Reland "Prevent material switch from recreating its render object when it...

Reland "Prevent material switch from recreating its render object when it becomes disabled (#61398)", reverted in #64062 (#64354)

packages/flutter/lib/src/widgets/actions.dart

@@ -1090,9 +1090,17 @@ class _FocusableActionDetectorState extends State<FocusableActionDetector> {
     return null;
   }
 
+  // This global key is needed to keep only the necessary widgets in the tree
+  // while maintaining the subtree's state.
+  //
+  // See https://github.com/flutter/flutter/issues/64058 for an explanation of
+  // why using a global key over keeping the shape of the tree.
+  final GlobalKey _mouseRegionKey = GlobalKey();
+
   @override
   Widget build(BuildContext context) {
     Widget child = MouseRegion(
+      key: _mouseRegionKey,
       onEnter: _handleMouseEnter,
       onExit: _handleMouseExit,
       cursor: widget.mouseCursor,

packages/flutter/test/material/checkbox_test.dart

@@ -101,6 +101,15 @@ void main() {
       ),
     ));
 
+    expect(tester.getSemantics(find.byWidgetPredicate((Widget widget) => widget.runtimeType.toString() == '_CheckboxRenderObjectWidget')), matchesSemantics(
+      hasCheckedState: true,
+      hasEnabledState: true,
+      // isFocusable is delayed by 1 frame.
+      isFocusable: true,
+    ));
+
+    await tester.pump();
+    // isFocusable should be false now after the 1 frame delay.
     expect(tester.getSemantics(find.byWidgetPredicate((Widget widget) => widget.runtimeType.toString() == '_CheckboxRenderObjectWidget')), matchesSemantics(
       hasCheckedState: true,
       hasEnabledState: true,

packages/flutter/test/material/radio_test.dart

@@ -237,7 +237,24 @@ void main() {
     expect(semantics, hasSemantics(TestSemantics.root(
       children: <TestSemantics>[
         TestSemantics.rootChild(
-          id: 2,
+          id: 1,
+          flags: <SemanticsFlag>[
+            SemanticsFlag.hasCheckedState,
+            SemanticsFlag.hasEnabledState,
+            SemanticsFlag.isInMutuallyExclusiveGroup,
+            SemanticsFlag.isFocusable,  // This flag is delayed by 1 frame.
+          ],
+        ),
+      ],
+    ), ignoreRect: true, ignoreTransform: true));
+
+    await tester.pump();
+
+    // Now the isFocusable should be gone.
+    expect(semantics, hasSemantics(TestSemantics.root(
+      children: <TestSemantics>[
+        TestSemantics.rootChild(
+          id: 1,
           flags: <SemanticsFlag>[
             SemanticsFlag.hasCheckedState,
             SemanticsFlag.hasEnabledState,
@@ -258,7 +275,7 @@ void main() {
     expect(semantics, hasSemantics(TestSemantics.root(
       children: <TestSemantics>[
         TestSemantics.rootChild(
-          id: 2,
+          id: 1,
           flags: <SemanticsFlag>[
             SemanticsFlag.hasCheckedState,
             SemanticsFlag.isChecked,

packages/flutter/test/material/slider_test.dart

@@ -1402,7 +1402,11 @@ void main() {
                       children: <TestSemantics>[
                         TestSemantics(
                           id: 4,
-                          flags: <SemanticsFlag>[SemanticsFlag.hasEnabledState],
+                          flags: <SemanticsFlag>[
+                            SemanticsFlag.hasEnabledState,
+                            // isFocusable is delayed by 1 frame.
+                            SemanticsFlag.isFocusable,
+                          ],
                           value: '50%',
                           increasedValue: '55%',
                           decreasedValue: '45%',
@@ -1420,6 +1424,47 @@ void main() {
         ignoreTransform: true,
       ),
     );
+
+    await tester.pump();
+    expect(
+      semantics,
+      hasSemantics(
+        TestSemantics.root(
+          children: <TestSemantics>[
+            TestSemantics(
+              id: 1,
+              textDirection: TextDirection.ltr,
+              children: <TestSemantics>[
+                TestSemantics(
+                  id: 2,
+                  children: <TestSemantics>[
+                    TestSemantics(
+                      id: 3,
+                      flags: <SemanticsFlag>[SemanticsFlag.scopesRoute],
+                      children: <TestSemantics>[
+                        TestSemantics(
+                          id: 4,
+                          flags: <SemanticsFlag>[
+                            SemanticsFlag.hasEnabledState,
+                          ],
+                          value: '50%',
+                          increasedValue: '55%',
+                          decreasedValue: '45%',
+                          textDirection: TextDirection.ltr,
+                        ),
+                      ],
+                    ),
+                  ],
+                ),
+              ],
+            ),
+          ],
+        ),
+        ignoreRect: true,
+        ignoreTransform: true,
+      ),
+    );
+
     semantics.dispose();
   }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.android,  TargetPlatform.fuchsia, TargetPlatform.linux, TargetPlatform.windows }));
 

packages/flutter/test/material/switch_test.dart

@@ -1015,4 +1015,51 @@ void main() {
 
     await tester.pumpAndSettle();
   });
+
+  testWidgets('Material switch should not recreate its render object when disabled', (WidgetTester tester) async {
+    // Regression test for https://github.com/flutter/flutter/issues/61247.
+    bool value = true;
+    bool enabled = true;
+    StateSetter stateSetter;
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: StatefulBuilder(
+          builder: (BuildContext context, StateSetter setState) {
+            stateSetter = setState;
+            return Material(
+              child: Center(
+                child: Switch(
+                  value: value,
+                  onChanged: !enabled ? null : (bool newValue) {
+                    setState(() {
+                      value = newValue;
+                    });
+                  },
+                ),
+              ),
+            );
+          },
+        ),
+      ),
+    );
+
+    final RenderToggleable oldSwitchRenderObject = tester
+      .renderObject(find.byWidgetPredicate((Widget widget) => widget is LeafRenderObjectWidget));
+
+    stateSetter(() { value = false; });
+    await tester.pump();
+    // Disable the switch when the implicit animation begins.
+    stateSetter(() { enabled = false; });
+    await tester.pump();
+
+    final RenderToggleable updatedSwitchRenderObject = tester
+      .renderObject(find.byWidgetPredicate((Widget widget) => widget is LeafRenderObjectWidget));
+
+
+    expect(updatedSwitchRenderObject.isInteractive, false);
+    expect(updatedSwitchRenderObject, oldSwitchRenderObject);
+    expect(updatedSwitchRenderObject.position.isCompleted, false);
+    expect(updatedSwitchRenderObject.position.isDismissed, false);
+  });
 }