Respect button/inputDecoration's borderRadius when barrierCoversButton is false

packages/dropdown_button2/CHANGELOG.md

@@ -15,6 +15,8 @@
 - Fix DropdownButtonFormField clips text when large text scale is used [Flutter core].
 - Fix DropdownButtonFormField padding when ButtonTheme.alignedDropdown is true [Flutter core].
 - Add barrierCoversButton to DropdownButtonFormField2.
+- Respect button's borderRadius when barrierCoversButton is false.
+- Respect inputDecoration's borderRadius when barrierCoversButton is false.
 
 ## 3.0.0-beta.21
 

packages/dropdown_button2/lib/src/dropdown_button2.dart

@@ -127,7 +127,8 @@ class DropdownButton2<T> extends StatefulWidget {
           'Only one of valueListenable or multiValueListenable can be used.',
         ),
         _inputDecoration = null,
-        _isEmpty = false;
+        _isEmpty = false,
+        _hasError = false;
 
   const DropdownButton2._formField({
     super.key,
@@ -161,9 +162,11 @@ class DropdownButton2<T> extends StatefulWidget {
     required this.openDropdownListenable,
     required InputDecoration inputDecoration,
     required bool isEmpty,
+    required bool hasError,
   })  : underline = null,
         _inputDecoration = inputDecoration,
-        _isEmpty = isEmpty;
+        _isEmpty = isEmpty,
+        _hasError = hasError;
 
   /// The list of items the user can select.
   ///
@@ -382,6 +385,8 @@ class DropdownButton2<T> extends StatefulWidget {
 
   final bool _isEmpty;
 
+  final bool _hasError;
+
   @override
   State<DropdownButton2<T>> createState() => _DropdownButton2State<T>();
 }
@@ -572,6 +577,30 @@ class _DropdownButton2State<T> extends State<DropdownButton2<T>> with WidgetsBin
     }
   }
 
+  Set<WidgetState> _materialState(InputDecoration decoration) => <WidgetState>{
+        if (!decoration.enabled) WidgetState.disabled,
+        if (_isFocused) WidgetState.focused,
+        if (_isHovering) WidgetState.hovered,
+        if (widget._hasError) WidgetState.error,
+      };
+
+  BorderRadius? _getInputDecorationBorderRadius(InputDecoration decoration) {
+    InputBorder? border;
+    if (!decoration.enabled) {
+      border = widget._hasError ? decoration.errorBorder : decoration.disabledBorder;
+    } else if (_isFocused) {
+      border = widget._hasError ? decoration.focusedErrorBorder : decoration.focusedBorder;
+    } else {
+      border = widget._hasError ? decoration.errorBorder : decoration.enabledBorder;
+    }
+    border ??= WidgetStateProperty.resolveAs(decoration.border, _materialState(decoration));
+
+    if (border is OutlineInputBorder) {
+      return border.borderRadius;
+    }
+    return null;
+  }
+
   EdgeInsetsGeometry _buttonAdditionalHPadding() {
     final TextDirection? textDirection = Directionality.maybeOf(context);
 
@@ -602,6 +631,9 @@ class _DropdownButton2State<T> extends State<DropdownButton2<T>> with WidgetsBin
     _dropdownRoute = _DropdownRoute<T>(
       items: items,
       buttonRect: _buttonRect,
+      buttonBorderRadius: widget._inputDecoration != null
+          ? _getInputDecorationBorderRadius(widget._inputDecoration!)
+          : _getButtonBorderRadius(context),
       selectedIndex: _selectedIndex ?? 0,
       isNoSelectedItem: _selectedIndex == null,
       onChanged: widget.onChanged,
@@ -1026,6 +1058,10 @@ class DropdownButtonFormField2<T> extends FormField<T> {
                 : effectiveHint != null || effectiveDisabledHint != null;
             final bool isEmpty = !showSelectedItem && !isHintOrDisabledHintAvailable;
 
+            final bool hasError = field.hasError ||
+                effectiveDecoration.errorText != null ||
+                effectiveDecoration.error != null;
+
             // An unFocusable Focus widget so that this widget can detect if its
             // descendants have focus or not.
             return Focus(
@@ -1067,6 +1103,7 @@ class DropdownButtonFormField2<T> extends FormField<T> {
                     hintText: effectiveDecoration.hintText != null ? '' : null,
                   ),
                   isEmpty: isEmpty,
+                  hasError: hasError,
                 ),
               ),
             );

packages/dropdown_button2/lib/src/dropdown_route.dart

@@ -4,6 +4,7 @@ class _DropdownRoute<T> extends PopupRoute<_DropdownRouteResult<T>> {
   _DropdownRoute({
     required this.items,
     required this.buttonRect,
+    required this.buttonBorderRadius,
     required this.selectedIndex,
     required this.isNoSelectedItem,
     required this.onChanged,
@@ -25,6 +26,7 @@ class _DropdownRoute<T> extends PopupRoute<_DropdownRouteResult<T>> {
 
   final List<DropdownItem<T>> items;
   final ValueNotifier<Rect?> buttonRect;
+  final BorderRadius? buttonBorderRadius;
   final int selectedIndex;
   final bool isNoSelectedItem;
   final ValueChanged<T?>? onChanged;
@@ -89,10 +91,11 @@ class _DropdownRoute<T> extends PopupRoute<_DropdownRouteResult<T>> {
               return barrierCoversButton
                   ? routePage
                   : _CustomModalBarrier(
-                      animation: animation,
                       barrierColor: _altBarrierColor,
+                      animation: animation,
                       barrierCurve: barrierCurve,
                       buttonRect: rect,
+                      buttonBorderRadius: buttonBorderRadius ?? BorderRadius.zero,
                       child: routePage,
                     );
             },
@@ -458,18 +461,20 @@ class _DropdownRouteResult<T> {
 /// It's used instead of the route barrier when `barrierCoversButton` is set to false.
 class _CustomModalBarrier extends StatefulWidget {
   const _CustomModalBarrier({
-    this.animation,
-    this.barrierColor,
+    required this.barrierColor,
+    required this.animation,
     required this.barrierCurve,
+    required this.buttonRect,
+    required this.buttonBorderRadius,
     required this.child,
-    this.buttonRect,
   });
 
-  final Animation<double>? animation;
   final Color? barrierColor;
+  final Animation<double>? animation;
   final Curve barrierCurve;
+  final Rect buttonRect;
+  final BorderRadius buttonBorderRadius;
   final Widget child;
-  final Rect? buttonRect;
 
   @override
   State<_CustomModalBarrier> createState() => _CustomModalBarrierState();
@@ -503,8 +508,9 @@ class _CustomModalBarrierState extends State<_CustomModalBarrier> {
           builder: (BuildContext context, Color? value, Widget? child) {
             return CustomPaint(
               painter: _DropdownBarrierPainter(
-                buttonRect: widget.buttonRect,
                 barrierColor: value,
+                buttonRect: widget.buttonRect,
+                buttonBorderRadius: widget.buttonBorderRadius,
                 pageSize: size,
               ),
             );
@@ -518,29 +524,47 @@ class _CustomModalBarrierState extends State<_CustomModalBarrier> {
 
 class _DropdownBarrierPainter extends CustomPainter {
   const _DropdownBarrierPainter({
-    this.buttonRect,
-    this.barrierColor,
+    required this.barrierColor,
+    required this.buttonRect,
+    required this.buttonBorderRadius,
     required this.pageSize,
   });
 
-  final Rect? buttonRect;
   final Color? barrierColor;
+  final Rect buttonRect;
+  final BorderRadius buttonBorderRadius;
   final Size pageSize;
 
   @override
   void paint(Canvas canvas, Size size) {
-    if (barrierColor != null && buttonRect != null) {
-      final Rect rect =
-          Rect.fromLTRB(-buttonRect!.left, -buttonRect!.top, pageSize.width, pageSize.height);
+    if (barrierColor != null) {
+      final Rect rect = Rect.fromLTRB(
+        -buttonRect.left,
+        -buttonRect.top,
+        pageSize.width,
+        pageSize.height,
+      );
+
       canvas.saveLayer(rect, Paint());
       canvas.drawRect(rect, Paint()..color = barrierColor!);
-      canvas.drawRect(buttonRect!, Paint()..blendMode = BlendMode.clear);
+
+      final RRect buttonRRect = RRect.fromRectAndCorners(
+        buttonRect,
+        topLeft: buttonBorderRadius.topLeft,
+        topRight: buttonBorderRadius.topRight,
+        bottomLeft: buttonBorderRadius.bottomLeft,
+        bottomRight: buttonBorderRadius.bottomRight,
+      );
+
+      canvas.drawRRect(buttonRRect, Paint()..blendMode = BlendMode.clear);
       canvas.restore();
     }
   }
 
   @override
   bool shouldRepaint(_DropdownBarrierPainter oldPainter) {
-    return oldPainter.buttonRect != buttonRect || oldPainter.barrierColor != barrierColor;
+    return oldPainter.buttonRect != buttonRect ||
+        oldPainter.barrierColor != barrierColor ||
+        oldPainter.buttonBorderRadius != buttonBorderRadius;
   }
 }