fix: "show dialog" functions should allow setting an AnimationStyle (#164002)

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fixes issue #154744

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---------

Co-authored-by: Tong Mu <dkwingsmt@users.noreply.github.com>

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

@@ -1466,6 +1466,7 @@ Future<T?> showDialog<T>({
   Offset? anchorPoint,
   TraversalEdgeBehavior? traversalEdgeBehavior,
   bool? requestFocus,
+  AnimationStyle? animationStyle,
 }) {
   assert(_debugIsActive(context));
   assert(debugCheckHasMaterialLocalizations(context));
@@ -1492,6 +1493,7 @@ Future<T?> showDialog<T>({
       anchorPoint: anchorPoint,
       traversalEdgeBehavior: traversalEdgeBehavior ?? TraversalEdgeBehavior.closedLoop,
       requestFocus: requestFocus,
+      animationStyle: animationStyle,
     ),
   );
 }
@@ -1516,6 +1518,7 @@ Future<T?> showAdaptiveDialog<T>({
   Offset? anchorPoint,
   TraversalEdgeBehavior? traversalEdgeBehavior,
   bool? requestFocus,
+  AnimationStyle? animationStyle,
 }) {
   final ThemeData theme = Theme.of(context);
   switch (theme.platform) {
@@ -1535,6 +1538,7 @@ Future<T?> showAdaptiveDialog<T>({
         anchorPoint: anchorPoint,
         traversalEdgeBehavior: traversalEdgeBehavior,
         requestFocus: requestFocus,
+        animationStyle: animationStyle,
       );
     case TargetPlatform.iOS:
     case TargetPlatform.macOS:
@@ -1628,7 +1632,9 @@ class DialogRoute<T> extends RawDialogRoute<T> {
     super.requestFocus,
     super.anchorPoint,
     super.traversalEdgeBehavior,
-  }) : super(
+    AnimationStyle? animationStyle,
+  }) : _animationStyle = animationStyle,
+       super(
          pageBuilder: (
            BuildContext buildContext,
            Animation<double> animation,
@@ -1642,16 +1648,21 @@ class DialogRoute<T> extends RawDialogRoute<T> {
            return dialog;
          },
          barrierLabel: barrierLabel ?? MaterialLocalizations.of(context).modalBarrierDismissLabel,
-         transitionDuration: const Duration(milliseconds: 150),
+         transitionDuration: animationStyle?.duration ?? const Duration(milliseconds: 150),
          transitionBuilder: _buildMaterialDialogTransitions,
        );
 
   CurvedAnimation? _curvedAnimation;
+  final AnimationStyle? _animationStyle;
 
   void _setAnimation(Animation<double> animation) {
     if (_curvedAnimation?.parent != animation) {
       _curvedAnimation?.dispose();
-      _curvedAnimation = CurvedAnimation(parent: animation, curve: Curves.easeOut);
+      _curvedAnimation = CurvedAnimation(
+        parent: animation,
+        curve: _animationStyle?.curve ?? Curves.easeOut,
+        reverseCurve: _animationStyle?.reverseCurve ?? Curves.easeOut,
+      );
     }
   }
 

packages/flutter/test/material/dialog_test.dart

@@ -2682,6 +2682,39 @@ void main() {
     expect(find.text('Dialog2'), findsOneWidget);
   });
 
+  testWidgets('Applies AnimationStyle to showAdaptiveDialog', (WidgetTester tester) async {
+    const AnimationStyle animationStyle = AnimationStyle(
+      duration: Duration(seconds: 1),
+      curve: Curves.easeInOut,
+    );
+
+    await tester.pumpWidget(
+      const MaterialApp(
+        home: Material(child: Center(child: ElevatedButton(onPressed: null, child: Text('Go')))),
+      ),
+    );
+    final BuildContext context = tester.element(find.text('Go'));
+    showAdaptiveDialog<void>(
+      context: context,
+      builder: (BuildContext context) {
+        return Container(
+          width: 100.0,
+          height: 100.0,
+          alignment: Alignment.center,
+          child: const Text('Dialog1'),
+        );
+      },
+      animationStyle: animationStyle,
+    );
+
+    await tester.pumpAndSettle(const Duration(seconds: 1));
+    expect(find.text('Dialog1'), findsOneWidget);
+
+    await tester.tapAt(const Offset(10.0, 10.0));
+    await tester.pumpAndSettle(const Duration(seconds: 1));
+    expect(find.text('Dialog1'), findsNothing);
+  });
+
   testWidgets('Uses open focus traversal when overridden', (WidgetTester tester) async {
     final FocusNode okNode = FocusNode();
     addTearDown(okNode.dispose);