设置一个Date, 然后打开一个Timer,
timer=[[NSTimerscheduledTimerWithTimeInterval:1target:selfselector:@selector(timerRun)userInfo:nilrepeats:YES]retain];
在这个函数中做相关的操作就可以。
cancel时,
[timerinvalidate];
timer=[[NSTimerscheduledTimerWithTimeInterval:1target:selfselector:@selector(timerRun)userInfo:nilrepeats:YES]retain];
[timerinvalidate];