Added Navigator.removeRoute() (#10298)

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

@@ -328,6 +328,10 @@ class _DropdownRoute<T> extends PopupRoute<_DropdownRouteResult<T>> {
       child: menu,
     );
   }
+
+  void _dismiss() {
+    navigator?.removeRoute(this);
+  }
 }
 
 /// An item in a menu created by a [DropdownButton].
@@ -486,7 +490,7 @@ class _DropdownButtonState<T> extends State<DropdownButton<T>> with WidgetsBindi
   @override
   void dispose() {
     WidgetsBinding.instance.removeObserver(this);
-    //TODO(hansmuller) if _dropDownRoute != null Navigator.remove(context, _dropdownRoute)
+    _removeDropdownRoute();
     super.dispose();
   }
 
@@ -494,7 +498,11 @@ class _DropdownButtonState<T> extends State<DropdownButton<T>> with WidgetsBindi
   // Defined by WidgetsBindingObserver
   @override
   void didChangeMetrics() {
-    //TODO(hansmuller) if _dropDownRoute != null Navigator.remove(context, _dropdownRoute)
+    _removeDropdownRoute();
+  }
+
+  void _removeDropdownRoute() {
+    _dropdownRoute?._dismiss();
     _dropdownRoute = null;
   }
 

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

@@ -6,6 +6,7 @@ import 'dart:async';
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter/rendering.dart';
+import 'package:flutter/scheduler.dart';
 
 import 'basic.dart';
 import 'binding.dart';
@@ -231,12 +232,15 @@ class NavigatorObserver {
   NavigatorState get navigator => _navigator;
   NavigatorState _navigator;
 
-  /// The [Navigator] pushed the given route.
+  /// The [Navigator] pushed `route`.
   void didPush(Route<dynamic> route, Route<dynamic> previousRoute) { }
 
-  /// The [Navigator] popped the given route.
+  /// The [Navigator] popped `route`.
   void didPop(Route<dynamic> route, Route<dynamic> previousRoute) { }
 
+  /// The [Navigator] removed `route`.
+  void didRemove(Route<dynamic> route, Route<dynamic> previousRoute) { }
+
   /// The [Navigator] is being controlled by a user gesture.
   ///
   /// Used for the iOS back gesture.
@@ -673,6 +677,19 @@ class Navigator extends StatefulWidget {
     return Navigator.of(context).pushReplacement(route, result: result);
   }
 
+  /// Immediately remove `route` and [Route.dispose] it.
+  ///
+  /// The route's animation does not run and the future returned from pushing
+  /// the route will not complete. Ongoing input gestures are cancelled. If
+  /// the [Navigator] has any [Navigator.observers], they will be notified with
+  /// [NavigatorObserver.didRemove].
+  ///
+  /// This method is used to dismiss dropdown menus that are up when the screen's
+  /// orientation changes.
+  static void removeRoute(BuildContext context, Route<dynamic> route) {
+    return Navigator.of(context).removeRoute(route);
+  }
+
   /// The state from the closest instance of this class that encloses the given context.
   ///
   /// Typical usage is as follows:
@@ -1100,6 +1117,36 @@ class NavigatorState extends State<Navigator> with TickerProviderStateMixin {
     return true;
   }
 
+  /// Immediately remove `route` and [Route.dispose] it.
+  ///
+  /// The route's animation does not run and the future returned from pushing
+  /// the route will not complete. Ongoing input gestures are cancelled. If
+  /// the [Navigator] has any [Navigator.observers], they will be notified with
+  /// [NavigatorObserver.didRemove].
+  ///
+  /// This method is used to dismiss dropdown menus that are up when the screen's
+  /// orientation changes.
+  void removeRoute(Route<dynamic> route) {
+    assert(route != null);
+    assert(!_debugLocked);
+    assert(() { _debugLocked = true; return true; });
+    assert(route._navigator == this);
+    final int index = _history.indexOf(route);
+    assert(index != -1);
+    final Route<dynamic> previousRoute = index > 0 ? _history[index - 1] : null;
+    final Route<dynamic> nextRoute = (index + 1 < _history.length) ? _history[index + 1] : null;
+    setState(() {
+      _history.removeAt(index);
+      previousRoute?.didChangeNext(nextRoute);
+      nextRoute?.didChangePrevious(previousRoute);
+      for (NavigatorObserver observer in widget.observers)
+        observer.didRemove(route, previousRoute);
+      route.dispose();
+    });
+    assert(() { _debugLocked = false; return true; });
+    _cancelActivePointers();
+  }
+
   /// Complete the lifecycle for a route that has been popped off the navigator.
   ///
   /// When the navigator pops a route, the navigator retains a reference to the
@@ -1178,10 +1225,15 @@ class NavigatorState extends State<Navigator> with TickerProviderStateMixin {
 
   void _cancelActivePointers() {
     // TODO(abarth): This mechanism is far from perfect. See https://github.com/flutter/flutter/issues/4770
-    final RenderAbsorbPointer absorber = _overlayKey.currentContext?.ancestorRenderObjectOfType(const TypeMatcher<RenderAbsorbPointer>());
-    setState(() {
-      absorber?.absorbing = true;
-    });
+    if (SchedulerBinding.instance.schedulerPhase == SchedulerPhase.idle) {
+      // If we're between frames (SchedulerPhase.idle) then absorb any
+      // subsequent pointers from this frame. The absorbing flag will be
+      // reset in the next frame, see build().
+      final RenderAbsorbPointer absorber = _overlayKey.currentContext?.ancestorRenderObjectOfType(const TypeMatcher<RenderAbsorbPointer>());
+      setState(() {
+        absorber?.absorbing = true;
+      });
+    }
     for (int pointer in _activePointers.toList())
       WidgetsBinding.instance.cancelPointer(pointer);
   }

packages/flutter/test/material/dropdown_test.dart

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 import 'dart:math' as math;
+import 'dart:ui' show window;
 
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/material.dart';
@@ -463,4 +464,16 @@ void main() {
     expect(menuRect.bottomLeft, new Offset(800.0 - menuRect.width, 600.0));
     expect(menuRect.bottomRight, const Offset(800.0, 600.0));
   });
+
+  testWidgets('Dropdown menus are dismissed on screen orientation changes', (WidgetTester tester) async {
+    await tester.pumpWidget(buildFrame());
+    await tester.tap(find.byType(dropdownButtonType));
+    await tester.pumpAndSettle();
+    expect(find.byType(ListView), findsOneWidget);
+
+    window.onMetricsChanged();
+    await tester.pump();
+    expect(find.byType(ListView, skipOffstage: false), findsNothing);
+  });
+
 }

packages/flutter/test/widgets/navigator_test.dart

@@ -8,7 +8,7 @@ import 'package:flutter/material.dart';
 class FirstWidget extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
-  return new GestureDetector(
+    return new GestureDetector(
       onTap: () {
         Navigator.pushNamed(context, '/second');
       },
@@ -85,12 +85,12 @@ class OnTapPage extends StatelessWidget {
   }
 }
 
-typedef void OnPushed(Route<dynamic> route, Route<dynamic> previousRoute);
-typedef void OnPopped(Route<dynamic> route, Route<dynamic> previousRoute);
+typedef void OnObservation(Route<dynamic> route, Route<dynamic> previousRoute);
 
 class TestObserver extends NavigatorObserver {
-  OnPushed onPushed;
-  OnPopped onPopped;
+  OnObservation onPushed;
+  OnObservation onPopped;
+  OnObservation onRemoved;
 
   @override
   void didPush(Route<dynamic> route, Route<dynamic> previousRoute) {
@@ -105,6 +105,12 @@ class TestObserver extends NavigatorObserver {
       onPopped(route, previousRoute);
     }
   }
+
+  @override
+  void didRemove(Route<dynamic> route, Route<dynamic> previousRoute) {
+    if (onRemoved != null)
+      onRemoved(route, previousRoute);
+  }
 }
 
 void main() {
@@ -445,4 +451,120 @@ void main() {
     final String replaceNamedValue = await value; // replaceNamed result was 'B'
     expect(replaceNamedValue, 'B');
   });
+
+  testWidgets('removeRoute', (WidgetTester tester) async {
+    final Map<String, WidgetBuilder> pageBuilders = <String, WidgetBuilder>{
+       '/': (BuildContext context) => new OnTapPage(id: '/', onTap: () { Navigator.pushNamed(context, '/A'); }),
+      '/A': (BuildContext context) => new OnTapPage(id: 'A', onTap: () { Navigator.pushNamed(context, '/B'); }),
+      '/B': (BuildContext context) => const OnTapPage(id: 'B'),
+    };
+    final Map<String, Route<String>> routes = <String, Route<String>>{};
+
+    Route<String> removedRoute;
+    Route<String> previousRoute;
+
+    final TestObserver observer = new TestObserver()
+      ..onRemoved = (Route<dynamic> route, Route<dynamic> previous) {
+        removedRoute = route;
+        previousRoute = previous;
+      };
+
+    await tester.pumpWidget(new MaterialApp(
+      navigatorObservers: <NavigatorObserver>[observer],
+      onGenerateRoute: (RouteSettings settings) {
+        routes[settings.name] = new PageRouteBuilder<String>(
+          settings: settings,
+          pageBuilder: (BuildContext context, Animation<double> _, Animation<double> __) {
+            return pageBuilders[settings.name](context);
+          },
+        );
+        return routes[settings.name];
+      }
+    ));
+
+    expect(find.text('/'), findsOneWidget);
+    expect(find.text('A'), findsNothing);
+    expect(find.text('B'), findsNothing);
+
+    await tester.tap(find.text('/')); // pushNamed('/A'), stack becomes /, /A
+    await tester.pumpAndSettle();
+    expect(find.text('/'), findsNothing);
+    expect(find.text('A'), findsOneWidget);
+    expect(find.text('B'), findsNothing);
+
+    await tester.tap(find.text('A')); // pushNamed('/B'), stack becomes /, /A, /B
+    await tester.pumpAndSettle();
+    expect(find.text('/'), findsNothing);
+    expect(find.text('A'), findsNothing);
+    expect(find.text('B'), findsOneWidget);
+
+    // Verify that the navigator's stack is ordered as expected.
+    expect(routes['/'].isActive, true);
+    expect(routes['/A'].isActive, true);
+    expect(routes['/B'].isActive, true);
+    expect(routes['/'].isFirst, true);
+    expect(routes['/B'].isCurrent, true);
+
+    final NavigatorState navigator = tester.state<NavigatorState>(find.byType(Navigator));
+    navigator.removeRoute(routes['/B']); // stack becomes /, /A
+    await tester.pump();
+    expect(find.text('/'), findsNothing);
+    expect(find.text('A'), findsOneWidget);
+    expect(find.text('B'), findsNothing);
+
+    // Verify that the navigator's stack no longer includes /B
+    expect(routes['/'].isActive, true);
+    expect(routes['/A'].isActive, true);
+    expect(routes['/B'].isActive, false);
+    expect(routes['/'].isFirst, true);
+    expect(routes['/A'].isCurrent, true);
+
+    expect(removedRoute, routes['/B']);
+    expect(previousRoute, routes['/A']);
+
+    navigator.removeRoute(routes['/A']); // stack becomes just /
+    await tester.pump();
+    expect(find.text('/'), findsOneWidget);
+    expect(find.text('A'), findsNothing);
+    expect(find.text('B'), findsNothing);
+
+    // Verify that the navigator's stack no longer includes /A
+    expect(routes['/'].isActive, true);
+    expect(routes['/A'].isActive, false);
+    expect(routes['/B'].isActive, false);
+    expect(routes['/'].isFirst, true);
+    expect(routes['/'].isCurrent, true);
+    expect(removedRoute, routes['/A']);
+    expect(previousRoute, routes['/']);
+  });
+
+  testWidgets('remove a route whose value is awaited', (WidgetTester tester) async {
+    Future<String> pageValue;
+    final Map<String, WidgetBuilder> pageBuilders = <String, WidgetBuilder>{
+       '/': (BuildContext context) => new OnTapPage(id: '/', onTap: () { pageValue = Navigator.pushNamed(context, '/A'); }),
+      '/A': (BuildContext context) => new OnTapPage(id: 'A', onTap: () { Navigator.pop(context, 'A'); }),
+    };
+    final Map<String, Route<String>> routes = <String, Route<String>>{};
+
+    await tester.pumpWidget(new MaterialApp(
+      onGenerateRoute: (RouteSettings settings) {
+        routes[settings.name] = new PageRouteBuilder<String>(
+          settings: settings,
+          pageBuilder: (BuildContext context, Animation<double> _, Animation<double> __) {
+            return pageBuilders[settings.name](context);
+          },
+        );
+        return routes[settings.name];
+      }
+    ));
+
+    await tester.tap(find.text('/')); // pushNamed('/A'), stack becomes /, /A
+    await tester.pumpAndSettle();
+    pageValue.then((String value) { assert(false); });
+
+    final NavigatorState navigator = tester.state<NavigatorState>(find.byType(Navigator));
+    navigator.removeRoute(routes['/A']); // stack becomes /, pageValue will not complete
+  });
+
+
 }