Merge pull request #3013 from abarth/dismiss_snackbar

Make it possible to dismiss a snackbar manually

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

@@ -304,6 +304,17 @@ class ScaffoldState extends State<Scaffold> {
     }
   }
 
+  void removeCurrentSnackBar() {
+    if (_snackBars.isEmpty)
+      return;
+    Completer<Null> completer = _snackBars.first._completer;
+    if (!completer.isCompleted)
+      completer.complete();
+    _snackBarTimer?.cancel();
+    _snackBarTimer = null;
+    _snackBarController.value = 0.0;
+  }
+
   void _hideSnackBar() {
     assert(_snackBarController.status == AnimationStatus.forward ||
            _snackBarController.status == AnimationStatus.completed);

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

@@ -7,6 +7,7 @@ import 'package:flutter/widgets.dart';
 import 'button.dart';
 import 'flat_button.dart';
 import 'material.dart';
+import 'scaffold.dart';
 import 'theme_data.dart';
 import 'theme.dart';
 import 'typography.dart';
@@ -118,6 +119,12 @@ class SnackBar extends StatelessWidget {
         },
         child: new Semantics(
           container: true,
+          child: new Dismissable(
+            key: new Key('dismissable'),
+            direction: DismissDirection.down,
+            onDismissed: (DismissDirection direction) {
+              Scaffold.of(context).removeCurrentSnackBar();
+            },
             child: new Material(
               elevation: 6,
               color: _kSnackBackground,
@@ -142,6 +149,7 @@ class SnackBar extends StatelessWidget {
             )
           )
         )
+      )
     );
   }