IPHONE MinutesToMidnight 出现的编译错误，已找到解决方法

原创于 2010-09-13 10:46:47 发布 · 147 阅读

CC 4.0 BY-SA版权

本文介绍了一种使用Objective-C实现的倒计时功能更新方法。通过改进日期组件的获取方式，提高了时间显示的准确性。利用NSCalendar和NSDateComponents精确计算剩余小时、分钟和秒数，并将其格式化显示。

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-(void)updateLabel {
NSDate* now = [NSDate date];
int hour = 23 - [[now dateWithCalendarFormat:nil timeZone:nil] hourOfDay];
int min = 59 - [[now dateWithCalendarFormat:nil timeZone:nil] minuteOfHour];
int sec = 59 - [[now dateWithCalendarFormat:nil timeZone:nil] secondOfMinute];
countdownLabel.text = [NSString stringWithFormat:@"%02d:%02d:%02d", hour, min,sec];
}

修改为：

-(void)updateLabel {
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
unsigned unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSHourCalendarUnit| NSMinuteCalendarUnit |NSSecondCalendarUnit;
NSDate *date = [NSDate date];
NSDateComponents *comps = [gregorian components:unitFlags fromDate:date];
int hour = 23 - [comps hour];
int min = 59 - [comps minute];
int sec = 59 - [comps second];
countdownLabel.text = [NSString stringWithFormat:@"%02d:%02d:%02d", hour, min,sec];
}