Opacity is effective both on and off, height changes only have animation effects when turned on, and not when turned off.

The following is a runnable code that I have tried for a long time, but it has not been successful. I suspect it may be a problem with the controller. I can use the global controller to control it and execute the reverse method

import 'package:flutter/material.dart';
import 'package:flutter/widgets.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        home: Scaffold(
      body: MyHomePage(),
    ));
  }
}

class MyHomePage extends StatelessWidget {
  void _showDismissibleDialog(BuildContext context) async {
    Navigator.of(context).push(DismissibleDialog());
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Dismissible Dialog Example'),
      ),
      body: Center(
        child: ElevatedButton(
          onPressed: () => _showDismissibleDialog(context),
          child: Text('Show Dialog'),
        ),
      ),
    );
  }
}

class DismissibleDialog<T> extends PopupRoute<T> {
  @override
  Color? get barrierColor => Colors.transparent;

  @override
  bool get barrierDismissible => true;

  @override
  String? get barrierLabel => 'Dismissible Dialog';

  @override
  Duration get transitionDuration => const Duration(milliseconds: 300);

  @override
  bool get opaque => false;

  @override
  Widget buildModalBarrier() {
    return const AnimatiedContainer(
      child: BuildBarrier(),
    );
  }

  @override
  Widget buildPage(
    BuildContext context,
    Animation<double> animation,
    Animation<double> secondaryAnimation,
  ) {
    return const AnimatiedContainer(
      child: BuildPage(),
    );
  }
}

class BuildBarrier extends StatelessWidget {
  const BuildBarrier({super.key});

  @override
  Widget build(BuildContext context) {
    final opacityController =
        AnimationControllerProvider.of(context).opacityController;
    final heightController =
        AnimationControllerProvider.of(context).heightController;

    return SafeArea(
      child: Stack(
        children: [
          Positioned(
            top: kToolbarHeight,
            left: 0,
            right: 0,
            bottom: 0,
            child: GestureDetector(
              onTap: () {
                Future.wait([
                  opacityController.reverse(),
                  heightController.reverse(),
                ]).then((res) {
                  Navigator.of(context).pop();
                });
              },
              child: FadeTransition(
                opacity: Tween<double>(begin: 0, end: 0.5).animate(
                  CurvedAnimation(
                      parent: opacityController, curve: Curves.easeInOut),
                ),
                child: Container(
                  color: Colors.black.withOpacity(0.5),
                ),
              ),
            ),
          )
        ],
      ),
    );
  }
}

class BuildPage extends StatelessWidget {
  const BuildPage({super.key});

  @override
  Widget build(BuildContext context) {
    final heightController =
        AnimationControllerProvider.of(context).heightController;

    return SafeArea(
      child: DefaultTextStyle(
        style: Theme.of(context).textTheme.bodyMedium!,
        child: Stack(
          children: [
            Positioned(
              top: kToolbarHeight,
              left: 0,
              child: SizeTransition(
                sizeFactor: Tween<double>(begin: 0, end: 1).animate(
                  CurvedAnimation(
                      parent: heightController, curve: Curves.easeInOut),
                ),
                axisAlignment: -1,
                child: Container(
                  width: MediaQuery.of(context).size.width,
                  padding: const EdgeInsets.all(20.0),
                  decoration: const BoxDecoration(
                    color: Colors.white,
                  ),
                  child: Column(
                    children: <Widget>[
                      Text(
                        'Dismissible Dialog',
                        style: Theme.of(context).textTheme.headlineSmall,
                      ),
                    ],
                  ),
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class AnimatiedContainer extends StatefulWidget {
  final Widget child;

  const AnimatiedContainer({super.key, required this.child});

  @override
  State<AnimatiedContainer> createState() => _AnimatiedContainerState();
}

class _AnimatiedContainerState extends State<AnimatiedContainer>
    with TickerProviderStateMixin {
  late final AnimationController _opacityController;
  late final AnimationController _heightController;

  bool isExpand = false;

  @override
  void initState() {
    super.initState();

    _heightController = AnimationController(
      duration: const Duration(milliseconds: 300),
      vsync: this,
    )..forward();

    _opacityController = AnimationController(
      duration: const Duration(milliseconds: 300),
      vsync: this,
    )..forward();
  }

  @override
  void dispose() {
    _opacityController.dispose();
    _heightController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return AnimationControllerProvider(
      opacityController: _opacityController,
      heightController: _heightController,
      isExpand: isExpand,
      child: Container(
        child: widget.child,
      ),
    );
  }
}

class AnimationControllerProvider extends InheritedWidget {
  final AnimationController opacityController;
  final AnimationController heightController;
  final bool isExpand;

  const AnimationControllerProvider({
    Key? key,
    required this.opacityController,
    required this.heightController,
    required Widget child,
    this.isExpand = false,
  }) : super(key: key, child: child);

  static AnimationControllerProvider of(BuildContext context) {
    final AnimationControllerProvider? result = context
        .dependOnInheritedWidgetOfExactType<AnimationControllerProvider>();
    assert(result != null, 'No AnimationController found in context');
    return result!;
  }

  @override
  bool updateShouldNotify(AnimationControllerProvider old) {
    return opacityController != old.opacityController ||
        heightController != old.heightController;
  }
}