Address previous comments, fix Intent.doNothing.

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

@@ -151,9 +151,17 @@ class ActionDispatcher extends Diagnosticable {
   /// The `action` and `intent` arguments must not be null.
   ///
   /// Returns true if the action was successfully invoked.
+  ///
+  /// If the `intent` argument is [Intent.doNothing], then this function will
+  /// return true, without invoking the action.
   bool invokeAction(Action action, Intent intent, {FocusNode focusNode}) {
     assert(action != null);
     assert(intent != null);
+
+    if (identical(intent, Intent.doNothing)) {
+      return true;
+    }
+
     focusNode ??= WidgetsBinding.instance.focusManager.primaryFocus;
     if (action != null && intent.isEnabled(focusNode.context)) {
       action.invoke(focusNode, intent);
@@ -280,7 +288,7 @@ class Actions extends InheritedWidget {
   /// found, then this method will return false instead of throwing.
   ///
   /// If the `intent` argument is [Intent.doNothing], then this function will
-  /// return false, without looking for a matching action.
+  /// return true, without looking for a matching action.
   static bool invoke(
     BuildContext context,
     Intent intent, {
@@ -293,7 +301,7 @@ class Actions extends InheritedWidget {
     Action action;
 
     if (identical(intent, Intent.doNothing)) {
-      return false;
+      return true;
     }
 
     bool visitAncestorElement(Element element) {

packages/flutter/test/widgets/actions_test.dart

@@ -71,6 +71,22 @@ void main() {
       expect(result, isTrue);
       expect(invoked, isTrue);
     });
+    test('$ActionDispatcher does nothing if Intent.doNothing is the intent.', () {
+      bool invoked = false;
+      const ActionDispatcher dispatcher = ActionDispatcher();
+      final FocusNode testNode = FocusNode(debugLabel: 'Test Node');
+      final bool result = dispatcher.invokeAction(
+        TestAction(
+          onInvoke: (FocusNode node, Intent invocation) {
+            invoked = true;
+          },
+        ),
+        Intent.doNothing,
+        focusNode: testNode,
+      );
+      expect(result, isTrue);
+      expect(invoked, isFalse);
+    });
   });
   group(Actions, () {
     Intent invokedIntent;
@@ -302,11 +318,11 @@ void main() {
       ).debugFillProperties(builder);
 
       final List<String> description = builder.properties
-          .where((DiagnosticsNode node) {
-            return !node.isFiltered(DiagnosticLevel.info);
-          })
-          .map((DiagnosticsNode node) => node.toString())
-          .toList();
+        .where((DiagnosticsNode node) {
+          return !node.isFiltered(DiagnosticLevel.info);
+        })
+        .map((DiagnosticsNode node) => node.toString())
+        .toList();
 
       expect(description[0], equalsIgnoringHashCodes('dispatcher: ActionDispatcher#00000'));
       expect(description[1], equals('actions: {}'));

packages/flutter/test/widgets/shortcuts_test.dart

@@ -37,22 +37,6 @@ class TestIntent extends Intent {
   const TestIntent() : super(TestAction.key);
 }
 
-class DoNothingAction extends Action {
-  const DoNothingAction({
-    @required OnInvokeCallback onInvoke,
-  })  : assert(onInvoke != null),
-        super(key);
-
-  static const LocalKey key = ValueKey<Type>(DoNothingAction);
-
-  @override
-  void invoke(FocusNode node, Intent invocation) {}
-}
-
-class DoNothingIntent extends Intent {
-  const DoNothingIntent() : super(DoNothingAction.key);
-}
-
 class TestShortcutManager extends ShortcutManager {
   TestShortcutManager(this.keys);
 
@@ -143,8 +127,8 @@ void main() {
         LogicalKeyboardKey.keyD,
         LogicalKeyboardKey.keyC,
         LogicalKeyboardKey.keyB,
-        LogicalKeyboardKey.keyA,}
-      );
+        LogicalKeyboardKey.keyA,
+      });
       final Map<LogicalKeySet, String> map = <LogicalKeySet, String>{set1: 'one'};
       expect(set2 == set3, isTrue);
       expect(set2 == set4, isTrue);
@@ -192,10 +176,12 @@ void main() {
       await tester.pumpWidget(
         Actions(
           actions: <LocalKey, ActionFactory>{
-            TestAction.key: () => TestAction(onInvoke: (FocusNode node, Intent intent) {
-              invoked = true;
-              return true;
-            }),
+            TestAction.key: () => TestAction(
+              onInvoke: (FocusNode node, Intent intent) {
+                invoked = true;
+                return true;
+              },
+            ),
           },
           child: Shortcuts(
             manager: testManager,
@@ -228,14 +214,16 @@ void main() {
           },
           child: Actions(
             actions: <LocalKey, ActionFactory>{
-              TestAction.key: () => TestAction(onInvoke: (FocusNode node, Intent intent) {
-                invoked = true;
-                return true;
-              }),
+              TestAction.key: () => TestAction(
+                onInvoke: (FocusNode node, Intent intent) {
+                  invoked = true;
+                  return true;
+                },
+              ),
             },
             child: Shortcuts(
               shortcuts: <LogicalKeySet, Intent>{
-                LogicalKeySet(LogicalKeyboardKey.keyA): const DoNothingIntent(),
+                LogicalKeySet(LogicalKeyboardKey.keyA): Intent.doNothing,
               },
               child: Focus(
                 autofocus: true,
@@ -251,5 +239,43 @@ void main() {
       expect(invoked, isTrue);
       expect(pressedKeys, equals(<LogicalKeyboardKey>[LogicalKeyboardKey.shiftLeft]));
     });
+    testWidgets('$Shortcuts can disable a shortcut with Intent.doNothing', (WidgetTester tester) async {
+      final GlobalKey containerKey = GlobalKey();
+      final List<LogicalKeyboardKey> pressedKeys = <LogicalKeyboardKey>[];
+      final TestShortcutManager testManager = TestShortcutManager(pressedKeys);
+      bool invoked = false;
+      await tester.pumpWidget(
+        Shortcuts(
+          manager: testManager,
+          shortcuts: <LogicalKeySet, Intent>{
+            LogicalKeySet(LogicalKeyboardKey.shift): const TestIntent(),
+          },
+          child: Actions(
+            actions: <LocalKey, ActionFactory>{
+              TestAction.key: () => TestAction(
+                onInvoke: (FocusNode node, Intent intent) {
+                  invoked = true;
+                  return true;
+                },
+              ),
+            },
+            child: Shortcuts(
+              shortcuts: <LogicalKeySet, Intent>{
+                LogicalKeySet(LogicalKeyboardKey.shift): Intent.doNothing,
+              },
+              child: Focus(
+                autofocus: true,
+                child: Container(key: containerKey, width: 100, height: 100),
+              ),
+            ),
+          ),
+        ),
+      );
+      await tester.pump();
+      expect(Shortcuts.of(containerKey.currentContext), isNotNull);
+      await tester.sendKeyDownEvent(LogicalKeyboardKey.shiftLeft);
+      expect(invoked, isFalse);
+      expect(pressedKeys, isEmpty);
+    });
   });
 }