计算两个NSDate之间，相隔多少秒数

计算两个NSDate之间，相隔多少秒数

//两个时间间隔秒数

- (NSInteger)intervalSecondsWithSmallDate:(NSDate*)smallDate bigDate:(NSDate*)bigDate

{

NSCalendar *calendar =[NSCalendar currentCalendar];

unsigned int unitFlags =kCFCalendarUnitYear|kCFCalendarUnitMonth|kCFCalendarUnitDay|kCFCalendarUnitHour|kCFCalendarUnitMinute|kCFCalendarUnitSecond;

NSDateComponents *dateComp= [calendar components:unitFlags fromDate:smallDate toDate:bigDate options:0];

NSInteger second = [dateComp hour]*3600+[dateComp minute]*60+[dateComp second];

return second;

}