import 'dart:convert'; import 'package:shared_preferences/shared_preferences.dart'; class SharedPreferencesUtil { // 单例对象 static final SharedPreferencesUtil _singleton = SharedPreferencesUtil._internal(); // 私有构造函数 SharedPreferencesUtil._internal(); // 工厂构造函数返回单例对象 factory SharedPreferencesUtil() => _singleton; // 获取 SharedPreferences 实例 Future get _instance async => await SharedPreferences.getInstance(); // 存储字符串 Future setString(String key, String value) async { final prefs = await _instance; prefs.setString(key, value); } // 读取字符串 Future getString(String key) async { final prefs = await _instance; return prefs.getString(key); } // 存储JSON数组 Future setJsonList(String key, List> jsonList) async { final prefs = await _instance; final jsonString = jsonEncode(jsonList); prefs.setString(key, jsonString); } // 读取JSON数组 Future>?> getJsonList(String key) async { final prefs = await _instance; final jsonString = prefs.getString(key); return jsonString != null ? List>.from(jsonDecode(jsonString)) : null; } // 存储可以转化为 JSON 的对象 Future setObject(String key, Map jsonValue) async { final prefs = await _instance; final jsonString = jsonEncode(jsonValue); prefs.setString(key, jsonString); } // 读取 JSON 对象,并返回 Map Future?> getObject(String key) async { final prefs = await _instance; final jsonString = prefs.getString(key); return jsonString != null ? jsonDecode(jsonString) as Map : null; } // 删除指定键的数据 Future delete(String key) async { final prefs = await _instance; prefs.remove(key); } // 删除所有数据 Future deleteAll() async { final prefs = await _instance; prefs.clear(); } }