From f6747dfa100b578c2425c2b684aade95260b444a Mon Sep 17 00:00:00 2001
From: Justin Hutchins <44933935+jushutch@users.noreply.github.com>
Date: Fri, 14 May 2021 13:39:13 -0400
Subject: [PATCH] Change cursor when hovering on DropdownButton (#80567)

---
 .../flutter/lib/src/material/dropdown.dart    | 19 ++++--
 .../flutter/test/material/dropdown_test.dart  | 59 +++++++++++++++++++
 2 files changed, 74 insertions(+), 4 deletions(-)

diff --git a/packages/flutter/lib/src/material/dropdown.dart b/packages/flutter/lib/src/material/dropdown.dart
index af799084231..4fb769dcdc0 100644
--- a/packages/flutter/lib/src/material/dropdown.dart
+++ b/packages/flutter/lib/src/material/dropdown.dart
@@ -19,6 +19,7 @@ import 'ink_well.dart';
 import 'input_decorator.dart';
 import 'material.dart';
 import 'material_localizations.dart';
+import 'material_state.dart';
 import 'scrollbar.dart';
 import 'shadows.dart';
 import 'theme.dart';
@@ -1501,6 +1502,13 @@ class _DropdownButtonState<T> extends State<DropdownButton<T>> with WidgetsBindi
       );
     }
 
+    final MouseCursor effectiveMouseCursor = MaterialStateProperty.resolveAs<MouseCursor>(
+      MaterialStateMouseCursor.clickable,
+      <MaterialState>{
+        if (!_enabled) MaterialState.disabled,
+      },
+    );
+
     return Semantics(
       button: true,
       child: Actions(
@@ -1509,10 +1517,13 @@ class _DropdownButtonState<T> extends State<DropdownButton<T>> with WidgetsBindi
           canRequestFocus: _enabled,
           focusNode: focusNode,
           autofocus: widget.autofocus,
-          child: GestureDetector(
-            onTap: _enabled ? _handleTap : null,
-            behavior: HitTestBehavior.opaque,
-            child: result,
+          child: MouseRegion(
+            cursor: effectiveMouseCursor,
+            child: GestureDetector(
+              onTap: _enabled ? _handleTap : null,
+              behavior: HitTestBehavior.opaque,
+              child: result,
+            ),
           ),
         ),
       ),
diff --git a/packages/flutter/test/material/dropdown_test.dart b/packages/flutter/test/material/dropdown_test.dart
index 22e1b788c27..2f0668a0535 100644
--- a/packages/flutter/test/material/dropdown_test.dart
+++ b/packages/flutter/test/material/dropdown_test.dart
@@ -5,6 +5,7 @@
 import 'dart:math' as math;
 import 'dart:ui' show window;
 
+import 'package:flutter/gestures.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
@@ -3390,4 +3391,62 @@ void main() {
       expect(feedback.hapticCount, 0);
     });
   });
+
+  testWidgets('DropdownButton changes mouse cursor when hovered', (WidgetTester tester) async {
+    const Key key = Key('testDropdownButton');
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: DropdownButton<String>(
+              key: key,
+              onChanged: (String? newValue) {},
+              items: <String>['One', 'Two', 'Three', 'Four']
+                  .map<DropdownMenuItem<String>>((String value) {
+                return DropdownMenuItem<String>(
+                  value: value,
+                  child: Text(value),
+                );
+              }).toList()
+          ),
+        ),
+      ),
+    );
+
+    final Finder dropdownButtonFinder = find.byKey(key);
+    final Offset onDropdownButton = tester.getCenter(dropdownButtonFinder);
+    final Offset offDropdownButton = tester.getBottomRight(dropdownButtonFinder) + const Offset(1, 1);
+    final TestGesture gesture = await tester.createGesture(kind: PointerDeviceKind.mouse, pointer: 1);
+
+    await gesture.addPointer(location: onDropdownButton);
+    addTearDown(gesture.removePointer);
+
+    await tester.pump();
+
+    expect(RendererBinding.instance!.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.click);
+    await gesture.moveTo(offDropdownButton);
+    expect(RendererBinding.instance!.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.basic);
+
+    // Test that mouse cursor doesn't change when button is disabled
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: DropdownButton<String>(
+              key: key,
+              items: <String>['One', 'Two', 'Three', 'Four']
+                  .map<DropdownMenuItem<String>>((String value) {
+                return DropdownMenuItem<String>(
+                  value: value,
+                  child: Text(value),
+                );
+              }).toList()
+          ),
+        ),
+      ),
+    );
+
+    await gesture.moveTo(onDropdownButton);
+    expect(RendererBinding.instance!.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.basic);
+    await gesture.moveTo(offDropdownButton);
+    expect(RendererBinding.instance!.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.basic);
+  });
 }