memo_NSDateから日時・時間を取得する方法

// Assume that (NSDate *)date already exists.

NSCalendar* calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
unsigned int flags = NSYearCalendarUnit |
      NSMonthCalendarUnit |
      NSDayCalendarUnit |
      NSHourCalendarUnit |
      NSMinuteCalendarUnit |
      NSSecondCalendarUnit;
NSDateComponents *components =  [calendar components:flags fromDate:date];
[calendar release];

// Here,  you can get information about (NSDate *)date 
// by using methods year, month, day, hour, minute, and second of instance (NSCalendar *)components.

[components release];

参考：
【Cocoa】NSDateから日時の値を取得する