说明：  前面已经讲了通过多线程下载网络文件的一部分核心代码，下面继续做我们的项目 当然如果我们做小一点的Android项目的时候可以先做界面，然后根据需要来扩展所需要的功能，当然有的时候我们宁愿先实现业务，业务功能做好了再实现界面，因为界面里面基本不含有技术，况且我们只是为了学习，界面不需要多美观的，能用就行。
(Has already been told by the multi-threaded download part of the core of the network file code below to continue to do our projects, of course, if we do the little Android project when you can do first interface, and then based on the need to extend the functionality required, of course, some when we would prefer to achieve business business functions well and then realize the interface because the interface does not contain the basic technology inside, the fact that we just to learn the interface does not require more than aesthetic, can be used on the line.)