iOS 时间相关 比较两个差值

//获取当前时间
    NSDate *currentDate = [NSDate date];//获取当前时间，日期
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"YYYY/MM/dd hh:mm:ss SS"];
    NSString *dateString = [dateFormatter stringFromDate:currentDate];
    NSLog(@"dateString:%@",dateString);

获取时间差
    
    NSDate *currentDate = [NSDate date];//获取当前时间，日期
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"hh:mm:ss"];
    self.endTime = [dateFormatter stringFromDate:currentDate];
    
    NSDate *date1 = [dateFormatter dateFromString:self.beginTime];
    NSDate *date2 = [dateFormatter dateFromString:self.endTime];

    NSCalendar *calendar = [NSCalendar currentCalendar];
    NSCalendarUnit type = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;
    // 4.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];
    long a =cmps.minute/10;
    int b=cmps.minute%10;
    long c =cmps.second/10;
    int d= cmps.second%10;
    self.closelabel.text =getStr(self.hidName);
    self.liveTime.text=[NSString stringWithFormat:@"%ld%d:%ld%d",a,b,c,d];
    
    
    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);