Csv 试图在未来函数中更新我的状态，在按钮小部件中

因此，我正在开发一个通过本地存储的.csv文件注册营养数据的应用程序。营养数据显示在应用程序的主页上。对于从.csv文件添加到应用程序主页的每一行数据，我都会动态添加一个删除按钮（应用程序中的垃圾桶）。我编写了一些代码，然后从.csv文件中删除相应的数据行，之后我想更新主屏幕，以便显示新的.csv文件内容（该行不再可见）。删除功能似乎可以工作，但是在我按下垃圾桶图标后，页面不会用新数据更新自身。只有当我按下显示“Toevoegen”的按钮重新加载页面并按下“Toevoegen”页面中的“back”按钮返回主页面后，主页面才更新为新的.csv文件

我认为这与异步读取.csv文件的函数有关

这是

main.dart

文件的代码：

import 'package:percent_indicator/linear_percent_indicator.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

import 'package:eifit_dual/utility.dart';
import 'package:eifit_dual/addMeal.dart';

void main() => runApp(App());

class App extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Navigation',
      home: EiFit(),
    );
  }
}

class EiFit extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return _EiFitState();
  }
}

class _EiFitState extends State<EiFit> {
  LinearPercentIndicator _percentageIndicator;
  List<Widget> morningContent = [];
  List<Widget> afternoonContent = [];
  List<Widget> eveningContent = [];

  @override
  void initState() {
    super.initState();
    _updatePercentage();
    _getCSVContent();
  }

  void _getCSVContent() async {
    final _newCSV = await readCSV();
    List<Widget> _morningContent = [];
    List<Widget> _afternoonContent = [];
    List<Widget> _eveningContent = [];

    for (var line in _newCSV) {
      if (line[1] == 'ochtend') {
        _morningContent.add(Row(
          children: [
            Text(mealNames[line[0]]),
            IconButton(
              icon: Icon(Icons.delete),
              onPressed: () {
                removeLineCSV(line).then((result) {});
              },
            ),
          ],
        ));
      } else if (line[1] == 'middag') {
        _afternoonContent.add(Row(
          children: [
            Text(mealNames[line[0]]),
            IconButton(icon: Icon(Icons.delete))
          ],
        ));
      } else if (line[1] == 'avond') {
        _eveningContent.add(Row(
          children: [
            Text(mealNames[line[0]]),
            IconButton(icon: Icon(Icons.delete))
          ],
        ));
      }
    }

    setState(() {
      morningContent = _morningContent;
      afternoonContent = _afternoonContent;
      eveningContent = _eveningContent;
    });
  }

  Future _updatePercentage() async {
    final exists = await existsCSV();
    double _currentPercentage;

    if (exists) {
      _currentPercentage = await getCurrentPoints() / 12;
      print(_currentPercentage);
    } else {
      _currentPercentage = 0;
    }

    setState(() {
      _percentageIndicator = LinearPercentIndicator(
        width: MediaQuery.of(context).size.width - 30,
        animation: true,
        lineHeight: 20.0,
        animationDuration: 400,
        percent: _currentPercentage > 1 ? 1 : _currentPercentage,
        center: Text((_currentPercentage * 100).toStringAsFixed(0) + '%'),
        linearStrokeCap: LinearStrokeCap.roundAll,
        progressColor: Colors.green,
      );
    });
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('EiFit'),
        ),
        body: SingleChildScrollView(
          child: Column(
            children: [
              Text(
                'Progressie',
                style: TextStyle(fontSize: 25, fontWeight: FontWeight.bold),
              ),
              Padding(
                padding: EdgeInsets.all(15.0),
                child: _percentageIndicator,
              ),
              Divider(
                color: Colors.grey,
              ),
              Text(
                'Ochtend',
                style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
              ),
              Column(
                children: morningContent,
              ),
              Divider(
                color: Colors.grey,
              ),
              Text(
                'Middag',
                style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
              ),
              Column(
                children: afternoonContent,
              ),
              Divider(
                color: Colors.grey,
              ),
              Text(
                'Avond',
                style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
              ),
              Column(
                children: eveningContent,
              ),
              Divider(
                color: Colors.grey,
              ),
            ],
          ),
        ),
        floatingActionButton: FloatingActionButton.extended(
          label: Text('Toevoegen'),
          icon: Icon(Icons.add),
          backgroundColor: Colors.green,
          onPressed: () {
            Navigator.of(context)
                .push(MaterialPageRoute(builder: (context) => AddMeal()))
                .then((context) {
              _updatePercentage();
              _getCSVContent();
            });
          },
        ),
      ),
    );
  }
}

方法

\u getCSVContent

调用读取.csv文件的函数。然后，逐行读取.csv文件，并为每行的数据创建一个

Row（）

小部件，其中包含一个

Text（）

小部件，其中包含.csv数据。在这个

Text（）

小部件的旁边，创建了一个

IconButton

，一旦按下它就会删除数据

我知道这是很多代码要弄清楚。我真的希望有人能理解这个问题并提出解决方案。谢谢你的阅读

import 'dart:convert';
import 'package:path_provider/path_provider.dart';
import 'dart:io';
import 'package:csv/csv.dart';
import 'package:collection/collection.dart';

Future<String> get localPath async {
  final directory = await getApplicationDocumentsDirectory();
  return directory.path;
}

Future<File> get localFile async {
  final path = await localPath;
  return File('$path/nutrition_data.csv');
}

Future<File> writeToCSV(newContent) async {
  final file = await localFile;
  final path = await localPath;
  final exists = await File('$path/nutrition_data.csv').exists();

  if (exists) {
    String content = await file.readAsString();
    print('CONTENT');
    print(content);
    return file.writeAsString(content + newContent);
  } else {
    return file.writeAsString(newContent);
  }
}

Future<void> clearCSV() async {
  final file = await localFile;
  final path = await localPath;
  final exists = await File('$path/nutrition_data.csv').exists();

  if (exists) {
    file.writeAsString('');
  } else {
    print('No such file was found.');
  }
}

Future<bool> existsCSV() async {
  final path = await localPath;
  final exists = await File('$path/nutrition_data.csv').exists();

  if (exists) {
    return true;
  } else {
    return false;
  }
}

Future<List> readCSV() async {
  final path = await localPath;

  final csv = File('$path/nutrition_data.csv').openRead();
  final fields = await csv
      .transform(utf8.decoder)
      .transform(new CsvToListConverter())
      .toList();

  return fields;
}

Future<double> getCurrentPoints() async {
  final csvData = await readCSV();
  double _total = 0;
  for (final row in csvData) {
    _total += row[2];
  }
  return _total;
}

Future<void> removeLineCSV(List deleteLine) async {
  Function equal = const ListEquality().equals;
  final path = await localPath;
  bool lineDeleted = false;

  final csv = File('$path/nutrition_data.csv').openRead();
  final fields = await csv
      .transform(utf8.decoder)
      .transform(new CsvToListConverter())
      .toList();

  clearCSV();

  for (var line in fields) {

    if (equal(deleteLine, line) && (!lineDeleted)) {
      lineDeleted = true;
    } else {
      writeToCSV(line[0].toString() +
          ',' +
          line[1].toString() +
          ',' +
          line[2].toString() +
          '\r\n');
    }
  }
}

// A Map, to map the encoded names of meals into a presentable format
Map mealNames = {
  'melk_yoghurt': 'Melk of yoghurt (1pt)',
  'ontbijtgranen': 'Ontbijtgranen (2pt)',
  'eiwitvoeding': 'Eiwitvoeding (2pt)',
  'brood_zoet': 'Brood, zoet beleg (1pt)',
  'brood_hartig': 'Brood, hartig beleg (2pt)',
  'kwart_bord': 'Kwart bord, warm (2pt)',
  'half_bord': 'Half bord, warm (3pt)',
  'heel_bord': 'Heel bord, warm (6pt)',
  'tussendoortje_zoet': 'Tussendoortje, zoet (0.5pt)',
  'tussendoortje_hartig': 'Tussendoortje, hartig (1pt)'
};