iPhone的Objective-C编程：每10分钟执行一次后台任务

minutesTimer = [NSTimer scheduledTimerWithTimeInterval:60*10 target:self selector:@selector(update) userInfo:NULL repeats:YES];

if ([countTimer isValid]==NO)
{
    countTimer=[NSTimer scheduledTimerWithTimeInterval:600 target:self selector:@selector(YourMethod) userInfo:nil repeats:YES];
}