界面微调，设备连接中断跳时间bug修复

Assets/Scenes/Ride/Scripts/Helper.cs

@@ -29,6 +29,8 @@ namespace Assets.Scenes.Ride.Scripts
         {
             try
             {
+                if (!Directory.Exists(srcPath))
+                    return;
                 DirectoryInfo dir = new DirectoryInfo(srcPath);
                 FileSystemInfo[] fileinfo = dir.GetFileSystemInfos();  //返回目录中所有文件和子目录
                 foreach (FileSystemInfo i in fileinfo)