title: iOS - Category method not getting called when testing of device
body: <p>I have this category:</p>
  
  <pre><code>@interface NSDate (PrettyDate)
  - (NSString *)prettyDate;
  @end
  
  
  
  #import "NSDate+PrettyDate.h"
  
  @implementation NSDate (PrettyDate)
  
  - (NSString *)prettyDate
  {
    NSString *prettyTimestamp = nil;
  
    float delta = [self timeIntervalSinceNow] * -1;
  
    if (delta &lt; 60) {
      prettyTimestamp = @"Just now";
    } else if (delta &lt; 120) {
      prettyTimestamp = @"One minute ago";
    } else if (delta &lt; 3600) {
      prettyTimestamp = [NSString stringWithFormat:@"%d minutes ago", (int) floor(delta/60.0) ];
    } else if (delta &lt; 7200) {
      prettyTimestamp = @"One hour ago";      
    } else if (delta &lt; 86400) {
      prettyTimestamp = [NSString stringWithFormat:@"%d hours ago", (int) floor(delta/3600.0) ];
    } else if (delta &lt; ( 86400 * 2 ) ) {
      prettyTimestamp = @"One day ago";       
    } else if (delta &lt; ( 86400 * 7 ) ) {
      prettyTimestamp = [NSString stringWithFormat:@"%d days ago", (int) floor(delta/86400.0) ];
    } else {
      NSDateFormatter * formatter = [[NSDateFormatter alloc] init];
      [formatter setDateStyle:NSDateFormatterMediumStyle];
  
      prettyTimestamp = [NSString stringWithFormat:@"On %@", [formatter stringFromDate:self]];
    }
  
    return prettyTimestamp;
  }
  
  @end
  </code></pre>
  
  <p>And I'm calling it like so:</p>
  
  <pre><code>NSDateFormatter *currentFormat = [[NSDateFormatter alloc] init];
  currentFormat.dateFormat = @"yyyy-MM-dd HH:mm:ss";
  NSDate *date = [currentFormat dateFromString:dateString];
  
  cell.detailTextLabel.text = [date prettyDate];  
  </code></pre>
  
  <p>It works fine on the simulator, but on the device the category method isn't even called, any ideas?</p>