如何使用nstimer显示秒数？

Question

我正在开发一个游戏项目.我需要知道如何在游戏开始到游戏结束时显示秒数？还需要以"00:01"的格式显示.如果时间超过60分钟,它还应该显示小时"1:00:01"

任何指导？

谢谢...

Answer 1

结合Nathan和Mark的答案后,完整的计时器方法看起来像这样:

- (void)timer:(NSTimer *)timer {
    NSInteger secondsSinceStart = (NSInteger)[[NSDate date] timeIntervalSinceDate:startDate];

    NSInteger seconds = secondsSinceStart % 60;
    NSInteger minutes = (secondsSinceStart / 60) % 60;
    NSInteger hours = secondsSinceStart / (60 * 60);
    NSString *result = nil;
    if (hours > 0) {
        result = [NSString stringWithFormat:@"%02d:%02d:%02d", hours, minutes, seconds];
    }
    else {
        result = [NSString stringWithFormat:@"%02d:%02d", minutes, seconds];        
    }
    // set result as label.text
}

当你开始游戏时,你设置startDate并启动计时器,如下所示:

self.startDate = [NSDate date];
timer = [NSTimer scheduledTimerWithTimeInterval:0.25 target:self selector:@selector(timer:) userInfo:nil repeats:YES];

停止游戏时你使用这个:

self.startDate = nil;
[timer invalidate];
timer = nil;