Add VoidCallbackAction and VoidCallbackIntent (#103518)

This adds a simple VoidCallbackAction and VoidCallbackIntent that allows configuring an intent that will invoke a void callback when the intent is sent to the action subsystem. This allows binding a shortcut directly to a void callback in a Shortcuts widget. I also added an instance of VoidCallbackAction to the default actions so that simply binding a shortcut to a VoidCallbackIntent works anywhere in the app, and you don't need to add a VoidCallbackAction at the top of your app to make it work.
dooully · May 17, 2022 · 1994027 · 1994027
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Showing 3 changed files with 123 additions and 82 deletions.
diff --git a/packages/flutter/lib/src/widgets/actions.dart b/packages/flutter/lib/src/widgets/actions.dart
@@ -1296,7 +1296,34 @@ class _FocusableActionDetectorState extends State<FocusableActionDetector> {
   }
 }
 
-/// An [Intent], that is bound to a [DoNothingAction].
+/// An [Intent] that keeps a [VoidCallback] to be invoked by a
+/// [VoidCallbackAction] when it receives this intent.
+class VoidCallbackIntent extends Intent {
+  /// Creates a [VoidCallbackIntent].
+  const VoidCallbackIntent(this.callback);
+
+  /// The callback that is to be called by the [VoidCallbackAction] that
+  /// receives this intent.
+  final VoidCallback callback;
+}
+
+/// An [Action] that invokes the [VoidCallback] given to it in the
+/// [VoidCallbackIntent] passed to it when invoked.
+///
+/// See also:
+///
+///  * [CallbackAction], which is an action that will invoke a callback with the
+///    intent passed to the action's invoke method. The callback is configured
+///    on the action, not the intent, like this class.
+class VoidCallbackAction extends Action<VoidCallbackIntent> {
+  @override
+  Object? invoke(VoidCallbackIntent intent) {
+    intent.callback();
+    return null;
+  }
+}
+
+/// An [Intent] that is bound to a [DoNothingAction].
 ///
 /// Attaching a [DoNothingIntent] to a [Shortcuts] mapping is one way to disable
 /// a keyboard shortcut defined by a widget higher in the widget hierarchy and
@@ -1317,7 +1344,7 @@ class DoNothingIntent extends Intent {
   const DoNothingIntent._();
 }
 
-/// An [Intent], that is bound to a [DoNothingAction], but, in addition to not
+/// An [Intent] that is bound to a [DoNothingAction], but, in addition to not
 /// performing an action, also stops the propagation of the key event bound to
 /// this intent to other key event handlers in the focus chain.
 ///
@@ -1342,7 +1369,7 @@ class DoNothingAndStopPropagationIntent extends Intent {
   const DoNothingAndStopPropagationIntent._();
 }
 
-/// An [Action], that doesn't perform any action when invoked.
+/// An [Action] that doesn't perform any action when invoked.
 ///
 /// Attaching a [DoNothingAction] to an [Actions.actions] mapping is a way to
 /// disable an action defined by a widget higher in the widget hierarchy.
@@ -1411,15 +1438,15 @@ class ButtonActivateIntent extends Intent {
   const ButtonActivateIntent();
 }
 
-/// An action that activates the currently focused control.
+/// An [Action] that activates the currently focused control.
 ///
 /// This is an abstract class that serves as a base class for actions that
 /// activate a control. By default, is bound to [LogicalKeyboardKey.enter],
 /// [LogicalKeyboardKey.gameButtonA], and [LogicalKeyboardKey.space] in the
 /// default keyboard map in [WidgetsApp].
 abstract class ActivateAction extends Action<ActivateIntent> { }
 
-/// An intent that selects the currently focused control.
+/// An [Intent] that selects the currently focused control.
 class SelectIntent extends Intent { }
 
 /// An action that selects the currently focused control.
@@ -1441,7 +1468,7 @@ class DismissIntent extends Intent {
   const DismissIntent();
 }
 
-/// An action that dismisses the focused widget.
+/// An [Action] that dismisses the focused widget.
 ///
 /// This is an abstract class that serves as a base class for dismiss actions.
 abstract class DismissAction extends Action<DismissIntent> { }

diff --git a/packages/flutter/lib/src/widgets/app.dart b/packages/flutter/lib/src/widgets/app.dart
@@ -1289,6 +1289,7 @@ class WidgetsApp extends StatefulWidget {
     DirectionalFocusIntent: DirectionalFocusAction(),
     ScrollIntent: ScrollAction(),
     PrioritizedIntents: PrioritizedAction(),
+    VoidCallbackIntent: VoidCallbackAction(),
   };
 
   @override

diff --git a/packages/flutter/test/widgets/actions_test.dart b/packages/flutter/test/widgets/actions_test.dart
@@ -9,83 +9,7 @@ import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
-typedef PostInvokeCallback = void Function({Action<Intent> action, Intent intent, ActionDispatcher dispatcher});
-
-class TestIntent extends Intent {
-  const TestIntent();
-}
-
-class SecondTestIntent extends TestIntent {
-  const SecondTestIntent();
-}
-
-class ThirdTestIntent extends SecondTestIntent {
-  const ThirdTestIntent();
-}
-
-class TestAction extends CallbackAction<TestIntent> {
-  TestAction({
-    required OnInvokeCallback onInvoke,
-  })  : assert(onInvoke != null),
-        super(onInvoke: onInvoke);
-
-  @override
-  bool isEnabled(TestIntent intent) => enabled;
-
-  bool get enabled => _enabled;
-  bool _enabled = true;
-  set enabled(bool value) {
-    if (_enabled == value) {
-      return;
-    }
-    _enabled = value;
-    notifyActionListeners();
-  }
-
-  @override
-  void addActionListener(ActionListenerCallback listener) {
-    super.addActionListener(listener);
-    listeners.add(listener);
-  }
-
-  @override
-  void removeActionListener(ActionListenerCallback listener) {
-    super.removeActionListener(listener);
-    listeners.remove(listener);
-  }
-  List<ActionListenerCallback> listeners = <ActionListenerCallback>[];
-
-  void _testInvoke(TestIntent intent) => invoke(intent);
-}
-
-class TestDispatcher extends ActionDispatcher {
-  const TestDispatcher({this.postInvoke});
-
-  final PostInvokeCallback? postInvoke;
-
-  @override
-  Object? invokeAction(Action<Intent> action, Intent intent, [BuildContext? context]) {
-    final Object? result = super.invokeAction(action, intent, context);
-    postInvoke?.call(action: action, intent: intent, dispatcher: this);
-    return result;
-  }
-}
-
-class TestDispatcher1 extends TestDispatcher {
-  const TestDispatcher1({super.postInvoke});
-}
-
 void main() {
-  testWidgets('CallbackAction passes correct intent when invoked.', (WidgetTester tester) async {
-    late Intent passedIntent;
-    final TestAction action = TestAction(onInvoke: (Intent intent) {
-      passedIntent = intent;
-      return true;
-    });
-    const TestIntent intent = TestIntent();
-    action._testInvoke(intent);
-    expect(passedIntent, equals(intent));
-  });
   group(ActionDispatcher, () {
     testWidgets('ActionDispatcher invokes actions when asked.', (WidgetTester tester) async {
       await tester.pumpWidget(Container());
@@ -1033,6 +957,29 @@ void main() {
     );
   });
 
+  group('Action subclasses', () {
+    testWidgets('CallbackAction passes correct intent when invoked.', (WidgetTester tester) async {
+      late Intent passedIntent;
+      final TestAction action = TestAction(onInvoke: (Intent intent) {
+        passedIntent = intent;
+        return true;
+      });
+      const TestIntent intent = TestIntent();
+      action._testInvoke(intent);
+      expect(passedIntent, equals(intent));
+    });
+    testWidgets('VoidCallbackAction', (WidgetTester tester) async {
+      bool called = false;
+      void testCallback() {
+        called = true;
+      }
+      final VoidCallbackAction action = VoidCallbackAction();
+      final VoidCallbackIntent intent = VoidCallbackIntent(testCallback);
+      action.invoke(intent);
+      expect(called, isTrue);
+    });
+  });
+
   group('Diagnostics', () {
     testWidgets('default Intent debugFillProperties', (WidgetTester tester) async {
       final DiagnosticPropertiesBuilder builder = DiagnosticPropertiesBuilder();
@@ -1766,6 +1713,72 @@ void main() {
   });
 }
 
+typedef PostInvokeCallback = void Function({Action<Intent> action, Intent intent, ActionDispatcher dispatcher});
+
+class TestIntent extends Intent {
+  const TestIntent();
+}
+
+class SecondTestIntent extends TestIntent {
+  const SecondTestIntent();
+}
+
+class ThirdTestIntent extends SecondTestIntent {
+  const ThirdTestIntent();
+}
+
+class TestAction extends CallbackAction<TestIntent> {
+  TestAction({
+    required OnInvokeCallback onInvoke,
+  })  : assert(onInvoke != null),
+        super(onInvoke: onInvoke);
+
+  @override
+  bool isEnabled(TestIntent intent) => enabled;
+
+  bool get enabled => _enabled;
+  bool _enabled = true;
+  set enabled(bool value) {
+    if (_enabled == value) {
+      return;
+    }
+    _enabled = value;
+    notifyActionListeners();
+  }
+
+  @override
+  void addActionListener(ActionListenerCallback listener) {
+    super.addActionListener(listener);
+    listeners.add(listener);
+  }
+
+  @override
+  void removeActionListener(ActionListenerCallback listener) {
+    super.removeActionListener(listener);
+    listeners.remove(listener);
+  }
+  List<ActionListenerCallback> listeners = <ActionListenerCallback>[];
+
+  void _testInvoke(TestIntent intent) => invoke(intent);
+}
+
+class TestDispatcher extends ActionDispatcher {
+  const TestDispatcher({this.postInvoke});
+
+  final PostInvokeCallback? postInvoke;
+
+  @override
+  Object? invokeAction(Action<Intent> action, Intent intent, [BuildContext? context]) {
+    final Object? result = super.invokeAction(action, intent, context);
+    postInvoke?.call(action: action, intent: intent, dispatcher: this);
+    return result;
+  }
+}
+
+class TestDispatcher1 extends TestDispatcher {
+  const TestDispatcher1({super.postInvoke});
+}
+
 class TestContextAction extends ContextAction<TestIntent> {
   List<BuildContext?> capturedContexts = <BuildContext?>[];