ios 時間類轉化為字符串

//  NSString* timeStr = [self stringWithDate: [NSDate dateWithTimeIntervalSince1970:userGifGrouptEntity.lastGiftSentTime / 1000]]


(NSString )stringWithDate:(NSDate )date  {
if (date == nil)

  return @"";


NSDate *now = [NSDate date];
NSTimeInterval time = [now timeIntervalSinceDate:date];
NSCalendar* calendar = [NSCalendar currentCalendar];
NSDateComponents *nowComponents = [calendar components:NSYearCalendarUnit | NSHourCalendarUnit fromDate:now];
NSDateComponents *dateComponets = [calendar components:NSYearCalendarUnit fromDate:date];



NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];

[dateFormatter setCalendar: [NSCalendar autoupdatingCurrentCalendar]];



if ([nowComponents year] != [dateComponets year]) {

        [dateFormatter setDateFormat:@"MM-dd-yyyy"];

         return [dateFormatter stringFromDate:date];

}

  int nowHour = (int)[nowComponents hour];

int days_ago = ((int)time + 3600*(24-nowHour))/(3600*24);



if (days_ago == 0){

    [dateFormatter setDateFormat:@"HH:mm"];

    return [dateFormatter stringFromDate:date];

}else if(days_ago == 1) {

                return @"Yesterday";

      }else{



        [dateFormatter setDateFormat:@"MM-dd"];



    return [dateFormatter stringFromDate:date];

}


}</pre>