Revise Action API (#42940)

This updates the Action API in accordance with the design doc for the changes: flutter.dev/go/actions-and-shortcuts-design-revision

Fixes #53276

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

@@ -213,7 +213,7 @@ class CupertinoApp extends StatefulWidget {
   ///   return WidgetsApp(
   ///     shortcuts: <LogicalKeySet, Intent>{
   ///       ... WidgetsApp.defaultShortcuts,
-  ///       LogicalKeySet(LogicalKeyboardKey.select): const Intent(ActivateAction.key),
+  ///       LogicalKeySet(LogicalKeyboardKey.select): const ActivateIntent(),
   ///     },
   ///     color: const Color(0xFFFF0000),
   ///     builder: (BuildContext context, Widget child) {
@@ -239,12 +239,12 @@ class CupertinoApp extends StatefulWidget {
   /// ```dart
   /// Widget build(BuildContext context) {
   ///   return WidgetsApp(
-  ///     actions: <LocalKey, ActionFactory>{
+  ///     actions: <Type, Action<Intent>>{
   ///       ... WidgetsApp.defaultActions,
-  ///       ActivateAction.key: () => CallbackAction(
-  ///         ActivateAction.key,
-  ///         onInvoke: (FocusNode focusNode, Intent intent) {
+  ///       ActivateAction: CallbackAction(
+  ///         onInvoke: (Intent intent) {
   ///           // Do something here...
+  ///           return null;
   ///         },
   ///       ),
   ///     },
@@ -257,7 +257,7 @@ class CupertinoApp extends StatefulWidget {
   /// ```
   /// {@end-tool}
   /// {@macro flutter.widgets.widgetsApp.actions.seeAlso}
-  final Map<LocalKey, ActionFactory> actions;
+  final Map<Type, Action<Intent>> actions;
 
   @override
   _CupertinoAppState createState() => _CupertinoAppState();

packages/flutter/lib/src/foundation/change_notifier.dart

@@ -183,9 +183,9 @@ class ChangeNotifier implements Listenable {
   /// Call all the registered listeners.
   ///
   /// Call this method whenever the object changes, to notify any clients the
-  /// object may have. Listeners that are added during this iteration will not
-  /// be visited. Listeners that are removed during this iteration will not be
-  /// visited after they are removed.
+  /// object may have changed. Listeners that are added during this iteration
+  /// will not be visited. Listeners that are removed during this iteration will
+  /// not be visited after they are removed.
   ///
   /// Exceptions thrown by listeners will be caught and reported using
   /// [FlutterError.reportError].

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

@@ -476,7 +476,7 @@ class MaterialApp extends StatefulWidget {
   ///   return WidgetsApp(
   ///     shortcuts: <LogicalKeySet, Intent>{
   ///       ... WidgetsApp.defaultShortcuts,
-  ///       LogicalKeySet(LogicalKeyboardKey.select): const Intent(ActivateAction.key),
+  ///       LogicalKeySet(LogicalKeyboardKey.select): const ActivateIntent(),
   ///     },
   ///     color: const Color(0xFFFF0000),
   ///     builder: (BuildContext context, Widget child) {
@@ -502,12 +502,12 @@ class MaterialApp extends StatefulWidget {
   /// ```dart
   /// Widget build(BuildContext context) {
   ///   return WidgetsApp(
-  ///     actions: <LocalKey, ActionFactory>{
+  ///     actions: <Type, Action<Intent>>{
   ///       ... WidgetsApp.defaultActions,
-  ///       ActivateAction.key: () => CallbackAction(
-  ///         ActivateAction.key,
-  ///         onInvoke: (FocusNode focusNode, Intent intent) {
+  ///       ActivateAction: CallbackAction(
+  ///         onInvoke: (Intent intent) {
   ///           // Do something here...
+  ///           return null;
   ///         },
   ///       ),
   ///     },
@@ -520,7 +520,7 @@ class MaterialApp extends StatefulWidget {
   /// ```
   /// {@end-tool}
   /// {@macro flutter.widgets.widgetsApp.actions.seeAlso}
-  final Map<LocalKey, ActionFactory> actions;
+  final Map<Type, Action<Intent>> actions;
 
   /// Turns on a [GridPaper] overlay that paints a baseline grid
   /// Material apps.

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

@@ -169,17 +169,17 @@ class Checkbox extends StatefulWidget {
 
 class _CheckboxState extends State<Checkbox> with TickerProviderStateMixin {
   bool get enabled => widget.onChanged != null;
-  Map<LocalKey, ActionFactory> _actionMap;
+  Map<Type, Action<Intent>> _actionMap;
 
   @override
   void initState() {
     super.initState();
-    _actionMap = <LocalKey, ActionFactory>{
-      ActivateAction.key: _createAction,
+    _actionMap = <Type, Action<Intent>>{
+      ActivateIntent: CallbackAction<ActivateIntent>(onInvoke: _actionHandler),
     };
   }
 
-  void _actionHandler(FocusNode node, Intent intent){
+  void _actionHandler(ActivateIntent intent) {
     if (widget.onChanged != null) {
       switch (widget.value) {
         case false:
@@ -193,17 +193,10 @@ class _CheckboxState extends State<Checkbox> with TickerProviderStateMixin {
           break;
       }
     }
-    final RenderObject renderObject = node.context.findRenderObject();
+    final RenderObject renderObject = context.findRenderObject();
     renderObject.sendSemanticsEvent(const TapSemanticEvent());
   }
 
-  Action _createAction() {
-    return CallbackAction(
-      ActivateAction.key,
-      onInvoke: _actionHandler,
-    );
-  }
-
   bool _focused = false;
   void _handleFocusHighlightChanged(bool focused) {
     if (focused != _focused) {

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

@@ -158,7 +158,7 @@ class _DropdownMenuItemButtonState<T> extends State<_DropdownMenuItemButton<T>>
   }
 
   static final Map<LogicalKeySet, Intent> _webShortcuts =<LogicalKeySet, Intent>{
-    LogicalKeySet(LogicalKeyboardKey.enter): const Intent(ActivateAction.key),
+    LogicalKeySet(LogicalKeyboardKey.enter): const ActivateIntent(),
   };
 
   @override
@@ -1080,7 +1080,7 @@ class _DropdownButtonState<T> extends State<DropdownButton<T>> with WidgetsBindi
   FocusNode _internalNode;
   FocusNode get focusNode => widget.focusNode ?? _internalNode;
   bool _hasPrimaryFocus = false;
-  Map<LocalKey, ActionFactory> _actionMap;
+  Map<Type, Action<Intent>> _actionMap;
   FocusHighlightMode _focusHighlightMode;
 
   // Only used if needed to create _internalNode.
@@ -1095,8 +1095,10 @@ class _DropdownButtonState<T> extends State<DropdownButton<T>> with WidgetsBindi
     if (widget.focusNode == null) {
       _internalNode ??= _createFocusNode();
     }
-    _actionMap = <LocalKey, ActionFactory>{
-      ActivateAction.key: _createAction,
+    _actionMap = <Type, Action<Intent>>{
+      ActivateIntent: CallbackAction<ActivateIntent>(
+        onInvoke: (ActivateIntent intent) => _handleTap(),
+      ),
     };
     focusNode.addListener(_handleFocusChanged);
     final FocusManager focusManager = WidgetsBinding.instance.focusManager;
@@ -1225,15 +1227,6 @@ class _DropdownButtonState<T> extends State<DropdownButton<T>> with WidgetsBindi
     }
   }
 
-  Action _createAction() {
-    return CallbackAction(
-      ActivateAction.key,
-      onInvoke: (FocusNode node, Intent intent) {
-        _handleTap();
-      },
-    );
-  }
-
   // When isDense is true, reduce the height of this button from _kMenuItemHeight to
   // _kDenseButtonHeight, but don't make it smaller than the text that it contains.
   // Similarly, we don't reduce the height of the button so much that its icon

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

@@ -559,27 +559,20 @@ class _InkResponseState<T extends InkResponse> extends State<T> with AutomaticKe
   InteractiveInkFeature _currentSplash;
   bool _hovering = false;
   final Map<_HighlightType, InkHighlight> _highlights = <_HighlightType, InkHighlight>{};
-  Map<LocalKey, ActionFactory> _actionMap;
+  Map<Type, Action<Intent>> _actionMap;
 
   bool get highlightsExist => _highlights.values.where((InkHighlight highlight) => highlight != null).isNotEmpty;
 
-  void _handleAction(FocusNode node, Intent intent) {
-    _startSplash(context: node.context);
-    _handleTap(node.context);
-  }
-
-  Action _createAction() {
-    return CallbackAction(
-      ActivateAction.key,
-      onInvoke:  _handleAction,
-    );
+  void _handleAction(ActivateIntent intent) {
+    _startSplash(context: context);
+    _handleTap(context);
   }
 
   @override
   void initState() {
     super.initState();
-    _actionMap = <LocalKey, ActionFactory>{
-      ActivateAction.key: _createAction,
+    _actionMap = <Type, Action<Intent>>{
+      ActivateIntent: CallbackAction<ActivateIntent>(onInvoke: _handleAction),
     };
     FocusManager.instance.addHighlightModeListener(_handleFocusHighlightModeChange);
   }

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

@@ -262,31 +262,26 @@ class Radio<T> extends StatefulWidget {
 
 class _RadioState<T> extends State<Radio<T>> with TickerProviderStateMixin {
   bool get enabled => widget.onChanged != null;
-  Map<LocalKey, ActionFactory> _actionMap;
+  Map<Type, Action<Intent>> _actionMap;
 
   @override
   void initState() {
     super.initState();
-    _actionMap = <LocalKey, ActionFactory>{
-      ActivateAction.key: _createAction,
+    _actionMap = <Type, Action<Intent>>{
+      ActivateIntent: CallbackAction<ActivateIntent>(
+        onInvoke: _actionHandler,
+      ),
     };
   }
 
-  void _actionHandler(FocusNode node, Intent intent) {
+  void _actionHandler(ActivateIntent intent) {
     if (widget.onChanged != null) {
       widget.onChanged(widget.value);
     }
-    final RenderObject renderObject = node.context.findRenderObject();
+    final RenderObject renderObject = context.findRenderObject();
     renderObject.sendSemanticsEvent(const TapSemanticEvent());
   }
 
-  Action _createAction() {
-    return CallbackAction(
-      ActivateAction.key,
-      onInvoke: _actionHandler,
-    );
-  }
-
   bool _focused = false;
   void _handleHighlightChanged(bool focused) {
     if (_focused != focused) {

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

@@ -230,31 +230,24 @@ class Switch extends StatefulWidget {
 }
 
 class _SwitchState extends State<Switch> with TickerProviderStateMixin {
-  Map<LocalKey, ActionFactory> _actionMap;
+  Map<Type, Action<Intent>> _actionMap;
 
   @override
   void initState() {
     super.initState();
-    _actionMap = <LocalKey, ActionFactory>{
-      ActivateAction.key: _createAction,
+    _actionMap = <Type, Action<Intent>>{
+      ActivateIntent: CallbackAction<ActivateIntent>(onInvoke: _actionHandler),
     };
   }
 
-  void _actionHandler(FocusNode node, Intent intent){
+  void _actionHandler(ActivateIntent intent) {
     if (widget.onChanged != null) {
       widget.onChanged(!widget.value);
     }
-    final RenderObject renderObject = node.context.findRenderObject();
+    final RenderObject renderObject = context.findRenderObject();
     renderObject.sendSemanticsEvent(const TapSemanticEvent());
   }
 
-  Action _createAction() {
-    return CallbackAction(
-      ActivateAction.key,
-      onInvoke: _actionHandler,
-    );
-  }
-
   bool _focused = false;
   void _handleFocusHighlightChanged(bool focused) {
     if (focused != _focused) {

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

@@ -78,7 +78,7 @@ export 'package:flutter/services.dart' show SmartQuotesType, SmartDashesType;
 ///         shortcuts: <LogicalKeySet, Intent>{
 ///           // Pressing enter on the field will now move to the next field.
 ///           LogicalKeySet(LogicalKeyboardKey.enter):
-///               Intent(NextFocusAction.key),
+///               NextFocusIntent(),
 ///         },
 ///         child: FocusTraversalGroup(
 ///           child: Form(

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

@@ -743,7 +743,7 @@ class WidgetsApp extends StatefulWidget {
   ///   return WidgetsApp(
   ///     shortcuts: <LogicalKeySet, Intent>{
   ///       ... WidgetsApp.defaultShortcuts,
-  ///       LogicalKeySet(LogicalKeyboardKey.select): const Intent(ActivateAction.key),
+  ///       LogicalKeySet(LogicalKeyboardKey.select): const ActivateIntent(),
   ///     },
   ///     color: const Color(0xFFFF0000),
   ///     builder: (BuildContext context, Widget child) {
@@ -790,12 +790,12 @@ class WidgetsApp extends StatefulWidget {
   /// ```dart
   /// Widget build(BuildContext context) {
   ///   return WidgetsApp(
-  ///     actions: <LocalKey, ActionFactory>{
+  ///     actions: <Type, Action<Intent>>{
   ///       ... WidgetsApp.defaultActions,
-  ///       ActivateAction.key: () => CallbackAction(
-  ///         ActivateAction.key,
-  ///         onInvoke: (FocusNode focusNode, Intent intent) {
+  ///       ActivateAction: CallbackAction(
+  ///         onInvoke: (Intent intent) {
   ///           // Do something here...
+  ///           return null;
   ///         },
   ///       ),
   ///     },
@@ -818,7 +818,7 @@ class WidgetsApp extends StatefulWidget {
   ///  * The [Intent] and [Action] classes, which allow definition of new
   ///    actions.
   /// {@endtemplate}
-  final Map<LocalKey, ActionFactory> actions;
+  final Map<Type, Action<Intent>> actions;
 
   /// If true, forces the performance overlay to be visible in all instances.
   ///
@@ -845,13 +845,13 @@ class WidgetsApp extends StatefulWidget {
 
   static final Map<LogicalKeySet, Intent> _defaultShortcuts = <LogicalKeySet, Intent>{
     // Activation
-    LogicalKeySet(LogicalKeyboardKey.enter): const Intent(ActivateAction.key),
-    LogicalKeySet(LogicalKeyboardKey.space): const Intent(ActivateAction.key),
-    LogicalKeySet(LogicalKeyboardKey.gameButtonA): const Intent(ActivateAction.key),
+    LogicalKeySet(LogicalKeyboardKey.enter): const ActivateIntent(),
+    LogicalKeySet(LogicalKeyboardKey.space): const ActivateIntent(),
+    LogicalKeySet(LogicalKeyboardKey.gameButtonA): const ActivateIntent(),
 
     // Keyboard traversal.
-    LogicalKeySet(LogicalKeyboardKey.tab): const Intent(NextFocusAction.key),
-    LogicalKeySet(LogicalKeyboardKey.shift, LogicalKeyboardKey.tab): const Intent(PreviousFocusAction.key),
+    LogicalKeySet(LogicalKeyboardKey.tab): const NextFocusIntent(),
+    LogicalKeySet(LogicalKeyboardKey.shift, LogicalKeyboardKey.tab): const PreviousFocusIntent(),
     LogicalKeySet(LogicalKeyboardKey.arrowLeft): const DirectionalFocusIntent(TraversalDirection.left),
     LogicalKeySet(LogicalKeyboardKey.arrowRight): const DirectionalFocusIntent(TraversalDirection.right),
     LogicalKeySet(LogicalKeyboardKey.arrowDown): const DirectionalFocusIntent(TraversalDirection.down),
@@ -869,11 +869,11 @@ class WidgetsApp extends StatefulWidget {
   // Default shortcuts for the web platform.
   static final Map<LogicalKeySet, Intent> _defaultWebShortcuts = <LogicalKeySet, Intent>{
     // Activation
-    LogicalKeySet(LogicalKeyboardKey.space): const Intent(ActivateAction.key),
+    LogicalKeySet(LogicalKeyboardKey.space): const ActivateIntent(),
 
     // Keyboard traversal.
-    LogicalKeySet(LogicalKeyboardKey.tab): const Intent(NextFocusAction.key),
-    LogicalKeySet(LogicalKeyboardKey.shift, LogicalKeyboardKey.tab): const Intent(PreviousFocusAction.key),
+    LogicalKeySet(LogicalKeyboardKey.tab): const NextFocusIntent(),
+    LogicalKeySet(LogicalKeyboardKey.shift, LogicalKeyboardKey.tab): const PreviousFocusIntent(),
 
     // Scrolling
     LogicalKeySet(LogicalKeyboardKey.arrowUp): const ScrollIntent(direction: AxisDirection.up),
@@ -887,12 +887,12 @@ class WidgetsApp extends StatefulWidget {
   // Default shortcuts for the macOS platform.
   static final Map<LogicalKeySet, Intent> _defaultMacOsShortcuts = <LogicalKeySet, Intent>{
     // Activation
-    LogicalKeySet(LogicalKeyboardKey.enter): const Intent(ActivateAction.key),
-    LogicalKeySet(LogicalKeyboardKey.space): const Intent(ActivateAction.key),
+    LogicalKeySet(LogicalKeyboardKey.enter): const ActivateIntent(),
+    LogicalKeySet(LogicalKeyboardKey.space): const ActivateIntent(),
 
     // Keyboard traversal
-    LogicalKeySet(LogicalKeyboardKey.tab): const Intent(NextFocusAction.key),
-    LogicalKeySet(LogicalKeyboardKey.shift, LogicalKeyboardKey.tab): const Intent(PreviousFocusAction.key),
+    LogicalKeySet(LogicalKeyboardKey.tab): const NextFocusIntent(),
+    LogicalKeySet(LogicalKeyboardKey.shift, LogicalKeyboardKey.tab): const PreviousFocusIntent(),
     LogicalKeySet(LogicalKeyboardKey.arrowLeft): const DirectionalFocusIntent(TraversalDirection.left),
     LogicalKeySet(LogicalKeyboardKey.arrowRight): const DirectionalFocusIntent(TraversalDirection.right),
     LogicalKeySet(LogicalKeyboardKey.arrowDown): const DirectionalFocusIntent(TraversalDirection.down),
@@ -932,13 +932,13 @@ class WidgetsApp extends StatefulWidget {
   }
 
   /// The default value of [WidgetsApp.actions].
-  static final Map<LocalKey, ActionFactory> defaultActions = <LocalKey, ActionFactory>{
-    DoNothingAction.key: () => const DoNothingAction(),
-    RequestFocusAction.key: () => RequestFocusAction(),
-    NextFocusAction.key: () => NextFocusAction(),
-    PreviousFocusAction.key: () => PreviousFocusAction(),
-    DirectionalFocusAction.key: () => DirectionalFocusAction(),
-    ScrollAction.key: () => ScrollAction(),
+  static Map<Type, Action<Intent>> defaultActions = <Type, Action<Intent>>{
+    DoNothingIntent: DoNothingAction(),
+    RequestFocusIntent: RequestFocusAction(),
+    NextFocusIntent: NextFocusAction(),
+    PreviousFocusIntent: PreviousFocusAction(),
+    DirectionalFocusIntent: DirectionalFocusAction(),
+    ScrollIntent: ScrollAction(),
   };
 
   @override

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

@@ -92,7 +92,8 @@ enum TraversalDirection {
 /// [FocusTraversalGroup] widget.
 ///
 /// The focus traversal policy is what determines which widget is "next",
-/// "previous", or in a direction from the currently focused [FocusNode].
+/// "previous", or in a direction from the widget associated with the currently
+/// focused [FocusNode] (usually a [Focus] widget).
 ///
 /// One of the pre-defined subclasses may be used, or define a custom policy to
 /// create a unique focus order.
@@ -1713,88 +1714,94 @@ class _FocusTraversalGroupMarker extends InheritedWidget {
   bool updateShouldNotify(InheritedWidget oldWidget) => false;
 }
 
-// A base class for all of the default actions that request focus for a node.
-class _RequestFocusActionBase extends Action {
-  _RequestFocusActionBase(LocalKey name) : super(name);
+/// An intent for use with the [RequestFocusAction], which supplies the
+/// [FocusNode] that should be focused.
+class RequestFocusIntent extends Intent {
+  /// A const constructor for a [RequestFocusIntent], so that subclasses may be
+  /// const.
+  const RequestFocusIntent(this.focusNode)
+      : assert(focusNode != null);
 
-  FocusNode _previousFocus;
-
-  @override
-  void invoke(FocusNode node, Intent intent) {
-    _previousFocus = primaryFocus;
-    node.requestFocus();
-  }
-
-  @override
-  void debugFillProperties(DiagnosticPropertiesBuilder properties) {
-    super.debugFillProperties(properties);
-    properties.add(DiagnosticsProperty<FocusNode>('previous', _previousFocus));
-  }
+  /// The [FocusNode] that is to be focused.
+  final FocusNode focusNode;
 }
 
-/// An [Action] that requests the focus on the node it is invoked on.
+/// An [Action] that requests the focus on the node it is given in its
+/// [RequestFocusIntent].
 ///
 /// This action can be used to request focus for a particular node, by calling
 /// [Action.invoke] like so:
 ///
 /// ```dart
-/// Actions.invoke(context, const Intent(RequestFocusAction.key), focusNode: _focusNode);
+/// Actions.invoke(context, const RequestFocusIntent(focusNode));
 /// ```
 ///
-/// Where the `_focusNode` is the node for which the focus will be requested.
+/// Where the `focusNode` is the node for which the focus will be requested.
 ///
 /// The difference between requesting focus in this way versus calling
-/// [_focusNode.requestFocus] directly is that it will use the [Action]
-/// registered in the nearest [Actions] widget associated with [key] to make the
-/// request, rather than just requesting focus directly. This allows the action
-/// to have additional side effects, like logging, or undo and redo
-/// functionality.
-///
-/// However, this [RequestFocusAction] is the default action associated with the
-/// [key] in the [WidgetsApp], and it simply requests focus and has no side
-/// effects.
-class RequestFocusAction extends _RequestFocusActionBase {
-  /// Creates a [RequestFocusAction] with a fixed [key].
-  RequestFocusAction() : super(key);
-
-  /// The [LocalKey] that uniquely identifies this action to an [Intent].
-  static const LocalKey key = ValueKey<Type>(RequestFocusAction);
-
+/// [FocusNode.requestFocus] directly is that it will use the [Action]
+/// registered in the nearest [Actions] widget associated with
+/// [RequestFocusIntent] to make the request, rather than just requesting focus
+/// directly. This allows the action to have additional side effects, like
+/// logging, or undo and redo functionality.
+///
+/// This [RequestFocusAction] class is the default action associated with the
+/// [RequestFocusIntent] in the [WidgetsApp], and it simply requests focus. You
+/// can redefine the associated action with your own [Actions] widget.
+///
+/// See [FocusTraversalPolicy] for more information about focus traversal.
+class RequestFocusAction extends Action<RequestFocusIntent> {
   @override
-  void invoke(FocusNode node, Intent intent) => _focusAndEnsureVisible(node);
+  void invoke(RequestFocusIntent intent) {
+    _focusAndEnsureVisible(intent.focusNode);
+  }
+}
+
+/// An [Intent] bound to [NextFocusAction], which moves the focus to the next
+/// focusable node in the focus traversal order.
+///
+/// See [FocusTraversalPolicy] for more information about focus traversal.
+class NextFocusIntent extends Intent {
+  /// Creates a const [NextFocusIntent] so subclasses can be const.
+  const NextFocusIntent();
 }
 
 /// An [Action] that moves the focus to the next focusable node in the focus
 /// order.
 ///
-/// This action is the default action registered for the [key], and by default
-/// is bound to the [LogicalKeyboardKey.tab] key in the [WidgetsApp].
-class NextFocusAction extends _RequestFocusActionBase {
-  /// Creates a [NextFocusAction] with a fixed [key];
-  NextFocusAction() : super(key);
-
-  /// The [LocalKey] that uniquely identifies this action to an [Intent].
-  static const LocalKey key = ValueKey<Type>(NextFocusAction);
-
+/// This action is the default action registered for the [NextFocusIntent], and
+/// by default is bound to the [LogicalKeyboardKey.tab] key in the [WidgetsApp].
+///
+/// See [FocusTraversalPolicy] for more information about focus traversal.
+class NextFocusAction extends Action<NextFocusIntent> {
   @override
-  void invoke(FocusNode node, Intent intent) => node.nextFocus();
+  void invoke(NextFocusIntent intent) {
+    primaryFocus.nextFocus();
+  }
+}
+
+/// An [Intent] bound to [PreviousFocusAction], which moves the focus to the
+/// previous focusable node in the focus traversal order.
+///
+/// See [FocusTraversalPolicy] for more information about focus traversal.
+class PreviousFocusIntent extends Intent {
+  /// Creates a const [PreviousFocusIntent] so subclasses can be const.
+  const PreviousFocusIntent();
 }
 
 /// An [Action] that moves the focus to the previous focusable node in the focus
 /// order.
 ///
-/// This action is the default action registered for the [key], and by default
-/// is bound to a combination of the [LogicalKeyboardKey.tab] key and the
-/// [LogicalKeyboardKey.shift] key in the [WidgetsApp].
-class PreviousFocusAction extends _RequestFocusActionBase {
-  /// Creates a [PreviousFocusAction] with a fixed [key];
-  PreviousFocusAction() : super(key);
-
-  /// The [LocalKey] that uniquely identifies this action to an [Intent].
-  static const LocalKey key = ValueKey<Type>(PreviousFocusAction);
-
+/// This action is the default action registered for the [PreviousFocusIntent],
+/// and by default is bound to a combination of the [LogicalKeyboardKey.tab] key
+/// and the [LogicalKeyboardKey.shift] key in the [WidgetsApp].
+///
+/// See [FocusTraversalPolicy] for more information about focus traversal.
+class PreviousFocusAction extends Action<PreviousFocusIntent> {
   @override
-  void invoke(FocusNode node, Intent intent) => node.previousFocus();
+  void invoke(PreviousFocusIntent intent) {
+    primaryFocus.previousFocus();
+  }
 }
 
 /// An [Intent] that represents moving to the next focusable node in the given
@@ -1804,12 +1811,13 @@ class PreviousFocusAction extends _RequestFocusActionBase {
 /// [LogicalKeyboardKey.arrowDown], [LogicalKeyboardKey.arrowLeft], and
 /// [LogicalKeyboardKey.arrowRight] keys in the [WidgetsApp], with the
 /// appropriate associated directions.
+///
+/// See [FocusTraversalPolicy] for more information about focus traversal.
 class DirectionalFocusIntent extends Intent {
-  /// Creates a [DirectionalFocusIntent] with a fixed [key], and the given
-  /// [direction].
+  /// Creates a [DirectionalFocusIntent] intending to move the focus in the
+  /// given [direction].
   const DirectionalFocusIntent(this.direction, {this.ignoreTextFields = true})
-      : assert(ignoreTextFields != null),
-        super(DirectionalFocusAction.key);
+      : assert(ignoreTextFields != null);
 
   /// The direction in which to look for the next focusable node when the
   /// associated [DirectionalFocusAction] is invoked.
@@ -1826,21 +1834,15 @@ class DirectionalFocusIntent extends Intent {
 /// An [Action] that moves the focus to the focusable node in the direction
 /// configured by the associated [DirectionalFocusIntent.direction].
 ///
-/// This is the [Action] associated with the [key] and bound by default to the
-/// [LogicalKeyboardKey.arrowUp], [LogicalKeyboardKey.arrowDown],
+/// This is the [Action] associated with [DirectionalFocusIntent] and bound by
+/// default to the [LogicalKeyboardKey.arrowUp], [LogicalKeyboardKey.arrowDown],
 /// [LogicalKeyboardKey.arrowLeft], and [LogicalKeyboardKey.arrowRight] keys in
 /// the [WidgetsApp], with the appropriate associated directions.
-class DirectionalFocusAction extends _RequestFocusActionBase {
-  /// Creates a [DirectionalFocusAction] with a fixed [key];
-  DirectionalFocusAction() : super(key);
-
-  /// The [LocalKey] that uniquely identifies this action to [DirectionalFocusIntent].
-  static const LocalKey key = ValueKey<Type>(DirectionalFocusAction);
-
+class DirectionalFocusAction extends Action<DirectionalFocusIntent> {
   @override
-  void invoke(FocusNode node, DirectionalFocusIntent intent) {
-    if (!intent.ignoreTextFields || node.context.widget is! EditableText) {
-      node.focusInDirection(intent.direction);
+  void invoke(DirectionalFocusIntent intent) {
+    if (!intent.ignoreTextFields || primaryFocus.context.widget is! EditableText) {
+      primaryFocus.focusInDirection(intent.direction);
     }
   }
 }

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

@@ -132,7 +132,7 @@ abstract class GlobalKey<T extends State<StatefulWidget>> extends Key {
 
   static final Map<GlobalKey, Element> _registry = <GlobalKey, Element>{};
   static final Set<Element> _debugIllFatedElements = HashSet<Element>();
-  // This map keeps track which child reserve the global key with the parent.
+  // This map keeps track which child reserves the global key with the parent.
   // Parent, child -> global key.
   // This provides us a way to remove old reservation while parent rebuilds the
   // child in the same slot.

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

@@ -889,8 +889,7 @@ class ScrollIntent extends Intent {
     @required this.direction,
     this.type = ScrollIncrementType.line,
   })  : assert(direction != null),
-        assert(type != null),
-        super(ScrollAction.key);
+        assert(type != null);
 
   /// The direction in which to scroll the scrollable containing the focused
   /// widget.
@@ -898,11 +897,6 @@ class ScrollIntent extends Intent {
 
   /// The type of scrolling that is intended.
   final ScrollIncrementType type;
-
-  @override
-  bool isEnabled(BuildContext context) {
-    return Scrollable.of(context) != null;
-  }
 }
 
 /// An [Action] that scrolls the [Scrollable] that encloses the current
@@ -912,13 +906,16 @@ class ScrollIntent extends Intent {
 /// for a [ScrollIntent.type] set to [ScrollIncrementType.page] is 80% of the
 /// size of the scroll window, and for [ScrollIncrementType.line], 50 logical
 /// pixels.
-class ScrollAction extends Action {
-  /// Creates a const [ScrollAction].
-  ScrollAction() : super(key);
-
+class ScrollAction extends Action<ScrollIntent> {
   /// The [LocalKey] that uniquely connects this action to a [ScrollIntent].
   static const LocalKey key = ValueKey<Type>(ScrollAction);
 
+  @override
+  bool get enabled {
+    final FocusNode focus = primaryFocus;
+    return focus != null && focus.context != null && Scrollable.of(focus.context) != null;
+  }
+
   // Returns the scroll increment for a single scroll request, for use when
   // scrolling using a hardware keyboard.
   //
@@ -1013,8 +1010,8 @@ class ScrollAction extends Action {
   }
 
   @override
-  void invoke(FocusNode node, ScrollIntent intent) {
-    final ScrollableState state = Scrollable.of(node.context);
+  void invoke(ScrollIntent intent) {
+    final ScrollableState state = Scrollable.of(primaryFocus.context);
     assert(state != null, '$ScrollAction was invoked on a context that has no scrollable parent');
     assert(state.position.pixels != null, 'Scrollable must be laid out before it can be scrolled via a ScrollAction');
     assert(state.position.viewportDimension != null);

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

@@ -286,6 +286,14 @@ class ShortcutManager extends ChangeNotifier with Diagnosticable {
   /// The optional `keysPressed` argument provides an override to keys that the
   /// [RawKeyboard] reports. If not specified, uses [RawKeyboard.keysPressed]
   /// instead.
+  ///
+  /// If a key mapping is found, then the associated action will be invoked
+  /// using the [Intent] that the [LogicalKeySet] maps to, and the currently
+  /// focused widget's context (from [FocusManager.primaryFocus]).
+  ///
+  /// The object returned is the result of [Action.invoke] being called on the
+  /// [Action] bound to the [Intent] that the key press maps to, or null, if the
+  /// key press didn't match any intent.
   @protected
   bool handleKeypress(
     BuildContext context,
@@ -316,10 +324,9 @@ class ShortcutManager extends ChangeNotifier with Diagnosticable {
     }
     if (matchedIntent != null) {
       final BuildContext primaryContext = primaryFocus?.context;
-      if (primaryContext == null) {
-        return false;
-      }
-      return Actions.invoke(primaryContext, matchedIntent, nullOk: true);
+      assert (primaryContext != null);
+      Actions.invoke(primaryContext, matchedIntent, nullOk: true);
+      return true;
     }
     return false;
   }

packages/flutter/test/material/debug_test.dart

@@ -174,6 +174,7 @@ void main() {
       '     Focus\n'
       '     _FocusTraversalGroupMarker\n'
       '     FocusTraversalGroup\n'
+      '     _ActionsMarker\n'
       '     Actions\n'
       '     _ShortcutsMarker\n'
       '     Semantics\n'

packages/flutter/test/material/ink_paint_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 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
@@ -259,11 +258,11 @@ void main() {
     final BorderRadius borderRadius = BorderRadius.circular(6.0);
 
     final FocusNode focusNode = FocusNode(debugLabel: 'Test Node');
-    Future<void> buildTest(LocalKey actionKey) async {
+    Future<void> buildTest(Intent intent) async {
       return await tester.pumpWidget(
         Shortcuts(
           shortcuts: <LogicalKeySet, Intent>{
-            LogicalKeySet(LogicalKeyboardKey.space): Intent(actionKey),
+            LogicalKeySet(LogicalKeyboardKey.space): intent,
           },
           child: Directionality(
             textDirection: TextDirection.ltr,
@@ -289,7 +288,7 @@ void main() {
       );
     }
 
-    await buildTest(ActivateAction.key);
+    await buildTest(const ActivateIntent());
     focusNode.requestFocus();
     await tester.pumpAndSettle();
 
@@ -322,7 +321,7 @@ void main() {
         );
     }
 
-    await buildTest(ActivateAction.key);
+    await buildTest(const ActivateIntent());
     await tester.pumpAndSettle();
     await tester.sendKeyEvent(LogicalKeyboardKey.space);
     await tester.pump();

packages/flutter/test/material/ink_well_test.dart

@@ -323,7 +323,7 @@ void main() {
     semantics.dispose();
   });
   testWidgets("ink response doesn't focus when disabled", (WidgetTester tester) async {
-    WidgetsBinding.instance.focusManager.highlightStrategy = FocusHighlightStrategy.alwaysTouch;
+    FocusManager.instance.highlightStrategy = FocusHighlightStrategy.alwaysTouch;
     final FocusNode focusNode = FocusNode(debugLabel: 'Ink Focus');
     final GlobalKey childKey = GlobalKey();
     await tester.pumpWidget(
@@ -359,7 +359,7 @@ void main() {
   });
 
   testWidgets("ink response doesn't hover when disabled", (WidgetTester tester) async {
-    WidgetsBinding.instance.focusManager.highlightStrategy = FocusHighlightStrategy.alwaysTouch;
+    FocusManager.instance.highlightStrategy = FocusHighlightStrategy.alwaysTouch;
     final FocusNode focusNode = FocusNode(debugLabel: 'Ink Focus');
     final GlobalKey childKey = GlobalKey();
     bool hovering = false;

packages/flutter/test/material/raw_material_button_test.dart

@@ -47,8 +47,8 @@ void main() {
     await tester.pumpWidget(
       Shortcuts(
         shortcuts: <LogicalKeySet, Intent>{
-          LogicalKeySet(LogicalKeyboardKey.enter): const Intent(ActivateAction.key),
-          LogicalKeySet(LogicalKeyboardKey.space): const Intent(ActivateAction.key),
+          LogicalKeySet(LogicalKeyboardKey.enter): const ActivateIntent(),
+          LogicalKeySet(LogicalKeyboardKey.space): const ActivateIntent(),
         },
         child: Directionality(
           textDirection: TextDirection.ltr,

packages/flutter/test/widgets/app_test.dart

@@ -8,15 +8,19 @@ import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 
-class TestAction extends Action {
-  TestAction() : super(key);
+class TestIntent extends Intent {
+  const TestIntent();
+}
+
+class TestAction extends Action<Intent> {
+  TestAction();
 
   static const LocalKey key = ValueKey<Type>(TestAction);
 
   int calls = 0;
 
   @override
-  void invoke(FocusNode node, Intent intent) {
+  void invoke(Intent intent) {
     calls += 1;
   }
 }
@@ -67,11 +71,11 @@ void main() {
     await tester.pumpWidget(
       WidgetsApp(
         key: key,
-        actions: <LocalKey, ActionFactory>{
-          TestAction.key: () => action,
+        actions: <Type, Action<Intent>>{
+          TestIntent: action,
         },
         shortcuts: <LogicalKeySet, Intent> {
-          LogicalKeySet(LogicalKeyboardKey.space): const Intent(TestAction.key),
+          LogicalKeySet(LogicalKeyboardKey.space): const TestIntent(),
         },
         builder: (BuildContext context, Widget child) {
           return Material(

packages/flutter/test/widgets/shortcuts_test.dart

@@ -9,13 +9,13 @@ import 'package:flutter/src/services/keyboard_key.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 
-typedef PostInvokeCallback = void Function({Action action, Intent intent, FocusNode focusNode, ActionDispatcher dispatcher});
+typedef PostInvokeCallback = void Function({Action<Intent> action, Intent intent, BuildContext context, ActionDispatcher dispatcher});
 
-class TestAction extends CallbackAction {
-  const TestAction({
+class TestAction extends CallbackAction<TestIntent> {
+  TestAction({
     @required OnInvokeCallback onInvoke,
   })  : assert(onInvoke != null),
-        super(key, onInvoke: onInvoke);
+        super(onInvoke: onInvoke);
 
   static const LocalKey key = ValueKey<Type>(TestAction);
 }
@@ -26,15 +26,15 @@ class TestDispatcher extends ActionDispatcher {
   final PostInvokeCallback postInvoke;
 
   @override
-  bool invokeAction(Action action, Intent intent, {FocusNode focusNode}) {
-    final bool result = super.invokeAction(action, intent, focusNode: focusNode);
-    postInvoke?.call(action: action, intent: intent, focusNode: focusNode, dispatcher: this);
+  Object invokeAction(Action<TestIntent> action, Intent intent, [BuildContext context]) {
+    final Object result = super.invokeAction(action, intent, context);
+    postInvoke?.call(action: action, intent: intent, context: context, dispatcher: this);
     return result;
   }
 }
 
 class TestIntent extends Intent {
-  const TestIntent() : super(TestAction.key);
+  const TestIntent();
 }
 
 class TestShortcutManager extends ShortcutManager {
@@ -210,10 +210,11 @@ void main() {
       bool invoked = false;
       await tester.pumpWidget(
         Actions(
-          actions: <LocalKey, ActionFactory>{
-            TestAction.key: () => TestAction(
-              onInvoke: (FocusNode node, Intent intent) {
+          actions: <Type, Action<Intent>>{
+            TestIntent: TestAction(
+              onInvoke: (Intent intent) {
                 invoked = true;
+                return true;
               },
             ),
           },
@@ -247,10 +248,11 @@ void main() {
             LogicalKeySet(LogicalKeyboardKey.shift): const TestIntent(),
           },
           child: Actions(
-            actions: <LocalKey, ActionFactory>{
-              TestAction.key: () => TestAction(
-                onInvoke: (FocusNode node, Intent intent) {
+            actions: <Type, Action<Intent>>{
+              TestIntent: TestAction(
+                onInvoke: (Intent intent) {
                   invoked = true;
+                  return invoked;
                 },
               ),
             },
@@ -285,10 +287,11 @@ void main() {
               LogicalKeySet(LogicalKeyboardKey.shift): const TestIntent(),
             },
             child: Actions(
-              actions: <LocalKey, ActionFactory>{
-                TestAction.key: () => TestAction(
-                  onInvoke: (FocusNode node, Intent intent) {
+              actions: <Type, Action<Intent>>{
+                TestIntent: TestAction(
+                  onInvoke: (Intent intent) {
                     invoked = true;
+                    return invoked;
                   },
                 ),
               },
@@ -317,7 +320,7 @@ void main() {
       Shortcuts(shortcuts: <LogicalKeySet, Intent>{LogicalKeySet(
         LogicalKeyboardKey.shift,
         LogicalKeyboardKey.keyA,
-      ) : const Intent(ActivateAction.key),
+      ) : const ActivateIntent(),
         LogicalKeySet(
         LogicalKeyboardKey.shift,
         LogicalKeyboardKey.arrowRight,
@@ -334,7 +337,7 @@ void main() {
       expect(
           description[0],
           equalsIgnoringHashCodes(
-              'shortcuts: {{Shift + Key A}: Intent#00000(key: [<ActivateAction>]), {Shift + Arrow Right}: DirectionalFocusIntent#00000(key: [<DirectionalFocusAction>])}'));
+              'shortcuts: {{Shift + Key A}: ActivateIntent#00000, {Shift + Arrow Right}: DirectionalFocusIntent#00000}'));
     });
     test('Shortcuts diagnostics work when debugLabel specified.', () {
       final DiagnosticPropertiesBuilder builder = DiagnosticPropertiesBuilder();
@@ -345,7 +348,7 @@ void main() {
           LogicalKeySet(
             LogicalKeyboardKey.keyA,
             LogicalKeyboardKey.keyB,
-          ): const Intent(ActivateAction.key)
+          ): const ActivateIntent(),
         },
       ).debugFillProperties(builder);
 
@@ -368,7 +371,7 @@ void main() {
           LogicalKeySet(
             LogicalKeyboardKey.keyA,
             LogicalKeyboardKey.keyB,
-          ): const Intent(ActivateAction.key)
+          ): const ActivateIntent(),
         },
       ).debugFillProperties(builder);
 
@@ -381,7 +384,7 @@ void main() {
 
       expect(description.length, equals(2));
       expect(description[0], equalsIgnoringHashCodes('manager: ShortcutManager#00000(shortcuts: {})'));
-      expect(description[1], equalsIgnoringHashCodes('shortcuts: {{Key A + Key B}: Intent#00000(key: [<ActivateAction>])}'));
+      expect(description[1], equalsIgnoringHashCodes('shortcuts: {{Key A + Key B}: ActivateIntent#00000}'));
     });
   });
 }