iOS時間處理（NSDate、NSDateComponents、NSCalendar、NSDateFormatter、NSTimeZone）

1.NSDate存儲的是世界標准時(UTC)，輸出時需要根據時區轉換為本地時間

2.NSTimeInterval： 時間戳，以double為單位

3.系統返回的時間都是格林尼治時間，要得到北京時間需要轉化

 

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NSDate類：

 

@interface NSDate (NSDateCreation)中方法：創建或初始化NSDate值

NSDate返回日期

 

@interface NSDate (NSExtendedDate)： NSDate的擴張方法

方法一：日前之間的前后比較

方法二：得到距離某一日起的時間間隔（時間戳）

方法三：得到在當前實例中保存的時間為基准， 過了sec的日期

方法四：將時間表示字符串：description  其實這個方法寫不寫一樣 系統會自動的

 

參考：

冷雨之家博客對該類方法作了詳盡的描述: http://hi.baidu.com/douxinchun/item/86c9732bc603349db73263ae

 

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NSDateComponents類：()

 

NSDateComponents封裝在一個可擴展的，面向對象的方式的日期組件。它是用來彌補時間的日期和時間組件提供一個指定日期：小時，分鍾，秒，日，月，年，等等。它也可以用來指定的時間，例如，5小時16分鍾。一個NSDateComponents對象不需要定義所有組件領域。當一個NSDateComponents的新實例被創建，日期組件被設置為NSUndefinedDateComponent。

一個NSDateComponents對象本身是毫無意義的;你需要知道它是針對什么日歷解釋，你需要知道它的值是否是正整數和值是多少。

NSDateComponents的實例不負責回答關於一個日期以外的信息，它是需要先初始化的。例如，如果你初始化一個對象為2004年5月6日，其星期幾NSUndefinedDateComponent，不是星期四。要得到正確的星期幾，你必須創建一個NSCalendar日歷實例，創建一個NSDate對象並使用dateFromComponents：方法，然后使用components:fromDate:檢索平周幾

 

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NSCalendar類：(日歷)

 

用於處理時間相關問題。比如比較時間前后、計算日期所的周別等。

 

//在當前日期上加上設定的值得到的日期

NSDate *newdate = [calendar dateByAddingComponents:comps toDate:currentDate  options:0];

 

參考：

NSCalendar類方法的詳細介紹： http://www.cnblogs.com/wujian1360/archive/2011/09/05/2168007.html

 

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NSDateFormatter類：  設定時間的格式

 

用於格式化NSDate對象，支持本地化的信息。

setDateStyle和setTimeStyle可同時設置，但不能和setDateFormat共存，只可選其一

 

//設置為中國格式輸出

dateFormater.locale = [[NSLocale alloc] initWithLocaleIdentifier:@"zh_CN"];

 

 

//設置日期、時間顯示格式；

- (void)setDateStyle:(NSDateFormatterStyle)style;

- (void)setTimeStyle:(NSDateFormatterStyle)style;

 

NSDateFormatterStyle系統選項包含的Style:

{

    NSDateFormatterNoStyle,

    NSDateFormatterShortStyle,    // “11/23/37” or “3:30pm”.

    NSDateFormatterMediumStyle,     //“Nov 23, 1937”.or “3:30:32pm”.   

    NSDateFormatterLongStyle,     //“November 23, 1937” or “3:30:32pm”.   GMT+08:00

    NSDateFormatterFullStyle     //“Tuesday, April 12, 1952 AD” or “3:30:42pm PST”.

}

 

 

而經常使用的會是setDateFormat方法,可自定義輸出格式

- (void)setDateFormat:(NSString *)string;

 

 

Symbol	Meaning	Example
G	era designator	G	AD
y	year	yy yyyy or y	96 1996
Y	year of "Week of Year"	Y	1997
u	extended year	u	4601
U	cyclic year name, as in Chinese lunar calendar	U	甲子
Q	quarter	Q or QQ QQQ QQQQ	02 Q2 2nd quarter
q	Stand Alone quarter	q or qq qqq qqqq	02 Q2 2nd quarter
M	month in year	M or MM MMM MMMM MMMMM	09 Sept September S
L	Stand Alone month in year	L or LL LLL LLLL LLLLL	09 Sept September S
w	week of year	w or ww	27
W	week of month	W	2
d	day in month	d dd	2 02
D	day of year	D	189
F	day of week in month		2 (2nd Wed in July)
g	modified julian day	g	2451334
E	day of week	E, EE, or EEE EEEE EEEEE	Tues Tuesday T
e	local day of week example: if Monday is 1st day, Tuesday is 2nd )	e or ee eee eeee eeeee	2 Tues Tuesday T
c	Stand Alone local day of week	e or ee eee eeee eeeee	2 Tues Tuesday T
a	am/pm marker	a	pm
h	hour in am/pm (1~12)	h hh	7 07
H	hour in day (0~23)	H HH	0 00
k	hour in day (1~24)	k kk	24 24
K	hour in am/pm (0~11)	K KK	0 00
m	minute in hour	m mm	4 04
s	second in minute	s ss	5 05
S	millisecond (maximum of 3 significant digits); for S or SS, truncates to the number of letters for SSSS or longer, fills additional places with 0	S SS SSS SSSS	2 23 235 2350
A	milliseconds in day	A	61201235
z	Time Zone: specific non-location	z, zz, or zzz zzzz	PDT Pacific Daylight Time
Z	Time Zone: RFC 822 Time Zone: localized GMT TIme Zone: ISO8601	Z, ZZ, or ZZZ ZZZZ ZZZZZ	-0800 GMT-08:00 -08:00
v	Time Zone: generic non-location	v vvvv	PT Pacific Time or United States (Los Angeles)
V	Time Zone: specific non-location, identical to z	V	PDT
VVVV	Time Zone: generic location	VVVV	United States (Los Angeles)
W	week in month		2
'	escape for text	'	(nothing)
' '	two single quotes produce one	' '	'

 

Format Pattern	Result
yyyy.MM.dd G 'at' HH:mm:ss zzz	1996.07.10 AD at 15:08:56 PDT
EEE, MMM d, ''yy	Wed, July 10, '96
h:mm a	12:08 PM
hh 'o''clock' a, zzzz	12 o'clock PM, Pacific Daylight Time
K:mm a, z	0:00 PM, PST
yyyyy.MMMM.dd GGG hh:mm aaa	01996.July.10 AD 12:08 PM

 

 

 

NSDateFormatter的格式串詳解：

a: AM/PM (上午/下午)

A:0~86399999(一天的第A微秒)

c/cc:1~7(一周的第一天,周天為1)

ccc: Sun/Mon/Tue/Wed/Thu/Fri/Sat (星期幾簡寫)

cccc: Sunday/Monday/Tuesday/Wednesday/Thursday/Friday/Saturday (星期幾全拼)

d:1~31(月份的第幾天,帶0)

D:1~366(年份的第幾天,帶0)

e:1~7(一周的第幾天,帶0)

E~EEE: Sun/Mon/Tue/Wed/Thu/Fri/Sat (星期幾簡寫)

EEEE: Sunday/Monday/Tuesday/Wednesday/Thursday/Friday/Saturday (星期幾全拼)

F:1~5(每月的第幾周,一周的第一天為周一)

g: Julian Day Number (number of days since4713BC January1)未知

G~GGG: BC/AD (Era Designator Abbreviated)未知

GGGG: Before Christ/Anno Domini未知

h:1~12(0padded Hour (12hr))帶0的時,12小時制

H:0~23(0padded Hour (24hr)) 帶0的時,24小時制

k:1~24(0padded Hour (24hr)帶0的時,24小時制

K:0~11(0padded Hour (12hr))帶0的時,12小時制

        

L/LL:1~12(0padded Month) 第幾月

LLL: Jan/Feb/Mar/Apr/May/Jun/Jul/Aug/Sep/Oct/Nov/Dec月份簡寫

LLLL: January/February/March/April/May/June/July/August/September/October/November/December月份全稱

        

m:0~59(0padded Minute)分鍾

M/MM:1~12(0padded Month)第幾月

MMM: Jan/Feb/Mar/Apr/May/Jun/Jul/Aug/Sep/Oct/Nov/Dec

MMMM: January/February/March/April/May/June/July/August/September/October/November/December

        

q/qq:1~4(0padded Quarter)第幾季度

qqq: Q1/Q2/Q3/Q4季度簡寫

qqqq:1st quarter/2nd quarter/3rd quarter/4th quarter季度全拼

Q/QQ:1~4(0padded Quarter)同小寫

QQQ: Q1/Q2/Q3/Q4同小寫

QQQQ:1st quarter/2nd quarter/3rd quarter/4th quarter同小寫

s:0~59(0padded Second)秒數

S: (rounded Sub-Second)未知

        

u: (0padded Year)未知

        

v~vvv: (General GMT Timezone Abbreviation)常規GMT時區的編寫

vvvv: (General GMT Timezone Name)常規GMT時區的名稱

        

w:1~53(0padded Week of Year,1st day of week = Sunday, NB:1st week of year starts from the last Sunday of last year)一年的第幾周,一周的開始為周日,第一周從去年的最后一個周日起算

W:1~5(0padded Week of Month,1st day of week = Sunday)一個月的第幾周

        

y/yyyy: (Full Year)完整的年份

yy/yyy: (2Digits Year) 2個數字的年份

Y/YYYY: (Full Year, starting from the Sunday of the1st week of year)這個年份未知干嘛用的

YY/YYY: (2Digits Year, starting from the Sunday of the1st week of year)這個年份未知干嘛用的

        

z~zzz: (Specific GMT Timezone Abbreviation)指定GMT時區的編寫

zzzz: (Specific GMT Timezone Name) Z: +0000 (RFC 822 Timezone) 指定GMT時區的名稱

 

eg.

NSString lastModifiedString = @"Mon, 06 Jun 2011 12:47:05 GMT";
 NSDateFormatter *df = [[NSDateFormatter alloc] init];  
 //df.dateFormat = @"EEE',' dd MMM yyyy HH':'mm':'ss 'GMT'";
 df.dateFormat = @"EEE, dd MMM yyyy HH:mm:ss z";
 df.locale = [[[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"] autorelease];  
 df.timeZone = [NSTimeZone timeZoneWithAbbreviation:@"GMT"];  

NSDate date = [df dateFromString:lastModifiedString];  

　　

設置上下午顯示格式：

NSDateFormatter* formatter = [[[NSDateFormatteralloc] init] autorelease];
 [formatter setDateFormat:dateFormatterString];
 [formatter setAMSymbol:@"am"];    //
 [formatter setPMSymbol:@"pm"];
return [formatter stringFromDate:self];

 

參考：

NSDateFormatter格式一覽表： http://www.th7.cn/Program/IOS/201210/109696.shtml

開源項目庫文檔： http://userguide.icu-project.org/formatparse/datetime （我是沒怎么看懂） 

NSDateFormatter的格式串詳解： http://linuxp.blog.163.com/blog/static/17096277201221313933377/  

 

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NSTimeZone：時區

    NSDate *date = [NSDate date];
    NSLog(@"date:%@",date);
    //系統時區
    NSTimeZone *zone = [NSTimeZone systemTimeZone];
    NSData *data = [zone data];
    NSLog(@"data:%@",data);
    //時間縮寫
    NSString *abbStr = [zone abbreviation];
    NSLog(@"abbStr:%@",abbStr);
    //當地時區
    NSTimeZone *localTime = [NSTimeZonelocalTimeZone];
    NSLog(@"localTime:%@",localTime);
    //和格林尼治時間差
    NSInteger timeOff = [zone secondsFromGMT];
    //視察轉化
    NSDate *timeOffDate = [date dateByAddingTimeInterval:timeOff];
    NSLog(@"timeOffDate:%@",timeOffDate);
    //所有地區名稱
    NSArray *zoneArrs = [NSTimeZone knownTimeZoneNames];
    NSLog(@"zoneArrs:%@",zoneArrs);
    //遍歷
    for (NSString *names in zoneArrs) {
        //時區
        NSTimeZone *timeZone = [[NSTimeZone alloc] initWithName:names];
        //設置格式
        NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
        [dateFormatter setDateStyle:kCFDateFormatterFullStyle];
        [dateFormatter setTimeStyle:kCFDateFormatterFullStyle];
        [dateFormatter setTimeZone:timeZone];
        NSString *string = [dateFormatter stringFromDate:date];
        NSLog(@"string:%@,[timeZone name]:%@",string,[timeZone name]);
        [dateFormatter release];
        [timeZone release];
    }

獲取中國標准時間（沒有看見有北京時區的，選了上海的）

    NSDate*date = [NSDate date];
    NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init]autorelease];
    dateFormatter.dateFormat = @"yyyy-MM-dd HH:mm:ss EEEE";
    NSTimeZone *timeZone = [[NSTimeZone alloc] initWithName:@"Asia/Shanghai"];
    [dateFormatter setTimeZone:timeZone];
    NSLog(@"時間：%@",[dateFormatter stringFromDate:date]);

 

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應用實例：

(1)獲得某一日期是周幾

NSDateComponents *comps = [[NSDateComponents alloc] init];
[comps setDay:11];
[comps setMonth:12];
[comps setYear:2012];
NSCalendar *gregorian = [[NSCalendar alloc]
    initWithCalendarIdentifier:NSGregorianCalendar];
NSDate *date = [gregorian dateFromComponents:comps];
[comps release];
NSDateComponents *weekdayComponents =
    [gregorian components:NSWeekdayCalendarUnit fromDate:date];
int weekday = [weekdayComponents weekday];
NSLog(@"%d",weekday);   //周二，值為3


   
   
   
           

//獲得昨天的Date

NSDate*yesterday = [NSDatedateWithTimeIntervalSinceNow: -(24 * 60 * 60)];

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

(2)獲得當前時間並取出年/月/日等值

NSDateFormatter*formatter =[[[NSDateFormatteralloc] init] autorelease];
    NSDate *date = [NSDatedate];
    [formatter setTimeStyle:NSDateFormatterMediumStyle];
    NSCalendar *calendar = [[[NSCalendaralloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
    NSDateComponents *comps = [[[NSDateComponentsalloc] init] autorelease];
    NSInteger unitFlags = NSYearCalendarUnit |
    NSMonthCalendarUnit |
    NSDayCalendarUnit |
    NSWeekdayCalendarUnit |
    NSHourCalendarUnit |
    NSMinuteCalendarUnit |
    NSSecondCalendarUnit;
   
    comps = [calendar components:unitFlags fromDate:date];
    int week = [comps weekday];
    int year=[comps year];
    int month = [comps month];
    int day = [comps day];
    int hour = [comps hour];
    int min = [comps minute];
    int sec = [comps second];
   
    NSLog(@"week%d",week);
    NSLog(@"year%d",year);
    NSLog(@"month%d",month);
    NSLog(@"day%d",day);
    NSLog(@"hour%d",hour);
    NSLog(@"min%d",min);

    NSLog(@"sec%d",sec);

（3）//得到毫秒

//得到毫秒
   NSDateFormatter*dateFormatter = [[NSDateFormatteralloc] init];
    [dateFormatter setDateStyle:NSDateFormatterMediumStyle];
    [dateFormatter setTimeStyle:NSDateFormatterShortStyle];
    //[dateFormatter setDateFormat:@"hh:mm:ss"]
    [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss.SSS"];
    NSLog(@"Date%@", [dateFormatter stringFromDate:[NSDatedate]]);
    [dateFormatter release];

（4）計算和所給時間和當天時間的差距

NSCalendar*calendar = [NSCalendarcurrentCalendar];//日歷
NSDateComponents *components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit fromDate:date toDate:[NSDate date] options:0];
int year = [components year];
int month = [components month];
int day = [components day];
//三天以內更改顯示格式
if (year == 0 && month == 0 && day < 3) {
    if (day == 0) {
        title = NSLocalizedString(@"今天",nil);
    } elseif (day == 1) {
        title = NSLocalizedString(@"昨天",nil);
    } elseif (day == 2) {
        title = NSLocalizedString(@"前天",nil);
    }
}