私はいくつかの値を格納するためにParse.comを使用しています:
これらはGMT値です。これらをデバイスの現在のタイムゾーンに変換し、結果としてNSDateを取得するにはどうすればよいですか?
NSDateは常にGMTで表されます。変化する可能性があるのは、それを表現する方法だけです。
日付をlabel.text
に出力する場合は、次のようにNSDateFormatter
および[NSTimeZone localTimeZone]
を使用して日付を文字列に変換します。
NSString *gmtDateString = @"08/12/2013 21:01";
NSDateFormatter *df = [NSDateFormatter new];
[df setDateFormat:@"dd/MM/yyyy HH:mm"];
//Create the date assuming the given string is in GMT
df.timeZone = [NSTimeZone timeZoneForSecondsFromGMT:0];
NSDate *date = [df dateFromString:gmtDateString];
//Create a date string in the local timezone
df.timeZone = [NSTimeZone timeZoneForSecondsFromGMT:[NSTimeZone localTimeZone].secondsFromGMT];
NSString *localDateString = [df stringFromDate:date];
NSLog(@"date = %@", localDateString);
// My local timezone is: Europe/London (GMT+01:00) offset 3600 (Daylight)
// prints out: date = 08/12/2013 22:01
私が見つけた最も簡単な方法はこれです:
NSDate *someDateInUTC = …;
NSTimeInterval timeZoneSeconds = [[NSTimeZone localTimeZone] secondsFromGMT];
NSDate *dateInLocalTimezone = [someDateInUTC dateByAddingTimeInterval:timeZoneSeconds];
これは、NSDateをローカルタイムゾーンの日付に変更する非常にクリーンな方法です。
extension NSDate {
func toLocalTime() -> NSDate {
let timeZone = NSTimeZone.local
let seconds : TimeInterval = Double(timeZone.secondsFromGMT(for:self as Date))
let localDate = NSDate(timeInterval: seconds, since: self as Date)
return localDate
}
}
https://agilewarrior.wordpress.com/2012/06/27/how-to-convert-nsdate-to-different-time-zones/ から取得
次のようなXcodeテストケースを作成すると、ルールを「永久に」記憶するのに役立ちます。
- (void)test2015_05_23_07_07_07_Toronto {
NSString *utcDateString = @"2015_05_23 12:07:07";
NSDateFormatter *dateFormatter = [NSDateFormatter new];
dateFormatter.dateFormat = @"yyyy_MM_dd HH:mm:ss";
dateFormatter.timeZone = [NSTimeZone timeZoneWithName:@"UTC"];
NSDate *date2015_05_23_12_07_07_UTC = [dateFormatter dateFromString:utcDateString];
XCTAssertTrue([date2015_05_23_12_07_07_UTC.description isEqualToString:@"2015-05-23 12:07:07 +0000"]);
dateFormatter.timeZone = [NSTimeZone timeZoneWithName:@"EST"];
NSString *torontoDateString = [dateFormatter stringFromDate:date2015_05_23_12_07_07_UTC];
XCTAssertTrue([torontoDateString isEqualToString:@"2015_05_23 07:07:07"]);
// change format to add ZZZ
dateFormatter.dateFormat = @"yyyy_MM_dd HH:mm:ss ZZZ";
torontoDateString = [dateFormatter stringFromDate:date2015_05_23_12_07_07_UTC];
XCTAssertTrue([torontoDateString isEqualToString:@"2015_05_23 07:07:07 -0500"]);
XCTAssertEqual(1432382827, [date2015_05_23_12_07_07_UTC timeIntervalSince1970]);
NSCalendar *calendar = [NSCalendar autoupdatingCurrentCalendar];
calendar.timeZone = [NSTimeZone timeZoneWithName:@"EST"];
NSDateComponents *components = [calendar components:(NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond) fromDate:date2015_05_23_12_07_07_UTC];
XCTAssertEqual(2015, components.year);
XCTAssertEqual(5, components.month);
XCTAssertEqual(23, components.day);
XCTAssertEqual(7, components.hour);
XCTAssertEqual(7, components.minute);
XCTAssertEqual(7, components.second);
}
NSDateFormatterを使用して、この結果を達成できます。
NSString *dateAsString = @"08/07/2013 04:06";
NSDateFormatter *df = [[NSDateFormatter alloc] init];
[df setDateFormat:@"dd/MM/yyyy HH:mm"];
NSTimeZone *gmt = [NSTimeZone timeZoneWithAbbreviation:@"GMT"];
[df setTimeZone:gmt];
NSDate *myDate = [df dateFromString: dateAsString];
NSLog(@"date: %@", myDate);
この質問には多くの答えがありますが、私はこれをお勧めします:
NSString *dateStr = @"2012-07-16 07:33:01";
NSDateFormatter *dateFormatter1 = [[NSDateFormatter alloc] init];
[dateFormatter1 setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
NSDate *date = [dateFormatter1 dateFromString:dateStr];
NSLog(@"date : %@",date);
NSTimeZone *currentTimeZone = [NSTimeZone localTimeZone]; // <- Local time zone
NSTimeZone *utcTimeZone = [NSTimeZone timeZoneWithAbbreviation:@"UTC"];
NSInteger currentGMTOffset = [currentTimeZone secondsFromGMTForDate:date1];
NSInteger gmtOffset = [utcTimeZone secondsFromGMTForDate:date1];
NSTimeInterval gmtInterval = currentGMTOffset - gmtOffset;
NSDate *destinationDate = [[[NSDate alloc] initWithTimeInterval:gmtInterval sinceDate:date1] autorelease];
NSDateFormatter *dateFormatters = [[NSDateFormatter alloc] init];
[dateFormatters setDateFormat:@"dd-MMM-yyyy hh:mm"];
[dateFormatters setDateStyle:NSDateFormatterShortStyle];
[dateFormatters setTimeStyle:NSDateFormatterShortStyle];
[dateFormatters setDoesRelativeDateFormatting:YES];
[dateFormatters setTimeZone:[NSTimeZone systemTimeZone]];
dateStr = [dateFormatters stringFromDate: destinationDate];
NSLog(@"DateString : %@", dateStr);