Add theme support for choosing android overscroll indicator (#88295)

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

@@ -696,6 +696,11 @@ class MaterialApp extends StatefulWidget {
 /// When using the desktop platform, if the [Scrollable] widget scrolls in the
 /// [Axis.vertical], a [Scrollbar] is applied.
 ///
+/// [MaterialScrollBehavior.androidOverscrollIndicator] specifies the
+/// overscroll indicator that is used on [TargetPlatform.android]. When null,
+/// [ThemeData.androidOverscrollIndicator] is used. If also null, the default
+/// overscroll indicator is the [GlowingOverscrollIndicator].
+///
 /// See also:
 ///
 ///  * [ScrollBehavior], the default scrolling behavior extended by this class.
@@ -703,9 +708,17 @@ class MaterialScrollBehavior extends ScrollBehavior {
   /// Creates a MaterialScrollBehavior that decorates [Scrollable]s with
   /// [GlowingOverscrollIndicator]s and [Scrollbar]s based on the current
   /// platform and provided [ScrollableDetails].
+  ///
+  /// [MaterialScrollBehavior.androidOverscrollIndicator] specifies the
+  /// overscroll indicator that is used on [TargetPlatform.android]. When null,
+  /// [ThemeData.androidOverscrollIndicator] is used. If also null, the default
+  /// overscroll indicator is the [GlowingOverscrollIndicator].
   const MaterialScrollBehavior({
     AndroidOverscrollIndicator? androidOverscrollIndicator,
-  }) : super(androidOverscrollIndicator: androidOverscrollIndicator);
+  }) : _androidOverscrollIndicator = androidOverscrollIndicator,
+       super(androidOverscrollIndicator: androidOverscrollIndicator);
+
+  final AndroidOverscrollIndicator? _androidOverscrollIndicator;
 
   @override
   TargetPlatform getPlatform(BuildContext context) => Theme.of(context).platform;
@@ -738,6 +751,9 @@ class MaterialScrollBehavior extends ScrollBehavior {
   Widget buildOverscrollIndicator(BuildContext context, Widget child, ScrollableDetails details) {
     // When modifying this function, consider modifying the implementation in
     // the base class as well.
+    final AndroidOverscrollIndicator indicator = _androidOverscrollIndicator
+        ?? Theme.of(context).androidOverscrollIndicator
+        ?? androidOverscrollIndicator;
     switch (getPlatform(context)) {
       case TargetPlatform.iOS:
       case TargetPlatform.linux:
@@ -745,7 +761,7 @@ class MaterialScrollBehavior extends ScrollBehavior {
       case TargetPlatform.windows:
         return child;
       case TargetPlatform.android:
-        switch (androidOverscrollIndicator) {
+        switch (indicator) {
           case AndroidOverscrollIndicator.stretch:
             return StretchingOverscrollIndicator(
               axisDirection: details.direction,

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

@@ -346,6 +346,7 @@ class ThemeData with Diagnosticable {
       'This feature was deprecated after v1.23.0-4.0.pre.',
     )
     bool? useTextSelectionTheme,
+    AndroidOverscrollIndicator? androidOverscrollIndicator,
   }) {
     assert(colorScheme?.brightness == null || brightness == null || colorScheme!.brightness == brightness);
     final Brightness _brightness = brightness ?? colorScheme?.brightness ?? Brightness.light;
@@ -561,6 +562,7 @@ class ThemeData with Diagnosticable {
       progressIndicatorTheme: progressIndicatorTheme,
       fixTextFieldOutlineLabel: fixTextFieldOutlineLabel,
       useTextSelectionTheme: useTextSelectionTheme,
+      androidOverscrollIndicator: androidOverscrollIndicator,
     );
   }
 
@@ -701,6 +703,7 @@ class ThemeData with Diagnosticable {
       'This feature was deprecated after v1.23.0-4.0.pre.',
     )
     required this.useTextSelectionTheme,
+    required this.androidOverscrollIndicator,
   }) : assert(visualDensity != null),
        assert(primaryColor != null),
        assert(primaryColorBrightness != null),
@@ -1358,6 +1361,20 @@ class ThemeData with Diagnosticable {
   )
   final bool useTextSelectionTheme;
 
+  /// Specifies which overscroll indicator to use on [TargetPlatform.android].
+  ///
+  /// When null, the default value of
+  /// [MaterialScrollBehavior.androidOverscrollIndicator] is
+  /// [AndroidOverscrollIndicator.glow].
+  ///
+  /// See also:
+  ///
+  ///   * [StretchingOverscrollIndicator], a material design edge effect
+  ///     that transforms the contents of a scrollable when overscrolled.
+  ///   * [GlowingOverscrollIndicator], an edge effect that paints a glow
+  ///     over the contents of a scrollable when overscrolled.
+  final AndroidOverscrollIndicator? androidOverscrollIndicator;
+
   /// Creates a copy of this theme but with the given fields replaced with the new values.
   ///
   /// The [brightness] value is applied to the [colorScheme].
@@ -1489,6 +1506,7 @@ class ThemeData with Diagnosticable {
       'This feature was deprecated after v1.23.0-4.0.pre.',
     )
     bool? useTextSelectionTheme,
+    AndroidOverscrollIndicator? androidOverscrollIndicator,
   }) {
     cupertinoOverrideTheme = cupertinoOverrideTheme?.noDefault();
     return ThemeData.raw(
@@ -1570,6 +1588,7 @@ class ThemeData with Diagnosticable {
       progressIndicatorTheme: progressIndicatorTheme ?? this.progressIndicatorTheme,
       fixTextFieldOutlineLabel: fixTextFieldOutlineLabel ?? this.fixTextFieldOutlineLabel,
       useTextSelectionTheme: useTextSelectionTheme ?? this.useTextSelectionTheme,
+      androidOverscrollIndicator: androidOverscrollIndicator ?? this.androidOverscrollIndicator,
     );
   }
 
@@ -1729,6 +1748,7 @@ class ThemeData with Diagnosticable {
       progressIndicatorTheme: ProgressIndicatorThemeData.lerp(a.progressIndicatorTheme, b.progressIndicatorTheme, t)!,
       fixTextFieldOutlineLabel: t < 0.5 ? a.fixTextFieldOutlineLabel : b.fixTextFieldOutlineLabel,
       useTextSelectionTheme: t < 0.5 ? a.useTextSelectionTheme : b.useTextSelectionTheme,
+      androidOverscrollIndicator: t < 0.5 ? a.androidOverscrollIndicator : b.androidOverscrollIndicator,
     );
   }
 
@@ -1815,7 +1835,8 @@ class ThemeData with Diagnosticable {
         && other.switchTheme == switchTheme
         && other.progressIndicatorTheme == progressIndicatorTheme
         && other.fixTextFieldOutlineLabel == fixTextFieldOutlineLabel
-        && other.useTextSelectionTheme == useTextSelectionTheme;
+        && other.useTextSelectionTheme == useTextSelectionTheme
+        && other.androidOverscrollIndicator == androidOverscrollIndicator;
   }
 
   @override
@@ -1902,6 +1923,7 @@ class ThemeData with Diagnosticable {
       progressIndicatorTheme,
       fixTextFieldOutlineLabel,
       useTextSelectionTheme,
+      androidOverscrollIndicator,
     ];
     return hashList(values);
   }
@@ -1984,6 +2006,7 @@ class ThemeData with Diagnosticable {
     properties.add(DiagnosticsProperty<RadioThemeData>('radioTheme', radioTheme, defaultValue: defaultData.radioTheme, level: DiagnosticLevel.debug));
     properties.add(DiagnosticsProperty<SwitchThemeData>('switchTheme', switchTheme, defaultValue: defaultData.switchTheme, level: DiagnosticLevel.debug));
     properties.add(DiagnosticsProperty<ProgressIndicatorThemeData>('progressIndicatorTheme', progressIndicatorTheme, defaultValue: defaultData.progressIndicatorTheme, level: DiagnosticLevel.debug));
+    properties.add(EnumProperty<AndroidOverscrollIndicator>('androidOverscrollIndicator', androidOverscrollIndicator, defaultValue: null, level: DiagnosticLevel.debug));
   }
 }
 

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

@@ -65,7 +65,14 @@ class ScrollBehavior {
     AndroidOverscrollIndicator? androidOverscrollIndicator,
   }): _androidOverscrollIndicator = androidOverscrollIndicator;
 
-  /// Specifies which overscroll indicatpr to use on [TargetPlatform.android].
+  /// Specifies which overscroll indicator to use on [TargetPlatform.android].
+  ///
+  /// Cannot be null. Defaults to [AndroidOverscrollIndicator.glow].
+  ///
+  /// See also:
+  ///
+  ///   * [MaterialScrollBehavior], which supports setting this property
+  ///     using [ThemeData].
   AndroidOverscrollIndicator get androidOverscrollIndicator => _androidOverscrollIndicator ?? _kDefaultAndroidOverscrollIndicator;
   final AndroidOverscrollIndicator? _androidOverscrollIndicator;
 

packages/flutter/test/material/app_test.dart

@@ -1106,6 +1106,45 @@ void main() {
     expect(find.byType(GlowingOverscrollIndicator), findsNothing);
   }, variant: TargetPlatformVariant.only(TargetPlatform.android));
 
+  testWidgets('Overscroll indicator can be set by theme', (WidgetTester tester) async {
+    await tester.pumpWidget(MaterialApp(
+      // The current default is glowing, setting via the theme should override.
+      theme: ThemeData().copyWith(androidOverscrollIndicator: AndroidOverscrollIndicator.stretch),
+      home: ListView(
+        children: const <Widget>[
+          SizedBox(
+            height: 1000.0,
+            width: 1000.0,
+            child: Text('Test'),
+          )
+        ]
+      )
+    ));
+
+    expect(find.byType(StretchingOverscrollIndicator), findsOneWidget);
+    expect(find.byType(GlowingOverscrollIndicator), findsNothing);
+  }, variant: TargetPlatformVariant.only(TargetPlatform.android));
+
+  testWidgets('Overscroll indicator in MaterialScrollBehavior takes precedence over theme', (WidgetTester tester) async {
+    await tester.pumpWidget(MaterialApp(
+      // MaterialScrollBehavior.androidOverscrollIndicator takes precedence over theme.
+      scrollBehavior: const MaterialScrollBehavior(androidOverscrollIndicator: AndroidOverscrollIndicator.stretch),
+      theme: ThemeData().copyWith(androidOverscrollIndicator: AndroidOverscrollIndicator.glow),
+      home: ListView(
+        children: const <Widget>[
+          SizedBox(
+            height: 1000.0,
+            width: 1000.0,
+            child: Text('Test'),
+          )
+        ]
+      )
+    ));
+
+    expect(find.byType(StretchingOverscrollIndicator), findsOneWidget);
+    expect(find.byType(GlowingOverscrollIndicator), findsNothing);
+  }, variant: TargetPlatformVariant.only(TargetPlatform.android));
+
   testWidgets('When `useInheritedMediaQuery` is true an existing MediaQuery is used if one is available', (WidgetTester tester) async {
     late BuildContext capturedContext;
     final UniqueKey uniqueKey = UniqueKey();

packages/flutter/test/material/theme_data_test.dart

@@ -346,6 +346,7 @@ void main() {
       progressIndicatorTheme: const ProgressIndicatorThemeData(),
       fixTextFieldOutlineLabel: false,
       useTextSelectionTheme: false,
+      androidOverscrollIndicator: null,
     );
 
     final SliderThemeData otherSliderTheme = SliderThemeData.fromPrimaryColors(
@@ -440,6 +441,7 @@ void main() {
       progressIndicatorTheme: const ProgressIndicatorThemeData(),
       fixTextFieldOutlineLabel: true,
       useTextSelectionTheme: true,
+      androidOverscrollIndicator: AndroidOverscrollIndicator.stretch,
     );
 
     final ThemeData themeDataCopy = theme.copyWith(