[英]iOS: Convert UTC NSDate to local Timezone
如何在 Objective C 或/和 Swift 中将 UTC NSDate
转换为本地时区 NSDate?
NSTimeInterval seconds; // assume this exists
NSDate* ts_utc = [NSDate dateWithTimeIntervalSince1970:seconds];
NSDateFormatter* df_utc = [[[NSDateFormatter alloc] init] autorelease];
[df_utc setTimeZone:[NSTimeZone timeZoneWithName:@"UTC"]];
[df_utc setDateFormat:@"yyyy.MM.dd G 'at' HH:mm:ss zzz"];
NSDateFormatter* df_local = [[[NSDateFormatter alloc] init] autorelease];
[df_local setTimeZone:[NSTimeZone timeZoneWithName:@"EST"]];
[df_local setDateFormat:@"yyyy.MM.dd G 'at' HH:mm:ss zzz"];
NSString* ts_utc_string = [df_utc stringFromDate:ts_utc];
NSString* ts_local_string = [df_local stringFromDate:ts_utc];
// you can also use NSDateFormatter dateFromString to go the opposite way
格式化字符串参数表:
https://waracle.com/iphone-nsdateformatter-date-formatting-table/
如果优先考虑性能,您可能需要考虑使用strftime
编辑当我写这篇文章时,我不知道我应该使用 dateformatter 这可能是一种更好的方法,所以也请查看slf
的答案。
我有一个以 UTC 返回日期的网络服务。 我用toLocalTime
将其转换为本地时间和toGlobalTime
到如果需要转换回。
这是我从这里得到答案的地方:
https://agilewarrior.wordpress.com/2012/06/27/how-to-convert-nsdate-to-different-time-zones/
@implementation NSDate(Utils)
-(NSDate *) toLocalTime
{
NSTimeZone *tz = [NSTimeZone defaultTimeZone];
NSInteger seconds = [tz secondsFromGMTForDate: self];
return [NSDate dateWithTimeInterval: seconds sinceDate: self];
}
-(NSDate *) toGlobalTime
{
NSTimeZone *tz = [NSTimeZone defaultTimeZone];
NSInteger seconds = -[tz secondsFromGMTForDate: self];
return [NSDate dateWithTimeInterval: seconds sinceDate: self];
}
@end
我发现的最简单的方法是这样的:
NSDate *someDateInUTC = …;
NSTimeInterval timeZoneSeconds = [[NSTimeZone localTimeZone] secondsFromGMT];
NSDate *dateInLocalTimezone = [someDateInUTC dateByAddingTimeInterval:timeZoneSeconds];
Swift 3+ : UTC 到本地和本地到 UTC
extension Date {
// Convert UTC (or GMT) to local time
func toLocalTime() -> Date {
let timezone = TimeZone.current
let seconds = TimeInterval(timezone.secondsFromGMT(for: self))
return Date(timeInterval: seconds, since: self)
}
// Convert local time to UTC (or GMT)
func toGlobalTime() -> Date {
let timezone = TimeZone.current
let seconds = -TimeInterval(timezone.secondsFromGMT(for: self))
return Date(timeInterval: seconds, since: self)
}
}
如果您想要本地日期和时间。 试试这个代码:-
NSString *localDate = [NSDateFormatter localizedStringFromDate:[NSDate date] dateStyle:NSDateFormatterMediumStyle timeStyle:NSDateFormatterMediumStyle];
将您的 UTC 日期转换为本地日期
-(NSString *)getLocalDateTimeFromUTC:(NSString *)strDate
{
NSDateFormatter *dtFormat = [[NSDateFormatter alloc] init];
[dtFormat setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
[dtFormat setTimeZone:[NSTimeZone timeZoneWithAbbreviation:@"UTC"]];
NSDate *aDate = [dtFormat dateFromString:strDate];
[dtFormat setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
[dtFormat setTimeZone:[NSTimeZone systemTimeZone]];
return [dtFormat stringFromDate:aDate];
}
像这样使用
NSString *localDate = [self getLocalDateTimeFromUTC:@"yourUTCDate"];
这里输入的是一个字符串 currentUTCTime(格式为 08/30/2012 11:11)将输入的 GMT 时间转换为系统设置的时区时间
//UTC time
NSDateFormatter *utcDateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[utcDateFormatter setDateFormat:@"MM/dd/yyyy HH:mm"];
[utcDateFormatter setTimeZone :[NSTimeZone timeZoneForSecondsFromGMT: 0]];
// utc format
NSDate *dateInUTC = [utcDateFormatter dateFromString: currentUTCTime];
// offset second
NSInteger seconds = [[NSTimeZone systemTimeZone] secondsFromGMT];
// format it and send
NSDateFormatter *localDateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[localDateFormatter setDateFormat:@"MM/dd/yyyy HH:mm"];
[localDateFormatter setTimeZone :[NSTimeZone timeZoneForSecondsFromGMT: seconds]];
// formatted string
NSString *localDate = [localDateFormatter stringFromDate: dateInUTC];
return localDate;
//This is basic way to get time of any GMT time.
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"hh:mm a"]; // 09:30 AM
[formatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:1]]; // For GMT+1
NSString *time = [formatter stringFromDate:[NSDate date]]; // Current time
将日期从 UTC 日历转换为具有适当本地NSTimeZone 的日期。
我编写此方法将日期时间转换为我们的 LocalTimeZone
- 这里 (NSString *)TimeZone 参数是服务器时区
-(NSString *)convertTimeIntoLocal:(NSString *)defaultTime :(NSString *)TimeZone
{
NSDateFormatter *serverFormatter = [[NSDateFormatter alloc] init];
[serverFormatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:TimeZone]];
[serverFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
NSDate *theDate = [serverFormatter dateFromString:defaultTime];
NSDateFormatter *userFormatter = [[NSDateFormatter alloc] init];
[userFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
[userFormatter setTimeZone:[NSTimeZone localTimeZone]];
NSString *dateConverted = [userFormatter stringFromDate:theDate];
return dateConverted;
}
由于似乎没有人使用NSDateComponents
,我想我会NSDateComponents
一分... 在这个版本中,没有使用NSDateFormatter
,因此没有字符串解析,并且NSDate
不用于表示 GMT (UTC) 之外的时间。 原始NSDate
位于变量i_date
。
NSCalendar *anotherCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:i_anotherCalendar];
anotherCalendar.timeZone = [NSTimeZone timeZoneWithName:i_anotherTimeZone];
NSDateComponents *anotherComponents = [anotherCalendar components:(NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond | NSCalendarUnitNanosecond) fromDate:i_date];
// The following is just for checking
anotherComponents.calendar = anotherCalendar; // anotherComponents.date is nil without this
NSDate *anotherDate = anotherComponents.date;
i_anotherCalendar
可以是NSCalendarIdentifierGregorian
或任何其他日历。 i_anotherTimeZone
允许的NSString
可以通过[NSTimeZone knownTimeZoneNames]
获取,但anotherCalendar.timeZone
可以是[NSTimeZone defaultTimeZone]
或[NSTimeZone localTimeZone]
或[NSTimeZone systemTimeZone]
。
它实际上是在新时区中保存时间的anotherComponents
。 您会注意到anotherDate
等于i_date
,因为它以格林威治标准时间 (UTC) 保存时间。
你可以试试这个:
NSDate *currentDate = [[NSDate alloc] init];
NSTimeZone *timeZone = [NSTimeZone defaultTimeZone];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateStyle:NSDateFormatterLongStyle];
[dateFormatter setTimeStyle:NSDateFormatterLongStyle];
[dateFormatter setTimeZone:timeZone];
[dateFormatter setDateFormat:@"ZZZ"];
NSString *localDateString = [dateFormatter stringFromDate:currentDate];
NSMutableString *mu = [NSMutableString stringWithString:localDateString];
[mu insertString:@":" atIndex:3];
NSString *strTimeZone = [NSString stringWithFormat:@"(GMT%@)%@",mu,timeZone.name];
NSLog(@"%@",strTimeZone);
请使用此代码。
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:@"UTC"]];
NSDate *date = [dateFormatter dateFromString:@"2015-04-01T11:42:00"]; // create date from string
[dateFormatter setDateFormat:@"EEE, MMM d, yyyy - h:mm a"];
[dateFormatter setTimeZone:[NSTimeZone localTimeZone]];
NSString *timestamp = [dateFormatter stringFromDate:date];
SwiftDate库的解决方案:
// Take date by seconds in UTC time zone
var viewModelDate: Date = DateInRegion(seconds: Double(backendModel.scheduledTimestamp)).date
...
// Convert date to local timezone and convert to string by format rule.
label.text = viewModelDate.convertTo(region: .current).toFormat(" EEE MM/dd j:mm")
将 UTC 时间转换为当前时区。
调用函数
NSLocale *locale = [NSLocale autoupdatingCurrentLocale];
NSString *myLanguageCode = [locale objectForKey: NSLocaleLanguageCode];
NSString *myCountryCode = [locale objectForKey: NSLocaleCountryCode];
NSString *rfc3339DateTimeString = @"2015-02-15 00:00:00"];
NSDate *myDateTime = (NSDate*)[_myCommonFunctions _ConvertUTCTimeToLocalTimeWithFormat:rfc3339DateTimeString LanguageCode:myLanguageCode CountryCode:myCountryCode Formated:NO];
功能
-NSObject*)_ConvertUTCTimeToLocalTimeWithFormat:rfc3339DateTimeString LanguageCode:(NSString *)lgc CountryCode:(NSString *)ctc Formated:(BOOL) formated
{
NSDateFormatter *sUserVisibleDateFormatter = nil;
NSDateFormatter *sRFC3339DateFormatter = nil;
NSTimeZone *timeZone = [NSTimeZone defaultTimeZone];
if (sRFC3339DateFormatter == nil)
{
sRFC3339DateFormatter = [[NSDateFormatter alloc] init];
NSLocale *myPOSIXLocale = [[NSLocale alloc] initWithLocaleIdentifier:[NSString stringWithFormat:@"%@", timeZone]];
[sRFC3339DateFormatter setLocale:myPOSIXLocale];
[sRFC3339DateFormatter setDateFormat:@"yyyy'-'MM'-'dd'T'HH':'mm':'ss'Z'"];
[sRFC3339DateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
}
// Convert the RFC 3339 date time string to an NSDate.
NSDate *date = [sRFC3339DateFormatter dateFromString:rfc3339DateTimeString];
if (formated == YES)
{
NSString *userVisibleDateTimeString;
if (date != nil)
{
if (sUserVisibleDateFormatter == nil)
{
sUserVisibleDateFormatter = [[NSDateFormatter alloc] init];
[sUserVisibleDateFormatter setDateStyle:NSDateFormatterMediumStyle];
[sUserVisibleDateFormatter setTimeStyle:NSDateFormatterShortStyle];
}
// Convert the date object to a user-visible date string.
userVisibleDateTimeString = [sUserVisibleDateFormatter stringFromDate:date];
return (NSObject*)userVisibleDateTimeString;
}
}
return (NSObject*)date;
}
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