实现了一个文件夹遍历操作，可以遍历拷贝计算机文件夹，并采用获取每个文件大小的方式控制进度条动画，对初学文件夹遍历，进度条控制提供一定参考-Achieved through operation of a folder, you can copy a computer through a folder, and file size used for the control of each progress bar animation, for beginners through the folder