如何在iPhone中获得时差
问题描述：
我有2个带有时间值的数组。它们采用以下格式。 mm：ss：几百秒。我想得到数组中两个[lastObjects]之间的区别。 NSDate无法正常工作，因为最后一个值是百分之一秒。
I have 2 arrays with time values in it. They are in the following format. mm:ss:hundreds of a sec. I want to get the difference between the two [lastObjects] in the arrays. NSDate is not working because the last value is in hundredsth of a sec.
一个问题。如果第二个日期大于第一个日期，它会给我一个负数，如-01：10：00？
A question. If the second date is larger than the first will it give me a negative number like -01:10:00 ?
答
你的问题有两个部分，解析时间并得到差异：
Your problem has two parts, parsing the time and getting the difference:
NSDateFormatter* dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[dateFormatter setLocale:[[[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"] autorelease]];
[dateFormatter setDateFormat:@"mm:ss:SS"];
NSDate* firstDate = [dateFormatter dateFromString:@"01:00:00"];
NSDate* secondDate = [dateFormatter dateFromString:@"01:02:00"];
NSTimeInterval timeDifference = [secondDate timeIntervalSinceDate:firstDate];