【IOS类扩展之日期操作】NSDate+Helpers

import “Date.h”

@implementation NSDate(Helpers)

//获取年月日如:19871127.

- (NSString *)getFormatYearMonthDay

{

NSString *string = [NSString stringWithFormat:@”%d%02d%02d”,[self getYear],[self getMonth],[self getDay]];

return string;

}

//该日期是该年的第几周

- (int )getWeekOfYear

{

int i;

int year = [self getYear];

NSDate *date = [self endOfWeek];

for (i = 1;[[date dateAfterDay:-7 * i] getYear] == year;i++)

{

}

return i;

}

//返回day天后的日期(若day为负数,则为|day|天前的日期)

- (NSDate *)dateAfterDay:(int)day

{

NSCalendar *calendar = [NSCalendar currentCalendar];

// Get the weekday component of the current date

// NSDateComponents *weekdayComponents = [calendar components:NSWeekdayCalendarUnit fromDate:self];

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

// to get the end of week for a particular date, add (7 - weekday) days

[componentsToAdd setDay:day];

NSDate *dateAfterDay = [calendar dateByAddingComponents:componentsToAdd toDate:self options:0];

[componentsToAdd release];

return dateAfterDay;

}

//month个月后的日期

- (NSDate *)dateafterMonth:(int)month

{

NSCalendar *calendar = [NSCalendar currentCalendar];

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

[componentsToAdd setMonth:month];

NSDate *dateAfterMonth = [calendar dateByAddingComponents:componentsToAdd toDate:self options:0];

[componentsToAdd release];

return dateAfterMonth;

}

//获取日

- (NSUInteger)getDay{

NSCalendar *calendar = [NSCalendar currentCalendar];

NSDateComponents *dayComponents = [calendar components:(NSDayCalendarUnit) fromDate:self];

return [dayComponents day];

}

//获取月

- (NSUInteger)getMonth

{

NSCalendar *calendar = [NSCalendar currentCalendar];

NSDateComponents *dayComponents = [calendar components:(NSMonthCalendarUnit) fromDate:self];

return [dayComponents month];

}

//获取年

- (NSUInteger)getYear

{

NSCalendar *calendar = [NSCalendar currentCalendar];

NSDateComponents *dayComponents = [calendar components:(NSYearCalendarUnit) fromDate:self];

return [dayComponents year];

}

//获取小时

- (int )getHour {

NSCalendar *calendar = [NSCalendar currentCalendar];

NSUInteger unitFlags =NSYearCalendarUnit| NSMonthCalendarUnit | NSDayCalendarUnit |NSHourCalendarUnit|NSMinuteCalendarUnit;

NSDateComponents *components = [calendar components:unitFlags fromDate:self];

NSInteger hour = [components hour];

return (int)hour;

}

//获取分钟

- (int)getMinute {

NSCalendar *calendar = [NSCalendar currentCalendar];

NSUInteger unitFlags =NSYearCalendarUnit| NSMonthCalendarUnit | NSDayCalendarUnit |NSHourCalendarUnit|NSMinuteCalendarUnit;

NSDateComponents *components = [calendar components:unitFlags fromDate:self];

NSInteger minute = [components minute];

return (int)minute;

}

- (int )getHour:(NSDate *)date {

NSCalendar *calendar = [NSCalendar currentCalendar];

NSUInteger unitFlags =NSYearCalendarUnit| NSMonthCalendarUnit | NSDayCalendarUnit |NSHourCalendarUnit|NSMinuteCalendarUnit;

NSDateComponents *components = [calendar components:unitFlags fromDate:date];

NSInteger hour = [components hour];

return (int)hour;

}

- (int)getMinute:(NSDate *)date {

NSCalendar *calendar = [NSCalendar currentCalendar];

NSUInteger unitFlags =NSYearCalendarUnit| NSMonthCalendarUnit | NSDayCalendarUnit |NSHourCalendarUnit|NSMinuteCalendarUnit;

NSDateComponents *components = [calendar components:unitFlags fromDate:date];

NSInteger minute = [components minute];

return (int)minute;

}

//在当前日期前几天

- (NSUInteger)daysAgo {

NSCalendar *calendar = [NSCalendar currentCalendar];

NSDateComponents *components = [calendar components:(NSDayCalendarUnit)

fromDate:self

toDate:[NSDate date]

options:0];

return [components day];

}

//午夜时间距今几天

- (NSUInteger)daysAgoAgainstMidnight {

// get a midnight version of ourself:

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

[mdf setDateFormat:@”yyyy-MM-dd”];

NSDate *midnight = [mdf dateFromString:[mdf stringFromDate:self]];

[mdf release];

return (int)[midnight timeIntervalSinceNow] / (60*60*24) *-1;

}

  • (NSString *)stringDaysAgo {

    return [self stringDaysAgoAgainstMidnight:YES];

    }

  • (NSString *)stringDaysAgoAgainstMidnight:(BOOL)flag {

    NSUInteger daysAgo = (flag) ? [self daysAgoAgainstMidnight] : [self daysAgo];

    NSString *text = nil;

    switch (daysAgo) {

    case 0:

    text = @”Today”;

    break;

    case 1:

    text = @”Yesterday”;

    break;

    default:

    text = [NSString stringWithFormat:@”%d days ago”, daysAgo];

    }

    return text;

    }

//返回一周的第几天(周末为第一天)

- (NSUInteger)weekday {

NSCalendar *calendar = [NSCalendar currentCalendar];

NSDateComponents *weekdayComponents = [calendar components:(NSWeekdayCalendarUnit) fromDate:self];

return [weekdayComponents weekday];

}

//转为NSString类型的

+ (NSDate )dateFromString:(NSString )string {

return [NSDate dateFromString:string withFormat:[NSDate dbFormatString]];

}

  • (NSDate )dateFromString:(NSString )string withFormat:(NSString *)format {

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

    [inputFormatter setDateFormat:format];

    NSDate *date = [inputFormatter dateFromString:string];

    [inputFormatter release];

    return date;

    }

  • (NSString )stringFromDate:(NSDate )date withFormat:(NSString *)format {

    return [date stringWithFormat:format];

    }

  • (NSString )stringFromDate:(NSDate )date {

    return [date string];

    }

  • (NSString )stringForDisplayFromDate:(NSDate )date prefixed:(BOOL)prefixed {

    /*

    • if the date is in today, display 12-hour time with meridian,
    • if it is within the last 7 days, display weekday name (Friday)
    • if within the calendar year, display as Jan 23
    • else display as Nov 11, 2008

      */

    NSDate *today = [NSDate date];

    NSCalendar *calendar = [NSCalendar currentCalendar];

    NSDateComponents *offsetComponents = [calendar components:(NSYearCalendarUnit | NSMonthCalendarUnit |NSDayCalendarUnit)

    fromDate:today];

    NSDate *midnight = [calendar dateFromComponents:offsetComponents];

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

    NSString *displayString = nil;

    // comparing against midnight

    if ([date compare:midnight] == NSOrderedDescending) {

    if (prefixed) {

    [displayFormatter setDateFormat:@“‘at’ h:mm a”]; // at 11:30 am

    } else {

    [displayFormatter setDateFormat:@”h:mm a”]; // 11:30 am

    }

    } else {

    // check if date is within last 7 days

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

    [componentsToSubtract setDay:-7];

    NSDate *lastweek = [calendar dateByAddingComponents:componentsToSubtract toDate:today options:0];

    [componentsToSubtract release];

    if ([date compare:lastweek] == NSOrderedDescending) {

    [displayFormatter setDateFormat:@”EEEE”]; // Tuesday

    } else {

    // check if same calendar year

    NSInteger thisYear = [offsetComponents year];

        NSDateComponents *dateComponents = [calendar components:(NSYearCalendarUnit | NSMonthCalendarUnit |NSDayCalendarUnit)
                                                   fromDate:date];
    NSInteger thatYear = [dateComponents year];
    if (thatYear >= thisYear) {
        [displayFormatter setDateFormat:@"MMM d"];
    } else {
        [displayFormatter setDateFormat:@"MMM d, yyyy"];
    }
}
if (prefixed) {
    NSString *dateFormat = [displayFormatter dateFormat];
    NSString *prefix = @"‘on‘ ";
    [displayFormatter setDateFormat:[prefix stringByAppendingString:dateFormat]];
}

    }

    // use display formatter to return formatted date string

    displayString = [displayFormatter stringFromDate:date];

    [displayFormatter release];

    return displayString;

    }

  • (NSString )stringForDisplayFromDate:(NSDate )date {

    return [self stringForDisplayFromDate:date prefixed:NO];

    }

  • (NSString )stringWithFormat:(NSString )format {

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

    [outputFormatter setDateFormat:format];

    NSString *timestamp_str = [outputFormatter stringFromDate:self];

    [outputFormatter release];

    return timestamp_str;

    }

  • (NSString *)string {

    return [self stringWithFormat:[NSDate dbFormatString]];

    }

  • (NSString *)stringWithDateStyle:(NSDateFormatterStyle)dateStyle timeStyle:(NSDateFormatterStyle)timeStyle {

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

    [outputFormatter setDateStyle:dateStyle];

    [outputFormatter setTimeStyle:timeStyle];

    NSString *outputString = [outputFormatter stringFromDate:self];

    [outputFormatter release];

    return outputString;

    }

    //返回周日的的开始时间

  • (NSDate *)beginningOfWeek {

    // largely borrowed from “Date and Time Programming Guide for Cocoa”

    // we’ll use the default calendar and hope for the best

    NSCalendar *calendar = [NSCalendar currentCalendar];

    NSDate *beginningOfWeek = nil;

    BOOL ok = [calendar rangeOfUnit:NSWeekCalendarUnit startDate:&beginningOfWeek

    interval:NULL forDate:self];

    if (ok) {

    return beginningOfWeek;

    }

    // couldn’t calc via range, so try to grab Sunday, assuming gregorian style

    // Get the weekday component of the current date

    NSDateComponents *weekdayComponents = [calendar components:NSWeekdayCalendarUnit fromDate:self];

    /*

    Create a date components to represent the number of days to subtract from the current date.

    The weekday value for Sunday in the Gregorian calendar is 1, so subtract 1 from the number of days to subtract from the date in question. (If today’s Sunday, subtract 0 days.)

    */

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

    [componentsToSubtract setDay: 0 - ([weekdayComponents weekday] - 1)];

    beginningOfWeek = nil;

    beginningOfWeek = [calendar dateByAddingComponents:componentsToSubtract toDate:self options:0];

    [componentsToSubtract release];

    //normalize to midnight, extract the year, month, and day components and create a new date from those components.

    NSDateComponents *components = [calendar components:(NSYearCalendarUnit | NSMonthCalendarUnit |NSDayCalendarUnit)

    fromDate:beginningOfWeek];

    return [calendar dateFromComponents:components];

    }

    //返回当前天的年月日.

  • (NSDate *)beginningOfDay {

    NSCalendar *calendar = [NSCalendar currentCalendar];

    // Get the weekday component of the current date

    NSDateComponents *components = [calendar components:(NSYearCalendarUnit | NSMonthCalendarUnit |NSDayCalendarUnit)

    fromDate:self];

    return [calendar dateFromComponents:components];

    }

    //返回该月的第一天

  • (NSDate *)beginningOfMonth

    {

    return [self dateAfterDay:-[self getDay] + 1];

    }

    //该月的最后一天

  • (NSDate *)endOfMonth

    {

    return [[[self beginningOfMonth] dateafterMonth:1] dateAfterDay:-1];

    }

    //返回当前周的周末

  • (NSDate *)endOfWeek {

    NSCalendar *calendar = [NSCalendar currentCalendar];

    // Get the weekday component of the current date

    NSDateComponents *weekdayComponents = [calendar components:NSWeekdayCalendarUnit fromDate:self];

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

    // to get the end of week for a particular date, add (7 - weekday) days

    [componentsToAdd setDay:(7 - [weekdayComponents weekday])];

    NSDate *endOfWeek = [calendar dateByAddingComponents:componentsToAdd toDate:self options:0];

    [componentsToAdd release];

    return endOfWeek;

    }

  • (NSString *)dateFormatString {

    return @”yyyy-MM-dd”;

    }

  • (NSString *)timeFormatString {

    return @”HH:mm:ss”;

    }

  • (NSString *)timestampFormatString {

    return @”yyyy-MM-dd HH:mm:ss”;

    }

// preserving for compatibility

+ (NSString *)dbFormatString {

return [NSDate timestampFormatString];

}

@end

时间： 2024-09-29 19:12:12

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