addClothingItem static method
添加衣物
Implementation
static Future<void> addClothingItem(ClothingItem item) async {
final prefs = await SharedPreferences.getInstance();
final items = await getAllClothingItems();
items.add(item);
final jsonList = items.map((item) => item.toJson()).toList();
await prefs.setString(_keyClothingItems, jsonEncode(jsonList));
}