protected void onCreate(Bundle savedInstanceState) {
 
    super.onCreate(savedInstanceState);
 
    requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);//先给Activity注册界面进度条功能
 
    setContentView(R.layout.main);
 
    setProgressBarIndeterminateVisibility(true);//在需要显示进度条的时候调用这个方法
 
    setProgressBarIndeterminateVisibility(false);//在不需要显示进度条的时候调用这个方法
 
}