/// <summary>
        /// Get parameter key list  (Android only supported now)
        /// </summary>
        /// <returns>parameter key list</returns>
        public List <string> GetParamList()
        {
            List <string> paramList = new List <string>();
            int           size      = NativeAPI.CameraDevice_getParamList();

            for (int i = 0; i < size; i++)
            {
                int    keyLength = NativeAPI.CameraDevice_Param_getKeyLength(i);
                byte[] keyBytes  = new byte[keyLength];
                NativeAPI.CameraDevice_Param_getKey(i, keyBytes);
                string keyString = Encoding.UTF8.GetString(keyBytes).TrimEnd('\0');
                paramList.Add(keyString);
            }

            return(paramList);
        }