看上去一个很普通的源码，但其实这个源码非常有趣，而它有趣的地方就在于这个进度条并不是使用进度条组件制作，而是使用了透明标签和分组框制作出来的，所以非常具有学习价值。-Looks a very common source, but in fact the source code is very interesting, but it is interesting is that this progress bar does not use the progress bar component production, but the use of transparent labels and boxes made out of a packet, so very Learning value.