如何从flutter中的firestore开发饼图

dependencies:
  cloud_firestore: ^2.5.3

import 'package:cloud_firestore/cloud_firestore.dart';

FirebaseFirestore firestore = FirebaseFirestore.instance;

CollectionReference pieChartCollection = firestore.collection('pie_chart');
QuerySnapshot querySnapshot = await pieChartCollection.get();
List<QueryDocumentSnapshot> documents = querySnapshot.docs;

dependencies:
  charts_flutter: ^0.11.0

import 'package:charts_flutter/flutter.dart' as charts;

List<charts.Series<PieData, String>> seriesList = [
  charts.Series(
    id: 'pie_chart',
    data: documents.map((doc) {
      // 假设文档中有"name"和"value"字段
      String name = doc['name'];
      int value = doc['value'];
      return PieData(name, value);
    }).toList(),
    domainFn: (PieData data, _) => data.name,
    measureFn: (PieData data, _) => data.value,
  ),
];

Widget pieChart = charts.PieChart(
  seriesList,
  animate: true,
);

class PieData {
  final String name;
  final int value;

  PieData(this.name, this.value);
}