我的日期和时间是20-Nov-2019 21:09,采用UTC 24小时格式。现在我想在12小时内将其转换为当地时间。 30-Nov-2019 08:00 AM像这样。
我的代码是:
// create dateFormatter with UTC time format
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"dd-MMM-yyyy HH:mm"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:@"UTC"]];
// change to a readable time format and change to local time zone
[dateFormatter setDateFormat:@"dd-MMM-yyyy HH:mm a"];
[dateFormatter setTimeZone:[NSTimeZone localTimeZone]];
NSString *timestamp = [dateFormatter stringFromDate:date];
当我将当地时间12点发送给UTC 24小时时的代码
-(NSString *)getUTCFormateDate:(NSDate *)localDate
{
// NSLog(@"%@", localDate);
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
NSTimeZone *timeZone = [NSTimeZone timeZoneWithName:@"UTC"];
[dateFormatter setTimeZone:timeZone];
[dateFormatter setDateFormat:@"dd-MMM-yyyy HH:mm"];
NSLocale *twelveHourLocale = [[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"];
dateFormatter.locale = twelveHourLocale;
NSTimeInterval timeZoneoffset = [[NSTimeZone defaultTimeZone] secondsFromGMT];
NSTimeInterval utcTimeInterval = [localDate timeIntervalSinceReferenceDate] - timeZoneoffset;
NSDate *utcCurrentDate = [NSDate dateWithTimeIntervalSinceReferenceDate:utcTimeInterval];
NSString *dateString = [dateFormatter stringFromDate:utcCurrentDate];
// NSLog(@"dateString %@", dateString);
return dateString;
}
-(NSDate *)getUTCDate:(NSString *)currentDate{
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:@"dd-MMM-yyyy HH:mm"];
NSDate *date1 = [dateFormat dateFromString:currentDate];
if (date1 == nil){
[dateFormat setDateFormat:@"dd-MMM-yyyy hh:mm a"];
date1 = [dateFormat dateFromString:currentDate];
}
return date1;
}
我认为您做得太多。格式“ hh”是12小时格式的小时,HH是24小时格式。您不必为此设置语言环境(尽管将en_US_POSIX设置为可以避免[NSLocale currentLocale]实例中用户的24小时偏好设置,该实例可以覆盖iOS上的偏好设置。)>
NSDate是时间上的绝对实例。您需要使用带有NSDateFormatter的日历和时区来获取数字中的年/月/日等值,但是您无需将偏移量调整为参考日期(即更改实际日期,而不是只需在其他时区重新格式化)。
NSString *utcString = @"20-Nov-2019 21:09";
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
formatter.timeZone = [NSTimeZone timeZoneWithName:@"UTC"];
formatter.locale = [NSLocale localeWithLocaleIdentifier:@"en_US_POSIX"];
formatter.dateFormat = @"dd-MMM-yyyy HH:mm";
NSDate *date = [formatter dateFromString:utcString];
formatter.timeZone = [NSTimeZone localTimeZone]; // GMT-5 for me
formatter.dateFormat = @"dd-MMM-yyyy hh:mm a";
NSLog(@"date: %@", [formatter stringFromDate:date]);
// date: 20-Nov-2019 04:09 PM