从nsdate中分别获取年月日的代码写法

-(NSString *)getDayWeek:(int)dayDelay{

NSString *weekDay;

NSDate *dateNow;

dateNow=[NSDate dateWithTimeIntervalSinceNow:dayDelay*24*60*60];//dayDelay代表向后推几天，如果是0则代表是今天，如果是1就代表向后推24小时，如果想向后推12小时，就可以改成dayDelay*12*60*60,让dayDelay＝1

NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];//设置成中国阳历

NSDateComponents *comps = [[NSDateComponents alloc] init];

NSInteger unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSWeekdayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;//这句我也不明白具体时用来做什么。。。

comps = [calendar components:unitFlags fromDate:dateNow];

long weekNumber = [comps weekday]; //获取星期对应的长整形字符串

long day=[comps day];//获取日期对应的长整形字符串

long year=[comps year];//获取年对应的长整形字符串

long month=[comps month];//获取月对应的长整形字符串

long hour=[comps hour];//获取小时对应的长整形字符串

long minute=[comps minute];//获取月对应的长整形字符串

long second=[comps second];//获取秒对应的长整形字符串

NSString *riQi =[NSString stringWithFormat:@"%ld日",day];//把日期长整形转成对应的汉字字符串

switch (weekNumber) {

case 1:

weekDay=@"星期日";

break;

case 2:

weekDay=@"星期一";

break;

case 3:

weekDay=@"星期二";

break;

case 4:

weekDay=@"星期三";

break;

case 5:

weekDay=@"星期四";

break;

case 6:

weekDay=@"星期五";

break;

case 7:

weekDay=@"星期六";

break;

default:

break;

}

weekDay=[riQi stringByAppendingString:weekDay];//这里我本身的程序里只需要日期和星期，所以上面的年月时分秒都没有用上

return weekDay;

}

NSDate总结日期操作

1 // 当前时间创建NSDate

NSDate *myDate = [NSDate date];

NSLog(@"myDate = %@",myDate);

2 //从现在开始的24小时

NSTimeInterval secondsPerDay = 24*60*60;

NSDate *tomorrow = [NSDate dateWithTimeIntervalSinceNow:secondsPerDay];

NSLog(@"myDate = %@",tomorrow);

3//根据已有日期创建日期

NSTimeInterval secondsPerDay1 = 24*60*60;

NSDate *now = [NSDate date];

NSDate *yesterDay = [now addTimeInterval:-secondsPerDay1];

NSLog(@"yesterDay = %@",yesterDay);

4//比较日期

BOOL sameDate = [now isEqualToDate:yesterDay];

NSLog(@"sameDate = %lu",sameDate);

4.1//获取较早的日期

NSDate *earlierDate = [yesterDay earlierDate:now];

NSLog(@"earlierDate = %@",earlierDate);

4.2//较晚的日期

NSDate *laterDate = [yesterDay laterDate:now];

NSLog(@"laterDate = %@",laterDate);

//两个日期之间相隔多少秒

NSTimeInterval secondsBetweenDates= [yesterDay timeIntervalSinceDate:now];

NSLog(@"secondsBetweenDates= %lf",secondsBetweenDates);

//通过NSCALENDAR类来创建日期

NSDateComponents *comp = [[NSDateComponentsalloc]init];

[comp setMonth:06];

[comp setDay:01];

[comp setYear:2001];

NSCalendar *myCal = [[NSCalendaralloc]initWithCalendarIdentifier:NSGregorianCalendar];

NSDate *myDate1 = [myCal dateFromComponents:comp];

NSLog(@"myDate1 = %@",myDate1);

//从已有日期获取日期

unsigned units = NSMonthCalendarUnit|NSDayCalendarUnit|NSYearCalendarUnit;

NSDateComponents *comp1 = [myCal components:units fromDate:now];

NSInteger month = [comp1 month];

NSInteger year = [comp1 year];

NSInteger day = [comp1 day];

//NSDateFormatter实现日期的输出

NSDateFormatter *formatter = [[NSDateFormatteralloc]init];

[formatter setDateStyle:NSDateFormatterFullStyle];//直接输出的话是机器码

//或者是手动设置样式[formatter setDateFormat:@"yyyy-mm-dd"];

NSString *string = [formatter stringFromDate:now];

NSLog(@"string = %@",string);

NSLog(@"formater = %@",formatter);

//获取日期格式对象

- (NSDateFormatter *)dateFormatter {

if (dateFormatter == nil) {

dateFormatter = [[NSDateFormatter alloc] init];

[dateFormatter setDateStyle:NSDateFormatterMediumStyle];

[dateFormatter setTimeStyle:NSDateFormatterNoStyle];

}

return dateFormatter;

}