如何运行在子部件 FLUTTER 中发挥作用

Question

在我的 main.dart 中，我有 StatefulWidget 并且 class 扩展了 State 和函数以将字符串写入和读取本地文件：

  Future<void> _writeDataToFile(favs) async {
    final _dirPath = await _getDirPath();
    final _myFile = File('$_dirPath/fav.txt');
    await _myFile.writeAsString("||${_myVariable}||");
  }

  Future<void> _readData() async {
    final dirPath = await _getDirPath();
    final myFile = File('$dirPath/fav.txt');
    final data = await myFile.readAsString(encoding: utf8);

    setState(() {
      _content = data;
    });
  }

我运行来自分隔文件的小部件：

itemBuilder: (context, index) => allRadioList(articles[index], context, _content),

我如何运行 _readData() 从 allRadioList 小部件更改状态。

这是我的 allRadioList(articles[index], context, _content) 代码：

Widget allRadioList(Article article, BuildContext context, String contentt) {
  return Card(
      child: ListTile(
    title: Text(article.title),
    subtitle: Text(contentt),
    leading: CircleAvatar(backgroundImage: NetworkImage("https://image.tmdb.org/t/p/w300/${article.urlToImage}")),
    trailing: IconButton(
      icon: contentt.contains(article.id.toString()) ? Icon(Icons.star_border_outlined, color: Colors.yellow) : Icon(Icons.star_border_outlined, color: Colors.white),
      tooltip: 'My Tootltip',
      onPressed: () {
        _writeDataToFile(article.id.toString());
        _readData();
      },
    ),
  ));
}

Answer 1

函数是对象，因此您可以将它们作为函数参数传递并在您的函数中调用它

// (){} is a anonymous function (with no name)
itemBuilder: (context, index) => allRadioList(articles[index], context, _content,onPressed: (){
        _writeDataToFile(articles[index].id.toString());
        _readData();
}),

和

Widget allRadioList(Article article, BuildContext context, String contentt,{Funtion onPressed}) {
  return Card(
      child: ListTile(
    title: Text(article.title),
    subtitle: Text(contentt),
    leading: CircleAvatar(backgroundImage: NetworkImage("https://image.tmdb.org/t/p/w300/${article.urlToImage}")),
    trailing: IconButton(
      icon: contentt.contains(article.id.toString()) ? Icon(Icons.star_border_outlined, color: Colors.yellow) : Icon(Icons.star_border_outlined, color: Colors.white),
      tooltip: 'My Tootltip',
      onPressed: onPressed,
    ),
  ));
}

Answer 2

您是否尝试将 onPressed 函数设为异步并使用 await 调用这些函数？喜欢;

onPressed: () async {
    await _writeDataToFile(article.id.toString());
    await _readData();
  },

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