NSCalendar 获取当前时间,年,月,日与当前时间对比

 // 1.获得年月日 _lastUpdateTime 获取时间与当前时间对比

    NSCalendar *calendar = [NSCalendarcurrentCalendar];

    NSUInteger unitFlags =NSYearCalendarUnit|NSMonthCalendarUnit |NSDayCalendarUnit |NSHourCalendarUnit |NSMinuteCalendarUnit;

    NSDateComponents *cmp1 = [calendar components:unitFlags fromDate:_lastUpdateTime];

    NSDateComponents *cmp2 = [calendar components:unitFlags fromDate:[NSDatedate]];

    

    // 2.格式化日期

    NSDateFormatter *formatter = [[NSDateFormatteralloc]init];

    if ([cmp1 day] == [cmp2day]) {// 今天

        formatter.dateFormat = @"今天 HH:mm";

    } else if ([cmp1year] == [cmp2year]) {// 今年

        formatter.dateFormat = @"MM-dd HH:mm";

    } else {

        formatter.dateFormat = @"yyyy-MM-dd HH:mm";

    }

    NSString *time = [formatter stringFromDate:self.lastUpdateTime];

    

    // 3.显示日期

    self.lastUpdateTimeLabel.text = [NSStringstringWithFormat:@"最后更新：%@", time];

 //获取当前时间
02    NSDate *now = [NSDate date];
03    NSLog(@”now date is: %@”, now);
04
05    NSCalendar *calendar = [NSCalendar currentCalendar];
06    NSUInteger unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;
07    NSDateComponents *dateComponent = [calendar components:unitFlags fromDate:now];
08     
09    int year = [dateComponent year];
10    int month = [dateComponent month];
11    int day = [dateComponent day];
12    int hour = [dateComponent hour];
13    int minute = [dateComponent minute];
14    int second = [dateComponent second];