NSTimer *myTimer = [NSTimer scheduledTimerWithTimeInterval:1.5 target:self selector:@selector(scrollTimer) userInfo:nil repeats:NO];
//关闭定时器
[myTimer setFireDate:[NSDate distantFuture]];
//开启定时器
[myTimer setFireDate:[NSDate distantPast]];
原文：http://www.cnblogs.com/leiqun123/p/3993847.html