Implement switch expressions

packages/dropdown_button2/CHANGELOG.md

@@ -4,6 +4,7 @@
 - DropdownRoutePage should dispose the created ScrollController [Flutter core].
 - Remove 'must be non-null' and 'must not be null' comments [Flutter core].
 - Form fields onChange callback should be called on reset [Flutter core].
+- Implement switch expressions.
 
 ## 3.0.0-beta.21
 

packages/dropdown_button2/lib/src/dropdown_button2.dart

@@ -623,28 +623,19 @@ class _DropdownButton2State<T> extends State<DropdownButton2<T>>
 
   Color get _iconColor {
     // These colors are not defined in the Material Design spec.
+    final Brightness brightness = Theme.of(context).brightness;
     if (_enabled) {
-      if (_iconStyle.iconEnabledColor != null) {
-        return _iconStyle.iconEnabledColor!;
-      }
-
-      switch (Theme.of(context).brightness) {
-        case Brightness.light:
-          return Colors.grey.shade700;
-        case Brightness.dark:
-          return Colors.white70;
-      }
+      return _iconStyle.iconEnabledColor ??
+          switch (brightness) {
+            Brightness.light => Colors.grey.shade700,
+            Brightness.dark => Colors.white70,
+          };
     } else {
-      if (_iconStyle.iconDisabledColor != null) {
-        return _iconStyle.iconDisabledColor!;
-      }
-
-      switch (Theme.of(context).brightness) {
-        case Brightness.light:
-          return Colors.grey.shade400;
-        case Brightness.dark:
-          return Colors.white10;
-      }
+      return _iconStyle.iconDisabledColor ??
+          switch (brightness) {
+            Brightness.light => Colors.grey.shade400,
+            Brightness.dark => Colors.white10,
+          };
     }
   }
 

packages/dropdown_button2/lib/src/dropdown_menu_item.dart

@@ -148,15 +148,11 @@ class _DropdownItemButton<T> extends StatefulWidget {
 
 class _DropdownItemButtonState<T> extends State<_DropdownItemButton<T>> {
   void _handleFocusChange(bool focused) {
-    final bool inTraditionalMode;
-    switch (FocusManager.instance.highlightMode) {
-      case FocusHighlightMode.touch:
-        inTraditionalMode = false;
-        break;
-      case FocusHighlightMode.traditional:
-        inTraditionalMode = true;
-        break;
-    }
+    final bool inTraditionalMode =
+        switch (FocusManager.instance.highlightMode) {
+      FocusHighlightMode.touch => false,
+      FocusHighlightMode.traditional => true,
+    };
 
     if (focused && inTraditionalMode) {
       final _MenuLimits menuLimits = widget.route.getMenuLimits(

packages/dropdown_button2/lib/src/dropdown_route.dart

@@ -401,49 +401,35 @@ class _DropdownMenuRouteLayout<T> extends SingleChildLayoutDelegate {
     assert(textDirection != null);
 
     final Offset offset = route.dropdownStyle.offset;
-    final double left;
-
-    switch (route.dropdownStyle.direction) {
-      case DropdownDirection.textDirection:
-        switch (textDirection!) {
-          case TextDirection.rtl:
-            left = clampDouble(
+    final double left = switch (route.dropdownStyle.direction) {
+      DropdownDirection.textDirection => switch (textDirection!) {
+          TextDirection.rtl => clampDouble(
               buttonRect.right - childSize.width + offset.dx,
               0.0,
               size.width - childSize.width,
-            );
-            break;
-          case TextDirection.ltr:
-            left = clampDouble(
+            ),
+          TextDirection.ltr => clampDouble(
               buttonRect.left + offset.dx,
               0.0,
               size.width - childSize.width,
-            );
-            break;
-        }
-        break;
-      case DropdownDirection.right:
-        left = clampDouble(
+            ),
+        },
+      DropdownDirection.right => clampDouble(
           buttonRect.left + offset.dx,
           0.0,
           size.width - childSize.width,
-        );
-        break;
-      case DropdownDirection.left:
-        left = clampDouble(
+        ),
+      DropdownDirection.left => clampDouble(
           buttonRect.right - childSize.width + offset.dx,
           0.0,
           size.width - childSize.width,
-        );
-        break;
-      case DropdownDirection.center:
-        left = clampDouble(
+        ),
+      DropdownDirection.center => clampDouble(
           (size.width - childSize.width) / 2 + offset.dx,
           0.0,
           size.width - childSize.width,
-        );
-        break;
-    }
+        ),
+    };
 
     return Offset(left, menuLimits.top);
   }