问内容在应用程序条曲线以颤振开始之前消失。

EN

import 'package:flutter/material.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  static const String _title = 'Flutter Code Sample';

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: _title,
      home: Scaffold(
        appBar: AppBar(title: const Text(_title), elevation: 0),
        body: Stack(children: [
          ListView(
            children: List.generate(
              100,
              (i) {
                return ListTile(
                  title: Text(
                    'item $i',
                    textAlign: TextAlign.center,
                  ),
                );
              },
            ),
          ),
          Positioned(
            top: 0,
            left: 0,
            right: 0,
            height: 100,
            child: CustomPaint(
              painter: ShapePainter(),
              child: Container(),
            ),
          ),
        ]),
      ),
    );
  }
}

class ShapePainter extends CustomPainter {
  @override
  void paint(Canvas canvas, Size size) {
    var path = Path();
    path.moveTo(0, 0);
    path.lineTo(size.width, 0);
    path.lineTo(size.width, size.height);
    path.arcToPoint(
      Offset(0, size.height),
      radius: Radius.circular(size.width * 0.7),
      clockwise: false,
    );
    path.close();

    var paint = Paint();
    paint.color = Colors.blue;
    paint.style = PaintingStyle.fill;

    canvas.drawPath(path, paint);
  }

  @override
  bool shouldRepaint(CustomPainter oldDelegate) => true;
}

        ),
      ),
    ),
  ),