NSDate

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;

}

NSDate和NSString的转换

用于uidate，picker。。

+(NSDate*) convertDateFromString:(NSString*)uiDate
{
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init] ;
    [formatter setDateFormat:@"yyyy年MM月dd日"];
    NSDate *date=[formatter dateFromString:uiDate];
    return date;
}

 

输入的日期字符串形如：@"1992-05-21 13:08:08"

- (NSDate *)dateFromString:(NSString *)dateString{

NSDateFormatter *dateFormatter = [[NSDateFormatteralloc] init];

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


 

NSDate *destDate= [dateFormatter dateFromString:dateString];

 

 

[dateFormatter release];

return destDate;

}

 

- (NSString *)stringFromDate:(NSDate *)date{

NSDateFormatter *dateFormatter = [[NSDateFormatteralloc] init]; 

 

//zzz表示时区，zzz可以删除，这样返回的日期字符将不包含时区信息。

[dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss zzz"];

 

NSString *destDateString = [dateFormatter stringFromDate:date];

 

 

[dateFormatter release];

return destDateString;

}

 

- (IBAction)handleDidPressBtn1{

NSLog(@"%@/n", [selfdateFromString:@"2011-08-09 12:02:01"]);

NSLog(@"%@/n", [selfstringFromDate:[selfdateFromString:@"2011-08-09 12:02:01"]]);

}

 

 

输出结果如下：

 

2011-08-09 04:02:01 +0000

2011-08-09 12:02:01 GMT+08:00