Add DismissDirection onDismissed() callback parameter

examples/widgets/card_collection.dart

@@ -298,7 +298,7 @@ class CardCollectionState extends State<CardCollection> {
     Widget card = new Dismissable(
       direction: _dismissDirection,
       onResized: () { _invalidator(<int>[index]); },
-      onDismissed: () { dismissCard(cardModel); },
+      onDismissed: (DismissDirection direction) { dismissCard(cardModel); },
       child: new Card(
         color: _primaryColor[cardModel.color],
         child: new Container(

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

@@ -15,6 +15,8 @@ const double _kMinFlingVelocityDelta = 400.0;
 const double _kFlingVelocityScale = 1.0 / 300.0;
 const double _kDismissCardThreshold = 0.4;
 
+typedef void DismissDirectionCallback(DismissDirection direction);
+
 /// The direction in which a [Dismissable] can be dismissed.
 enum DismissDirection {
   /// The [Dismissable] can be dismissed by dragging either up or down.
@@ -57,7 +59,7 @@ class Dismissable extends StatefulComponent {
   final VoidCallback onResized;
 
   /// Called when the widget has been dismissed, after finishing resizing.
-  final VoidCallback onDismissed;
+  final DismissDirectionCallback onDismissed;
 
   /// The direction in which the widget can be dismissed.
   final DismissDirection direction;
@@ -232,8 +234,14 @@ class _DismissableState extends State<Dismissable> {
 
   void _handleResizeProgressChanged() {
     if (_resizeController.isCompleted) {
-      if (config.onDismissed != null)
-        config.onDismissed();
+      if (config.onDismissed != null) {
+        DismissDirection direction;
+        if (_directionIsXAxis)
+           direction = _dragExtent > 0 ? DismissDirection.right : DismissDirection.left;
+        else
+           direction = _dragExtent > 0 ? DismissDirection.down : DismissDirection.up;
+        config.onDismissed(direction);
+      }
     } else {
       if (config.onResized != null)
         config.onResized();

packages/flutter/test/widget/dismissable_test.dart

@@ -10,13 +10,15 @@ import 'package:test/test.dart';
 const double itemExtent = 100.0;
 Axis scrollDirection = Axis.vertical;
 DismissDirection dismissDirection = DismissDirection.horizontal;
+DismissDirection reportedDismissDirection;
 List<int> dismissedItems = <int>[];
 
 void handleOnResized(int item) {
   expect(dismissedItems.contains(item), isFalse);
 }
 
-void handleOnDismissed(int item) {
+void handleOnDismissed(DismissDirection direction, int item) {
+  reportedDismissDirection = direction;
   expect(dismissedItems.contains(item), isFalse);
   dismissedItems.add(item);
 }
@@ -25,7 +27,7 @@ Widget buildDismissableItem(int item) {
   return new Dismissable(
     key: new ValueKey<int>(item),
     direction: dismissDirection,
-    onDismissed: () { handleOnDismissed(item); },
+    onDismissed: (DismissDirection direction) { handleOnDismissed(direction, item); },
     onResized: () { handleOnResized(item); },
     child: new Container(
       width: itemExtent,
@@ -129,10 +131,12 @@ void main() {
       dismissItem(tester, 0, gestureDirection: DismissDirection.right);
       expect(tester.findText('0'), isNull);
       expect(dismissedItems, equals([0]));
+      expect(reportedDismissDirection, DismissDirection.right);
 
       dismissItem(tester, 1, gestureDirection: DismissDirection.left);
       expect(tester.findText('1'), isNull);
       expect(dismissedItems, equals([0, 1]));
+      expect(reportedDismissDirection, DismissDirection.left);
     });
   });
 
@@ -148,10 +152,12 @@ void main() {
       dismissItem(tester, 0, gestureDirection: DismissDirection.up);
       expect(tester.findText('0'), isNull);
       expect(dismissedItems, equals([0]));
+      expect(reportedDismissDirection, DismissDirection.up);
 
       dismissItem(tester, 1, gestureDirection: DismissDirection.down);
       expect(tester.findText('1'), isNull);
       expect(dismissedItems, equals([0, 1]));
+      expect(reportedDismissDirection, DismissDirection.down);
     });
   });
 
@@ -167,10 +173,12 @@ void main() {
       dismissItem(tester, 0, gestureDirection: DismissDirection.right);
       expect(tester.findText('0'), isNotNull);
       expect(dismissedItems, isEmpty);
+      dismissItem(tester, 1, gestureDirection: DismissDirection.right);
 
       dismissItem(tester, 0, gestureDirection: DismissDirection.left);
       expect(tester.findText('0'), isNull);
       expect(dismissedItems, equals([0]));
+      dismissItem(tester, 1, gestureDirection: DismissDirection.left);
     });
   });