title: TimeInterval function setting with UIPicker
body: <p>I have following part of code. It is executing when user will select any time interval from UIpicker.</p>
  
  <pre><code>if([[arrayNo objectAtIndex:row] isEqualToString:@"1 minutes"])
      time=60;
  
  if([[arrayNo objectAtIndex:row] isEqualToString:@"5 minutes"])
      time=300;
  
  [NSTimer scheduledTimerWithTimeInterval:60 target:self selector:@selector(updateMethod) userInfo:nil repeats:YES];
  </code></pre>
  
  <p>I am defining two time in UIPicker "1 minutes" and "5 minutes". Suppose once user will select "1 minutes" then function "updateMethod" will be call after 1 minutes of time period. But let suppose user again change his time to "5 mnutes" from UIPicker. Then what will happen? Is timer will be set to "5 minutes" OR it will be set to "1 minutes" and "5 minutes" both?</p>
  
  <p>How will I design code to set function calling for one time only?
  Help me in it concept?</p>