title: How to change message's aligment in UIAlertView?
body: <p>　　When I use UIAlertView,I find the message's textAligment is Center. e.g.,When I write this code:　</p>
  
  <pre><code>    UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:nil
                                                     message:@"this is first line     \nsecondLine should be center"
                                                    delegate:nil
                                           cancelButtonTitle:nil
                                           otherButtonTitles:nil, nil];
  [alertView show];
  </code></pre>
  
  <p>the effect is follow:<a href="https://i.stack.imgur.com/jrXXF.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jrXXF.jpg" alt="enter image description here"></a><br>
  　　As we see, the text"this is first line" is in the center,but I want to change it to left.I know UILabel can change text's alignment,but I don't know whether can I change it in UIAlertView. </p>