Implementing switch expressions in lib/src/material/ (#142793)

This PR is the 6�ʰ step in the journey to solve issue #136139 and make the entire Flutter repo more readable.

(previous pull requests: #139048, #139882, #141591, #142279, #142634)

The current focus is on `packages/flutter/lib/src/material/`. The previous 2 PRs covered files in this directory starting with letters `a-m`; this one takes care of everything else.

Author: nate-thegrate

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

@@ -866,14 +866,10 @@ mixin _ZoomTransitionBase<S extends StatefulWidget> on State<S> {
   }
 
   void onAnimationStatusChange(AnimationStatus status) {
-    switch (status) {
-      case AnimationStatus.dismissed:
-      case AnimationStatus.completed:
-        controller.allowSnapshotting = false;
-      case AnimationStatus.forward:
-      case AnimationStatus.reverse:
-        controller.allowSnapshotting = useSnapshot;
-    }
+    controller.allowSnapshotting = switch (status) {
+      AnimationStatus.dismissed || AnimationStatus.completed => false,
+      AnimationStatus.forward   || AnimationStatus.reverse   => useSnapshot,
+    };
   }
 
   @override

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

@@ -730,12 +730,10 @@ class _PopupMenuRouteLayout extends SingleChildLayoutDelegate {
       x = position.left;
     } else {
       // Menu button is equidistant from both edges, so grow in reading direction.
-      switch (textDirection) {
-        case TextDirection.rtl:
-          x = size.width - position.right - childSize.width;
-        case TextDirection.ltr:
-          x = position.left;
-      }
+      x = switch (textDirection) {
+        TextDirection.rtl => size.width - position.right - childSize.width,
+        TextDirection.ltr => position.left,
+      };
     }
     final Offset wantedPosition = Offset(x, y);
     final Offset originCenter = position.toRect(Offset.zero & size).center;
@@ -1395,12 +1393,10 @@ class PopupMenuButtonState<T> extends State<PopupMenuButton<T>> {
 
   bool get _canRequestFocus {
     final NavigationMode mode = MediaQuery.maybeNavigationModeOf(context) ?? NavigationMode.traditional;
-    switch (mode) {
-      case NavigationMode.traditional:
-        return widget.enabled;
-      case NavigationMode.directional:
-        return true;
-    }
+    return switch (mode) {
+      NavigationMode.traditional => widget.enabled,
+      NavigationMode.directional => true,
+    };
   }
 
   @override

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

@@ -191,13 +191,10 @@ class _LinearProgressIndicatorPainter extends CustomPainter {
         return;
       }
 
-      final double left;
-      switch (textDirection) {
-        case TextDirection.rtl:
-          left = size.width - width - x;
-        case TextDirection.ltr:
-          left = x;
-      }
+      final double left = switch (textDirection) {
+        TextDirection.rtl => size.width - width - x,
+        TextDirection.ltr => x,
+      };
 
       final Rect rect = Offset(left, 0.0) & Size(width, size.height);
       if (indicatorBorderRadius != BorderRadius.zero) {

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

@@ -453,13 +453,10 @@ class _RadioState<T> extends State<Radio<T>> with TickerProviderStateMixin, Togg
     final VisualDensity effectiveVisualDensity = widget.visualDensity
       ?? radioTheme.visualDensity
       ?? defaults.visualDensity!;
-    Size size;
-    switch (effectiveMaterialTapTargetSize) {
-      case MaterialTapTargetSize.padded:
-        size = const Size(kMinInteractiveDimension, kMinInteractiveDimension);
-      case MaterialTapTargetSize.shrinkWrap:
-        size = const Size(kMinInteractiveDimension - 8.0, kMinInteractiveDimension - 8.0);
-    }
+    Size size = switch (effectiveMaterialTapTargetSize) {
+      MaterialTapTargetSize.padded     => const Size(kMinInteractiveDimension,       kMinInteractiveDimension),
+      MaterialTapTargetSize.shrinkWrap => const Size(kMinInteractiveDimension - 8.0, kMinInteractiveDimension - 8.0),
+    };
     size += effectiveVisualDensity.baseSizeAdjustment;
 
     final MaterialStateProperty<MouseCursor> effectiveMouseCursor = MaterialStateProperty.resolveWith<MouseCursor>((Set<MaterialState> states) {

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

@@ -485,15 +485,10 @@ class RadioListTile<T> extends StatelessWidget {
     }
 
     Widget? leading, trailing;
-    switch (controlAffinity) {
-      case ListTileControlAffinity.leading:
-      case ListTileControlAffinity.platform:
-        leading = control;
-        trailing = secondary;
-      case ListTileControlAffinity.trailing:
-        leading = secondary;
-        trailing = control;
-    }
+    (leading, trailing) = switch (controlAffinity) {
+      ListTileControlAffinity.leading || ListTileControlAffinity.platform => (control, secondary),
+      ListTileControlAffinity.trailing => (secondary, control),
+    };
     final ThemeData theme = Theme.of(context);
     final RadioThemeData radioThemeData = RadioTheme.of(context);
     final Set<MaterialState> states = <MaterialState>{

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

@@ -558,16 +558,10 @@ class _RangeSliderState extends State<RangeSlider> with TickerProviderStateMixin
     // thumb selection is determined by the direction of the dx. The left thumb
     // is chosen for negative dx, and the right thumb is chosen for positive dx.
     if (inStartTouchTarget && inEndTouchTarget) {
-      final bool towardsStart;
-      final bool towardsEnd;
-      switch (textDirection) {
-        case TextDirection.ltr:
-          towardsStart = dx < 0;
-          towardsEnd = dx > 0;
-        case TextDirection.rtl:
-          towardsStart = dx > 0;
-          towardsEnd = dx < 0;
-      }
+      final (bool towardsStart, bool towardsEnd) = switch (textDirection) {
+        TextDirection.ltr => (dx < 0, dx > 0),
+        TextDirection.rtl => (dx > 0, dx < 0),
+      };
       if (towardsStart) {
         return Thumb.start;
       }
@@ -1102,16 +1096,12 @@ class _RenderRangeSlider extends RenderBox with RelayoutWhenSystemFontsChangeMix
   }
 
   bool get showValueIndicator {
-    switch (_sliderTheme.showValueIndicator!) {
-      case ShowValueIndicator.onlyForDiscrete:
-        return isDiscrete;
-      case ShowValueIndicator.onlyForContinuous:
-        return !isDiscrete;
-      case ShowValueIndicator.always:
-        return true;
-      case ShowValueIndicator.never:
-        return false;
-    }
+    return switch (_sliderTheme.showValueIndicator!) {
+      ShowValueIndicator.onlyForDiscrete   => isDiscrete,
+      ShowValueIndicator.onlyForContinuous => !isDiscrete,
+      ShowValueIndicator.always => true,
+      ShowValueIndicator.never  => false,
+    };
   }
 
   Size get _thumbSize => _sliderTheme.rangeThumbShape!.getPreferredSize(isEnabled, isDiscrete);
@@ -1142,16 +1132,10 @@ class _RenderRangeSlider extends RenderBox with RelayoutWhenSystemFontsChangeMix
       return;
     }
 
-    final String text;
-    final TextPainter labelPainter;
-    switch (thumb) {
-      case Thumb.start:
-        text = labels.start;
-        labelPainter = _startLabelPainter;
-      case Thumb.end:
-        text = labels.end;
-        labelPainter = _endLabelPainter;
-    }
+    final (String text, TextPainter labelPainter) = switch (thumb) {
+      Thumb.start => (labels.start, _startLabelPainter),
+      Thumb.end   => (labels.end, _endLabelPainter),
+    };
 
     labelPainter
       ..text = TextSpan(
@@ -1205,12 +1189,10 @@ class _RenderRangeSlider extends RenderBox with RelayoutWhenSystemFontsChangeMix
   }
 
   double _getValueFromVisualPosition(double visualPosition) {
-    switch (textDirection) {
-      case TextDirection.rtl:
-        return 1.0 - visualPosition;
-      case TextDirection.ltr:
-        return visualPosition;
-    }
+    return switch (textDirection) {
+      TextDirection.rtl => 1.0 - visualPosition,
+      TextDirection.ltr => visualPosition,
+    };
   }
 
   double _getValueFromGlobalPosition(Offset globalPosition) {
@@ -1399,16 +1381,10 @@ class _RenderRangeSlider extends RenderBox with RelayoutWhenSystemFontsChangeMix
     // The visual position is the position of the thumb from 0 to 1 from left
     // to right. In left to right, this is the same as the value, but it is
     // reversed for right to left text.
-    final double startVisualPosition;
-    final double endVisualPosition;
-    switch (textDirection) {
-      case TextDirection.rtl:
-        startVisualPosition = 1.0 - startValue;
-        endVisualPosition = 1.0 - endValue;
-      case TextDirection.ltr:
-        startVisualPosition = startValue;
-        endVisualPosition = endValue;
-    }
+    final (double startVisualPosition, double endVisualPosition) = switch (textDirection) {
+      TextDirection.rtl => (1.0 - startValue, 1.0 - endValue),
+      TextDirection.ltr => (startValue, endValue),
+    };
 
     final Rect trackRect = _sliderTheme.rangeTrackShape!.getPreferredRect(
         parentBox: this,
@@ -1585,15 +1561,10 @@ class _RenderRangeSlider extends RenderBox with RelayoutWhenSystemFontsChangeMix
         labelPainter: _endLabelPainter,
         textScaleFactor: textScaleFactor,
       ).width / 2;
-      double innerOverflow = startHalfWidth + endHalfWidth;
-      switch (textDirection) {
-        case TextDirection.ltr:
-          innerOverflow += startOffset;
-          innerOverflow -= endOffset;
-        case TextDirection.rtl:
-          innerOverflow -= startOffset;
-          innerOverflow += endOffset;
-      }
+      final double innerOverflow = startHalfWidth + endHalfWidth + switch (textDirection) {
+        TextDirection.ltr => startOffset - endOffset,
+        TextDirection.rtl => endOffset - startOffset,
+      };
 
       _state.paintTopValueIndicator = (PaintingContext context, Offset offset) {
         if (attached) {

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

@@ -357,15 +357,10 @@ class RefreshIndicatorState extends State<RefreshIndicator> with TickerProviderS
       });
       return false;
     }
-    bool? indicatorAtTopNow;
-    switch (notification.metrics.axisDirection) {
-      case AxisDirection.down:
-      case AxisDirection.up:
-        indicatorAtTopNow = true;
-      case AxisDirection.left:
-      case AxisDirection.right:
-        indicatorAtTopNow = null;
-    }
+    final bool? indicatorAtTopNow = switch (notification.metrics.axisDirection) {
+      AxisDirection.down || AxisDirection.up    => true,
+      AxisDirection.left || AxisDirection.right => null,
+    };
     if (indicatorAtTopNow != _isIndicatorAtTop) {
       if (_mode == _RefreshIndicatorMode.drag || _mode == _RefreshIndicatorMode.armed) {
         _dismiss(_RefreshIndicatorMode.canceled);

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

@@ -874,13 +874,10 @@ class _SliderState extends State<Slider> with TickerProviderStateMixin {
         };
     }
 
-    final Map<ShortcutActivator, Intent> shortcutMap;
-    switch (MediaQuery.navigationModeOf(context)) {
-      case NavigationMode.directional:
-        shortcutMap = _directionalNavShortcutMap;
-      case NavigationMode.traditional:
-        shortcutMap = _traditionalNavShortcutMap;
-    }
+    final Map<ShortcutActivator, Intent> shortcutMap = switch (MediaQuery.navigationModeOf(context)) {
+      NavigationMode.directional => _directionalNavShortcutMap,
+      NavigationMode.traditional => _traditionalNavShortcutMap,
+    };
 
     final double fontSize = sliderTheme.valueIndicatorTextStyle?.fontSize ?? kDefaultFontSize;
     final double fontSizeToScale = fontSize == 0.0 ? kDefaultFontSize : fontSize;
@@ -1386,16 +1383,12 @@ class _RenderSlider extends RenderBox with RelayoutWhenSystemFontsChangeMixin {
   }
 
   bool get showValueIndicator {
-    switch (_sliderTheme.showValueIndicator!) {
-      case ShowValueIndicator.onlyForDiscrete:
-        return isDiscrete;
-      case ShowValueIndicator.onlyForContinuous:
-        return !isDiscrete;
-      case ShowValueIndicator.always:
-        return true;
-      case ShowValueIndicator.never:
-        return false;
-    }
+    return switch (_sliderTheme.showValueIndicator!) {
+      ShowValueIndicator.onlyForDiscrete   => isDiscrete,
+      ShowValueIndicator.onlyForContinuous => !isDiscrete,
+      ShowValueIndicator.always => true,
+      ShowValueIndicator.never  => false,
+    };
   }
 
   double get _adjustmentUnit {
@@ -1466,12 +1459,10 @@ class _RenderSlider extends RenderBox with RelayoutWhenSystemFontsChangeMixin {
   }
 
   double _getValueFromVisualPosition(double visualPosition) {
-    switch (textDirection) {
-      case TextDirection.rtl:
-        return 1.0 - visualPosition;
-      case TextDirection.ltr:
-        return visualPosition;
-    }
+    return switch (textDirection) {
+      TextDirection.rtl => 1.0 - visualPosition,
+      TextDirection.ltr => visualPosition,
+    };
   }
 
   double _getValueFromGlobalPosition(Offset globalPosition) {
@@ -1566,12 +1557,10 @@ class _RenderSlider extends RenderBox with RelayoutWhenSystemFontsChangeMixin {
       case SliderInteraction.slideThumb:
         if (_active && isInteractive) {
           final double valueDelta = details.primaryDelta! / _trackRect.width;
-          switch (textDirection) {
-            case TextDirection.rtl:
-              _currentDragValue -= valueDelta;
-            case TextDirection.ltr:
-              _currentDragValue += valueDelta;
-          }
+          _currentDragValue += switch (textDirection) {
+            TextDirection.rtl => -valueDelta,
+            TextDirection.ltr =>  valueDelta,
+          };
           onChanged!(_discretize(_currentDragValue));
         }
       case SliderInteraction.tapOnly: