Revert "Added MaterialState.scrolledUnder and support in AppBar.backgroundColor (#79999)" (#80380)

This reverts commit 17870d5d7eb81bc2021454093e9115c2c0d3c850.

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

@@ -19,7 +19,6 @@ import 'icon_button.dart';
 import 'icons.dart';
 import 'material.dart';
 import 'material_localizations.dart';
-import 'material_state.dart';
 import 'scaffold.dart';
 import 'tabs.dart';
 import 'text_theme.dart';
@@ -703,28 +702,6 @@ class _AppBarState extends State<AppBar> {
   static const double _defaultElevation = 4.0;
   static const Color _defaultShadowColor = Color(0xFF000000);
 
-  ScrollNotificationObserverState? _scrollNotificationObserver;
-  bool _scrolledUnder = false;
-
-  @override
-  void didChangeDependencies() {
-    super.didChangeDependencies();
-    if (_scrollNotificationObserver != null)
-      _scrollNotificationObserver!.removeListener(_handleScrollNotification);
-    _scrollNotificationObserver = ScrollNotificationObserver.of(context);
-    if (_scrollNotificationObserver != null)
-      _scrollNotificationObserver!.addListener(_handleScrollNotification);
-  }
-
-  @override
-  void dispose() {
-    if (_scrollNotificationObserver != null) {
-      _scrollNotificationObserver!.removeListener(_handleScrollNotification);
-      _scrollNotificationObserver = null;
-    }
-    super.dispose();
-  }
-
   void _handleDrawerButton() {
     Scaffold.of(context).openDrawer();
   }
@@ -733,22 +710,6 @@ class _AppBarState extends State<AppBar> {
     Scaffold.of(context).openEndDrawer();
   }
 
-  void _handleScrollNotification(ScrollNotification notification) {
-    final bool oldScrolledUnder = _scrolledUnder;
-    _scrolledUnder = notification.depth == 0 && notification.metrics.extentBefore > 0;
-    if (_scrolledUnder != oldScrolledUnder) {
-      setState(() {
-        // React to a change in MaterialState.scrolledUnder
-      });
-    }
-  }
-
-  Color _resolveColor(Set<MaterialState> states, Color? widgetColor, Color? themeColor, Color defaultColor) {
-    return MaterialStateProperty.resolveAs<Color?>(widgetColor, states)
-        ?? MaterialStateProperty.resolveAs<Color?>(themeColor, states)
-        ?? MaterialStateProperty.resolveAs<Color>(defaultColor, states);
-  }
-
   @override
   Widget build(BuildContext context) {
     assert(!widget.primary || debugCheckHasMediaQuery(context));
@@ -759,11 +720,6 @@ class _AppBarState extends State<AppBar> {
     final ScaffoldState? scaffold = Scaffold.maybeOf(context);
     final ModalRoute<dynamic>? parentRoute = ModalRoute.of(context);
 
-    final FlexibleSpaceBarSettings? settings = context.dependOnInheritedWidgetOfExactType<FlexibleSpaceBarSettings>();
-    final Set<MaterialState> states = <MaterialState>{
-      if (settings?.isScrolledUnder ?? _scrolledUnder) MaterialState.scrolledUnder,
-    };
-
     final bool hasDrawer = scaffold?.hasDrawer ?? false;
     final bool hasEndDrawer = scaffold?.hasEndDrawer ?? false;
     final bool canPop = parentRoute?.canPop ?? false;
@@ -776,11 +732,9 @@ class _AppBarState extends State<AppBar> {
       ? widget.backgroundColor
         ?? appBarTheme.backgroundColor
         ?? theme.primaryColor
-      : _resolveColor(
+      : widget.backgroundColor
-          states,
+        ?? appBarTheme.backgroundColor
-          widget.backgroundColor,
+        ?? (colorScheme.brightness == Brightness.dark ? colorScheme.surface : colorScheme.primary);
-          appBarTheme.backgroundColor,
-          colorScheme.brightness == Brightness.dark ? colorScheme.surface : colorScheme.primary);
 
     final Color foregroundColor = widget.foregroundColor
       ?? appBarTheme.foregroundColor
@@ -1182,7 +1136,6 @@ class _SliverAppBarDelegate extends SliverPersistentHeaderDelegate {
     final double extraToolbarHeight = math.max(minExtent - _bottomHeight - topPadding - (toolbarHeight ?? kToolbarHeight), 0.0);
     final double visibleToolbarHeight = visibleMainHeight - _bottomHeight - extraToolbarHeight;
 
-    final bool isScrolledUnder = overlapsContent || (pinned && shrinkOffset > maxExtent - minExtent);
     final bool isPinnedWithOpacityFade = pinned && floating && bottom != null && extraToolbarHeight == 0.0;
     final double toolbarOpacity = !pinned || isPinnedWithOpacityFade
       ? (visibleToolbarHeight / (toolbarHeight ?? kToolbarHeight)).clamp(0.0, 1.0)
@@ -1193,7 +1146,6 @@ class _SliverAppBarDelegate extends SliverPersistentHeaderDelegate {
       maxExtent: maxExtent,
       currentExtent: math.max(minExtent, maxExtent - shrinkOffset),
       toolbarOpacity: toolbarOpacity,
-      isScrolledUnder: isScrolledUnder,
       child: AppBar(
         leading: leading,
         automaticallyImplyLeading: automaticallyImplyLeading,
@@ -1203,7 +1155,7 @@ class _SliverAppBarDelegate extends SliverPersistentHeaderDelegate {
           ? Semantics(child: flexibleSpace, header: true)
           : flexibleSpace,
         bottom: bottom,
-        elevation: forceElevated || isScrolledUnder ? elevation : 0.0,
+        elevation: forceElevated || overlapsContent || (pinned && shrinkOffset > maxExtent - minExtent) ? elevation : 0.0,
         shadowColor: shadowColor,
         backgroundColor: backgroundColor,
         foregroundColor: foregroundColor,
@@ -1562,10 +1514,6 @@ class SliverAppBar extends StatefulWidget {
   /// {@macro flutter.material.appbar.backgroundColor}
   ///
   /// This property is used to configure an [AppBar].
-  ///
-  /// If this color is a [MaterialStateColor] it will be resolved against
-  /// [MaterialState.scrolledUnder] when the content of the app's
-  /// primary scrollable overlaps the app bar.
   final Color? backgroundColor;
 
   /// {@macro flutter.material.appbar.foregroundColor}

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

@@ -210,9 +210,8 @@ class FlexibleSpaceBar extends StatefulWidget {
   /// height of the resulting [FlexibleSpaceBar] when fully expanded.
   /// `currentExtent` sets the scale of the [FlexibleSpaceBar.background] and
   /// [FlexibleSpaceBar.title] widgets of [FlexibleSpaceBar] upon
-  /// initialization. `scrolledUnder` is true if the the [FlexibleSpaceBar]
+  /// initialization.
-  /// overlaps the app's primary scrollable, false if it does not, and null
+  ///
-  /// if the caller has not determined as much.
   /// See also:
   ///
   ///  * [FlexibleSpaceBarSettings] which creates a settings object that can be
@@ -221,7 +220,6 @@ class FlexibleSpaceBar extends StatefulWidget {
     double? toolbarOpacity,
     double? minExtent,
     double? maxExtent,
-    bool? isScrolledUnder,
     required double currentExtent,
     required Widget child,
   }) {
@@ -230,7 +228,6 @@ class FlexibleSpaceBar extends StatefulWidget {
       toolbarOpacity: toolbarOpacity ?? 1.0,
       minExtent: minExtent ?? currentExtent,
       maxExtent: maxExtent ?? currentExtent,
-      isScrolledUnder: isScrolledUnder,
       currentExtent: currentExtent,
       child: child,
     );
@@ -444,7 +441,6 @@ class FlexibleSpaceBarSettings extends InheritedWidget {
     required this.maxExtent,
     required this.currentExtent,
     required Widget child,
-    this.isScrolledUnder,
   }) : assert(toolbarOpacity != null),
        assert(minExtent != null && minExtent >= 0),
        assert(maxExtent != null && maxExtent >= 0),
@@ -469,23 +465,11 @@ class FlexibleSpaceBarSettings extends InheritedWidget {
   /// these elements upon initialization.
   final double currentExtent;
 
-  /// True if the FlexibleSpaceBar overlaps the primary scrollable's contents.
-  ///
-  /// This value is used by the [AppBar] to resolve
-  /// [AppBar.backgroundColor] against [MaterialState.scrolledUnder],
-  /// i.e.  to enable apps to specify different colors when content
-  /// has been scrolled up and behind the app bar.
-  ///
-  /// Null if the caller hasn't determined if the FlexibleSpaceBar
-  /// overlaps the primary scrollable's contents.
-  final bool? isScrolledUnder;
-
   @override
   bool updateShouldNotify(FlexibleSpaceBarSettings oldWidget) {
     return toolbarOpacity != oldWidget.toolbarOpacity
         || minExtent != oldWidget.minExtent
         || maxExtent != oldWidget.maxExtent
-        || currentExtent != oldWidget.currentExtent
+        || currentExtent != oldWidget.currentExtent;
-        || isScrolledUnder != oldWidget.isScrolledUnder;
   }
 }

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

@@ -63,13 +63,7 @@ enum MaterialState {
   /// See: https://material.io/design/interaction/states.html#selected.
   selected,
 
-  /// The state when this widget overlaps the content of a scrollable below.
+  /// The state when this widget disabled and can not be interacted with.
-  ///
-  /// Used by [AppBar] to indicate that the primary scrollable's
-  /// content has scrolled up and behind the app bar.
-  scrolledUnder,
-
-  /// The state when this widget is disabled and cannot be interacted with.
   ///
   /// Disabled widgets should not respond to hover, focus, press, or drag
   /// interactions.

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

@@ -3238,7 +3238,6 @@ class ScaffoldState extends State<Scaffold> with TickerProviderStateMixin, Resto
     return _ScaffoldScope(
       hasDrawer: hasDrawer,
       geometryNotifier: _geometryNotifier,
-      child: ScrollNotificationObserver(
       child: Material(
         color: widget.backgroundColor ?? themeData.scaffoldBackgroundColor,
         child: AnimatedBuilder(animation: _floatingActionButtonMoveController, builder: (BuildContext context, Widget? child) {
@@ -3261,7 +3260,6 @@ class ScaffoldState extends State<Scaffold> with TickerProviderStateMixin, Resto
           );
         }),
       ),
-      ),
     );
   }
 }

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

@@ -1,174 +0,0 @@
-// Copyright 2014 The Flutter 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 'dart:collection';
-
-import 'package:flutter/foundation.dart';
-
-import 'framework.dart';
-import 'notification_listener.dart';
-import 'scroll_notification.dart';
-
-/// A [ScrollNotification] listener for [ScrollNotificationObserver].
-///
-/// [ScrollNotificationObserver] is similar to
-/// [NotificationListener]. It supports a listener list instead of
-/// just a single listener and its listeners run unconditionally, they
-/// do not require a gating boolean return value.
-typedef ScrollNotificationCallback = void Function(ScrollNotification notification);
-
-class _ScrollNotificationObserverScope extends InheritedWidget {
-  const _ScrollNotificationObserverScope({
-    Key? key,
-    required Widget child,
-    required ScrollNotificationObserverState scrollNotificationObserverState,
-  }) : _scrollNotificationObserverState = scrollNotificationObserverState,
-      super(key: key, child: child);
-
-  final ScrollNotificationObserverState  _scrollNotificationObserverState;
-
-  @override
-  bool updateShouldNotify(_ScrollNotificationObserverScope old) => _scrollNotificationObserverState != old._scrollNotificationObserverState;
-}
-
-class _ListenerEntry extends LinkedListEntry<_ListenerEntry> {
-  _ListenerEntry(this.listener);
-  final ScrollNotificationCallback listener;
-}
-
-/// Notifies its listeners when a descendant scrolls.
-///
-/// To add a listener to a [ScrollNotificationObserver] ancestor:
-/// ```dart
-/// void listener(ScrollNotification notification) {
-///   // Do something, maybe setState()
-/// }
-/// ScrollNotificationObserver.of(context).addListener(listener)
-/// ```
-///
-/// To remove the listener from a [ScrollNotificationObserver] ancestor:
-/// ```dart
-/// ScrollNotificationObserver.of(context).removeListener(listener);
-///```
-///
-/// Stateful widgets that share an ancestor [ScrollNotificationObserver] typically
-/// add a listener in [State.didChangeDependencies] (removing the old one
-/// if necessary) and remove the listener in their [State.dispose] method.
-///
-/// This widget is similar to [NotificationListener]. It supports
-/// a listener list instead of just a single listener and its listeners
-/// run unconditionally, they do not require a gating boolean return value.
-class ScrollNotificationObserver extends StatefulWidget {
-  /// Create a [ScrollNotificationObserver].
-  ///
-  /// The [child] parameter must not be null.
-  const ScrollNotificationObserver({
-    Key? key,
-    required this.child,
-  }) : assert(child != null), super(key: key);
-
-  /// The subtree below this widget.
-  final Widget child;
-
-  /// The closest instance of this class that encloses the given context.
-  ///
-  /// If there is no enclosing [ScrollNotificationObserver] widget, then null is returned.
-  static ScrollNotificationObserverState? of(BuildContext context) {
-    return context.dependOnInheritedWidgetOfExactType<_ScrollNotificationObserverScope>()?._scrollNotificationObserverState;
-  }
-
-  @override
-  ScrollNotificationObserverState createState() => ScrollNotificationObserverState();
-}
-
-/// The listener list state for a [ScrollNotificationObserver] returned by
-/// [ScrollNotificationObserver.of].
-///
-/// [ScrollNotificationObserver] is similar to
-/// [NotificationListener]. It supports a listener list instead of
-/// just a single listener and its listeners run unconditionally, they
-/// do not require a gating boolean return value.
-class ScrollNotificationObserverState extends State<ScrollNotificationObserver> {
-  LinkedList<_ListenerEntry>? _listeners = LinkedList<_ListenerEntry>();
-
-  bool _debugAssertNotDisposed() {
-    assert(() {
-      if (_listeners == null) {
-        throw FlutterError(
-          'A $runtimeType was used after being disposed.\n'
-          'Once you have called dispose() on a $runtimeType, it can no longer be used.',
-        );
-      }
-      return true;
-    }());
-    return true;
-  }
-
-  /// Add a [ScrollNotificationCallback] that will be called each time
-  /// a descendant scrolls.
-  void addListener(ScrollNotificationCallback listener) {
-    assert(_debugAssertNotDisposed());
-    _listeners!.add(_ListenerEntry(listener));
-  }
-
-  /// Remove the specified [ScrollNotificationCallback].
-  void removeListener(ScrollNotificationCallback listener) {
-    assert(_debugAssertNotDisposed());
-    for (final _ListenerEntry entry in _listeners!) {
-      if (entry.listener == listener) {
-        entry.unlink();
-        return;
-      }
-    }
-  }
-
-  void _notifyListeners(ScrollNotification notification) {
-    assert(_debugAssertNotDisposed());
-    if (_listeners!.isEmpty)
-      return;
-
-    final List<_ListenerEntry> localListeners = List<_ListenerEntry>.from(_listeners!);
-    for (final _ListenerEntry entry in localListeners) {
-      try {
-        if (entry.list != null)
-          entry.listener(notification);
-      } catch (exception, stack) {
-        FlutterError.reportError(FlutterErrorDetails(
-          exception: exception,
-          stack: stack,
-          library: 'widget library',
-          context: ErrorDescription('while dispatching notifications for $runtimeType'),
-          informationCollector: () sync* {
-            yield DiagnosticsProperty<ScrollNotificationObserverState>(
-              'The $runtimeType sending notification was',
-              this,
-              style: DiagnosticsTreeStyle.errorProperty,
-            );
-          },
-        ));
-      }
-    }
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    return NotificationListener<ScrollNotification>(
-      onNotification: (ScrollNotification notification) {
-        _notifyListeners(notification);
-        return false;
-      },
-      child: _ScrollNotificationObserverScope(
-        scrollNotificationObserverState: this,
-        child: widget.child,
-      ),
-    );
-  }
-
-  @override
-  void dispose() {
-    assert(_debugAssertNotDisposed());
-    _listeners = null;
-    super.dispose();
-  }
-}

packages/flutter/lib/widgets.dart

@@ -98,7 +98,6 @@ export 'src/widgets/scroll_context.dart';
 export 'src/widgets/scroll_controller.dart';
 export 'src/widgets/scroll_metrics.dart';
 export 'src/widgets/scroll_notification.dart';
-export 'src/widgets/scroll_notification_observer.dart';
 export 'src/widgets/scroll_physics.dart';
 export 'src/widgets/scroll_position.dart';
 export 'src/widgets/scroll_position_with_single_context.dart';

packages/flutter/test/material/app_bar_test.dart

@@ -2518,239 +2518,4 @@ void main() {
     expect(actionIconTheme.color, foregroundColor);
   });
 
-  testWidgets('SliverAppBar.backgroundColor MaterialStateColor scrolledUnder', (WidgetTester tester) async {
-    const double collapsedHeight = kToolbarHeight;
-    const double expandedHeight = 200.0;
-    const Color scrolledColor = Color(0xff00ff00);
-    const Color defaultColor = Color(0xff0000ff);
-
-    await tester.pumpWidget(
-      MaterialApp(
-        home: Scaffold(
-          body: CustomScrollView(
-            slivers: <Widget>[
-              SliverAppBar(
-                backwardsCompatibility: false,
-                elevation: 0,
-                backgroundColor: MaterialStateColor.resolveWith((Set<MaterialState> states) {
-                  return states.contains(MaterialState.scrolledUnder) ? scrolledColor : defaultColor;
-                }),
-                expandedHeight: expandedHeight,
-                pinned: true,
-              ),
-              SliverList(
-                delegate: SliverChildListDelegate(
-                    <Widget>[
-                      Container(height: 1200.0, color: Colors.teal),
-                    ],
-                ),
-              ),
-            ],
-          ),
-        ),
-      ),
-    );
-
-    Finder findAppBarMaterial() {
-      return find.descendant(of: find.byType(AppBar), matching: find.byType(Material));
-    }
-
-    Color? getAppBarBackgroundColor() {
-      return tester.widget<Material>(findAppBarMaterial()).color;
-    }
-
-    expect(getAppBarBackgroundColor(), defaultColor);
-    expect(tester.getSize(findAppBarMaterial()).height, expandedHeight);
-
-    TestGesture gesture = await tester.startGesture(const Offset(50.0, 400.0));
-    await gesture.moveBy(const Offset(0.0, -expandedHeight));
-    await gesture.up();
-    await tester.pumpAndSettle();
-
-    expect(getAppBarBackgroundColor(), scrolledColor);
-    expect(tester.getSize(findAppBarMaterial()).height, collapsedHeight);
-
-    gesture = await tester.startGesture(const Offset(50.0, 300.0));
-    await gesture.moveBy(const Offset(0.0, expandedHeight));
-    await gesture.up();
-    await tester.pumpAndSettle();
-
-    expect(getAppBarBackgroundColor(), defaultColor);
-    expect(tester.getSize(findAppBarMaterial()).height, expandedHeight);
-  });
-
-  testWidgets('SliverAppBar.backgroundColor with FlexibleSpace MaterialStateColor scrolledUnder', (WidgetTester tester) async {
-    const double collapsedHeight = kToolbarHeight;
-    const double expandedHeight = 200.0;
-    const Color scrolledColor = Color(0xff00ff00);
-    const Color defaultColor = Color(0xff0000ff);
-
-    await tester.pumpWidget(
-      MaterialApp(
-        home: Scaffold(
-          body: CustomScrollView(
-            slivers: <Widget>[
-              SliverAppBar(
-                backwardsCompatibility: false,
-                elevation: 0,
-                backgroundColor: MaterialStateColor.resolveWith((Set<MaterialState> states) {
-                  return states.contains(MaterialState.scrolledUnder) ? scrolledColor : defaultColor;
-                }),
-                expandedHeight: expandedHeight,
-                pinned: true,
-                flexibleSpace: const FlexibleSpaceBar(
-                  title: Text('SliverAppBar'),
-                ),
-              ),
-              SliverList(
-                delegate: SliverChildListDelegate(
-                    <Widget>[
-                      Container(height: 1200.0, color: Colors.teal),
-                    ],
-                ),
-              ),
-            ],
-          ),
-        ),
-      ),
-    );
-
-    Finder findAppBarMaterial() {
-      // There are 2 Material widgets below AppBar. The second is only added if
-      // flexibleSpace is non-null.
-      return find.descendant(of: find.byType(AppBar), matching: find.byType(Material)).first;
-    }
-
-    Color? getAppBarBackgroundColor() {
-      return tester.widget<Material>(findAppBarMaterial()).color;
-    }
-
-    expect(getAppBarBackgroundColor(), defaultColor);
-    expect(tester.getSize(findAppBarMaterial()).height, expandedHeight);
-
-    TestGesture gesture = await tester.startGesture(const Offset(50.0, 400.0));
-    await gesture.moveBy(const Offset(0.0, -expandedHeight));
-    await gesture.up();
-    await tester.pumpAndSettle();
-
-    expect(getAppBarBackgroundColor(), scrolledColor);
-    expect(tester.getSize(findAppBarMaterial()).height, collapsedHeight);
-
-    gesture = await tester.startGesture(const Offset(50.0, 300.0));
-    await gesture.moveBy(const Offset(0.0, expandedHeight));
-    await gesture.up();
-    await tester.pumpAndSettle();
-
-    expect(getAppBarBackgroundColor(), defaultColor);
-    expect(tester.getSize(findAppBarMaterial()).height, expandedHeight);
-  });
-
-  testWidgets('AppBar.backgroundColor MaterialStateColor scrolledUnder', (WidgetTester tester) async {
-    const Color scrolledColor = Color(0xff00ff00);
-    const Color defaultColor = Color(0xff0000ff);
-
-    await tester.pumpWidget(
-      MaterialApp(
-        home: Scaffold(
-          appBar: AppBar(
-            backwardsCompatibility: false,
-            elevation: 0,
-            backgroundColor: MaterialStateColor.resolveWith((Set<MaterialState> states) {
-              return states.contains(MaterialState.scrolledUnder) ? scrolledColor : defaultColor;
-            }),
-            title: const Text('AppBar'),
-          ),
-          body: ListView(
-            children: <Widget>[
-              Container(height: 1200.0, color: Colors.teal),
-            ],
-          ),
-        ),
-      ),
-    );
-
-    Finder findAppBarMaterial() {
-      return find.descendant(of: find.byType(AppBar), matching: find.byType(Material));
-    }
-
-    Color? getAppBarBackgroundColor() {
-      return tester.widget<Material>(findAppBarMaterial()).color;
-    }
-
-    expect(getAppBarBackgroundColor(), defaultColor);
-    expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);
-
-    TestGesture gesture = await tester.startGesture(const Offset(50.0, 400.0));
-    await gesture.moveBy(const Offset(0.0, -kToolbarHeight));
-    await gesture.up();
-    await tester.pumpAndSettle();
-
-    expect(getAppBarBackgroundColor(), scrolledColor);
-    expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);
-
-    gesture = await tester.startGesture(const Offset(50.0, 300.0));
-    await gesture.moveBy(const Offset(0.0, kToolbarHeight));
-    await gesture.up();
-    await tester.pumpAndSettle();
-
-    expect(getAppBarBackgroundColor(), defaultColor);
-    expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);
-  });
-
-  testWidgets('AppBar.backgroundColor with FlexibleSpace MaterialStateColor scrolledUnder', (WidgetTester tester) async {
-    const Color scrolledColor = Color(0xff00ff00);
-    const Color defaultColor = Color(0xff0000ff);
-
-    await tester.pumpWidget(
-      MaterialApp(
-        home: Scaffold(
-          appBar: AppBar(
-            backwardsCompatibility: false,
-            elevation: 0,
-            backgroundColor: MaterialStateColor.resolveWith((Set<MaterialState> states) {
-              return states.contains(MaterialState.scrolledUnder) ? scrolledColor : defaultColor;
-            }),
-            title: const Text('AppBar'),
-            flexibleSpace: const FlexibleSpaceBar(
-              title: Text('FlexibleSpace'),
-            ),
-          ),
-          body: ListView(
-            children: <Widget>[
-              Container(height: 1200.0, color: Colors.teal),
-            ],
-          ),
-        ),
-      ),
-    );
-
-    Finder findAppBarMaterial() {
-      // There are 2 Material widgets below AppBar. The second is only added if
-      // flexibleSpace is non-null.
-      return find.descendant(of: find.byType(AppBar), matching: find.byType(Material)).first;
-    }
-
-    Color? getAppBarBackgroundColor() {
-      return tester.widget<Material>(findAppBarMaterial()).color;
-    }
-
-    expect(getAppBarBackgroundColor(), defaultColor);
-    expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);
-
-    TestGesture gesture = await tester.startGesture(const Offset(50.0, 400.0));
-    await gesture.moveBy(const Offset(0.0, -kToolbarHeight));
-    await gesture.up();
-    await tester.pumpAndSettle();
-
-    expect(getAppBarBackgroundColor(), scrolledColor);
-    expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);
-
-    gesture = await tester.startGesture(const Offset(50.0, 300.0));
-    await gesture.moveBy(const Offset(0.0, kToolbarHeight));
-    await gesture.up();
-    await tester.pumpAndSettle();
-
-    expect(getAppBarBackgroundColor(), defaultColor);
-    expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);
-  });
 }

packages/flutter/test/material/scaffold_test.dart

@@ -2190,9 +2190,6 @@ void main() {
       '     PhysicalModel\n'
       '     AnimatedPhysicalModel\n'
       '     Material\n'
-      '     _ScrollNotificationObserverScope\n'
-      '     NotificationListener<ScrollNotification>\n'
-      '     ScrollNotificationObserver\n'
       '     _ScaffoldScope\n'
       '     Scaffold\n'
       '     MediaQuery\n'

packages/flutter/test/widgets/scroll_notification_test.dart

@@ -150,69 +150,4 @@ void main() {
     expect(notificationTypes, equals(types));
   });
 
-  testWidgets('ScrollNotificationObserver', (WidgetTester tester) async {
-    late ScrollNotificationObserverState observer;
-    ScrollNotification? notification;
-
-    void handleNotification(ScrollNotification value) {
-      if (value is ScrollStartNotification || value is ScrollUpdateNotification || value is ScrollEndNotification)
-        notification = value;
-    }
-
-    await tester.pumpWidget(
-      ScrollNotificationObserver(
-        child: Builder(
-          builder: (BuildContext context) {
-            observer = ScrollNotificationObserver.of(context)!;
-            return const SingleChildScrollView(
-              child: SizedBox(height: 1200.0),
-            );
-          },
-        ),
-      ),
-    );
-
-    observer.addListener(handleNotification);
-
-    TestGesture gesture = await tester.startGesture(const Offset(100.0, 100.0));
-    await tester.pumpAndSettle();
-    expect(notification, isA<ScrollStartNotification>());
-    expect(notification!.depth, equals(0));
-
-    final ScrollStartNotification start = notification! as ScrollStartNotification;
-    expect(start.dragDetails, isNotNull);
-    expect(start.dragDetails!.globalPosition, equals(const Offset(100.0, 100.0)));
-
-    await gesture.moveBy(const Offset(-10.0, -10.0));
-    await tester.pumpAndSettle();
-    expect(notification, isA<ScrollUpdateNotification>());
-    expect(notification!.depth, equals(0));
-    final ScrollUpdateNotification update = notification! as ScrollUpdateNotification;
-    expect(update.dragDetails, isNotNull);
-    expect(update.dragDetails!.globalPosition, equals(const Offset(90.0, 90.0)));
-    expect(update.dragDetails!.delta, equals(const Offset(0.0, -10.0)));
-
-    await gesture.up();
-    await tester.pumpAndSettle();
-    expect(notification, isA<ScrollEndNotification>());
-    expect(notification!.depth, equals(0));
-    final ScrollEndNotification end = notification! as ScrollEndNotification;
-    expect(end.dragDetails, isNotNull);
-    expect(end.dragDetails!.velocity, equals(Velocity.zero));
-
-    observer.removeListener(handleNotification);
-    notification = null;
-
-    gesture = await tester.startGesture(const Offset(100.0, 100.0));
-    await tester.pumpAndSettle();
-    expect(notification, isNull);
-
-    await gesture.moveBy(const Offset(-10.0, -10.0));
-    await tester.pumpAndSettle();
-    expect(notification, isNull);
-
-    await gesture.up();
-    await tester.pumpAndSettle();
-    expect(notification, isNull);
-  });
 }