android - 从文件中读取值并放入Flutter中的ListView

Question

我正在尝试从文本文件中读取逗号分隔的值，用逗号分隔字符串，然后将这些值中的每一个显示为ListTile中的ListView。

我真的不知道如何正确地做到这一点。这个异步代码正在杀死我!

tiles.txt

first,second,third,fourth,fifth

这是没有从文本文件中读取任何内容的代码:

main.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Scaffold(
        appBar: AppBar(
          title: Text("My App"),
        ),
        body: MainPage(),
      ),
    );
  }
}

class MainPage extends StatelessWidget {
  final listItems = [];

  @override
  Widget build(BuildContext context){
    return ListView.separated(
      itemCount: listItems.length,
      itemBuilder: (context, index){
        return ListTile(
          leading: Icon(Icons.invert_colors),
          title: Text(listItems[index]),
        );
      },
      separatorBuilder: (context, index){
        return Divider();
      },
    );
  }
}

如果有人能弄清楚如何从文件中读取并将其显示为 ListView，那将是很好的，即使这不是我编写的方式!

Answer 1

您可以在下面复制粘贴运行完整代码
您可以使用https://pub.dev/packages/csv软件包
步骤1:以读取模式打开文件

final input = new File('$appDocPath/tiles.txt').openRead();

步骤2:使用 transform和 CsvToListConverter

listItems = await input
    .transform(utf8.decoder)
    .transform(new CsvToListConverter())
    .toList();

假设您在 tile.text目录中有一个 /data/user/0/yourDomain.yourProjectname/app_flutter


程式码片段

Directory appDocDir = await getApplicationDocumentsDirectory();
String appDocPath = appDocDir.path;
print(appDocPath);
final input = new File('$appDocPath/tiles.txt').openRead();
listItems = await input
        .transform(utf8.decoder)
        .transform(new CsvToListConverter())
        .toList();

...
ListView.separated(
                      itemCount: listItems[0].length,
                      itemBuilder: (context, index) {
                        return ListTile(
                          leading: Icon(Icons.invert_colors),
                          title: Text(listItems[0][index]),
                        );

工作演示



完整的代码

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

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;
  dynamic listItems;

  void _incrementCounter() async {
    Directory appDocDir = await getApplicationDocumentsDirectory();
    String appDocPath = appDocDir.path;
    print(appDocPath);
    final input = new File('$appDocPath/tiles.txt').openRead();
    listItems = await input
        .transform(utf8.decoder)
        .transform(new CsvToListConverter())
        .toList();
    print(listItems[0][0].toString());
    setState(() {
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            listItems == null
                ? Container()
                : Expanded(
                    child: ListView.separated(
                      itemCount: listItems[0].length,
                      itemBuilder: (context, index) {
                        return ListTile(
                          leading: Icon(Icons.invert_colors),
                          title: Text(listItems[0][index]),
                        );
                      },
                      separatorBuilder: (context, index) {
                        return Divider();
                      },
                    ),
                  ),
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}