title: Making alarm clock with NSTimer
body: <p>I just went through trying to make an alarm clock app with local notifications but that didn't do the trick because I needed an alert to appear instead of it going into notification centre in iOS 5+</p>
  
  <p>So far I've been struggling greatly with nstimer and its functions so I was wondering if anyone could help out. </p>
  
  <p>I want when the user selects a time (through UIDatePicker, only time) for an alert to be displayed at exactly this time. I have figured out how to get the time from UIDatePicker but I do not know how to properly set the firing function of nstimer. This is what I have attempted so far, if anyone could help... be much appreciated. Thank you</p>
  
  <p>Example (it keeps going into the function every second opposed to a certain time I told it too... not what I want):    </p>
  
  <pre><code>NSDate *timestamp;
  NSDateComponents *comps = [[[NSDateComponents alloc] init] autorelease];
  
  [comps setHour:2];
  [comps setMinute:8];
  timestamp = [[NSCalendar currentCalendar] dateFromComponents:comps];
  
  NSTimer *f = [[NSTimer alloc] initWithFireDate:timestamp
                               interval:0
                                 target:self
                               selector:@selector(test)
                               userInfo:nil repeats:YES];
  
  NSRunLoop *runner = [NSRunLoop currentRunLoop];
  [runner addTimer:f forMode: NSDefaultRunLoopMode]; 
  </code></pre>