如何在Flutter中创建自定义圆形进度条？

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

class CircularProgressWidget extends CustomPainter {
  final double progress;
  final Color progressColor;
  final Color backgroundColor;

  CircularProgressWidget({
    required this.progress,
    required this.progressColor,
    required this.backgroundColor,
  });

  @override
  void paint(Canvas canvas, Size size) {
    final double strokeWidth = 10; // 进度条宽度
    final double radius = min(size.width, size.height) / 2 - strokeWidth / 2; // 圆形半径
    final Offset center = Offset(size.width / 2, size.height / 2); // 圆心坐标

    // 绘制背景圆形
    final Paint backgroundPaint = Paint()
      ..color = backgroundColor
      ..style = PaintingStyle.stroke
      ..strokeWidth = strokeWidth;
    canvas.drawCircle(center, radius, backgroundPaint);

    // 绘制进度条
    final Paint progressPaint = Paint()
      ..color = progressColor
      ..style = PaintingStyle.stroke
      ..strokeWidth = strokeWidth;
    final double startAngle = -pi / 2; // 进度条开始的角度（-pi/2为12点钟方向）
    final double sweepAngle = 2 * pi * progress; // 进度条跨越的角度
    canvas.drawArc(
      Rect.fromCircle(center: center, radius: radius),
      startAngle,
      sweepAngle,
      false,
      progressPaint,
    );
  }

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

// 在Flutter应用中使用自定义圆形进度条
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Circular Progress'),
        ),
        body: Center(
          child: CustomPaint(
            painter: CircularProgressWidget(
              progress: 0.7, // 设置进度值
              progressColor: Colors.blue, // 设置进度条颜色
              backgroundColor: Colors.grey, // 设置背景颜色
            ),
            child: Container(
              width: 200,
              height: 200,
            ),
          ),
        ),
      ),
    );
  }
}

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