flutter/lib/src/: refactoring if-chains into switch expressions

packages/flutter/lib/src/animation/animation_controller.dart

@@ -886,13 +886,11 @@ class _InterpolationSimulation extends Simulation {
   @override
   double x(double timeInSeconds) {
     final double t = clampDouble(timeInSeconds / _durationInSeconds, 0.0, 1.0);
-    if (t == 0.0) {
-      return _begin;
-    } else if (t == 1.0) {
-      return _end;
-    } else {
-      return _begin + (_end - _begin) * _curve.transform(t);
-    }
+    return switch (t) {
+      0.0 => _begin,
+      1.0 => _end,
+      _ => _begin + (_end - _begin) * _curve.transform(t),
+    };
   }
 
   @override

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

@@ -1298,15 +1298,14 @@ class _ContextMenuRouteStaticState extends State<_ContextMenuRouteStatic> with T
           child: AnimatedBuilder(
             animation: _moveController,
             builder: _buildAnimation,
-            child: widget.orientation == Orientation.portrait
-              ? Column(
-                crossAxisAlignment: CrossAxisAlignment.start,
-                children: children,
-              )
-              : Row(
-                crossAxisAlignment: CrossAxisAlignment.start,
-                children: children,
-              ),
+            child: Flex(
+              direction: switch (widget.orientation) {
+                Orientation.portrait  => Axis.vertical,
+                Orientation.landscape => Axis.horizontal,
+              },
+              crossAxisAlignment: CrossAxisAlignment.start,
+              children: children,
+            ),
           ),
         ),
       ),

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

@@ -251,37 +251,20 @@ class _CupertinoListTileState extends State<CupertinoListTile> {
 
   @override
   Widget build(BuildContext context) {
-    final TextStyle titleTextStyle =
-        widget._type == _CupertinoListTileType.base || widget.subtitle == null
-            ? CupertinoTheme.of(context).textTheme.textStyle
-            : CupertinoTheme.of(context).textTheme.textStyle.merge(
-                  TextStyle(
-                    fontWeight: FontWeight.w600,
-                    fontSize: widget.leading == null ? _kNotchedTitleWithSubtitleFontSize : null,
-                  ),
-                );
-
-    final TextStyle subtitleTextStyle = widget._type == _CupertinoListTileType.base
-        ? CupertinoTheme.of(context).textTheme.textStyle.merge(
-              TextStyle(
-                fontSize: _kSubtitleFontSize,
-                color: CupertinoColors.secondaryLabel.resolveFrom(context),
-              ),
-            )
-        : CupertinoTheme.of(context).textTheme.textStyle.merge(
-              TextStyle(
-                fontSize: _kNotchedSubtitleFontSize,
-                color: CupertinoColors.secondaryLabel.resolveFrom(context),
-              ),
-            );
-
-    final TextStyle? additionalInfoTextStyle = widget.additionalInfo != null
-        ? CupertinoTheme.of(context).textTheme.textStyle.merge(
-            TextStyle(color: CupertinoColors.secondaryLabel.resolveFrom(context)))
-        : null;
+    final TextStyle textStyle = CupertinoTheme.of(context).textTheme.textStyle;
+    final TextStyle coloredStyle = textStyle.copyWith(
+      color: CupertinoColors.secondaryLabel.resolveFrom(context),
+    );
 
+    final bool baseType = switch (widget._type) {
+      _CupertinoListTileType.base    => true,
+      _CupertinoListTileType.notched => false,
+    };
     final Widget title = DefaultTextStyle(
-      style: titleTextStyle,
+      style: baseType || widget.subtitle == null ? textStyle : textStyle.copyWith(
+        fontWeight: FontWeight.w600,
+        fontSize: widget.leading == null ? _kNotchedTitleWithSubtitleFontSize : null,
+      ),
       maxLines: 1,
       overflow: TextOverflow.ellipsis,
       child: widget.title,
@@ -294,25 +277,6 @@ class _CupertinoListTileState extends State<CupertinoListTile> {
       _CupertinoListTileType.notched => _kNotchedPaddingWithoutLeading,
     };
 
-    Widget? subtitle;
-    if (widget.subtitle != null) {
-      subtitle = DefaultTextStyle(
-        style: subtitleTextStyle,
-        maxLines: 1,
-        overflow: TextOverflow.ellipsis,
-        child: widget.subtitle!,
-      );
-    }
-
-    Widget? additionalInfo;
-    if (widget.additionalInfo != null) {
-      additionalInfo = DefaultTextStyle(
-        style: additionalInfoTextStyle!,
-        maxLines: 1,
-        child: widget.additionalInfo!,
-      );
-    }
-
     // The color for default state tile is set to either what user provided or
     // null and it will resolve to the correct color provided by context. But if
     // the tile was tapped, it is set to what user provided or if null to the
@@ -323,7 +287,7 @@ class _CupertinoListTileState extends State<CupertinoListTile> {
     }
 
     final double minHeight = switch (widget._type) {
-      _CupertinoListTileType.base when subtitle != null => _kMinHeightWithSubtitle,
+      _CupertinoListTileType.base when widget.subtitle != null => _kMinHeightWithSubtitle,
       _CupertinoListTileType.notched when widget.leading != null => _kNotchedMinHeight,
       _CupertinoListTileType.base => _kMinHeight,
       _CupertinoListTileType.notched => _kNotchedMinHeightWithoutLeading,
@@ -336,13 +300,10 @@ class _CupertinoListTileState extends State<CupertinoListTile> {
         padding: padding,
         child: Row(
           children: <Widget>[
-            if (widget.leading != null) ...<Widget>[
-              SizedBox(
-                width: widget.leadingSize,
-                height: widget.leadingSize,
-                child: Center(
-                  child: widget.leading,
-                ),
+            if (widget.leading case final Widget leading) ...<Widget>[
+              SizedBox.square(
+                dimension: widget.leadingSize,
+                child: Center(child: leading),
               ),
               SizedBox(width: widget.leadingToTitle),
             ] else
@@ -353,15 +314,28 @@ class _CupertinoListTileState extends State<CupertinoListTile> {
                 crossAxisAlignment: CrossAxisAlignment.start,
                 children: <Widget>[
                   title,
-                  if (subtitle != null) ...<Widget>[
+                  if (widget.subtitle case final Widget subtitle) ...<Widget>[
                     const SizedBox(height: _kNotchedTitleToSubtitle),
-                    subtitle,
+                    DefaultTextStyle(
+                      style: coloredStyle.copyWith(
+                        fontSize: baseType
+                            ? _kSubtitleFontSize
+                            : _kNotchedSubtitleFontSize,
+                      ),
+                      maxLines: 1,
+                      overflow: TextOverflow.ellipsis,
+                      child: subtitle,
+                    ),
                   ],
                 ],
               ),
             ),
-            if (additionalInfo != null) ...<Widget>[
-              additionalInfo,
+            if (widget.additionalInfo case final Widget additionalInfo) ...<Widget>[
+              DefaultTextStyle(
+                style: coloredStyle,
+                maxLines: 1,
+                child: additionalInfo,
+              ),
               if (widget.trailing != null)
                 const SizedBox(width: _kAdditionalInfoToTrailing),
             ],

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

@@ -718,17 +718,17 @@ class _CupertinoBackGestureDetectorState<T> extends State<_CupertinoBackGestureD
     assert(debugCheckHasDirectionality(context));
     // For devices with notches, the drag area needs to be larger on the side
     // that has the notch.
-    double dragAreaWidth = Directionality.of(context) == TextDirection.ltr ?
-                           MediaQuery.paddingOf(context).left :
-                           MediaQuery.paddingOf(context).right;
-    dragAreaWidth = max(dragAreaWidth, _kBackGestureWidth);
+    final double dragAreaWidth = switch (Directionality.of(context)) {
+      TextDirection.rtl => MediaQuery.paddingOf(context).right,
+      TextDirection.ltr => MediaQuery.paddingOf(context).left,
+    };
     return Stack(
       fit: StackFit.passthrough,
       children: <Widget>[
         widget.child,
         PositionedDirectional(
           start: 0.0,
-          width: dragAreaWidth,
+          width: max(dragAreaWidth, _kBackGestureWidth),
           top: 0.0,
           bottom: 0.0,
           child: Listener(

packages/flutter/lib/src/gestures/monodrag.dart

@@ -607,14 +607,12 @@ abstract class DragGestureRecognizer extends OneSequenceGestureRecognizer {
          event is PointerMoveEvent ||
          event is PointerPanZoomStartEvent ||
          event is PointerPanZoomUpdateEvent)) {
-      final VelocityTracker tracker = _velocityTrackers[event.pointer]!;
-      if (event is PointerPanZoomStartEvent) {
-        tracker.addPosition(event.timeStamp, Offset.zero);
-      } else if (event is PointerPanZoomUpdateEvent) {
-        tracker.addPosition(event.timeStamp, event.pan);
-      } else {
-        tracker.addPosition(event.timeStamp, event.localPosition);
-      }
+      final Offset position = switch (event) {
+        PointerPanZoomStartEvent() => Offset.zero,
+        PointerPanZoomUpdateEvent() => event.pan,
+        _ => event.localPosition,
+      };
+      _velocityTrackers[event.pointer]!.addPosition(event.timeStamp, position);
     }
     if (event is PointerMoveEvent && event.buttons != _initialButtons) {
       _giveUpPointer(event.pointer);

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

@@ -325,10 +325,10 @@ class _CalendarDatePickerState extends State<CalendarDatePicker> {
         _DatePickerModeToggleButton(
           mode: _mode,
           title: _localizations.formatMonthYear(_currentDisplayedMonthDate),
-          onTitlePressed: () {
-            // Toggle the day/year mode.
-            _handleModeChanged(_mode == DatePickerMode.day ? DatePickerMode.year : DatePickerMode.day);
-          },
+          onTitlePressed: () => _handleModeChanged(switch (_mode) {
+            DatePickerMode.day => DatePickerMode.year,
+            DatePickerMode.year => DatePickerMode.day,
+          }),
         ),
       ],
     );

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

@@ -765,10 +765,10 @@ class _CheckboxPainter extends ToggleablePainter {
 
     final Paint strokePaint = _createStrokePaint();
     final Offset origin = size / 2.0 - const Size.square(_kEdgeSize) / 2.0 as Offset;
-    final AnimationStatus status = position.status;
-    final double tNormalized = status == AnimationStatus.forward || status == AnimationStatus.completed
-      ? position.value
-      : 1.0 - position.value;
+    final double tNormalized = switch (position.status) {
+      AnimationStatus.forward || AnimationStatus.completed => position.value,
+      AnimationStatus.reverse || AnimationStatus.dismissed => 1.0 - position.value,
+    };
 
     // Four cases: false to null, false to true, null to false, true to false
     if (previousValue == false || value == false) {

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

@@ -2809,11 +2809,10 @@ class _InputDateRangePickerDialog extends StatelessWidget {
     if (start == null || end == null) {
       return localizations.unspecifiedDateRange;
     }
-    if (Directionality.of(context) == TextDirection.ltr) {
-      return '$startText – $endText';
-    } else {
-      return '$endText – $startText';
-    }
+    return switch (Directionality.of(context)) {
+      TextDirection.rtl => '$endText – $startText',
+      TextDirection.ltr => '$startText – $endText',
+    };
   }
 
   @override

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

@@ -970,16 +970,14 @@ class _IconButtonM3 extends ButtonStyleButton {
   @override
   ButtonStyle? themeStyleOf(BuildContext context) {
     final IconThemeData iconTheme = IconTheme.of(context);
-    final bool isDark = Theme.of(context).brightness == Brightness.dark;
-
-    bool isIconThemeDefault(Color? color) {
-      if (isDark) {
-        return identical(color, kDefaultIconLightColor);
-      }
-      return identical(color, kDefaultIconDarkColor);
-    }
-    final bool isDefaultColor = isIconThemeDefault(iconTheme.color);
     final bool isDefaultSize = iconTheme.size == const IconThemeData.fallback().size;
+    final bool isDefaultColor = identical(
+      iconTheme.color,
+      switch (Theme.of(context).brightness) {
+        Brightness.light => kDefaultIconDarkColor,
+        Brightness.dark => kDefaultIconLightColor,
+      },
+    );
 
     final ButtonStyle iconThemeStyle = IconButton.styleFrom(
       foregroundColor: isDefaultColor ? null : iconTheme.color,

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

@@ -236,14 +236,12 @@ class Ink extends StatefulWidget {
   final double? height;
 
   EdgeInsetsGeometry get _paddingIncludingDecoration {
-    if (decoration == null) {
-      return padding ?? EdgeInsets.zero;
-    }
-    final EdgeInsetsGeometry decorationPadding = decoration!.padding;
-    if (padding == null) {
-      return decorationPadding;
-    }
-    return padding!.add(decorationPadding);
+    return switch ((padding, decoration?.padding)) {
+      (null, null) => EdgeInsets.zero,
+      (null, final EdgeInsetsGeometry padding) => padding,
+      (final EdgeInsetsGeometry padding, null) => padding,
+      _ => padding!.add(decoration!.padding),
+    };
   }
 
   @override

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

@@ -287,13 +287,11 @@ class _Shaker extends AnimatedWidget {
   double get translateX {
     const double shakeDelta = 4.0;
     final double t = animation.value;
-    if (t <= 0.25) {
-      return -t * shakeDelta;
-    } else if (t < 0.75) {
-      return (t - 0.5) * shakeDelta;
-    } else {
-      return (1.0 - t) * 4.0 * shakeDelta;
-    }
+    return shakeDelta * switch (t) {
+      <= 0.25 => -t,
+      <  0.75 => t - 0.5,
+      _ => (1.0 - t) * 4.0,
+    };
   }
 
   @override

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

@@ -271,10 +271,10 @@ class _MaterialScrollbarState extends RawScrollbarState<_MaterialScrollbar> {
     final Brightness brightness = _colorScheme.brightness;
     return MaterialStateProperty.resolveWith((Set<MaterialState> states) {
       if (showScrollbar && _trackVisibility.resolve(states)) {
-        return _scrollbarTheme.trackColor?.resolve(states)
-          ?? (brightness == Brightness.light
-            ? onSurface.withOpacity(0.03)
-            : onSurface.withOpacity(0.05));
+        return _scrollbarTheme.trackColor?.resolve(states) ?? switch (brightness) {
+          Brightness.light => onSurface.withOpacity(0.03),
+          Brightness.dark  => onSurface.withOpacity(0.05),
+        };
       }
       return const Color(0x00000000);
     });
@@ -285,10 +285,10 @@ class _MaterialScrollbarState extends RawScrollbarState<_MaterialScrollbar> {
     final Brightness brightness = _colorScheme.brightness;
     return MaterialStateProperty.resolveWith((Set<MaterialState> states) {
       if (showScrollbar && _trackVisibility.resolve(states)) {
-        return _scrollbarTheme.trackBorderColor?.resolve(states)
-          ?? (brightness == Brightness.light
-            ? onSurface.withOpacity(0.1)
-            : onSurface.withOpacity(0.25));
+        return _scrollbarTheme.trackBorderColor?.resolve(states) ?? switch (brightness) {
+          Brightness.light => onSurface.withOpacity(0.1),
+          Brightness.dark  => onSurface.withOpacity(0.25),
+        };
       }
       return const Color(0x00000000);
     });