本文转载至 http://www.cnblogs.com/Ewenblog/p/3891791.html
两个时间段,判断之间的相差,做一些时间范围限制使用
NSDateFormatter * dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"yyyyMMddHHmmss"];
NSDate* toDate = [dateFormatter dateFromString:@"20140702142033"];
NSDate* startDate = [ [ NSDate alloc] init ];
NSCalendar* chineseClendar = [ [ NSCalendar alloc ] initWithCalendarIdentifier:NSGregorianCalendar ];
NSUInteger unitFlags = NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit | NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit;
NSDateComponents *cps = [ chineseClendar components:unitFlags fromDate:startDate toDate:toDate options:0];
NSInteger diffYear = [cps year];
NSInteger diffMon = [cps month];
NSInteger diffDay = [cps day];
NSInteger diffHour = [cps hour];
NSInteger diffMin = [cps minute];
NSInteger diffSec = [cps second];
NSLog(@" From Now to %@, diff: Years: %d Months: %d, Days; %d, Hours: %d, Mins:%d, sec:%d", [toDate description], diffYear, diffMon, diffDay, diffHour, diffMin,diffSec );