 +206,7 @@ class _RadioState<T> extends State<Radio<T>> with TickerProviderStateMixin {
 
   Action _createAction() {
     return CallbackAction(
-      SelectAction.key,
+      ActivateAction.key,
       onInvoke: _actionHandler,
     );
   }

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

@@ -219,8 +219,7 @@ class _SwitchState extends State<Switch> with TickerProviderStateMixin {
   void initState() {
     super.initState();
     _actionMap = <LocalKey, ActionFactory>{
-      SelectAction.key: _createAction,
-      if (!kIsWeb) ActivateAction.key: _createAction,
+      ActivateAction.key: _createAction,
     };
   }
 
@@ -234,7 +233,7 @@ class _SwitchState extends State<Switch> with TickerProviderStateMixin {
 
   Action _createAction() {
     return CallbackAction(
-      SelectAction.key,
+      ActivateAction.key,
       onInvoke: _actionHandler,
     );
   }

packages/flutter/lib/src/widgets/actions.dart

@@ -738,8 +738,7 @@ abstract class ActivateAction extends Action {
 /// An action that selects the currently focused control.
 ///
 /// This is an abstract class that serves as a base class for actions that
-/// select something, like a checkbox or a radio button. By default, it is bound
-/// to [LogicalKeyboardKey.space] in the default keyboard map in [WidgetsApp].
+/// select something. It is not bound to any key by default.
 abstract class SelectAction extends Action {
   /// Creates a [SelectAction] with a fixed [key];
   const SelectAction() : super(key);

packages/flutter/test/material/ink_paint_test.dart

@@ -322,46 +322,12 @@ void main() {
         );
     }
 
-    // Now activate it with a keypress.
-    await tester.sendKeyEvent(LogicalKeyboardKey.space);
-    await tester.pump();
-
-    RenderBox box = Material.of(tester.element(find.byType(InkWell))) as dynamic;
-
-    if (kIsWeb) {
-      expect(box, isNot(ripplePattern(30.0, 0)));
-    } else {
-      // ripplePattern always add a translation of topLeft.
-      expect(box, ripplePattern(30.0, 0));
-
-      // The ripple fades in for 75ms. During that time its alpha is eased from
-      // 0 to the splashColor's alpha value.
-      await tester.pump(const Duration(milliseconds: 50));
-      expect(box, ripplePattern(56.0, 120));
-
-      // At 75ms the ripple has faded in: it's alpha matches the splashColor's
-      // alpha.
-      await tester.pump(const Duration(milliseconds: 25));
-      expect(box, ripplePattern(73.0, 180));
-
-      // At this point the splash radius has expanded to its limit: 5 past the
-      // ink well's radius parameter. The fade-out is about to start.
-      // The fade-out begins at 225ms = 50ms + 25ms + 150ms.
-      await tester.pump(const Duration(milliseconds: 150));
-      expect(box, ripplePattern(105.0, 180));
-
-      // After another 150ms the fade-out is complete.
-      await tester.pump(const Duration(milliseconds: 150));
-      expect(box, ripplePattern(105.0, 0));
-    }
-
-    // Now try it with a select action instead.
-    await buildTest(SelectAction.key);
+    await buildTest(ActivateAction.key);
     await tester.pumpAndSettle();
     await tester.sendKeyEvent(LogicalKeyboardKey.space);
     await tester.pump();
 
-    box = Material.of(tester.element(find.byType(InkWell))) as dynamic;
+    final RenderBox box = Material.of(tester.element(find.byType(InkWell))) as dynamic;
 
     // ripplePattern always add a translation of topLeft.
     expect(box, ripplePattern(30.0, 0));

packages/flutter/test/material/raw_material_button_test.dart

@@ -48,7 +48,7 @@ void main() {
       Shortcuts(
         shortcuts: <LogicalKeySet, Intent>{
           LogicalKeySet(LogicalKeyboardKey.enter): const Intent(ActivateAction.key),
-          LogicalKeySet(LogicalKeyboardKey.space): const Intent(SelectAction.key),
+          LogicalKeySet(LogicalKeyboardKey.space): const Intent(ActivateAction.key),
         },
         child: Directionality(
           textDirection: TextDirection.ltr,
@@ -78,7 +78,7 @@ void main() {
 
     await tester.pumpAndSettle();
 
-    expect(pressed, kIsWeb ? isFalse : isTrue);
+    expect(pressed, isTrue);
 
     pressed = false;
     await tester.sendKeyEvent(LogicalKeyboardKey.space);

packages/flutter/test/widgets/app_test.dart

@@ -3,9 +3,23 @@
 // found in the LICENSE file.
 
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+class TestAction extends Action {
+  TestAction() : super(key);
+
+  static const LocalKey key = ValueKey<Type>(TestAction);
+
+  int calls = 0;
+
+  @override
+  void invoke(FocusNode node, Intent intent) {
+    calls += 1;
+  }
+}
+
 void main() {
   testWidgets('WidgetsApp with builder only', (WidgetTester tester) async {
     final GlobalKey key = GlobalKey();
@@ -21,6 +35,67 @@ void main() {
     expect(find.byKey(key), findsOneWidget);
   });
 
+  testWidgets('WidgetsApp can override default key bindings', (WidgetTester tester) async {
+    bool checked = false;
+    final GlobalKey key = GlobalKey();
+    await tester.pumpWidget(
+      WidgetsApp(
+        key: key,
+        builder: (BuildContext context, Widget child) {
+          return Material(
+            child: Checkbox(
+              value: checked,
+              autofocus: true,
+              onChanged: (bool value) {
+                checked = value;
+              },
+            ),
+          );
+        },
+        color: const Color(0xFF123456),
+      ),
+    );
+    await tester.pump(); // Wait for focus to take effect.
+    await tester.sendKeyEvent(LogicalKeyboardKey.space);
+    await tester.pumpAndSettle();
+    // Default key mapping worked.
+    expect(checked, isTrue);
+    checked = false;
+
+    final TestAction action = TestAction();
+    await tester.pumpWidget(
+      WidgetsApp(
+        key: key,
+        actions: <LocalKey, ActionFactory>{
+          TestAction.key: () => action,
+        },
+        shortcuts: <LogicalKeySet, Intent> {
+          LogicalKeySet(LogicalKeyboardKey.space): const Intent(TestAction.key),
+        },
+        builder: (BuildContext context, Widget child) {
+          return Material(
+            child: Checkbox(
+              value: checked,
+              autofocus: true,
+              onChanged: (bool value) {
+                checked = value;
+              },
+            ),
+          );
+        },
+        color: const Color(0xFF123456),
+      ),
+    );
+    await tester.pump();
+
+    await tester.sendKeyEvent(LogicalKeyboardKey.space);
+    await tester.pumpAndSettle();
+    // Default key mapping was not invoked.
+    expect(checked, isFalse);
+    // Overridden mapping was invoked.
+    expect(action.calls, equals(1));
+  });
+
   group('error control test', () {
     Future<void> expectFlutterError({
       GlobalKey<NavigatorState> key,

packages/flutter/test/widgets/scrollable_test.dart

@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:io';
 import 'dart:ui' as ui;
 
 import 'package:flutter/foundation.dart';
@@ -36,11 +35,7 @@ Future<void> pumpTest(
 
 const double dragOffset = 200.0;
 
-// TODO(gspencergoog): Change this to use TargetPlatform.macOS once that is available.
-// https://github.com/flutter/flutter/issues/31366
-// Can't be const, since Platform.macOS asserts if called in const context.
-// ignore: prefer_const_declarations
-final LogicalKeyboardKey modifierKey = (!kIsWeb && Platform.isMacOS)
+final LogicalKeyboardKey modifierKey = defaultTargetPlatform == TargetPlatform.macOS
     ? LogicalKeyboardKey.metaLeft
     : LogicalKeyboardKey.controlLeft;