title: how to make overlay with activity indicator programatically
body: <p>i need to set the activity indicator with the blur overlay background in objective c.How to do that.</p>
  
  <p>I tried this code but not able to set overlay for view.Note that i have only view controller with one button.After press that button i need to make a overlay with the activity indicator.</p>
  
  <pre><code> spinner = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(150, 225, 20, 30)];
      [spinner setActivityIndicatorViewStyle:UIActivityIndicatorViewStyleGray];
      spinner.center = CGPointMake([[UIScreen mainScreen]bounds].size.width/2, [[UIScreen mainScreen]bounds].size.height/2);
      spinner.color = [UIColor redColor];
      [self.view addSubview:spinner];
  </code></pre>
  
  <p>How to do that ??</p>