title: Disabling UIAlertView button
body: <p>I am making a <code>UIAlertView</code> with a text input.</p>
  
  <pre><code>UIAlertView *alertView=[[UIAlertView alloc]initWithTitle:@"Save" message:@"Please Enter the Name of PDF" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"OK", nil];
  [alertView setAlertViewStyle:UIAlertViewStylePlainTextInput]
  </code></pre>
  
  <p>what i want to do when UITextField is empty i disable the OK button with a delegate function</p>
  
  <pre><code>- (BOOL)alertViewShouldEnableFirstOtherButton:(UIAlertView *)alertView
  {
  
  return NO;
  }
  </code></pre>
  
  <p>When the user begins to write something in the textfield the OK button should become enabled.</p>