自学iOS-获取当前时间

NSDate *  senddate=[NSDate date];  

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

[dateformatter setDateFormat:@"YYYYMMdd"];  

NSString *  locationString=[dateformatter stringFromDate:senddate];    

NSLog(@"locationString:%@",locationString);

 [dateformatter release]; //这个有问题，显示日期不对

关大叔的写法

    //获取当前时间
    NSDate *now = [NSDate date];
    NSLog(@”now date is: %@”, now);

    NSCalendar *calendar = [NSCalendar currentCalendar];
    NSUInteger unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;
    NSDateComponents *dateComponent = [calendar components:unitFlags fromDate:now];

    int year = [dateComponent year];
    int month = [dateComponent month];
    int day = [dateComponent day];
    int hour = [dateComponent hour];
    int minute = [dateComponent minute];
    int second = [dateComponent second];

    NSLog(@”year is: %d”, year);
    NSLog(@”month is: %d”, month);
    NSLog(@”day is: %d”, day);
    NSLog(@”hour is: %d”, hour);
    NSLog(@”minute is: %d”, minute);
    NSLog(@”second is: %d”, second);

获取星期几（好用的）可以获取：年、月、日、星期几

　　 NSDate *datet = [NSDate date];//现在时间
    NSArray *weekdays = [NSArray arrayWithObjects: [NSNull null], @"Sunday", @"周一", @"周二", @"周三", @"周四", @"周五", @"周六", nil];

    NSCalendar *calendars = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];

    NSTimeZone *timeZone = [[NSTimeZone alloc] initWithName:@"Asia/Shanghai"];

    [calendars setTimeZone: timeZone];

    NSCalendarUnit calendarUnit = NSCalendarUnitWeekday;

    NSDateComponents *theComponents = [calendars components:calendarUnit fromDate:datet];

    NSInteger unitFlagss = NSCalendarUnitYear |
    NSCalendarUnitMonth |
    NSCalendarUnitDay |
    NSCalendarUnitWeekday |
    NSCalendarUnitHour |
    NSCalendarUnitMinute |
    NSCalendarUnitSecond;

    theComponents = [calendars components:unitFlagss fromDate:datet];
    int week = [theComponents weekday];
    int year=[theComponents year];
    int month = [theComponents month];
    int day = [theComponents day];

    NSLog(@"%d年%d月",year,month);
    NSLog(@"%d",day);

    NSLog(@"xingqi%@",[weekdays objectAtIndex:theComponents.weekday]);