title: NSTimer does not stop
body: <pre><code>     [self performSelectorInBackground:@selector(method) withObject:nil];
  
      -(void)method 
      {
      timer1 = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(getLastImageName1) userInfo:nil repeats:YES];
                  runLoop = [NSRunLoop currentRunLoop];
                  [runLoop addTimer:timer1 forMode:NSRunLoopCommonModes];
                  [runLoop run];
      }
  
  -(void)viewdidunload
  {
    [timer1 invalidate];
    timer1=nil;
  }
  </code></pre>
  
  <p>I start <code>Timer</code> in <code>HomeViewController</code> even I invalidate, it keeps running in <code>OtherViewController</code>. What is wrong with my code?</p>