flutter如何从底部制作模态路径动画

import 'package:flutter/material.dart';

class ModalPathAnimation extends StatefulWidget {
  @override
  _ModalPathAnimationState createState() => _ModalPathAnimationState();
}

class _ModalPathAnimationState extends State<ModalPathAnimation>
    with SingleTickerProviderStateMixin {
  AnimationController _controller;
  Animation<double> _animation;

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(
      vsync: this,
      duration: Duration(milliseconds: 500),
    );
    _animation = CurvedAnimation(
      parent: _controller,
      curve: Curves.easeInOut,
    );
  }

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  void _toggleAnimation() {
    if (_controller.isCompleted) {
      _controller.reverse();
    } else {
      _controller.forward();
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Modal Path Animation'),
      ),
      body: Center(
        child: ElevatedButton(
          child: Text('Show Modal'),
          onPressed: _toggleAnimation,
        ),
      ),
      floatingActionButton: AnimatedBuilder(
        animation: _animation,
        builder: (context, child) {
          return Transform.translate(
            offset: Offset(0.0, _animation.value * 200.0),
            child: FloatingActionButton(
              child: Icon(_controller.isCompleted ? Icons.close : Icons.add),
              onPressed: _toggleAnimation,
            ),
          );
        },
      ),
    );
  }
}

void main() {
  runApp(MaterialApp(
    home: ModalPathAnimation(),
  ));
}