Fixed the color curve issue (#115188)

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

@@ -620,9 +620,15 @@ class _MaterialSwitchState extends State<_MaterialSwitch> with TickerProviderSta
       // During a drag we may have modified the curve, reset it if its possible
       // to do without visual discontinuation.
       if (position.value == 0.0 || position.value == 1.0) {
-        position
+        if (Theme.of(context).useMaterial3) {
-          ..curve = Curves.easeIn
+          position
-          ..reverseCurve = Curves.easeOut;
+            ..curve = Curves.easeOutBack
+            ..reverseCurve = Curves.easeOutBack.flipped;
+        } else {
+          position
+            ..curve = Curves.easeIn
+            ..reverseCurve = Curves.easeOut;
+        }
       }
       animateToValue();
     }
@@ -693,7 +699,7 @@ class _MaterialSwitchState extends State<_MaterialSwitch> with TickerProviderSta
 
   void _handleDragEnd(DragEndDetails details) {
     if (position.value >= 0.5 != widget.value) {
-      widget.onChanged!(!widget.value);
+      widget.onChanged?.call(!widget.value);
       // Wait with finishing the animation until widget.value has changed to
       // !widget.value as part of the widget.onChanged call above.
       setState(() {
@@ -709,7 +715,7 @@ class _MaterialSwitchState extends State<_MaterialSwitch> with TickerProviderSta
   void _handleChanged(bool? value) {
     assert(value != null);
     assert(widget.onChanged != null);
-    widget.onChanged!(value!);
+    widget.onChanged?.call(value!);
   }
 
   @override
@@ -727,11 +733,6 @@ class _MaterialSwitchState extends State<_MaterialSwitch> with TickerProviderSta
     final SwitchThemeData defaults = theme.useMaterial3 ? _SwitchDefaultsM3(context) : _SwitchDefaultsM2(context);
 
     positionController.duration = Duration(milliseconds: switchConfig.toggleDuration);
-    if (theme.useMaterial3) {
-      position
-        ..curve = Curves.easeOutBack
-        ..reverseCurve = Curves.easeOutBack.flipped;
-    }
 
     // Colors need to be resolved in selected and non selected states separately
     // so that they can be lerped between.
@@ -780,12 +781,20 @@ class _MaterialSwitchState extends State<_MaterialSwitch> with TickerProviderSta
       ?? defaults.overlayColor!.resolve(hoveredStates)!;
 
     final Set<MaterialState> activePressedStates = activeStates..add(MaterialState.pressed);
+    final Color effectiveActivePressedThumbColor = widget.thumbColor?.resolve(activePressedStates)
+      ?? _widgetThumbColor.resolve(activePressedStates)
+      ?? switchTheme.thumbColor?.resolve(activePressedStates)
+      ?? defaults.thumbColor!.resolve(activePressedStates)!;
     final Color effectiveActivePressedOverlayColor = widget.overlayColor?.resolve(activePressedStates)
       ?? switchTheme.overlayColor?.resolve(activePressedStates)
       ?? activeThumbColor?.withAlpha(kRadialReactionAlpha)
       ?? defaults.overlayColor!.resolve(activePressedStates)!;
 
     final Set<MaterialState> inactivePressedStates = inactiveStates..add(MaterialState.pressed);
+    final Color effectiveInactivePressedThumbColor = widget.thumbColor?.resolve(inactivePressedStates)
+      ?? _widgetThumbColor.resolve(inactivePressedStates)
+      ?? switchTheme.thumbColor?.resolve(inactivePressedStates)
+      ?? defaults.thumbColor!.resolve(inactivePressedStates)!;
     final Color effectiveInactivePressedOverlayColor = widget.overlayColor?.resolve(inactivePressedStates)
       ?? switchTheme.overlayColor?.resolve(inactivePressedStates)
       ?? inactiveThumbColor?.withAlpha(kRadialReactionAlpha)
@@ -830,6 +839,8 @@ class _MaterialSwitchState extends State<_MaterialSwitch> with TickerProviderSta
             ..isHovered = states.contains(MaterialState.hovered)
             ..activeColor = effectiveActiveThumbColor
             ..inactiveColor = effectiveInactiveThumbColor
+            ..activePressedColor = effectiveActivePressedThumbColor
+            ..inactivePressedColor = effectiveInactivePressedThumbColor
             ..activeThumbImage = widget.activeThumbImage
             ..onActiveThumbImageError = widget.onActiveThumbImageError
             ..inactiveThumbImage = widget.inactiveThumbImage
@@ -926,6 +937,28 @@ class _SwitchPainter extends ToggleablePainter {
     notifyListeners();
   }
 
+  Color get activePressedColor => _activePressedColor!;
+  Color? _activePressedColor;
+  set activePressedColor(Color? value) {
+    assert(value != null);
+    if (value == _activePressedColor) {
+      return;
+    }
+    _activePressedColor = value;
+    notifyListeners();
+  }
+
+  Color get inactivePressedColor => _inactivePressedColor!;
+  Color? _inactivePressedColor;
+  set inactivePressedColor(Color? value) {
+    assert(value != null);
+    if (value == _inactivePressedColor) {
+      return;
+    }
+    _inactivePressedColor = value;
+    notifyListeners();
+  }
+
   double get activeThumbRadius => _activeThumbRadius!;
   double? _activeThumbRadius;
   set activeThumbRadius(double value) {
@@ -1180,7 +1213,7 @@ class _SwitchPainter extends ToggleablePainter {
         visualPosition = currentValue;
         break;
     }
-    if (reaction.status == AnimationStatus.reverse && _stopPressAnimation == false) {
+    if (reaction.status == AnimationStatus.reverse && !_stopPressAnimation) {
       _stopPressAnimation = true;
     } else {
       _stopPressAnimation = false;
@@ -1189,7 +1222,7 @@ class _SwitchPainter extends ToggleablePainter {
     // To get the thumb radius when the press ends, the value can be any number
     // between activeThumbRadius/inactiveThumbRadius and pressedThumbRadius.
     if (!_stopPressAnimation) {
-      if (reaction.status == AnimationStatus.completed) {
+      if (reaction.isCompleted) {
         // This happens when the thumb is dragged instead of being tapped.
         _pressedInactiveThumbRadius = lerpDouble(inactiveThumbRadius, pressedThumbRadius, reaction.value);
         _pressedActiveThumbRadius = lerpDouble(activeThumbRadius, pressedThumbRadius, reaction.value);
@@ -1248,10 +1281,10 @@ class _SwitchPainter extends ToggleablePainter {
     }
 
     Size thumbSize;
-    if (reaction.status == AnimationStatus.completed) {
+    if (reaction.isCompleted) {
       thumbSize = Size.fromRadius(pressedThumbRadius);
     } else {
-      if (position.status == AnimationStatus.dismissed || position.status == AnimationStatus.forward) {
+      if (position.isDismissed || position.status == AnimationStatus.forward) {
         thumbSize = thumbSizeAnimation(true).value;
       } else {
         thumbSize = thumbSizeAnimation(false).value;
@@ -1262,10 +1295,21 @@ class _SwitchPainter extends ToggleablePainter {
     final double inset = thumbOffset == null ? 0 : 1.0 - (currentValue - thumbOffset!).abs() * 2.0;
     thumbSize = Size(thumbSize.width - inset, thumbSize.height - inset);
 
-    final Color trackColor = Color.lerp(inactiveTrackColor, activeTrackColor, currentValue)!;
+    final double colorValue = CurvedAnimation(parent: positionController, curve: Curves.easeOut, reverseCurve: Curves.easeIn).value;
+    final Color trackColor = Color.lerp(inactiveTrackColor, activeTrackColor, colorValue)!;
     final Color? trackOutlineColor = inactiveTrackOutlineColor == null ? null
-      : Color.lerp(inactiveTrackOutlineColor, Colors.transparent, currentValue);
+        : Color.lerp(inactiveTrackOutlineColor, Colors.transparent, colorValue);
-    final Color lerpedThumbColor = Color.lerp(inactiveColor, activeColor, currentValue)!;
+    Color lerpedThumbColor;
+    if (!reaction.isDismissed) {
+      lerpedThumbColor = Color.lerp(inactivePressedColor, activePressedColor, colorValue)!;
+    } else if (positionController.status == AnimationStatus.forward) {
+      lerpedThumbColor = Color.lerp(inactivePressedColor, activeColor, colorValue)!;
+    } else if (positionController.status == AnimationStatus.reverse) {
+      lerpedThumbColor = Color.lerp(inactiveColor, activePressedColor, colorValue)!;
+    } else {
+      lerpedThumbColor = Color.lerp(inactiveColor, activeColor, colorValue)!;
+    }
+
     // Blend the thumb color against a `surfaceColor` background in case the
     // thumbColor is not opaque. This way we do not see through the thumb to the
     // track underneath.
@@ -1289,7 +1333,7 @@ class _SwitchPainter extends ToggleablePainter {
     _paintThumbWith(
       thumbPaintOffset,
       canvas,
-      currentValue,
+      colorValue,
       thumbColor,
       thumbImage,
       thumbErrorListener,
@@ -1381,7 +1425,7 @@ class _SwitchPainter extends ToggleablePainter {
 
       thumbPainter.paint(
         canvas,
-        thumbPaintOffset + Offset(0, inset),
+        thumbPaintOffset,
         configuration.copyWith(size: thumbSize),
       );
 

packages/flutter/test/material/switch_test.dart

@@ -2438,6 +2438,89 @@ void main() {
       );
     });
 
+    testWidgets('Switch thumb shows correct pressed color - M3', (WidgetTester tester) async {
+      final ThemeData themeData = ThemeData(useMaterial3: true);
+      final ColorScheme colors = themeData.colorScheme;
+      Widget buildApp({bool enabled = true, bool value = true}) {
+        return MaterialApp(
+          theme: themeData,
+          home: Material(
+            child: Center(
+              child: StatefulBuilder(builder: (BuildContext context, StateSetter setState) {
+                return Switch(
+                  value: value,
+                  onChanged: enabled ? (bool newValue) {
+                    setState(() {
+                      value = newValue;
+                    });
+                  } : null,
+                );
+              }),
+            ),
+          ),
+        );
+      }
+
+      await tester.pumpWidget(buildApp());
+      await tester.press(find.byType(Switch));
+      await tester.pumpAndSettle();
+
+      expect(Material.of(tester.element(find.byType(Switch))),
+        paints..rrect(
+          color: colors.primary, // track color
+          style: PaintingStyle.fill,
+        )..rrect(
+          color: Colors.transparent, // track outline color
+          style: PaintingStyle.stroke,
+        )..rrect(color: colors.primaryContainer, rrect: RRect.fromLTRBR(26.0, 10.0, 54.0, 38.0, const Radius.circular(14.0))),
+      );
+
+      await tester.pumpWidget(Container());
+      await tester.pumpWidget(buildApp(value: false));
+      await tester.press(find.byType(Switch));
+      await tester.pumpAndSettle();
+
+      expect(Material.of(tester.element(find.byType(Switch))),
+        paints..rrect(
+          color: colors.surfaceVariant, // track color
+          style: PaintingStyle.fill
+        )..rrect(
+          color: colors.outline, // track outline color
+          style: PaintingStyle.stroke,
+        )..rrect(color: colors.onSurfaceVariant),
+      );
+
+      await tester.pumpWidget(Container());
+      await tester.pumpWidget(buildApp(enabled: false));
+      await tester.press(find.byType(Switch));
+      await tester.pumpAndSettle();
+
+      expect(Material.of(tester.element(find.byType(Switch))),
+        paints..rrect(
+          color: colors.onSurface.withOpacity(0.12), // track color
+          style: PaintingStyle.fill,
+        )..rrect(
+          color: Colors.transparent, // track outline color
+          style: PaintingStyle.stroke,
+        )..rrect(color: colors.surface.withOpacity(1.0)),
+      );
+
+      await tester.pumpWidget(Container());
+      await tester.pumpWidget(buildApp(enabled: false, value: false));
+      await tester.press(find.byType(Switch));
+      await tester.pumpAndSettle();
+
+      expect(Material.of(tester.element(find.byType(Switch))),
+        paints..rrect(
+          color: colors.surfaceVariant.withOpacity(0.12), // track color
+          style: PaintingStyle.fill,
+        )..rrect(
+          color: colors.onSurface.withOpacity(0.12), // track outline color
+          style: PaintingStyle.stroke,
+        )..rrect(color: Color.alphaBlend(colors.onSurface.withOpacity(0.38), colors.surface)),
+      );
+    }, variant: TargetPlatformVariant.mobile());
+
     testWidgets('Switch thumb color resolves in active/enabled states - M3', (WidgetTester tester) async {
       final ThemeData themeData = ThemeData(useMaterial3: true, colorSchemeSeed: const Color(0xff6750a4), brightness: Brightness.light);
       final ColorScheme colors = themeData.colorScheme;