title: UIAlertView crash by adding clickedButtonAtIndex
body: <p>I create a class to call UIAlertview show on my screen. I write the UIAlert function in another class. <strong>Both these two classes are not my viewController class</strong>.</p>
  
  <p>I use this UIAlert, which is a UITextfield inside, to store texts into a plist file.</p>
  
  <p>here is the class to call UIAlert:</p>
  
  <pre><code>#import "Story.h"
  
  @implementation Story
  
  ...
  + (void)stage1
  {
      AlertClass *pointer = [AlertClass new];
      [pointer doAlert];
  }
  </code></pre>
  
  <p>here is the class AlertClass.m file:</p>
  
  <pre><code>- (void)doAlert
  {
      UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Title" message:@"Message" delegate:self cancelButtonTitle:@"Done" otherButtonTitles:nil];
      alert.alertViewStyle = UIAlertViewStylePlainTextInput;
      [alert show];
  
  }
  //this makes crash!
  - (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{
      self.storyFlow.text = [alertView textFieldAtIndex:0].text;
  }
  </code></pre>
  
  <p>Before I add UIAlertViewDelegate in the .h and override the method "clickedButtonAtIndex", it works great. However, I need to store some data from the UITextfield inside the alert view. I get crash and don't know the message it responds as following.</p>
  
  <p>Please help me to solve this problem. Thanks.</p>
  
  <p>[crash pic] <a href="https://dl.dropbox.com/u/47381923/crash.tiff" rel="nofollow">https://dl.dropbox.com/u/47381923/crash.tiff</a></p>