ios日期格式轉換
分類: iphone iphone開發2012-11-23 18:07 26792人閱讀 評論(1) 收藏 舉報
1、如何如何將一個字符串如“ 20110826134106”裝化爲任意的日期時間格式,下面列舉兩種類型:
NSString* string = @"20110826134106";
NSDateFormatter *inputFormatter = [[[NSDateFormatter alloc] init] autorelease];
[inputFormatter setLocale:[[[NSLocale alloc] initWithLocaleIdentifier:@"en_US"] autorelease]];
[inputFormatter setDateFormat:@"yyyyMMddHHmmss"];
NSDate* inputDate = [inputFormatter dateFromString:string];
NSLog(@"date = %@", inputDate);
NSDateFormatter *outputFormatter = [[[NSDateFormatter alloc] init] autorelease];
[outputFormatter setLocale:[NSLocale currentLocale]];
[outputFormatter setDateFormat:@"yyyy年MM月dd日 HH時mm分ss秒"];
NSString *str = [outputFormatter stringFromDate:inputDate];
NSLog(@"testDate:%@", str);
兩次打印的結果爲:
date = 2011-08-26 05:41:06 +0000
testDate:2011年08月26日 13時41分06秒
/*
NSDateFormatter *dateFormatter=[[NSDateFormatteralloc]init];
[dateFormatter setDateFormat:@"yyyy"];
NSString *Str=[dateFormatter stringFromDate:[NSDate date]];
[dateFormatter release];
NSDateFormatter *dateFormatter1=[[NSDateFormatteralloc]init];
[dateFormatter1 setDateFormat:@"MM"];
NSString *Str1=[dateFormatter1 stringFromDate:[NSDate date]];
[dateFormatter1 release];
NSDateFormatter *dateFormatter2=[[NSDateFormatteralloc]init];
[dateFormatter2 setDateFormat:@"dd"];
NSString *Str3=[dateFormatter2 stringFromDate:[NSDate date]];
[dateFormatter2 release];
NSString *dateStr=[NSStringstringWithFormat:@"%@-%@-%@ 00:00:00",Str,Str1,Str3];
NSLog(@"dateStr------------%@",dateStr);
//將傳入時間轉換成需要的格式
NSDateFormatter *format=[[NSDateFormatteralloc]init];
//[dateFormatter setLocale:[[NSLocale alloc]initWithLocaleIdentifier:@"zh_CN"]];//location設置爲中國
// [format setLocale:[[NSLocale alloc]initWithLocaleIdentifier:@"zh_CN"]];//location設置爲中國
[format setLocale:[NSLocalecurrentLocale]];
[format setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
NSDate *inputDate=[[format dateFromString:dateStr] retain];
NSTimeZone *fromzone = [NSTimeZonesystemTimeZone];
NSInteger frominterval = [fromzonesecondsFromGMTForDate: inputDate];
fromDate = [[inputDate dateByAddingTimeInterval: frominterval] retain];
NSLog(@"fromDate------zh---------%@",fromDate);
- (id)initWithFrame:(CGRect)frame {
if ((self = [super initWithFrame:frame])) {
//默認日期格式爲yyyy-MM-dd
dateFormatter= [[NSDateFormatter alloc] init];
[dateFormatter setLocale:[[NSLocale alloc]initWithLocaleIdentifier:@"zh_CN"]];//location設置爲中國
[dateFormatter setDateFormat:@"yyyy-MM-dd"];
//picker的默認時間爲當前時間
date=[NSDate date];
//picker的默認style爲只顯示日期
datePickerMode=UIDatePickerModeDate;
//構造一個子視圖,用於顯示日期選擇器
subview=[[UIView alloc]initWithFrame:CGRectMake(0, 0, 320, 480)];
subview.backgroundColor=[UIColor clearColor];
subview.tag=0;
*/
說明:上面的時間是美國時間,下面的沒有設置
NSString* string = @"Wed, 05 May 2011 10:50:00 +0800";
NSDateFormatter *inputFormatter = [[[NSDateFormatter alloc] init] autorelease];
[inputFormatter setLocale:[[[NSLocale alloc] initWithLocaleIdentifier:@"en_US"] autorelease]];
[inputFormatter setDateFormat:@"EEE, d MMM yyyy HH:mm:ss Z"];
NSDate* inputDate = [inputFormatter dateFromString:string];
NSLog(@"date = %@", inputDate);
// 獲得本地時間指定時區
NSDate *dates = [NSDate date];
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
NSTimeZone* timeZone = [NSTimeZone timeZoneWithName:@"Asia/beijing"];
[formatter setTimeZone:timeZone];
NSString *loctime = [formatter stringFromDate:dates];
2、以前一直爲這個事情糾結,無奈只能拼接字符串:
NSString *str=@"20120403000000";
NSString *dateStr=[NSString stringWithFormat:@"有效期至:%@年%@月%@日",
[str substringWithRange:NSMakeRange(0, 4)],
[str substringWithRange:NSMakeRange(4, 2)],
[str substringWithRange:NSMakeRange(6, 2)]];
這個方法笨,可是沒辦法,查了好多資料,都沒明白,今天突然明白了,呵呵,只要把那個[inputFormatter setDateFormat:@"EEE, d MMM yyyy HH:mm:ss Z"];@“”裏面的格式轉化爲你字符串的格式一切就OK了,不知道我說明白了嗎
3、iOS-NSDateFormatter 格式說明:
G: 公元時代,例如AD公元
yy: 年的後2位
yyyy: 完整年
MM: 月,顯示爲1-12
MMM: 月,顯示爲英文月份簡寫,如 Jan
MMMM: 月,顯示爲英文月份全稱,如 Janualy
dd: 日,2位數表示,如02
d: 日,1-2位顯示,如 2
EEE: 簡寫星期幾,如Sun
EEEE: 全寫星期幾,如Sunday
aa: 上下午,AM/PM
H: 時,24小時制,0-23
K:時,12小時制,0-11
m: 分,1-2位
mm: 分,2位
s: 秒,1-2位
ss: 秒,2位
S: 毫秒
常用日期結構:
yyyy-MM-dd HH:mm:ss.SSS
yyyy-MM-dd HH:mm:ss
yyyy-MM-dd
MM dd yyyy
下面得到日期是數字,可以避免語言不同問題
取得當前的年月日,當前的時分秒獲得,周幾和星期幾獲得
NSDate*date = [NSDate date];
NSCalendar*calendar = [NSCalendar currentCalendar];
NSDateComponents*comps;
// 年月日獲得
comps =[calendar components:(NSYearCalendarUnit | NSMonthCalendarUnit |NSDayCalendarUnit)
fromDate:date];
NSIntegeryear = [comps year];
NSIntegermonth = [comps month];
NSIntegerday = [comps day];
NSLog(@"year:%d month: %d, day: %d", year, month, day);
//當前的時分秒獲得
comps =[calendar components:(NSHourCalendarUnit | NSMinuteCalendarUnit |NSSecondCalendarUnit)
fromDate:date];
NSIntegerhour = [comps hour];
NSIntegerminute = [comps minute];
NSIntegersecond = [comps second];
NSLog(@"hour:%d minute: %d second: %d", hour, minute, second);
// 周幾和星期幾獲得
comps =[calendar components:(NSWeekCalendarUnit | NSWeekdayCalendarUnit |NSWeekdayOrdinalCalendarUnit)
fromDate:date];
NSInteger week = [comps week]; // 今年的第幾周
NSIntegerweekday = [comps weekday]; // 星期幾(注意,週日是“1”,週一是“2”。。。。)
NSIntegerweekdayOrdinal = [comps weekdayOrdinal]; // 這個月的第幾周
NSLog(@"week:%d weekday: %d weekday ordinal: %d", week, weekday, weekdayOrdinal);
NSDateFormatter*dateFormatter = [[NSDateFormatter alloc]init];
if(dateSwitch.on)
[dateFormattersetDateFormat:@"dd-MMM-yyy,hh:mm:ss"];
else
[dateFormatter setDateFormat:@"hh:mm:ss"];
labelTime.text = [dateFormatter stringFromDate:[NSDatedate]];
labelTime.font = [UIFontsystemFontOfSize:fontSlider.value];
[dateFormatter release];
#pramark -------------------
NSDate存儲的是世界標準時(UTC),輸出時需要根據時區轉換爲本地時間
Dates
NSDate類提供了創建date,比較date以及計算兩個date之間間隔的功能。Date對象是不可改變的。
如果你要創建date對象並表示當前日期,你可以alloc一個NSDate對象並調用init初始化:
NSDate *now = [[NSDate alloc] init];
或者使用NSDate的date類方法來創建一個日期對象。如果你需要與當前日期不同的日期,你可以使用NSDate的initWithTimeInterval...或dateWithTimeInterval...方法,你也可以使用更復雜的calendar或date components對象。
創建一定時間間隔的NSDate對象:
NSTimeInterval secondsPerDay = 24 * 60 * 60;
NSDate *tomorrow = [[NSDate alloc] initWithTimeIntervalSinceNow:secondsPerDay];
NSDate *yesterday = [[NSDate alloc] initWithTimeIntervalSinceNow:-secondsPerDay];
[tomorrow release];
[yesterday release];
使用增加時間間隔的方式來生成NSDate對象:
NSTimeInterval secondsPerDay = 24 * 60 * 60;
NSDate *today = [[NSDate alloc] init];
NSDate *tomorrow, *yesterday;
tomorrow = [today dateByAddingTimeInterval: secondsPerDay];
yesterday = [today dateByAddingTimeInterval: -secondsPerDay];
[today release];
如果要對NSDate對象進行比較,可以使用isEqualToDate:, compare:, laterDate:和 earlierDate:方法。這些方法都進行精確比較,也就是說這些方法會一直精確比較到NSDate對象中秒一級。例如,你可能比較兩個日期,如果他們之間的間隔在一分鐘之內則認爲這兩個日期是相等的。在這種情況下使用,timeIntervalSinceDate:方法來對兩個日期進行比較。下面的代碼進行了示例:
if (fabs([date2 timeIntervalSinceDate:date1]) < 60) ...
NSCalendar & NSDateComponents
日曆對象封裝了對系統日期的計算,包括這一年開始,總天數以及劃分。你將使用日曆對象對絕對日期與date components(包括年,月,日,時,分,秒)進行轉換。
NSCalendar定義了不同的日曆,包括佛教歷,格里高利曆等(這些都與系統提供的本地化設置相關)。NSCalendar與NSDateComponents對象緊密相關。
你可以通過NSCalendar對象的currentCalendar方法來獲得當前系統用戶設置的日曆。
NSCalendar *currentCalendar = [NSCalendar currentCalendar];
NSCalendar *japaneseCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSJapaneseCalendar];
NSCalendar *usersCalendar = [[NSLocale currentLocale] objectForKey:NSLocaleCalendar];
usersCalendar和currentCalendar對象是相等的,儘管他們是不同的對象。
你可以使用NSDateComponents對象來表示一個日期對象的組件——例如年,月,日和小時。如果要使一個NSDateComponents對象有意義,你必須將其與一個日曆對象相關聯。下面的代碼示例瞭如何創建一個NSDateComponents對象:
NSDateComponents *components = [[NSDateComponents alloc] init];
[components setDay:6];
[components setMonth:5];
[components setYear:2004];
NSInteger weekday = [components weekday]; // Undefined (== NSUndefinedDateComponent)
要將一個日期對象解析到相應的date components,你可以使用NSCalendar的components:fromDate:方法。此外日期本身,你需要指定NSDateComponents對象返回組件。
NSDate *today = [NSDate date];
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *weekdayComponents = [gregorian components:(NSDayCalendarUnit | NSWeekdayCalendarUnit) fromDate:today];
NSInteger day = [weekdayComponents day];
NSInteger weekday = [weekdayComponents weekday];
同樣你也可以從NSDateComponents對象來創建NSDate對象:
NSDateComponents *components = [[NSDateComponents alloc] init];
[components setWeekday:2]; // Monday
[components setWeekdayOrdinal:1]; // The first Monday in the month
[components setMonth:5]; // May
[components setYear:2008];
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDate *date = [gregorian dateFromComponents:components];
爲了保證正確的行爲,您必須確保使用的組件在日曆上是有意義的。指定“出界”日曆組件,如一個-6或2月30日在公曆中的日期值產生未定義的行爲。
你也可以創建一個不帶年份的NSDate對象,這樣的操作系統會自動生成一個年份,但在後面的代碼中不會使用其自動生成的年份。
NSDateComponents *components = [[NSDateComponents alloc] init];
[components setMonth:11];
[components setDay:7];
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDate *birthday = [gregorian dateFromComponents:components];
下面的示例顯示瞭如何從一個日曆置換到另一個日曆:
NSDateComponents *comps = [[NSDateComponents alloc] init];
[comps setDay:6];
[comps setMonth:5];
[comps setYear:2004];
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDate *date = [gregorian dateFromComponents:comps];
[comps release];
[gregorian release];
NSCalendar *hebrew = [[NSCalendar alloc] initWithCalendarIdentifier:NSHebrewCalendar];
NSUInteger unitFlags = NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit;
NSDateComponents *components = [hebrew components:unitFlags fromDate:date];
NSInteger day = [components day]; // 15
NSInteger month = [components month]; // 9
NSInteger year = [components year]; // 5764
曆法計算
在當前時間加上一個半小時:
NSDate *today = [[NSDate alloc] init];
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *offsetComponents = [[NSDateComponents alloc] init];
[offsetComponents setHour:1];
[offsetComponents setMinute:30];
// Calculate when, according to Tom Lehrer, World War III will end
NSDate *endOfWorldWar3 = [gregorian dateByAddingComponents:offsetComponents toDate:today options:0];
獲得當前星期中的星期天(使用格里高利曆):
NSDate *today = [[NSDate alloc] init];
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
// Get the weekday component of the current date
NSDateComponents *weekdayComponents = [gregorian components:NSWeekdayCalendarUnit fromDate:today];
/*
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 is Sunday, subtract 0 days.)
*/
NSDateComponents *componentsToSubtract = [[NSDateComponents alloc] init];
[componentsToSubtract setDay: 0 - ([weekdayComponents weekday] - 1)];
NSDate *beginningOfWeek = [gregorian dateByAddingComponents:componentsToSubtract toDate:today options:0];
/*
Optional step:
beginningOfWeek now has the same hour, minute, and second as the original date (today).
To normalize to midnight, extract the year, month, and day components and create a new date from those components.
*/
NSDateComponents *components = [gregorian components:(NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit) fromDate: beginningOfWeek];
beginningOfWeek = [gregorian dateFromComponents:components];
如何可以計算出一週的第一天(根據系統的日曆設置):
NSDate *today = [[NSDate alloc] init];
NSDate *beginningOfWeek = nil;
BOOL ok = [gregorian rangeOfUnit:NSWeekCalendarUnit startDate:&beginningOfWeek interval:NULL forDate: today];
獲得兩個日期之間的間隔:
NSDate *startDate = ...;
NSDate *endDate = ...;
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSUInteger unitFlags = NSMonthCalendarUnit | NSDayCalendarUnit;
NSDateComponents *components = [gregorian components:unitFlags fromDate:startDate toDate:endDate options:0];
NSInteger months = [components month];
NSInteger days = [components day];
使用Category來計算同一時代(AD|BC)兩個日期午夜之間的天數:
@implementation NSCalendar (MySpecialCalculations)
-(NSInteger)daysWithinEraFromDate:(NSDate *) startDate toDate:(NSDate *) endDate {
NSInteger startDay=[self ordinalityOfUnit:NSDayCalendarUnit inUnit: NSEraCalendarUnit forDate:startDate];
NSInteger endDay=[self ordinalityOfUnit:NSDayCalendarUnit inUnit: NSEraCalendarUnit forDate:endDate];
return endDay-startDay;
}
@end
使用Category來計算不同時代(AD|BC)兩個日期的天數:
@implementation NSCalendar (MyOtherMethod)
-(NSInteger) daysFromDate:(NSDate *) startDate toDate:(NSDate *) endDate {
NSCalendarUnit units=NSEraCalendarUnit | NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit;
NSDateComponents *comp1=[self components:units fromDate:startDate];
NSDateComponents *comp2=[self components:units fromDate endDate];
[comp1 setHour:12];
[comp2 setHour:12];
NSDate *date1=[self dateFromComponents: comp1];
NSDate *date2=[self dateFromComponents: comp2];
return [[self components:NSDayCalendarUnit fromDate:date1 toDate:date2 options:0] day];
}
@end
判斷一個日期是否在當前一週內(使用格里高利曆):
-(BOOL)isDateThisWeek:(NSDate *)date {
NSDate *start;
NSTimeInterval extends;
NSCalendar *cal=[NSCalendar autoupdatingCurrentCalendar];
NSDate *today=[NSDate date];
BOOL success= [cal rangeOfUnit:NSWeekCalendarUnit startDate:&start interval: &extends forDate:today];
if(!success)
return NO;
NSTimeInterval dateInSecs = [date timeIntervalSinceReferenceDate];
NSTimeInterval dayStartInSecs= [start timeIntervalSinceReferenceDate];
if(dateInSecs > dayStartInSecs && dateInSecs < (dayStartInSecs+extends)){
return YES;
}
else {
return NO;
}
}
來源:http://blog.csdn.net/lingedeng/article/details/6996599
1、獲取當前時間
NSDateFormatter*formatter = [[NSDateFormatteralloc] init];
[formatter setDateFormat:@"yyyy-MM-dd hh:mm:ss"];
NSString *locationString=[formatter stringFromDate: [NSDate date]];
另外的方法:
-(NSString *)getDate
{
NSDateFormatter*formatter = [[NSDateFormatteralloc] init];
[formatter setDateFormat:@"yyyy-MM-dd EEEE HH:mm:ss a"];
NSString *locationString=[formatter stringFromDate: [NSDate date]];
[formatter release];
return locationString;
}
//大寫的H日期格式將默認爲24小時制,小寫的h日期格式將默認爲12小時
//不需要特別設置,只需要在dataFormat裏設置類似"yyyy-MMM-dd"這樣的格式就可以了
日期格式如下:
y 年 Year 1996; 96
M 年中的月份 Month July; Jul; 07
w 年中的週數 Number 27
W 月份中的週數 Number 2
D 年中的天數 Number 189
d 月份中的天數 Number 10
F 月份中的星期 Number 2
E 星期中的天數 Text Tuesday; Tue
a Am/pm 標記 Text PM
H 一天中的小時數(0-23) Number 0
k 一天中的小時數(1-24) Number 24
K am/pm 中的小時數(0-11) Number 0
h am/pm 中的小時數(1-12) Number 12
m 小時中的分鐘數 Number 30
s 分鐘中的秒數 Number 55
S 毫秒數 Number 978
z 時區 General time zone Pacific Standard Time; PST; GMT-08:00
Z 時區 RFC 822 time zone -0800