如何在颤动行小部件中绘制水平线？

import 'package:flutter/material.dart';

class HorizontalLine extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return CustomPaint(
      size: Size(double.infinity, 2), // 设置线的宽度和高度
      painter: MyPainter(),
    );
  }
}

class MyPainter extends CustomPainter {
  @override
  void paint(Canvas canvas, Size size) {
    final paint = Paint()
      ..color = Colors.black // 设置线的颜色
      ..strokeWidth = size.height // 设置线的宽度
      ..style = PaintingStyle.stroke; // 设置为描边样式

    canvas.drawLine( // 绘制线
      Offset(0, size.height / 2), // 起点
      Offset(size.width, size.height / 2), // 终点
      paint,
    );
  }

  @override
  bool shouldRepaint(MyPainter oldDelegate) {
    return false;
  }
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Horizontal Line Example'),
        ),
        body: Center(
          child: HorizontalLine(),
        ),
      ),
    );
  }
}