目标c中的定时器程序

Question

我必须制作一个从00:03:30开始的计时器程序 并停在0 在2:30秒我必须发出哔哔声如何在目标c中实现该程序

Answer 1

以下是代码：

的 ViewController.h

NSDate *startDate, *beepSoundDate, *endDate;
NSTimer *timer;

<强> ViewController.m

-(void)setTimer
{

    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"HH:mm:ss"];
    [dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0.0]];
    startDate = [dateFormatter dateFromString:@"00:03:30"];
    beepSoundDate = [dateFormatter dateFromString:@"00:02:30"];
    endDate = [dateFormatter dateFromString:@"00:00:00"];

//    startDate = [NSDate date];
    timer = [NSTimer scheduledTimerWithTimeInterval:1.0
                                                 target:self
                                               selector:@selector(getTimerInterval)
                                               userInfo:nil
                                                repeats:YES];

}
-(void)getTimerInterval
{

    NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
    NSDateComponents *offsetComponents = [[NSDateComponents alloc] init];
    [offsetComponents setSecond:-1];
    startDate = [gregorian dateByAddingComponents:offsetComponents toDate:startDate options:0];

    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"HH:mm:ss"];
    [dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0.0]];
    NSString *timeString=[dateFormatter stringFromDate:startDate];
    NSLog(@"%@",timeString);

    if(startDate == beepSoundDate)
    {
        // Play beep sound
        NSLog(@"************************************");
    }

    if(startDate == endDate)
    {
        [timer invalidate];
        timer = nil;
    }
}

如果您想开始 计时器，可以致电 setTimer 。