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I recently started programming mobile applications with flutter. I have a problem with reading a file. In practice, while the app is running I write a string to a text file (and I can also read it correctly). My need is to read from this file every time the app is accessed; therefore, in the initState () function I call the readContent () function but I get the following message: "FileSystemException: Cannot open file, path = '/var/mobile/Containers/Data/Application/F8A5A202-45C9-47F6-93C9-E4BAE2AF3C7E/Documents/counter.txt' (OS Error: No such file or directory, errno = 2)". Could you help me?

This is my code:

Future<String> get _localPath async {
    final directory = await getApplicationDocumentsDirectory();
    print("directory path: "+directory.path);
    return directory.path;
  }

  Future<io.File> get _localFile async {
    final path = await _localPath;
    return io.File('$path/counter.txt');
  }

  String datas = "";

  //questa funzione viene richiamata all'avvio della schermata e serve per leggere il valore del flag checkSendingReport dal file
  @override
  void initState() {
    super.initState();
    readContent().then((String value) {
      print(value);
      setState(() {
        String data = value;

        List data_file_split = data.split("#");
        checkSendingReport = data_file_split[1];
        check_sending_report = data_file_split[1];
      });
    });
  }

  //Questa funzione serve per leggere il file locale scritto in precenza
  Future<String> readContent() async {
    try {
      final file = await _localFile;

      // Read the file
      String contents = await file.readAsString();
      //Returning the contents of the file
      return contents;

    } catch (e) {
      // If encountering an error, return
      return 'Error! '+e.toString();
    }
  }

  //questa funzione serve per scrivere il file locale
  Future<io.File> writeContent(datetime) async {
    final file = await _localFile;

    //Setto a true la variabile flag check_sending_report
    check_sending_report = true;

    //Creo la stringa da inserire nel file: composta da datetime#flag
    String data_file = datetime + "#" + check_sending_report.toString();

    // Write the file
    return file.writeAsString(data_file);
  }
Viir7
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  • have you tried to use a future builder, provider or bloc to read the file? since in the init state you cannot use asynchronous code – FJCG Apr 01 '22 at 14:45

2 Answers2

2

I guess this error is coming due to initially file does not exist. so, you can add a check for file exist or not

if(file.existsSync())

if File does not exist, you can create one.

new File('$path/counter.txt').create(recursive: true);
Sparsh Jain
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  • thanks, but it is not the solution to my problem. I need to read the string from the previously created file... – Viir7 Jan 12 '22 at 11:04
1

this answer done with me

 Future<File>  _getLocalFile(String pathFlie) async {
      final root = await getApplicationDocumentsDirectory();
      final path = root+'/'+pathFile;
      return File(path).create(recursive: true);
 }
Hamed
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