誰能告訴我我做錯了什么？當我在編輯器中玩游戲時，一切正常。當我構建游戲并在那里嘗試保存游戲作品時，但在加載游戲數據時出現此錯誤：ArgumentNullException: Value cannot be null. 我一直在尋找解決方案，但似乎找不到任何解決方案。public void SaveGame(){    checkGameData();    XmlSerializer serializer = new XmlSerializer(typeof(PoliceSave));    FileStream stream = new FileStream(Application.persistentDataPath + "/gameData.xml", FileMode.Create);    serializer.Serialize(stream, policeSave);    stream.Close();    policeSave.GameData.Clear();    policeSave.Characters.Clear();    policeSave.Vehicles.Clear();    vehicleDetails.passenger.characters.Clear();    Debug.Log("[Server] Your game has been saved.");}public void LoadGame(){    clearGameObjects();    XmlSerializer serializer = new XmlSerializer(typeof(PoliceSave));    FileStream stream = new FileStream(Application.persistentDataPath + "/gameData.xml", FileMode.Open);    //try    //{        policeSave = serializer.Deserialize(stream) as PoliceSave;    //}catch    //{        Debug.Log("[Server] Error while loading game data!");    //}    stream.Close();    loadGameObjects();    policeSave.GameData.Clear();    policeSave.Characters.Clear();    policeSave.Vehicles.Clear();    vehicleDetails.passenger.characters.Clear();    Debug.Log("[Server] Your game has been loaded.");}[System.Serializable]public class GameData{    [XmlAttribute("Funds")]    public int funds;    [XmlAttribute("MissionID")]    public int missionId;}[System.Serializable]public class Passenger{    [XmlAttribute("Name")]    public List<string> characters;}[System.Serializable]public class Vec2Position{    [XmlAttribute("x")]    public float x;    [XmlAttribute("y")]    public float y;}[System.Serializable]public class Rotation{    [XmlAttribute("z")]    public float z;}[System.Serializable]public class CharacterDetails{    [XmlAttribute("Name")]    public string characterName;    [XmlAttribute("IsCameraSubject")]    public bool isCameraSubject;    public Vec2Position Position;    public Rotation Rotation;}