sharedpreferences 不适用于硬件 android

Question

我使用共享首选项通过保存 json 来保存我的对象。 这一切在 Android Studio 中工作正常，但如果我在手机上尝试它，当我启动应用程序时，它不会保存/加载我的对象。

这是我加载共享首选项的地方

  List<String> productName = [];
  List<String> productUnit = [];
  List<double> productPrice = [];
  List<String> productImage = [];
  List<int> productStock = [];
  List<String> productCurrency = [];

  late SharedPreferences sharedPreferences;

  @override //Initialises the sharedPreference data
  void initState() {
    super.initState();
    initialGetSavedData();
  }

  // Function that loads sharedPreference
  void initialGetSavedData() async {
    final prefs = await SharedPreferences.getInstance();
    final keys = prefs.getKeys();
    prefs.clear();
    //This is how it was just in case final prefsMap = Map<String, dynamic>();
    //ToDO check if I have to reverse it
    final prefsMap = <String, dynamic>{};

    for(String key in keys) {
      prefsMap[key] = prefs.get(key);
      Product product = Product.fromJson(jsonDecode(prefsMap[key]));

      setState(() {
      productName.add(product.name);
      productUnit.add(product.unit);
      productPrice.add(product.price);
      productImage.add(product.image);
      productStock.add(product.stock);
      productCurrency.add(product.currency);
      });
    }
  }

这就是我在 SharedPreferences 中保存的方式

  save(String key, value) async {
    final prefs = await SharedPreferences.getInstance();


    prefs.setString(key, json.encode(value));
  }

这就是我的课

class Product{
 late String name;
 late String unit;
 late String image;
 late double price;
 late int stock;
 late String currency;


  Product({required this.name, required this.price, required this.unit, required this.image, required this.stock, required this.currency});

  //Method that converts json to object instance
  Product.fromJson(Map<String, dynamic> json){
    name = json['name'] as String;
    price = json['price'] as double;
    unit = json['unit'] as String;
    image = json['image'] as String;
    stock = json['stock'] as int;
    currency = json['currency'] as String;
  }


  //Method that converts object to json String
  Map<String, dynamic> toJson() => {
    'name': name,
    'price': price,
    'unit': unit,
    'image': image,
    'stock': stock,
    'currency': currency,
  };


}

我现在的问题是，如何修复我的硬件 android？

我尝试重新安装该应用程序，并在安装后尝试将其与电脑断开连接。 但这并没有帮助。

Answer 1

NVM

在initialGetSavedData()中我调用prefs.clear(); 所以我在启动应用程序时删除了所有保存的数据