Android提供的ProgressBar Widget控件与ProgressDialog应用目标不同，在程序一开始即可在main.xml Layout当中布局，先将部署在Layout里的ProgressBar的属性设为隐藏（一开始看不见），而后使用进程来“假装”程序忙碌中，但不同的是，可在进程当中取得运行时的进度，在“运行”的过程中，将运行进度通过TextView显示出来。本范例除了学习ProgressBar Widget的显示及使用之外，另一个学习关键则是Handler的使用，因为新起的进程无法访问Activity里的Widget，也无法将运行状态外送出来，所以需要通过Handler及Message对象，将进程里的状态往外传递，最后由Activity的Handler事件接收取得运行的状态。-ProgressBar Widget controls and ProgressDialog target applications provided by Android, a program can be started at main.xml in Layout layout, the first attribute will be deployed in the Layout ProgressBar set to hide (initially invisible), and then use the process to　pretend　program is busy, but the difference is that in the operation can be achieved the process of progress, in the　run　in the process of operation will show progress through TextView. This example shows in addition to learning ProgressBar Widget and use, another key is the use of Handler, because the new process cannot access Activity Widget, could send status so, through the Handler and Message objects, will process state to transfer, and finally by the Activity Handler event has receiving state.