Flutter实现每日数据按月分组并汇总人员收入明细

明确实体类结构 #

假设你的实体类定义如下（若和实际结构有出入，调整字段名即可）：

class StaffIncome {
  final String staffName;
  final double amount;

  StaffIncome({required this.staffName, required this.amount});
}

class DailySummary {
  final DateTime date;
  final double totalDaily;
  final List<StaffIncome> staffIncomes;

  DailySummary({
    required this.date,
    required this.totalDaily,
    required this.staffIncomes,
  });
}

核心实现逻辑 #

借助collection包的groupBy先按月份分组每日数据，再对每个月的分组完成两层汇总：

• 月度总金额：累加当月所有每日总金额
• 人员月度收入：将当月所有StaffIncome按人员名称分组，再求和每个人员的收入总额

import 'package:collection/collection.dart';

// 定义月度汇总实体类（按需调整字段）
class MonthlySummary {
  final String monthKey; // 格式示例："2024-05"
  final double totalMonthly;
  final Map<String, double> staffMonthlyIncomes;

  MonthlySummary({
    required this.monthKey,
    required this.totalMonthly,
    required this.staffMonthlyIncomes,
  });
}

List<MonthlySummary> generateMonthlySummaries(List<DailySummary> dailySummaries) {
  // 第一步：按"yyyy-MM"格式的月份字符串分组每日数据
  final groupedByMonth = groupBy(dailySummaries, (DailySummary ds) {
    return "${ds.date.year}-${ds.date.month.toString().padLeft(2, '0')}";
  });

  // 第二步：遍历每个月的分组，生成月度汇总数据
  return groupedByMonth.entries.map((entry) {
    final monthKey = entry.key;
    final dailyList = entry.value;

    // 计算当月总金额
    final totalMonthly = dailyList.fold(0.0, (sum, ds) => sum + ds.totalDaily);

    // 扁平化当月所有人员收入记录，再按人员分组求和
    final allStaffIncomes = dailyList.expand((ds) => ds.staffIncomes).toList();
    final staffGrouped = groupBy(allStaffIncomes, (StaffIncome si) => si.staffName);
    final staffMonthlyIncomes = staffGrouped.map((staffName, incomes) {
      final staffTotal = incomes.fold(0.0, (sum, si) => sum + si.amount);
      return MapEntry(staffName, staffTotal);
    });

    return MonthlySummary(
      monthKey: monthKey,
      totalMonthly: totalMonthly,
      staffMonthlyIncomes: staffMonthlyIncomes,
    );
  }).toList();
}

输入输出示例验证 #

输入示例

final dailyData = [
  DailySummary(
    date: DateTime(2024, 5, 1),
    totalDaily: 500.0,
    staffIncomes: [
      StaffIncome(staffName: "张三", amount: 200.0),
      StaffIncome(staffName: "李四", amount: 300.0),
    ],
  ),
  DailySummary(
    date: DateTime(2024, 5, 15),
    totalDaily: 600.0,
    staffIncomes: [
      StaffIncome(staffName: "张三", amount: 250.0),
      StaffIncome(staffName: "王五", amount: 350.0),
    ],
  ),
  DailySummary(
    date: DateTime(2024, 6, 2),
    totalDaily: 400.0,
    staffIncomes: [
      StaffIncome(staffName: "李四", amount: 180.0),
      StaffIncome(staffName: "王五", amount: 220.0),
    ],
  ),
];

输出结果

调用generateMonthlySummaries(dailyData)后，会得到：

[
  MonthlySummary(
    monthKey: "2024-05",
    totalMonthly: 1100.0,
    staffMonthlyIncomes: {
      "张三": 450.0,
      "李四": 300.0,
      "王五": 350.0,
    },
  ),
  MonthlySummary(
    monthKey: "2024-06",
    totalMonthly: 400.0,
    staffMonthlyIncomes: {
      "李四": 180.0,
      "王五": 220.0,
    },
  ),
]

关键说明 #

• 月份分组使用yyyy-MM格式的字符串作为key，确保同一月份的不同日期数据会被分到同一组
• 通过expand方法将每日的人员收入列表扁平化为一个大列表，再按人员分组求和，自动适配新增的人员
• 所有求和操作使用fold实现，逻辑清晰且性能高效

内容的提问来源于stack exchange，提问作者Jacob Handaya