如何在Flutter中的圆环图的孔中添加饼图，我尝试使用Stack控件，但它只适用于文本

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

class PieChart extends StatelessWidget {
  final List<double> data;

  PieChart({required this.data});

  @override
  Widget build(BuildContext context) {
    return CustomPaint(
      painter: PieChartPainter(data: data),
    );
  }
}

class PieChartPainter extends CustomPainter {
  final List<double> data;

  PieChartPainter({required this.data});

  @override
  void paint(Canvas canvas, Size size) {
    double total = data.reduce((value, element) => value + element);
    double startRadian = -pi / 2; // 从12点钟方向开始绘制

    for (int i = 0; i < data.length; i++) {
      double sweepRadian = data[i] / total * 2 * pi;

      Paint paint = Paint()
        ..style = PaintingStyle.fill
        ..color = _getColor(i);

      canvas.drawArc(
        Rect.fromCircle(center: size.center(Offset.zero), radius: size.width / 2),
        startRadian,
        sweepRadian,
        true,
        paint,
      );

      startRadian += sweepRadian;
    }
  }

  Color _getColor(int index) {
    // 根据需要自定义颜色
    List<Color> colors = [
      Colors.red,
      Colors.green,
      Colors.blue,
      Colors.yellow,
      Colors.orange,
    ];

    return colors[index % colors.length];
  }

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

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Pie Chart'),
      ),
      body: Center(
        child: Container(
          width: 200,
          height: 200,
          child: Stack(
            children: [
              Container(
                decoration: BoxDecoration(
                  shape: BoxShape.circle,
                  border: Border.all(
                    color: Colors.black,
                    width: 2,
                  ),
                ),
              ),
              PieChart(data: [30, 40, 20, 10]),
            ],
          ),
        ),
      ),
    );
  }
}

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