Create a CupertinoPageRoute (#10686)

* started copying stuff into cupertino page route

* extracted from material page route. Ready for testing

* works with button and gesture

* tests and docs

* review notes

* review notes

packages/flutter/lib/cupertino.dart

@@ -18,3 +18,4 @@ export 'src/cupertino/scaffold.dart';
 export 'src/cupertino/slider.dart';
 export 'src/cupertino/switch.dart';
 export 'src/cupertino/thumb_painter.dart';
+export 'widgets.dart';

packages/flutter/lib/src/cupertino/page.dart

@@ -46,95 +46,150 @@ final DecorationTween _kGradientShadowTween = new DecorationTween(
   ),
 );
 
-/// A custom [Decoration] used to paint an extra shadow on the left edge of the
-/// box it's decorating. It's like a [BoxDecoration] with only a gradient except
-/// it paints to the left of the box instead of behind the box.
-class _CupertinoEdgeShadowDecoration extends Decoration {
-  const _CupertinoEdgeShadowDecoration({ this.edgeGradient });
-
-  /// A Decoration with no decorating properties.
-  static const _CupertinoEdgeShadowDecoration none =
-      const _CupertinoEdgeShadowDecoration();
+/// A modal route that replaces the entire screen with an iOS transition.
+///
+/// The page slides in from the right and exits in reverse.
+/// The page also shifts to the left in parallax when another page enters to cover it.
+///
+/// The page slides in from the bottom and exits in reverse with no parallax effect
+/// for fullscreen dialogs.
+///
+/// By default, when a modal route is replaced by another, the previous route
+/// remains in memory. To free all the resources when this is not necessary, set
+/// [maintainState] to false.
+///
+/// See also:
+///
+///  * [MaterialPageRoute] for an adaptive [PageRoute] that uses a platform appropriate transition.
+class CupertinoPageRoute<T> extends PageRoute<T> {
+  /// Creates a page route for use in an iOS designed app.
+  CupertinoPageRoute({
+    @required this.builder,
+    RouteSettings settings: const RouteSettings(),
+    this.maintainState: true,
+    bool fullscreenDialog: false,
+  }) : assert(builder != null),
+       assert(opaque),
+       super(settings: settings, fullscreenDialog: fullscreenDialog);
+
+  /// Builds the primary contents of the route.
+  final WidgetBuilder builder;
 
-  /// A gradient to draw to the left of the box being decorated.
-  /// FractionalOffsets are relative to the original box translated one box
-  /// width to the left.
-  final LinearGradient edgeGradient;
+  @override
+  final bool maintainState;
 
-  /// Linearly interpolate between two edge shadow decorations decorations.
-  ///
-  /// See also [Decoration.lerp].
-  static _CupertinoEdgeShadowDecoration lerp(
-    _CupertinoEdgeShadowDecoration a,
-    _CupertinoEdgeShadowDecoration b,
-    double t
-  ) {
-    if (a == null && b == null)
-      return null;
-    return new _CupertinoEdgeShadowDecoration(
-      edgeGradient: LinearGradient.lerp(a?.edgeGradient, b?.edgeGradient, t),
-    );
-  }
+  @override
+  Duration get transitionDuration => const Duration(milliseconds: 350);
 
   @override
-  _CupertinoEdgeShadowDecoration lerpFrom(Decoration a, double t) {
-    if (a is! _CupertinoEdgeShadowDecoration)
-      return _CupertinoEdgeShadowDecoration.lerp(null, this, t);
-    return _CupertinoEdgeShadowDecoration.lerp(a, this, t);
-  }
+  Color get barrierColor => null;
 
   @override
-  _CupertinoEdgeShadowDecoration lerpTo(Decoration b, double t) {
-    if (b is! _CupertinoEdgeShadowDecoration)
-      return _CupertinoEdgeShadowDecoration.lerp(this, null, t);
-    return _CupertinoEdgeShadowDecoration.lerp(this, b, t);
+  bool canTransitionFrom(TransitionRoute<dynamic> nextRoute) {
+    return nextRoute is CupertinoPageRoute<dynamic>;
   }
 
   @override
-  _CupertinoEdgeShadowPainter createBoxPainter([VoidCallback onChanged]) {
-    return new _CupertinoEdgeShadowPainter(this, onChanged);
+  bool canTransitionTo(TransitionRoute<dynamic> nextRoute) {
+    // Don't perform outgoing animation if the next route is a fullscreen dialog.
+    return nextRoute is CupertinoPageRoute && !nextRoute.fullscreenDialog;
   }
 
   @override
-  bool operator ==(dynamic other) {
-    if (identical(this, other))
-      return true;
-    if (other.runtimeType != _CupertinoEdgeShadowDecoration)
-      return false;
-    final _CupertinoEdgeShadowDecoration typedOther = other;
-    return edgeGradient == typedOther.edgeGradient;
+  void dispose() {
+    _backGestureController?.dispose();
+    // If the route is never installed (i.e. pushed into a Navigator) such as the
+    // case when [MaterialPageRoute] delegates transition building to [CupertinoPageRoute],
+    // don't dispose super.
+    if (overlayEntries.isNotEmpty)
+      super.dispose();
   }
 
+  CupertinoBackGestureController _backGestureController;
+
+  /// Support for dismissing this route with a horizontal swipe.
+  ///
+  /// Swiping will be disabled if the page is a fullscreen dialog or if
+  /// dismissals can be overriden because a [WillPopCallback] was
+  /// defined for the route.
+  ///
+  /// See also:
+  ///
+  ///  * [hasScopedWillPopCallback], which is true if a `willPop` callback
+  ///    is defined for this route.
   @override
-  int get hashCode {
-    return edgeGradient.hashCode;
+  NavigationGestureController startPopGesture() {
+    return startPopGestureForRoute(this);
   }
-}
 
-/// A [BoxPainter] used to draw the page transition shadow using gradients.
-class _CupertinoEdgeShadowPainter extends BoxPainter {
-  _CupertinoEdgeShadowPainter(
-    this._decoration,
-    VoidCallback onChange
-  ) : assert(_decoration != null),
-      super(onChange);
+  /// Create a CupertinoBackGestureController using a specific PageRoute.
+  ///
+  /// Used when [MaterialPageRoute] delegates the back gesture to [CupertinoPageRoute]
+  /// since the [CupertinoPageRoute] is not actually inserted into the Navigator.
+  NavigationGestureController startPopGestureForRoute(PageRoute<T> hostRoute) {
+    // If attempts to dismiss this route might be vetoed such as in a page
+    // with forms, then do not allow the user to dismiss the route with a swipe.
+    if (hostRoute.hasScopedWillPopCallback)
+      return null;
+    // Fullscreen dialogs aren't dismissable by back swipe.
+    if (fullscreenDialog)
+      return null;
+    if (hostRoute.controller.status != AnimationStatus.completed)
+      return null;
+    assert(_backGestureController == null);
+    _backGestureController = new CupertinoBackGestureController(
+      navigator: hostRoute.navigator,
+      controller: hostRoute.controller,
+    );
 
-  final _CupertinoEdgeShadowDecoration _decoration;
+    Function handleBackGestureEnded;
+    handleBackGestureEnded = (AnimationStatus status) {
+      if (status == AnimationStatus.completed) {
+        _backGestureController?.dispose();
+        _backGestureController = null;
+        hostRoute.controller.removeStatusListener(handleBackGestureEnded);
+      }
+    };
+
+    hostRoute.controller.addStatusListener(handleBackGestureEnded);
+    return _backGestureController;
+  }
 
   @override
-  void paint(Canvas canvas, Offset offset, ImageConfiguration configuration) {
-    final LinearGradient gradient = _decoration.edgeGradient;
-    if (gradient == null)
-      return;
-    // The drawable space for the gradient is a rect with the same size as
-    // its parent box one box width to the left of the box.
-    final Rect rect =
-        (offset & configuration.size).translate(-configuration.size.width, 0.0);
-    final Paint paint = new Paint()
-      ..shader = gradient.createShader(rect);
+  Widget buildPage(BuildContext context, Animation<double> animation, Animation<double> secondaryAnimation) {
+    final Widget result = builder(context);
+    assert(() {
+      if (result == null) {
+        throw new FlutterError(
+          'The builder for route "${settings.name}" returned null.\n'
+          'Route builders must never return null.'
+        );
+      }
+      return true;
+    });
+    return result;
+  }
 
-    canvas.drawRect(rect, paint);
+  @override
+  Widget buildTransitions(BuildContext context, Animation<double> animation, Animation<double> secondaryAnimation, Widget child) {
+    if (fullscreenDialog)
+      return new CupertinoFullscreenDialogTransition(
+        animation: animation,
+        child: child,
+      );
+    else
+      return new CupertinoPageTransition(
+        primaryRouteAnimation: animation,
+        secondaryRouteAnimation: secondaryAnimation,
+        child: child,
+        // In the middle of a back gesture drag, let the transition be linear to match finger
+        // motions.
+        linearTransition: _backGestureController != null,
+      );
   }
+
+  @override
+  String get debugLabel => '${super.debugLabel}(${settings.name})';
 }
 
 /// Provides an iOS-style page transition animation.
@@ -303,3 +358,94 @@ class CupertinoBackGestureController extends NavigationGestureController {
       navigator.pop();
   }
 }
+
+/// A custom [Decoration] used to paint an extra shadow on the left edge of the
+/// box it's decorating. It's like a [BoxDecoration] with only a gradient except
+/// it paints to the left of the box instead of behind the box.
+class _CupertinoEdgeShadowDecoration extends Decoration {
+  const _CupertinoEdgeShadowDecoration({ this.edgeGradient });
+
+  /// A Decoration with no decorating properties.
+  static const _CupertinoEdgeShadowDecoration none =
+      const _CupertinoEdgeShadowDecoration();
+
+  /// A gradient to draw to the left of the box being decorated.
+  /// FractionalOffsets are relative to the original box translated one box
+  /// width to the left.
+  final LinearGradient edgeGradient;
+
+  /// Linearly interpolate between two edge shadow decorations decorations.
+  ///
+  /// See also [Decoration.lerp].
+  static _CupertinoEdgeShadowDecoration lerp(
+    _CupertinoEdgeShadowDecoration a,
+    _CupertinoEdgeShadowDecoration b,
+    double t
+  ) {
+    if (a == null && b == null)
+      return null;
+    return new _CupertinoEdgeShadowDecoration(
+      edgeGradient: LinearGradient.lerp(a?.edgeGradient, b?.edgeGradient, t),
+    );
+  }
+
+  @override
+  _CupertinoEdgeShadowDecoration lerpFrom(Decoration a, double t) {
+    if (a is! _CupertinoEdgeShadowDecoration)
+      return _CupertinoEdgeShadowDecoration.lerp(null, this, t);
+    return _CupertinoEdgeShadowDecoration.lerp(a, this, t);
+  }
+
+  @override
+  _CupertinoEdgeShadowDecoration lerpTo(Decoration b, double t) {
+    if (b is! _CupertinoEdgeShadowDecoration)
+      return _CupertinoEdgeShadowDecoration.lerp(this, null, t);
+    return _CupertinoEdgeShadowDecoration.lerp(this, b, t);
+  }
+
+  @override
+  _CupertinoEdgeShadowPainter createBoxPainter([VoidCallback onChanged]) {
+    return new _CupertinoEdgeShadowPainter(this, onChanged);
+  }
+
+  @override
+  bool operator ==(dynamic other) {
+    if (identical(this, other))
+      return true;
+    if (other.runtimeType != _CupertinoEdgeShadowDecoration)
+      return false;
+    final _CupertinoEdgeShadowDecoration typedOther = other;
+    return edgeGradient == typedOther.edgeGradient;
+  }
+
+  @override
+  int get hashCode {
+    return edgeGradient.hashCode;
+  }
+}
+
+/// A [BoxPainter] used to draw the page transition shadow using gradients.
+class _CupertinoEdgeShadowPainter extends BoxPainter {
+  _CupertinoEdgeShadowPainter(
+    this._decoration,
+    VoidCallback onChange
+  ) : assert(_decoration != null),
+      super(onChange);
+
+  final _CupertinoEdgeShadowDecoration _decoration;
+
+  @override
+  void paint(Canvas canvas, Offset offset, ImageConfiguration configuration) {
+    final LinearGradient gradient = _decoration.edgeGradient;
+    if (gradient == null)
+      return;
+    // The drawable space for the gradient is a rect with the same size as
+    // its parent box one box width to the left of the box.
+    final Rect rect =
+        (offset & configuration.size).translate(-configuration.size.width, 0.0);
+    final Paint paint = new Paint()
+      ..shader = gradient.createShader(rect);
+
+    canvas.drawRect(rect, paint);
+  }
+}

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

@@ -54,25 +54,34 @@ class _MountainViewPageTransition extends StatelessWidget {
 ///
 /// Specify whether the incoming page is a fullscreen modal dialog. On iOS, those
 /// pages animate bottom->up rather than right->left.
+///
+/// See also:
+///
+///  * [CupertinoPageRoute], that this [PageRoute] delegates transition animations to for iOS.
 class MaterialPageRoute<T> extends PageRoute<T> {
   /// Creates a page route for use in a material design app.
   MaterialPageRoute({
     @required this.builder,
     RouteSettings settings: const RouteSettings(),
     this.maintainState: true,
-    this.fullscreenDialog: false,
+    bool fullscreenDialog: false,
   }) : assert(builder != null),
        assert(opaque),
-       super(settings: settings);
+       super(settings: settings, fullscreenDialog: fullscreenDialog);
 
   /// Builds the primary contents of the route.
   final WidgetBuilder builder;
 
-  /// Whether this route is a full-screen dialog.
-  ///
-  /// Prevents [startPopGesture] from poping the route using an edge swipe on
-  /// iOS.
-  final bool fullscreenDialog;
+  /// A delegate PageRoute to which iOS themed page operations are delegated to.
+  /// It's lazily created on first use.
+  CupertinoPageRoute<T> _internalCupertinoPageRoute;
+  CupertinoPageRoute<T> get _cupertinoPageRoute {
+    _internalCupertinoPageRoute ??= new CupertinoPageRoute<T>(
+      builder: builder, // Not used.
+      fullscreenDialog: fullscreenDialog,
+    );
+    return _internalCupertinoPageRoute;
+  }
 
   @override
   final bool maintainState;
@@ -85,23 +94,22 @@ class MaterialPageRoute<T> extends PageRoute<T> {
 
   @override
   bool canTransitionFrom(TransitionRoute<dynamic> nextRoute) {
-    return nextRoute is MaterialPageRoute<dynamic>;
+    return nextRoute is MaterialPageRoute<dynamic> || nextRoute is CupertinoPageRoute<dynamic>;
   }
 
   @override
   bool canTransitionTo(TransitionRoute<dynamic> nextRoute) {
     // Don't perform outgoing animation if the next route is a fullscreen dialog.
-    return nextRoute is MaterialPageRoute && !nextRoute.fullscreenDialog;
+    return (nextRoute is MaterialPageRoute && !nextRoute.fullscreenDialog)
+        || (nextRoute is CupertinoPageRoute && !nextRoute.fullscreenDialog);
   }
 
   @override
   void dispose() {
-    _backGestureController?.dispose();
+    _internalCupertinoPageRoute?.dispose();
     super.dispose();
   }
 
-  CupertinoBackGestureController _backGestureController;
-
   /// Support for dismissing this route with a horizontal swipe is enabled
   /// for [TargetPlatform.iOS]. If attempts to dismiss this route might be
   /// vetoed because a [WillPopCallback] was defined for the route then the
@@ -109,35 +117,14 @@ class MaterialPageRoute<T> extends PageRoute<T> {
   ///
   /// See also:
   ///
+  ///  * [CupertinoPageRoute] that backs the gesture for iOS.
   ///  * [hasScopedWillPopCallback], which is true if a `willPop` callback
   ///    is defined for this route.
   @override
   NavigationGestureController startPopGesture() {
-    // If attempts to dismiss this route might be vetoed, then do not
-    // allow the user to dismiss the route with a swipe.
-    if (hasScopedWillPopCallback)
-      return null;
-    // Fullscreen dialogs aren't dismissable by back swipe.
-    if (fullscreenDialog)
-      return null;
-    if (controller.status != AnimationStatus.completed)
-      return null;
-    assert(_backGestureController == null);
-    _backGestureController = new CupertinoBackGestureController(
-      navigator: navigator,
-      controller: controller,
-    );
-
-    controller.addStatusListener(_handleBackGestureEnded);
-    return _backGestureController;
-  }
-
-  void _handleBackGestureEnded(AnimationStatus status) {
-    if (status == AnimationStatus.completed) {
-      _backGestureController?.dispose();
-      _backGestureController = null;
-      controller.removeStatusListener(_handleBackGestureEnded);
-    }
+    return Theme.of(navigator.context).platform == TargetPlatform.iOS
+        ? _cupertinoPageRoute.startPopGestureForRoute(this)
+        : null;
   }
 
   @override
@@ -158,20 +145,7 @@ class MaterialPageRoute<T> extends PageRoute<T> {
   @override
   Widget buildTransitions(BuildContext context, Animation<double> animation, Animation<double> secondaryAnimation, Widget child) {
     if (Theme.of(context).platform == TargetPlatform.iOS) {
-      if (fullscreenDialog)
-        return new CupertinoFullscreenDialogTransition(
-          animation: animation,
-          child: child,
-        );
-      else
-        return new CupertinoPageTransition(
-          primaryRouteAnimation: animation,
-          secondaryRouteAnimation: secondaryAnimation,
-          child: child,
-          // In the middle of a back gesture drag, let the transition be linear to match finger
-          // motions.
-          linearTransition: _backGestureController != null,
-        );
+      return _cupertinoPageRoute.buildTransitions(context, animation, secondaryAnimation, child);
     } else {
       return new _MountainViewPageTransition(
         routeAnimation: animation,

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

@@ -13,9 +13,18 @@ import 'routes.dart';
 abstract class PageRoute<T> extends ModalRoute<T> {
   /// Creates a modal route that replaces the entire screen.
   PageRoute({
-    RouteSettings settings: const RouteSettings()
+    RouteSettings settings: const RouteSettings(),
+    this.fullscreenDialog: false,
   }) : super(settings: settings);
 
+  /// Whether this page route is a full-screen dialog.
+  ///
+  /// In Material and Cupertino, being fullscreen has the effects of making
+  /// the app bars have a close button instead of a back button. On
+  /// iOS, dialogs transitions animate differently and are also not closeable
+  /// with the back swipe gesture.
+  final bool fullscreenDialog;
+
   @override
   bool get opaque => true;
 

packages/flutter/test/cupertino/activity_indicator_test.dart

@@ -4,7 +4,6 @@
 
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/scheduler.dart';
-import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 void main() {

packages/flutter/test/cupertino/bottom_tab_bar_test.dart

@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 import 'package:flutter/cupertino.dart';
-import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 import '../services/mocks_for_image_cache.dart';

packages/flutter/test/cupertino/button_test.dart

@@ -4,7 +4,6 @@
 
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/scheduler.dart';
-import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 const TextStyle testStyle = const TextStyle(

packages/flutter/test/cupertino/nav_bar_test.dart

@@ -4,7 +4,6 @@
 
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/rendering.dart';
-import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 void main() {

packages/flutter/test/cupertino/page_test.dart

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/cupertino.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('test iOS page transition', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      new WidgetsApp(
+        color: const Color(0xFFFFFFFF),
+        onGenerateRoute: (RouteSettings settings) {
+          return new CupertinoPageRoute<Null>(
+            settings: settings,
+            builder: (BuildContext context) {
+              final String pageNumber = settings.name == '/' ? "1" : "2";
+              return new Center(child: new Text('Page $pageNumber'));
+            }
+          );
+        },
+      ),
+    );
+
+    final Offset widget1InitialTopLeft = tester.getTopLeft(find.text('Page 1'));
+
+    tester.state<NavigatorState>(find.byType(Navigator)).pushNamed('/next');
+
+    await tester.pump();
+    await tester.pump(const Duration(milliseconds: 150));
+
+    Offset widget1TransientTopLeft = tester.getTopLeft(find.text('Page 1'));
+    Offset widget2TopLeft = tester.getTopLeft(find.text('Page 2'));
+
+    // Page 1 is moving to the left.
+    expect(widget1TransientTopLeft.dx < widget1InitialTopLeft.dx, true);
+    // Page 1 isn't moving vertically.
+    expect(widget1TransientTopLeft.dy == widget1InitialTopLeft.dy, true);
+    // iOS transition is horizontal only.
+    expect(widget1InitialTopLeft.dy == widget2TopLeft.dy, true);
+    // Page 2 is coming in from the right.
+    expect(widget2TopLeft.dx > widget1InitialTopLeft.dx, true);
+
+    await tester.pumpAndSettle();
+
+    // Page 2 covers page 1.
+    expect(find.text('Page 1'), findsNothing);
+    expect(find.text('Page 2'), isOnstage);
+
+    tester.state<NavigatorState>(find.byType(Navigator)).pop();
+    await tester.pump();
+    await tester.pump(const Duration(milliseconds: 100));
+
+    widget1TransientTopLeft = tester.getTopLeft(find.text('Page 1'));
+    widget2TopLeft = tester.getTopLeft(find.text('Page 2'));
+
+    // Page 1 is coming back from the left.
+    expect(widget1TransientTopLeft.dx < widget1InitialTopLeft.dx, true);
+    // Page 1 isn't moving vertically.
+    expect(widget1TransientTopLeft.dy == widget1InitialTopLeft.dy, true);
+    // iOS transition is horizontal only.
+    expect(widget1InitialTopLeft.dy == widget2TopLeft.dy, true);
+    // Page 2 is leaving towards the right.
+    expect(widget2TopLeft.dx > widget1InitialTopLeft.dx, true);
+
+    await tester.pumpAndSettle();
+
+    expect(find.text('Page 1'), isOnstage);
+    expect(find.text('Page 2'), findsNothing);
+
+    widget1TransientTopLeft = tester.getTopLeft(find.text('Page 1'));
+
+    // Page 1 is back where it started.
+    expect(widget1InitialTopLeft == widget1TransientTopLeft, true);
+  });
+
+  testWidgets('test iOS fullscreen dialog transition', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      new WidgetsApp(
+        color: const Color(0xFFFFFFFF),
+        onGenerateRoute: (RouteSettings settings) {
+          return new CupertinoPageRoute<Null>(
+            settings: settings,
+            builder: (BuildContext context) {
+              return const Center(child: const Text('Page 1'));
+            }
+          );
+        },
+      ),
+    );
+
+    final Offset widget1InitialTopLeft = tester.getTopLeft(find.text('Page 1'));
+
+    tester.state<NavigatorState>(find.byType(Navigator)).push(new CupertinoPageRoute<Null>(
+      builder: (BuildContext context) {
+        return const Center(child: const Text('Page 2'));
+      },
+      fullscreenDialog: true,
+    ));
+
+    await tester.pump();
+    await tester.pump(const Duration(milliseconds: 100));
+
+    Offset widget1TransientTopLeft = tester.getTopLeft(find.text('Page 1'));
+    Offset widget2TopLeft = tester.getTopLeft(find.text('Page 2'));
+
+    // Page 1 doesn't move.
+    expect(widget1TransientTopLeft == widget1InitialTopLeft, true);
+    // Fullscreen dialogs transitions vertically only.
+    expect(widget1InitialTopLeft.dx == widget2TopLeft.dx, true);
+    // Page 2 is coming in from the bottom.
+    expect(widget2TopLeft.dy > widget1InitialTopLeft.dy, true);
+
+    await tester.pumpAndSettle();
+
+    // Page 2 covers page 1.
+    expect(find.text('Page 1'), findsNothing);
+    expect(find.text('Page 2'), isOnstage);
+
+    tester.state<NavigatorState>(find.byType(Navigator)).pop();
+    await tester.pump();
+    await tester.pump(const Duration(milliseconds: 100));
+
+    widget1TransientTopLeft = tester.getTopLeft(find.text('Page 1'));
+    widget2TopLeft = tester.getTopLeft(find.text('Page 2'));
+
+    // Page 1 doesn't move.
+    expect(widget1TransientTopLeft == widget1InitialTopLeft, true);
+    // Fullscreen dialogs transitions vertically only.
+    expect(widget1InitialTopLeft.dx == widget2TopLeft.dx, true);
+    // Page 2 is leaving towards the bottom.
+    expect(widget2TopLeft.dy > widget1InitialTopLeft.dy, true);
+
+    await tester.pumpAndSettle();
+
+    expect(find.text('Page 1'), isOnstage);
+    expect(find.text('Page 2'), findsNothing);
+
+    widget1TransientTopLeft = tester.getTopLeft(find.text('Page 1'));
+
+    // Page 1 is back where it started.
+    expect(widget1InitialTopLeft == widget1TransientTopLeft, true);
+  });
+}
\ No newline at end of file

packages/flutter/test/cupertino/scaffold_test.dart

@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 import 'package:flutter/cupertino.dart';
-import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 import '../rendering/rendering_tester.dart';

packages/flutter/test/cupertino/switch_test.dart

@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 import 'package:flutter/cupertino.dart';
-import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 void main() {

packages/flutter/test/material/page_test.dart

@@ -38,7 +38,7 @@ void main() {
     // Animation begins from the top of the page.
     expect(widget2TopLeft.dy < widget2Size.height, true);
 
-    await tester.pumpAndSettle();
+    await tester.pump(const Duration(milliseconds: 300));
 
     // Page 2 covers page 1.
     expect(find.text('Page 1'), findsNothing);
@@ -53,7 +53,7 @@ void main() {
     // Page 2 starts to move down.
     expect(widget1TopLeft.dy < widget2TopLeft.dy, true);
 
-    await tester.pumpAndSettle();
+    await tester.pump(const Duration(milliseconds: 300));
 
     expect(find.text('Page 1'), isOnstage);
     expect(find.text('Page 2'), findsNothing);
@@ -302,4 +302,79 @@ void main() {
     // Page 2 didn't move
     expect(tester.getTopLeft(find.text('Page 2')), Offset.zero);
   });
+
+  testWidgets('test adaptable transitions switch during execution', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      new MaterialApp(
+        theme: new ThemeData(platform: TargetPlatform.android),
+        home: const Material(child: const Text('Page 1')),
+        routes: <String, WidgetBuilder>{
+          '/next': (BuildContext context) {
+            return const Material(child: const Text('Page 2'));
+          },
+        },
+      )
+    );
+
+    final Offset widget1InitialTopLeft = tester.getTopLeft(find.text('Page 1'));
+
+    tester.state<NavigatorState>(find.byType(Navigator)).pushNamed('/next');
+    await tester.pump();
+    await tester.pump(const Duration(milliseconds: 100));
+
+    Offset widget2TopLeft = tester.getTopLeft(find.text('Page 2'));
+    final Size widget2Size = tester.getSize(find.text('Page 2'));
+
+    // Android transition is vertical only.
+    expect(widget1InitialTopLeft.dx == widget2TopLeft.dx, true);
+    // Page 1 is above page 2 mid-transition.
+    expect(widget1InitialTopLeft.dy < widget2TopLeft.dy, true);
+    // Animation begins from the top of the page.
+    expect(widget2TopLeft.dy < widget2Size.height, true);
+
+    await tester.pump(const Duration(milliseconds: 300));
+
+    // Page 2 covers page 1.
+    expect(find.text('Page 1'), findsNothing);
+    expect(find.text('Page 2'), isOnstage);
+
+    // Re-pump the same app but with iOS instead of Android.
+    await tester.pumpWidget(
+      new MaterialApp(
+        theme: new ThemeData(platform: TargetPlatform.iOS),
+        home: const Material(child: const Text('Page 1')),
+        routes: <String, WidgetBuilder>{
+          '/next': (BuildContext context) {
+            return const Material(child: const Text('Page 2'));
+          },
+        },
+      )
+    );
+
+    tester.state<NavigatorState>(find.byType(Navigator)).pop();
+    await tester.pump();
+    await tester.pump(const Duration(milliseconds: 100));
+
+    Offset widget1TransientTopLeft = tester.getTopLeft(find.text('Page 1'));
+    widget2TopLeft = tester.getTopLeft(find.text('Page 2'));
+
+    // Page 1 is coming back from the left.
+    expect(widget1TransientTopLeft.dx < widget1InitialTopLeft.dx, true);
+    // Page 1 isn't moving vertically.
+    expect(widget1TransientTopLeft.dy == widget1InitialTopLeft.dy, true);
+    // iOS transition is horizontal only.
+    expect(widget1InitialTopLeft.dy == widget2TopLeft.dy, true);
+    // Page 2 is leaving towards the right.
+    expect(widget2TopLeft.dx > widget1InitialTopLeft.dx, true);
+
+    await tester.pump(const Duration(milliseconds: 300));
+
+    expect(find.text('Page 1'), isOnstage);
+    expect(find.text('Page 2'), findsNothing);
+
+    widget1TransientTopLeft = tester.getTopLeft(find.text('Page 1'));
+
+    // Page 1 is back where it started.
+    expect(widget1InitialTopLeft == widget1TransientTopLeft, true);
+  });
 }