title: A floating button fixed at the bottom of UITableview with scrollViewDidScroll not working properly
body: <p>I am using this piece of code to make a UIButton floating fixed at
  bottom of the UITable, but initially the UIButton will append exactly below
  the last cell of the UITableView, only when I scroll the page the UIButton will 
  get to the bottom, what can I do to make the button come to the bottom at first?
  Thanks in advance!</p>
  
  <pre><code>  - (void)scrollViewDidScroll:(UIScrollView *)scrollView {
          CGRect frame = self.chatButtonView.frame;
          frame.origin.y = scrollView.contentOffset.y + self.tableView.frame.size.height - self.chatButtonView.frame.size.height;
          self.chatButtonView.frame = frame;
  
          [self.view bringSubviewToFront:self.chatButtonView];
      }
  </code></pre>