如何在Flutter中使用pdf包生成多成员多页PDF报表

核心改造思路 #

将原单页报表逻辑改为遍历成员列表，为每个成员单独生成报表页面并合并到同一个PDF文档中，同时调整参数结构以支持批量传入成员信息及对应交易数据。

改造后完整代码 #

import 'package:bachat_gat/common/common_index.dart';
import 'package:bachat_gat/features/groups/models/models_index.dart';
import 'package:flutter/services.dart';
import 'package:pdf/pdf.dart';
import 'package:pdf/widgets.dart' as pw;
import 'package:printing/printing.dart';

import 'getFontLoad.dart';

class PdfApi {
  // 改造方法：接收成员名列表和按成员分组的交易数据
  static Future<Uint8List> generateMultiMemberTable(
    Map<String, List<MemberTransactionDetails>> memberDataMap,
    String groupName,
    List<String> memberNames,
  ) async {
    // 一次性加载所有字体，避免重复加载浪费资源
    final rfont = await FontLoaders.loadFont('assets/fonts/NotoSansDevanagari-Regular.ttf');
    final mfont = await FontLoaders.loadFont('assets/fonts/NotoSansDevanagari-Medium.ttf');
    final bfont = await FontLoaders.loadFont('assets/fonts/NotoSansDevanagari-Bold.ttf');
    final sbfont = await FontLoaders.loadFont('assets/fonts/NotoSansDevanagari-SemiBold.ttf');
    final nfont = await FontLoaders.loadFont('assets/fonts/marathi.ttf');

    var myTheme = pw.ThemeData.withFont(
      base: rfont,
      bold: bfont,
      fontFallback: [nfont, mfont, sbfont],
    );
    final pdf = pw.Document(theme: myTheme);
    final headers = [
      'Month',
      'Paid Shares',
      'Loan Taken',
      'Paid Interest',
      'Paid Loan',
      'Remaining Loan',
      'Late Fee',
      'Others',
      'Total Paid'
    ];

    // 遍历每个成员，生成对应报表页面
    for (String memberName in memberNames) {
      final memberData = memberDataMap[memberName] ?? [];
      List<double> totalPaid = [];
      for (var m in memberData) {
        double total = m.paidOtherAmount! +
            m.paidInterest! +
            m.paidLoan! +
            m.paidLateFee! +
            m.paidShares!;
        totalPaid.add(total);
      }

      final data = memberData
          .asMap()
          .entries
          .map((entry) => [
                entry.value.trxPeriod ?? '',
                entry.value.paidShares?.toString() ?? '',
                entry.value.loanTaken?.toString() ?? '',
                entry.value.paidInterest?.toString() ?? '',
                entry.value.paidLoan?.toString() ?? '',
                entry.value.remainingLoan?.toString() ?? '',
                entry.value.paidLateFee?.toString() ?? '',
                entry.value.paidOtherAmount?.toString() ?? '',
                totalPaid[entry.key].toString(),
              ])
          .toList();

      // 为当前成员添加独立页面
      pdf.addPage(pw.Page(build: (context) {
        return pw.Column(
          children: [
            pw.Text(groupName,
                style: pw.TextStyle(
                  fontSize: 20,
                  fontWeight: pw.FontWeight.bold,
                )),
            pw.SizedBox(height: 20),
            pw.Text("Member Name: $memberName",
                style: pw.TextStyle(
                  fontSize: 15,
                  fontWeight: pw.FontWeight.normal,
                  fontStyle: pw.FontStyle.normal,
                )),
            pw.SizedBox(height: 15),
            pw.TableHelper.fromTextArray(
              headers: headers,
              data: data,
            ),
          ],
        );
      }));
    }

    return pdf.save();
  }

  static Future<void> previewPDF(Uint8List bytes) async {
    await Printing.layoutPdf(onLayout: (PdfPageFormat format) => bytes);
  }

  static Future<void> saveAsPDF(String fileName, Uint8List bytes) async {
    await AppUtils.saveAsBytes(fileName, "pdf", bytes);
  }
}

关键修改说明 #

1. 参数结构调整：将原单个成员的memberData和memberName改为Map<String, List<MemberTransactionDetails>>（键为成员名，值为对应交易数据）和List<String>成员列表，实现批量处理。
2. 字体加载优化：字体仅在方法开头加载一次，避免循环中重复加载导致性能损耗。
3. 多页生成逻辑：通过for循环遍历成员列表，为每个成员计算交易总额、生成表格数据，再调用pdf.addPage()添加独立页面。
4. 空值兼容处理：获取成员交易数据时增加?? []判断，避免成员无数据时出现异常。

内容的提问来源于stack exchange，提问作者BTCOD278 Pranav Mohite