第一种:
//计算任意2个时间的之间的间隔

- (NSTimeInterval)pleaseInsertStarTime:(NSString *)starTime andInsertEndTime:(NSString *)endTime{
    NSDateFormatter* formater = [[NSDateFormatter alloc] init];
    [formater setDateFormat:@"mm:ss"];//根据自己的需求定义格式
    NSDate* startDate = [formater dateFromString:starTime];
    NSDate* endDate = [formater dateFromString:endTime];
    NSTimeInterval time = [endDate timeIntervalSinceDate:startDate];
    return time;
}

第二种:

- (void)pleaseInsertStarTimeo:(NSString *)time1 andInsertEndTime:(NSString *)time2{
// 1.将时间转换为date
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
formatter.dateFormat = @"yyyy-MM-dd HH:mm:ss";
NSDate *date1 = [formatter dateFromString:time1];
NSDate *date2 = [formatter dateFromString:time2];
// 2.创建日历
NSCalendar *calendar = [NSCalendar currentCalendar];
NSCalendarUnit type = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;
// 3.利用日历对象比较两个时间的差值
NSDateComponents *cmps = [calendar components:type fromDate:date1 toDate:date2 options:0];
// 4.输出结果
NSLog(@"两个时间相差%ld年%ld月%ld日%ld小时%ld分钟%ld秒", cmps.year, cmps.month, cmps.day, cmps.hour, cmps.minute, cmps.second);
}

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