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  late File jsonFile;
  late Directory dir;
  String fileName = "myJSONfile.json";
  bool fileExists = false;
  Map fileContent = <String, String>{};
  //late Map<String, String> fileContent;
  //late Map<String, String> fileContent = {};
  //var fileContent = <String, String>{};

  @override
  void initState() {
    super.initState();

    getApplicationDocumentsDirectory().then((Directory directory) {
      dir = directory;
      jsonFile = new File(dir.path + "/" + fileName);

      fileExists = jsonFile.existsSync();
      if (fileExists)
        this.setState(
            () => fileContent = json.decode(jsonFile.readAsStringSync()));
    });
  }

  void createFile(Map<String, String> content, Directory dir, String fileName) {
    print("Creating file!");
    File file = new File(dir.path + "/" + fileName);
    file.createSync();
    fileExists = true;
    file.writeAsStringSync(json.encode(content));
  }

  void writeFile(String key, String value) {
    print("Writing to file!");
    Map<String, String> content = {key: value};
    if (fileExists) {
      print("File exists");

      Map<String, String> jsonFIleContent =
          json.decode(jsonFile.readAsStringSync());
      jsonFIleContent.addAll(content);
      jsonFile.writeAsStringSync(json.encode(jsonFIleContent));
    } else {
      print("FIle does not exists!");
      createFile(content, dir, fileName);
    }
    this.setState(() => fileContent = json.decode(jsonFile.readAsStringSync()));
  }

嘿，我是 Flutter 的新手，我正在尝试使用 JSON 文件保存数据并再次读取，但它不起作用

这是错误：（颤振 I/颤振（4140）：类型 '_InternalLinkedHashMap<String, dynamic>' 不是类型 'Map<String, String>' 的子类型）

我已经在互联网上搜索但我没有找到任何答案，有人可以告诉我这个错误是什么以及我该如何解决它？

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0 回答 0